Search

This study evaluates the impact of varying planting densities on hybrid winter wheat (Triticum aestivum L.) varieties in the eastern Huang-Huai-Hai region, an area critical to China's wheat production. Focusing on 'Jingmai 17', a hybrid variety, and 'Jimai 22', a conventional type, across three planting densities (150, 300, and 450 plants·m−2) during the 2021–2023 growing seasons, the investigation centered on key agronomic metrics such as leaf area per culm (LAC), SPAD values for chlorophyll content, dry matter, nitrogen accumulation and remobilization, alongside grain yield and its components. The results highlight 'Jingmai 17"s superior performance over 'Jimai 22', notably in maintaining a larger LAC post-anthesis, a slower decline in SPAD values during grain filling, and an extended green leaf area duration. These characteristics are conducive to higher biomass accumulation and efficient post-anthesis remobilization. Importantly, a planting density of 300 plants·m−2 emerged as optimal, enhancing canopy structure for maximal light interception and promoting a higher nitrogen use efficiency (NUE) and yield for both varieties. The NUE of Jingmai 17 and Jimai 22 in both years increased by 2.2%, 0.4% and 1.7%, 1.4%, respectively, relative to the 450 plants·m−2 treatment; and the yield increased by 10%, 4%, 9%, 4%, and 10%, 5%, 8%, 2%, relative to the 150 plants·m−2 and 450 plants·m−2 treatments, respectively. This optimal density represents a strategic balance, enabling robust wheat growth while maximizing resource use efficiency. For the eastern Huang-Huai-Hai region, these findings suggest a potent strategy to augment wheat yields and improve agricultural sustainability. Adopting a planting density of 300 plants·m−2 could significantly enhance the productivity of hybrid winter wheat varieties, tapping into their heterosis advantages for substantial yield improvements. By refining planting density practices, the eastern Huang-Huai-Hai region stands to achieve marked gains in wheat yield efficiency, contributing to the broader goals of food security and sustainable farming practices. [ABSTRACT FROM AUTHOR]

To investigate the effects of nitrogen (N) application rate and planting density (D) on the contents of lipid and free fatty acid, fatty acid composition, yield and quality of rice grain, a field experiment was conducted using Koshihikari (japonica) as experimental material from 2021 to 2022 with three N levels (90, 150 and 210 kg ha-1, denoted as N1, N2 and N3, respectively) and three transplanting densities (19.0 × 104, 26.7 × 104 and 40.0 × 104 plants ha-1, denoted as D1, D2 and D3, respectively). The results showed that N application rate and planting density had highly significant impacts only on the contents of free fatty acid and saturated fatty acid, respectively. Increased N and planting density enhanced the contents of lipid (29.41 mg g-1) and free fatty acid (21.47%). The highest values were obtained under N3D3 increasing by 7.02% and 3.23 percentage points, respectively, compared to other treatments. No significant differences in lipid content were found among treatments, whereas free fatty acid exhibited significant differences. The unsaturated fatty acid content increased with increasing N but first decreased and then increased with increasing planting density, while saturated fatty acid content showed the opposite trend. Appropriate N level and planting density improved the relative chlorophyll content and net photosynthetic rate of rice flag leaves, as well as increased grain yield, effective panicle number and spikelete number per panicle, but decreased the seed setting rate. Under N2D2, the relative chlorophyll content and net photosynthetic rate remained relatively high throughout the grain filling stage, resulting in the highest grain yield, with increases of 43.87-47.03% compared to other treatments. A moderate N level improved the milling quality of rice, while increased planting density reduced it. However, both increased N and planting density reduced the appearance quality and cooking and eating quality of rice. Overall, the effects of increasing N application rate and planting density on enhancing rice lipid and free fatty acid contents were limited. A combination of 150 kg ha-1 N application rate and 26.7 × 104 plants ha-1 was recommended for achieving relatively higher yield, lipid content and better grain quality. [ABSTRACT FROM AUTHOR]

The growth of timber assortment is related to site conditions and forest management measures. To our knowledge, however, the effects and relative importance of these factors on the growth of different timber assortments of Chinese fir have not yet been explored. Based on data from long-term fixed observation plots in the northwest of the Chinese fir distribution zone, we examined the effects of planting density and the site index on the timber assortment structure of Chinese fir. Furthermore, we quantified the relative importance of stand factors (age, planting density, stand density index, number of living trees, Gini coefficient, and site index) in determining the growth of various timber assortments. The results showed that the wood yield of all timber assortment types increased as the site quality improved. The outturn and outturn rate of large- and medium-diameter timber were negatively correlated with the planting density. Before the age of 22, planting density had a negative impact on total timber yield and small-diameter timber outturn. After 22 years, planting density had a positive impact on total timber yield and small-diameter timber outturn. SDI (stand density index), age, and SD (stand density) were the most important factors influencing total timber yield and small-diameter timber. The relative importance of age to large-diameter timber was the greatest, followed by SI (site index) and SD. The effects of age, SD, SI, and PD (planting density) on the medium-diameter timber were greater than those of SDI and Gini coefficient. The results indicate small- and medium-diameter timber as the primary target timber assortment types to be cultivated in the study area, while large-diameter timber cannot be effectively produced under the current site conditions. Our findings provide valuable insights for the management of Chinese fir plantations and the directed cultivation of target timber assortments in the northwest of the Chinese fir distribution zone. [ABSTRACT FROM AUTHOR]

In order to study the effect of cultivation measures on the size of watermelon fruit, the varieties ‘Sumi 518’ and‘8424’ were used as test and control materials in this study, respectively. Two experimental treatments including different pruning methods combined with different numbers of watermelon fruits, and combined with different planting densities were used in this study, watermelon fruit weight, fruit longitudinal diameter and diameter, pericarp thickness, center sugar content, and edge sugar content under different treatments were record and analyzed. The results showed that the experiment treatment of four lateral branches with different numbers of watermelon fruits did not yield the expected results, two fruits per plant could get in this treatment, and there was a significant difference between these two fruits. The weight of small watermelon fruit was ranged from 2. 09 kg to 2. 54 kg for ‘Sumi 518’ and 2. 24-2. 54 kg for‘8424’. The weight of watermelon fruits could be effectively controlled by using high-density cultivation method. In the treatment of high-density cultivation combined with keeping two fruits per plant, there was a significant difference between big and small fruits. The small watermelon fruits had thin peels, slightly lower central sugar content, and little difference in edge sugar content when comparing with big watermelon fruits. The weight of small watermelon fruits could be controlled within 2 kg in the treatment of three lateral branches with two watermelon fruits per plant, combined with plant spacing of 30 cm. This study explored the feasibility of regulating watermelon fruit size through cultivation measures, which has certain application value in regulating watermelon fruit size and yield in production. [ABSTRACT FROM AUTHOR]

Agricultural strategies are urgently needed to mitigate greenhouse gas emissions without reducing crop yield. Seedling rate per hill will affect the quantity and quality of tillers, which may affect rice yield and CH4 emissions. Therefore, it is hypothesized that high yields with low yield-scaled CH4 emissions could be achieved with optimal seedling rate per hill. A field experiment was conducted with three densities (low seedling rate, LSR; moderate seedling rate, MSR; and high seedling rate, HSR) for two consecutive rice seasons. The CH4 fluxes were determined by the static chamber–GC method. The results showed no significant differences in rice yields, seasonal CH4 emissions, or yield-scaled CH4 emissions between the three treatments. For early rice, the HSR tended to achieve high yield without increasing yield-scaled CH4 emissions. As for late rice, the MSR showed similar rice yield, and tended to have lower yield-scaled CH4 emissions in comparison with the HSR. The results suggest that choosing an appropriate seedling rate per hill to increase grain yield while maintaining lower or comparable yield-scaled CH4 emissions can be a promising option to reduce CH4 emissions from rice paddies. [ABSTRACT FROM AUTHOR]

Planting density is a crucial factor in sweet potato output. However, the relationship among photosynthetic performance, yield, and storage root commercial features that respond to planting density is not well understood. We conducted a three-year field experiment with four planting densities (83,280 plants hm−2, plant spacing 15 cm, D15; 62,520 plants hm−2, plant spacing 20 cm, D20; 50,025 plants hm−2, panting spacing 25 cm, D25; and 41,640 plants hm−2, 30 cm, D30; 80 cm row space for all) to investigate the dynamic of photosynthetic performance, dry matter, yield, carbohydrate metabolism, and commercial features of storage root. The result showed that the highest yield was observed in the D20 treatment, and the yield increment was by 8.47–24.92% when compared to the D25 control treatment during the three growth periods. The observation can be attributed to the fact that appropriate planting density D20 can shape a good canopy structure to improve photosynthetic performance by significantly increasing IPAR, TPAR, light transmission, and extinction coefficient through different canopy levels. Hence, the Pn, Tr, Ci, Gs and WUE, and the chlorophyll fluorescence parameters were significantly improved. Eventually, promoting root sink development by up-regulating starch, fructose, glucose, and sucrose in storage roots, resulting in vigorous carbon flux from the source toward the root sink. Therefore, the optimal planting density D20 treatment increased individual plant yield and commercial features by increasing the number of storage roots, particularly medium-sized ones. Herein, we claim that optimizing the plant population density of sweet potatoes can be a good way to increase the yield and commercial features, and our results are great and important for improving the market value and profits of sweet potatoes. [ABSTRACT FROM AUTHOR]

To study the impact of different varieties and planting densities on the transpiration rate of cotton in Xinjiang, a field experiment was conducted in 2022 in Wulanwusu, Xinjiang. Three cotton varieties (' Zhongmian 979' ' Zhongmian 703' and 'Guoxin cotton' ) and two planting densities (D1:22 plants·m−2 ; D2:11 plants·m−2 ) were establish for treatment. The transpiration rate was measured using a heat ratio stem flow meter, and the differences in daily average transpiration, daily transpiration change, and cumulative transpiration of cotton under different weather conditions (sunny, rainy) and time scales were compared to clarify the water consumption rules of cotton under different varieties and densities in northern Xinjiang. The results showed that: (1) planting density had a significant impact on the cumulative and daily transpiration rates of cotton population. The cumulative and daily transpiration rates of cotton increased significantly under D1 planting density. Under D1 planting density treatment, the cumulative and daily transpiration rates of three varieties were significantly higher than those under D2 planting density treatment (an average increase of 51.2%). (2) Cotton varieties had a significant impact on individual and group transpiration, with' Zhongmian 703' higher stem flow rate, daily transpiration rate, and cumulative transpiration than other varieties. (3) The transpiration of a single cotton plant showed a "几" shaped variation pattern on a daily scale. During the day (9: 00−21: 00), the transpiration was relatively stable, but there was still a slight stem flow at night due to root pressure. (4) The transpiration rate and amount of cotton decreased month by month from July to September. The daily transpiration curve of cotton in September gradually transitioned to a unimodal pattern, and the daytime transpiration starts later (10: 00) and ends earlier (20：00). (5) Accumulated transpiration had a positive correlation with both seed cotton yield and average leaf area, but it was not significant. [ABSTRACT FROM AUTHOR]

Copyright of Acta Agronomica Sinica is the property of Crop Science Society of China and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

There are few studies on how nitrogen (N) fertilizer application rates and transplanting densities impact rice yield, root distribution, and N use efficiency in the cold regions of Northeast China. This research involved a two-year field trial utilizing Jinongda 667 as the material. In 2021, three N split-fertilizer applications—T1 (6:3:1), T2 (5:3:2), T3 (4:3:3)—and two transplanting densities—D1 (30 cm × 13.3 cm) and D2 (30 cm × 20 cm)—were compared with the conventional cultivation mode (T0: 175 kg N hm−2, 6:3:1), whereby the N application mode most suitable for increasing density was explored. In 2022, four N application levels—0 (N0), 125 (N1), 150 (N2), and 175 (N3) kg N hm−2—were assessed under the same density treatment to analyze the yield, resource utilization efficiency, and root traits of Jinongda 667. The results indicated that when the transplanting density was 30 cm × 13.3 cm, the application of 5:3:2 fertilizer was more conducive to improving rice yield. Increasing planting density under reduced N input significantly enhanced both rice yield and N use efficiency. In contrast to the conventional cultivation method (D2N3), the treatment of increased planting density (D1N2) under reduced N input led to a 21.2% rise in the number of panicles per square meter and an 8.6% boost in rice yield. Furthermore, increasing planting density under reduced N input significantly enhanced the agronomic efficiency of N fertilizer, the apparent utilization rate, and the N harvest index. It also boosted the SPAD value, photosynthetic rate, and the utilization efficiency of light and N resources in rice. However, it was noted that root enzyme activity decreased. This study demonstrated that increasing planting density, combined with the N application mode of 5:3:2 and an N application rate of 150 kg hm−2, maximized resource utilization efficiency, optimized root absorption capacity, and resulted in higher yields. [ABSTRACT FROM AUTHOR]

Southern Xinjiang is an important soybean production region in China. However, the short growing season and the cultivation of winter crops (such as wheat) in the region limit the expansion of soybean planting areas. An increased planting density can compensate for the loss in yield due to delayed sowing. To identify the quantitative relationship between increased density and delayed days, a two-year field experiment was conducted at the Tarim University Agronomy Experiment Station. Two sowing dates (April 7 (S1) and May 7 (S2)) and three planting densities of 206,800 plants·ha−1 (D1), 308,600 plants·ha−1 (D2), and 510,200 plants·ha−1 (D3) were used to compare various plant growth parameters and canopy characteristics. Late sowing and a high planting density significantly increased the plant height (S2 was 37.3% higher than S1, and D3 was 17.6% and 8.8% higher than D1 and D2), main stem internode, petiole length, and the mean tilt angle of the leaves (S2 was 22.5% higher than S1, and D3 was 11.7% higher than D2) but reduced the stem diameter (D3 was 28.6% and 12.5% lower than D1 and D2), branch number (S2 was 26.7% lower than S1, and D2 was 75% lower than D1), canopy light transmittance (S2 was 49.2% lower than S1, and D3 was 36.7% and 20.8% lower than D1 and D2), photosynthetic rate, and dry matter. The highest yield was achieved at S1D1, but the lowest yield was found for S2D1. Overall, the results suggest that earlier sowing and a lower planting density contribute to achieving an optimum canopy structure and higher yield. Our conclusions provide a reference for soybean production in southern Xinjiang. [ABSTRACT FROM AUTHOR]

Research indicates that, owing to the enhanced grain-filling rate of tetraploid rice, its yield has notably improved compared to previous levels. Studies conducted on diploid rice have revealed that optimal planting density and fertilization rates play crucial roles in regulating rice yield. In this study, we investigated the effects of different nitrogen application and planting density treatments on the growth, development, yield, and nitrogen utilization in tetraploid (represented by T7, an indica–japonica conventional allotetraploid rice) and diploid rice (Fengliangyou-4, represented by FLY4, a two-line super hybrid rice used as a reference variety for the approval of super rice with a good grain yield performance). The results indicated that the highest grain-filling rate of T7 could reach 77.8% under field experimental conditions due to advancements in tetraploid rice breeding. This is a significant improvement compared with the rate seen in previous research. Under the same conditions, T7 exhibited a significantly lower grain yield than FLY4, which could be attributed to its lower grain-filling rate, spikelets per panicle, panicle number m−2, and harvest index score. Nitrogen application and planting density displayed little effect on the grain yield of both genotypes. A higher planting density significantly enhanced the leaf area index and biomass accumulation, but decreased the harvest index score. Compared with T7, FLY4 exhibited a significantly higher nitrogen use efficiency (NUEg), which was mainly due to the higher nitrogen content in the straw. Increasing nitrogen application significantly decreased NUEg due to its minimal effect on grain yield combined with its significant enhancement of nitrogen uptake. Our results suggest that the yield and grain-filling rate of T7 have been improved compared with those of previously tested polyploid rice, but are still lower than those of FLY4, and the yield of tetraploid rice can be further improved by enhancing the grain-filling rate, panicle number m−2, and spikelets per panicle via genotype improvement. [ABSTRACT FROM AUTHOR]

Optimizing planting density is crucial for balancing resource competition, light penetration, and tree productivity in orchard systems. This study investigateed the impact of planting density on the yield and fruit quality of the hazelnut cultivar 'Tonda Francescana®' grafted onto Corylus colurna L. rootstocks. The research aimed to assess how different planting densities influenced light penetration, canopy volume, yield, and the nutritional profile of hazelnuts during their sixth growing season. Three planting densities were tested: 625, 1250, and 2500 trees per hectare (low, medium, and high density, respectively). The results show that medium-density planting provided the best balance between light availability, canopy development, and yield efficiency. The synthesis of monounsaturated fatty acids (MUFA) and α-tocopherol (vitamin E) was more prominent in the medium-density system (80.2% and 10.3%, respectively), suggesting a favorable metabolic response to moderate competition for resources. In contrast, high-density planting yielded the most per hectare (2898 kg/ha) but exhibited lower individual tree productivity (1.16 kg). Low-density planting had the highest light penetration (53%) but lower overall yield (822 kg/ha) and quality, with greater starch accumulation in the fruit. In general, medium-density planting optimized both yield and kernel quality, with potential implications for orchard management and breeding strategies to enhance hazelnut production and nutritional value. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the effects of planting density, irrigation volume, and nitrogen application on the resistance of rapeseed to lodging and yield and to provide technical support for achieving high yield and lodging resistance. We employed an L9 (34) orthogonal array, different planting densities, irrigation levels, and nitrogen applications to investigate their impact on rapeseed lodging and yield. The results showed the following: (1) Irrigation had the greatest effect on rapeseed lodging. This effect was most pronounced for the combination (A3B3C2), which exhibited the most severe lodging phenomenon (90%). Planting density had the greatest effect on yield, and the optimal combination was A2B2C3, which reached 3744 kg/hm2 in 2023 and 3420 kg/hm2 in 2024. (2) The agronomic practices increased the content of lignin, cellulose, hemicellulose, crude fiber, pectin, and soluble sugar fractions in the stalks by enhancing their flexural, puncture, and stress resistance. This led to the highest yield while reducing the rate of lodging. This emphasizes the importance of agricultural practices for rapeseed lodging and yield, providing critical insights into rapeseed cultivation in the Aksu region of Xinjiang. [ABSTRACT FROM AUTHOR]

To explore the optimal sowing date, planting density and fertilizer dosage of Shishan rapeseed, to realize the combination of good breeding and high yield cultivation techniques in the suitable area of Yuxi City. Using three-factor and three-level orthogonal test, we researched the optimal sowing date, planting density and fertilizer dosage of Shishan rapeseed in Yuxi City, as well as the effects of shoot, seed yield and economic benefit. The effects of three factors on shoot yield from big to small were in the order of sowing date, planting density,urea dosage;the effects of three factors on seed yield from big to small were in the order of planting density,sowing date,urea dosage, the shoot and seed yield difference of each treatment reached a significant level, sowing date had significant effects on the first picking time, harvesting days, times and growth period of Shishan rapeseed. Planting density was negatively correlated with shoot thickness, fresh weight per shoot, pod number and pods per plant. However, the effect of urea dosage amount on growth period and agronomic traits was not obvious. The optimal combination of cultivation factors for Shishan rapeseed were September 30 for planting date, 60 000 plants/ hm² for density, 375 kg/hm² for urea at seedling stage, the yield of fresh shoot could reach 31 183. 8 kg/hm², seed yield could reach 1 888. 75 kg/hm², the net income was 165 200 yuan/hm², output-input ratio was 3. 55, and the economic benefits were relatively high. [ABSTRACT FROM AUTHOR]

The experiment aimd to investigate the adaptability of Cenchrus fungigraminus cultivation in high-altitude areas of Ganzi Prefecture. The research conducted an introduction trial of Cenchrus fungigraminus at an altitude of 3 400 m in Seca Village, Daofu County, Ganzi Prefecture. Four 10 m × 10 m plots were established within the experimental site as sample plots, with different planting densities of 400 (D1), 300 (D2), 200 (D3), and 100 plants/100 m2 (D4). The first determination of agronomic traits was conducted 3 weeks after the planting of Cenchrus fungigraminus, and subsequent measurements were taken every 15 days throughout the experiment. The results showed that the plant height and leaf length of Cenchrus fungigraminus increased with increasing density. The D1 group had higher plant height and leaf length, while the D2 group had wider leaves and higher yield. The D4 group had more tillers. The study indicates that in Daofu County, the survival rate of the introduced giant fungus grass is high and it has good adaptability. Over-dense planting restricts the photosynthetic efficiency of individual Cenchrus fungigraminus plants, reducing the yield of giant fescue. A planting density of 300 plants/100 m² can ensure the good growth and yield of Cenchrus fungigraminus in high-altitude areas. [ABSTRACT FROM AUTHOR]

[Objective] To provide theoretical and practical guidance for high yield and lodging resistance of maize cultivation in Sichuan and promote the development of mechanical grain harvesting technology of maize, this study investigated the effects of different sowing dates and densities on stalk characteristics and lodging resistant mechanical properties. [Method] The maize cultivar 'Zhongyu 3' was selected for field experiments including six sowing dates (March 27th, April 6th, April 16th, April 26th, May 6th and May 16th) and two planting densities (6.75 and 8.25X104 plants/hm²). All samples were collected 10 days after physiological maturity of maize to measure stalk lodging rates (root lodging rate and stalk breaking rate), yield, plant agronomic traits (plant height, ear height and coefficient of ear height), basal stem morphology (internode length, internode diameter and internode length-to-diameter ratio (L/D)), quality traits (internode dry weight (DW), dry weight per unit length (DWUL), dry weight per unit volume (DWUV) and stem moisture content (MC)) and mechanical strength indexes including crushing strength (CS), rind penetration strength (RPS) and bending strength (BS) of the third stem internode. [Result] Maize lodging resistance was significantly affected by sowing date and planting density. With the delay of sowing date, stalk lodging rate, root lodging rate and stalk breaking rate decreased first and then increased, while maize yield decreased gradually. The plant height, ear height, the third internode length and ratio of length-to-diameter increased significantly, while DW, DWUL and DWUV of the third internode increased after initial decreases.On the contrary, the third internode MC and mechanical strength indexes increased first and then decreased significantly. When the sowing date was delayed from April 26th to May 6th, internode morphology, quality traits, mechanical strength and stalk lodging rate reached the maximum or minimum, respectively. Increasing density further promoted the increasing or decreasing effects, which led to significant increases of stalk lodging rate.Correlation analysis showed that stalk lodging rates at different sowing dates were significantly affected by rainfall and wind after physiological maturity, and it was significantly correlated with L/D, DW, DWUL and RPS, CS and BS of the third internode. The change in stalk mechanical strength was the main reason of lodging rate variations, and the changes in DWUL and L/D were the main factors affecting mechanical properties of lodging resistance. [Conclusion] Optimizing planting density and sowing date could achieve high population yield and lodging resistance. It was suggested to sow spring maize in mid-to-late April and summer maize in early May with planting density of 6.75X104 plants/hm² for coordinated high yield and lodging resistance. [ABSTRACT FROM AUTHOR]

A comprehension of the effects planting density and nitrogen (N) fertilization have on the physiological and morphological characteristics of trees is critical for optimizing the require size and characteristics of wood products. We evaluated the growth traits and the leaf and wood characteristics of three clone poplars including Populus simonii × P. nigra 'Xiaohei', 'Xiaohei-14' and 'Bailin-3' under five planting densities (1666, 1111, 833, 666, and 555 tree ha−1) and four N fertilization rates (0, 100, 160, and 220 g tree−1 year−1). The results show that the clone type significantly affected all observed indicators, while planting density and N fertilization treatments had a significant effect on growth traits and leaf characteristics, but not on wood characteristics. Specifically, the clone 'Bailin-3' exhibited the largest annual increments in tree height and diameter at breast height (DBH), leaf width, N content, and soluble protein content. A decrease in initial planting density (from 1666 to 555 tree ha−1) led to an increased annual incremental tree height and DBH, regardless of clone type and N fertilization treatment. N fertilization treatment significantly impacted the annual increment in DBH, but not that of tree height. Further, the annual increments in tree height and DBH were positively correlated with leaf width, N content, chlorophyll content, and soluble protein content, and negatively correlated with hemicellulose content. In addition, the chlorophyll and soluble protein contents were identified as the most reliable predictors of the annual increments in tree height and DBH. Our results demonstrate the clone 'Bailin-3' with 555 tree ha−1 under 160 g N tree−1 yr−1 showed superior growth traits and leaf characteristics. Thus, it is recommended for future poplar silviculture of larger diameter timber production at similar sites. The results contribute to understanding of the effects of planting density and fertilization on the growth traits and the leaf and wood characteristics of three poplar clones, offering valuable guidance for the sustainable development and long-term productivity of poplar plantations. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Ecology & Rural Environment is the property of Journal of Ecology & Rural Environment Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract The growth of timber assortment is related to site conditions and forest management measures. To our knowledge, however, the effects and relative importance of these factors on the growth of different timber assortments of Chinese fir have not yet been explored. Based on data from long-term fixed observation plots in the northwest of the Chinese fir distribution zone, we examined the effects of planting density and the site index on the timber assortment structure of Chinese fir. Furthermore, we quantified the relative importance of stand factors (age, planting density, stand density index, number of living trees, Gini coefficient, and site index) in determining the growth of various timber assortments. The results showed that the wood yield of all timber assortment types increased as the site quality improved. The outturn and outturn rate of large- and medium-diameter timber were negatively correlated with the planting density. Before the age of 22, planting density had a negative impact on total timber yield and small-diameter timber outturn. After 22 years, planting density had a positive impact on total timber yield and small-diameter timber outturn. SDI (stand density index), age, and SD (stand density) were the most important factors influencing total timber yield and small-diameter timber. The relative importance of age to large-diameter timber was the greatest, followed by SI (site index) and SD. The effects of age, SD, SI, and PD (planting density) on the medium-diameter timber were greater than those of SDI and Gini coefficient. The results indicate small- and medium-diameter timber as the primary target timber assortment types to be cultivated in the study area, while large-diameter timber cannot be effectively produced under the current site conditions. Our findings provide valuable insights for the management of Chinese fir plantations and the directed cultivation of target timber assortments in the northwest of the Chinese fir distribution zone.

Evaluating the costs of establishment and maintenance of table grape plantations, grown through the Pergola management system, is a significant opportunity for winegrowers in the Republic of Moldova. This system, relatively new in the country, remains unadopted for many of the table grape producers. The present research highlights the methodological and technical aspects related to the costs associated with the cultivation of table grapes through the Pergola management system, which must be adapted to the specific climatic conditions of Moldova and to the current market requirements. The main objective of the research is to analyze the structure of costs that influence the yield of plantations in the long term, including the initial establishment expenses and the subsequent maintenance expenses. The author points out that although the maintenance costs of Pergola table grape plantations are high, the growing demand for quality grapes adds significant economic value to this vineyard management system. The research details the composition of the establishment and maintenance costs of table grape plantations, namely fertilization costs, irrigation costs, mechanized service costs. Concrete examples show what the structure of these costs is, thus demonstrating the importance of a correct assessment of costs in the process of establishing and maintaining table grape plantations.

【Objective】 Forage maize is a crop cultivated in the Yinda Irrigation District in Gansu province, China. This paper investigates the influence of planting density on its growth, yield and quality. 【Method】 The variety of Long Silage No.1 was used as the model plant. The field experiments compared five planting densities: 5.6×104 plants/hm2 (M1), 6.8×104 plants/hm2 (M2), 8.0×104 plants/hm2 (M3), 9.2×104 plants/hm2 (M4), and 10.4×104 plants/hm2 (M5). In each treatment, we measured plant traits, yield and quality of the plant at its maturity stage. 【Result】 ① Plant height and stem thickness both varied with planting density parabolically. With the increase in planting density, cob length, cob thickness, fresh cob weight, the number of rows of grains and the number of rows in cobs all increased first and then decreased when planting density exceeded 8.0×104 plants/hm2. ② With the increase in planting density, fresh grass, hay and kernel yields increased to 182 146.72 kg/hm2, 91 054.35 kg/hm2, and 24 278.68 kg/hm2, respectively, when planting density was 8.0×104 plants/hm2, and then decreased after planting density exceeded 8.0×104 plants/hm2. ③ Compared with M4 and M5, M3 increased the crude protein by 8.31% and 12.49%, the crude starch by 10.58% and 15.71%, and the fat contents by 10.38 and 19.71%, respectively. It was found that the neutral washing fiber was the highest in M5 and the least in M3. Compared to M3, M5 increased the neutral detergent fiber by 7.78%. 【Conclusion】 A planting density of 8.0×104 plants/hm2 is optimal for yield and quality of forage maize cultivated in the Yinda Irrigation District.

[Objective] This study aims to investigate the carbon storage, carbon sink function, and response mechanism to climate in Pinus sylvestris var. mongolica plantations with different initial planting densities on the southern edge of Horqin Sandy Land. The goal is to facilitate the assessment of the carbon sequestration function and adaptive management of forest ecosystems. [Methods] Estimating carbon storage and carbon sequestration rate of Pinus sylvestris plantations using stand height and cross-sectional area, and analyzing their responses to temperature, precipitation, and evaporation in conjunction with meteorological factors. The GM (1,1) grey prediction model was used to predict forest carbon storage in 2030. [Results] The carbon storage and sequestration rate of Pinus sylvestris plantations with different initial planting densities exhibited similar annual fluctuations, with an overall increase in carbon storage each year. The curve of the sequestration rate showed a “U” shape. Both thinly and excessive initial planting densities can reduce the carbon carbon sequestration capacity of Pinus sylvestris plantations. Before reaching 32 years old, the highest carbon sequestration intensity was observed in stands with initial planting densities of 1 500~2 000 tree/hm2, and for stands aged 35~46 years, the optimal density was 1 000~1 200 tree/hm2. The carbon storage increased logarithmically with increasing stand density.The response pattern of the planted Pinus sylvestris forests’carbon sequestration rate differed among stands with different initial planting densities regarding temperature but not precipitation. For high and extremely high-density Pinus sylvestris plantations, the average temperature in August of the previous year and in March, May, June and July of the current year were the main climatic factors limiting carbon sink. For low and medium-density plantations, the average temperature in August of the previous year and in March and October of the current year were the main climatic factors that constrain carbon sink. The correlation analysis between evapotranspiration and carbon sequestration rate in different planting density stands showed that carbon sink of low-density Pinus sylvestris plantations was more sensitive to evapotranspiration. Based on the GM (1,1) grey model, it was found that excessively high or low initial planting density would reduce the carbon sequestration potential of future Pinus sylvestris plantations. The optimal planting density for carbon sequestration rate was 1 772 tree/hm2. [Conclusion] The initial planting density of Pinus sylvestris has a significant impact on carbon storage and carbon sequestration, as well as their response to climate change in sandy areas. Adjusting the initial planting density may be one of the key adaptive management measures for Pinus sylvestris plantations under climate change.

Twenty-five years after planting, we measured the survival, growth and reproduction of 153 Quercus ilex plantations promoted by the afforestation programme of the European Union's Common Agricultural Policy in agricultural fields in the east of the Iberian Peninsula, as a function of climatic aridity and stand characteristics related to water supply and competition among trees for water. Using field sampling, we found that, on average, 80% of the trees in plantations survived, more than 55% had already produced acorns and the tallest tree in each field exceeded 4 m, which are all higher values than those reported for forest plantations of this species in the same area and which represent the overcoming of the limitations imposed by climatic aridity on the natural regeneration of the species. A small proportion of the variation in all success variables was explained by water-related plantation characteristics, such as planting density, drought intensity in the year after planting, and soil permeability. However, climatic aridity only influenced the proportion of reproductive trees, but not the other variables of plantation success. However, most of the variation in planting success variables was linked to who owned the field, which nursery produced the seedlings, and the year of planting. Our results support the idea that the deep soils of agricultural fields counteract the negative effect of climatic aridity on plant performance, but that it is necessary to standardise nursery and planting practices, adapt planting density to the environmental characteristics of the site and provide irrigation supply in the early years to ensure the success of future plantations. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Irrigation & Drainage is the property of Journal of Irrigation & Drainage Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Plant Production is the property of Egyptian National Agricultural Library (ENAL) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The study aimed to explore the impact of variety and planting density on the yield, agronomic traits, and nutritional quality of cassava stems and leaves. Using cassava varieties including GR891, YRS No. 2 and SC205 as experimental materials, a randomized block design with variety (A) and planting density (B) as two factors was conducted in the dry and hot valley region of Yunnan with seven planting densities for field comparative experiments. The results showed that the yield of cassava stems and leaves first increased and then decreased with the increase of planting density, with higher stem and leaf yields obtained by planting according to B6 and B5, indicating that lower planting density was more suitable for the accumulation of dry matter in stems and leaves compared to higher planting density. Plant height increased with the increase of planting density, while stem thickness gradually decreased. From the perspective of the average membership function, varieties A1 and A3 showed the best nutritional quality when planted according to B4, and variety A2 showed the best nutritional quality when planted according to B2, with relatively higher crude protein content. Among the different varieties, A2 and A3 had superior yield, agronomic traits, and nutritional quality compared to A1. The study indicates that YRS No.2 is the most suitable variety for planting in the dry and hot valley region of Yunnan, with the optimal planting density of 50 000 plants/hm2, which can yield higher biomass of stems and leaves and has excellent nutritional quality. [ABSTRACT FROM AUTHOR]

Increasing wheat (Triticum aestivum L.) planting density is the most effective production management method for increasing yields; however, excessive crop populations under high planting densities may experience elevated risk of stem lodging. We conducted this study to assess the relationship between reduced lodging and increased yield, investigate the effects of planting density on wheat population structure, stem strength, and material transport, and provide a basis for rationale planting densities. The experiments were carried out using a split-plot design with three replicates. The main plots contained two wheat varieties: Bainong 5819 (BN5819) and Bainong 4199 (BN4199), and the sub-plots contained four planting density treatments: 90 × 104 plants/ha (D1), 180 × 104 plants/ha (D2), 270 × 104 plants/ha (D3), and 360 × 104 plants/ha (D4). A two-year field trial was conducted in 2021–2023. The relationships between population structure characteristics, changes in stem strength, activation, and retransport of stem material after anthesis, and achievement of high and stable yields were investigated at the different planting densities. When the planting density of wheat increased from D1 to D4 treatment, the activity of fructan hydrolase was significantly increased. Compared with D1 treatment, the highest activity of fructan hydrolase was increased by 457.47 μg/h/g under D4 treatment. At the same time, the increase of density also increased the contribution rate of dry matter accumulation (CDMA) to grain after anthesis increased, with the highest increase in CDMA at 33.67%, which significantly reduced stem strength. Correlation analysis revealed a significant negative association between CDMA and stem strength. Specifically, CDMA levels were significantly lower with the D3 treatment than the D4 treatment, while stem strength remained higher after anthesis as an adaptive response to mitigate lodging risk. Stem storage compounds can promote grain filling and a weight increase in inferior grains. The number of spikes per unit area increased significantly with increasing planting density, but the number of grains per spike and 1000-grain weight decreased significantly. In two years, the number of spikes in D3 treatment increased by a maximum of 211.67 × 104 ha−1 and 99.17 × 104 ha−1, respectively, compared to D1 and D2 treatments. The number of grains per spike was significantly higher than that of D4 treatment, the highest being 3.68 grains. Therefore, in the North China Plain with suitable water, fertilizer, and temperature, the sowing density of 270 × 104 plants/ha established population structure, significantly reduced CDMA, maintained post-anthesis stem strength, enhanced resilience of stems against post-anthesis lodging, and resulted in high yields by stabilizing the number of grains per spike and increasing the number of wheat spikes. [ABSTRACT FROM AUTHOR]

With growing concerns about global warming, it is crucial to adopt agronomic practices that enhance rice yields from paddy fields while reducing greenhouse gas (GHG) emissions for sustainable agriculture. An optimal nitrogen (N) fertilization rate and planting density are vital to ensure high rice yields, minimize GHG emissions, and understand emission behavior for better field management. We hypothesized that optimizing N application rates and planting density to improve nitrogen use efficiency (NUE) in rice cultivation would reduce resource losses and GHG emissions. To test this hypothesis, we implemented five treatments with a rice straw return cultural system: two planting densities (16 hills m−2 (traditional density, D1) and 20 hills m−2 (25% higher density, D2)) and three N application rates (no N fertilizer (N0), 180 kg N ha−1 (N1), and 144 kg N ha−1 (N2)). The control treatment (CK) was traditional planting density with no N fertilizer. The four new cropping modes were N1D1, N1D2, N2D1, and N2D2. We investigated the effects of N application rates and planting density on rice grain yield, NUE, and GHG emissions in multiple rice-growing seasons. The N1D2 treatment exhibited the highest grain yield over the three years, with a value of 10,452 kg ha−1, representing an increase of 12.2% compared to CK. Moreover, N uptake in N1D2 was the highest, averaging 39.2% (p < 0.05) higher than CK, and 8.5%, 3.5%, and 2.8% (p < 0.05) higher than N1D1, N2D1 and N2D2, respectively. N2D2 exhibited the highest NUE, with a value of 58.99 kg kg−1, surpassing all other treatments over the three years. GHG emissions, global warming potential (GWP), and greenhouse gas intensity (GHGI) in N2D2 were lower than in N1D1, N1D2, and N2D1. Additionally, reducing N application (comparing N1D1 to N2D1) and increasing plant density (comparing N1D1 to N1D2) improved N agronomic efficiency (NAE) and N partial productivity (PFPN). The negative correlation between the NAE and PFPN with GWP and GHG emissions further supports the potential for optimized N management and denser planting density to reduce environmental impact. These findings have important implications for sustainable rice cultivation practices in Southwest China and similar agroecosystems, emphasizing the need for integrated nutrient management strategies to achieve food security and climate change mitigation goals. [ABSTRACT FROM AUTHOR]

Utilizing the potential of crops to suppress weeds is an important strategy for sustainable management. Feathertop Rhodes grass (FTR) (Chloris virgata Sw.) is a problematic warm-season weed in Australia that has recently expanded into colder seasons. This study investigated the growth and seed production of FTR at two planting times (May and July) and three wheat planting densities (0, 82, and 164 plants m−2) using a neighborhood design over two years. In both years, the plant height, tiller production, and panicle production of FTR were lower in the presence of wheat compared to when wheat was absent. Surrounding FTR with wheat delayed its pinnacle emergence, varying from 1 to 6 days in the first year and 4 to 21 days in the second year, depending on the planting date and wheat density. During both years and planting times, wheat's presence caused approximately a 99% decrease in the dry matter and seed production of FTR compared to wheat's absence. Additionally, the wheat height, an important competitive factor, was higher at both densities in the May planting compared to the July planting. The emergence, establishment, and continuous production of FTR seeds throughout the year indicate that inadequate management could result in the further spread of this weed. Our findings suggest that adjusting the date and density of wheat planting could be a viable strategy for sustainably managing this weed during colder seasons. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Soil & Water Conservation (1009-2242) is the property of Institute of Soil & Water Conservation and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Acacia hybrid (Acacia mangium Willd. × A. auriculiformis A. Cunn. Ex Benth.) dominates plantation wood production in central Vietnam. Dependence on a single species may increase biological risks. The potential of eucalypt as an alternative was examined by comparing the growth and survival of acacia hybrid and eucalypt hybrid (Eucalyptus urophylla S.T. Blake × E. pellita F. Muell.) clones in Quang Tri province at three planting densities (1333, 1667 and 2222 trees ha−1). The experiment was planted on an eroded shallow soil common in the region. At age 5 years, survival of acacia (74%) was higher than that of eucalypt (67%), a consequence of high mortality from wind damage for one eucalypt clone. Eucalypt was taller by about 2 m, but stem diameters of acacia and eucalypt were very similar. For both taxa, diameter decreased significantly as planting density increased. Across planting densities, mean standing volume was 107 and 108 m3 ha−1 for acacia and eucalyptus, respectively. Linear regressions of stocking at 5 years on volume accounted for over half of the variance in acacia and eucalypt plot volumes, demonstrating the strong effect of stocking on yield. There were similarly strong effects of stocking on stem diameter. Acacia hybrid plantations of nearby small growers had stockings at age 5 years that averaged over 2500 stems ha−1. Growers planted at higher densities and allowed their trees to multi-stem. Their standing volumes at age 5 years ranged from 83 to 102 m3 ha−1. Understanding how to reduce tree mortality would assist growers to choose planting densities and stand management that optimise growth, log diameter classes and net returns. [ABSTRACT FROM AUTHOR]

Planting density is an important factor affecting plant growth and yield formation in rapeseed. However, the understanding of the mechanism underlying the impact of planting density on biomass, canopy, and ultimate seed yield remains limited. A field experiment was conducted to investigate the effect of planting density on seed yield, yield components, biomass accumulation and partitioning, and canopy structure. Five planting density levels were set as D1 (2.4 × 105 plants ha−1), D2 (3.6 × 105 plants ha−1), D3 (5.4 × 105 plants ha−1), D4 (6.0 × 105 plants ha−1), and D5 (7.2 × 105 plants ha−1). The results showed that with planting density increasing from D1 to D3, the seed yield, number of pods in population, and 1000-seed weight increased, while seedling survival rate, yield per plant, number of pods per plant, and number of seeds per plant decreased. When planting density increased to D4 and D5, seed yield dramatically decreased due to a decreased number of seeds per pod and 1000-seed weight. Increasing planting density from D1 to D3 increased biomass accumulation in all organs. D3 produced the highest biomass partitioning in seeds. In addition, D2 and D3 treatments had a high level of pod area index (5.3–5.8), which caused an approximately 93% of the light to be intercepted. The distribution of light in D2 and D3 was more evenly spread, with the upper and lower parts of the canopy displaying a distribution ratio of roughly 7:3. Therefore, D2 and D3 produced the highest seed yields. In conclusion, D2 and D3 are recommended in rapeseed production due to their role in improving biomass accumulation and partitioning and canopy structure. [ABSTRACT FROM AUTHOR]

In order to explore the efficient cultivation techniques of soybean variety Shangdou 151 in the eastern region of Henan, field experiments were conducted. Three planting densities (180 000, 225 000, 270 000 plants/hm²) and three irrigation quotas (70, 100, 130 mm) were set up to investigate their effects on the water use efficiency, yield and composition factors of Shangdou 151. The results showed that both planting density and irrigation amount significantly affected the yield. When the planting density was E3 and the irrigation quota was W1, the yield and water use efficiency both reached the maximum values of 2 491.77 kg/hm² and 8.27 kg/(hm² mm). The analysis of variance results showed that the effects of planting density, irrigation amount and their interaction on yield traits reached a significant level, such as pod number per plant, grain number per plant and grain weight per plant. [ABSTRACT FROM AUTHOR]

The low efficiency of light and nitrogen resources, poor yield and profit, and environmental pollution of maize production are main problems in many areas of China. We hypothesized that optimizing nitrogen fertilizer density management strategies could alleviate the above issues. To address this, a 3-year on-site experiment with three planting densities and four nitrogen rates was conducted in the Sichuan Hilly Region. The results indicated that increasing the planting density could increase the extinction coefficient and solar radiation interception of maize populations as well as enhance the utilization efficiency of light and nitrogen resources and yield. For every 100 kg ha−1 increase in nitrogen fertilizer, RUE increased by 0.16%, NUE decreased by 25.0%, and soil apparent nitrogen loss quantity increased by 67.8 kg ha−1. There was a certain interaction between planting density and nitrogen rate. The appropriate planting density and nitrogen rate combination was 67,500 plants ha−1 with 180 kg N ha−1 under the experimental condition. Excessive close planting in weak-light areas and excessive nitrogen reduction after densification are not advisable. This study indicated that nitrogen–density strategies should be matched with the local natural resources such as sunlight. The results provide a theoretical for high-yield and high-quality maize production in these areas. [ABSTRACT FROM AUTHOR]

The optimal combination of the nitrogen fertilizer application and planting density with reference to the silage maize yield and quality remains unclear. We hypothesized that increasing both would increase yields following the law of diminishing returns. Yayu26, a silage maize cultivar, was used in a split-plot experiment to investigate the effects of nitrogen fertilizer and planting density on growth, nutrient characteristics, and chlorophyll fluorescence. The main plots were assigned to three planting densities: 60,000 (A1), 75,000 (A2), and 90,000 (A3) plants hm−2, and the subplots were assigned to four nitrogen fertilizer rates: 0 (B1), 120 (B2), 240 (B3), and 360 (B4) kg hm−2. The results showed that increasing the nitrogen application rate and planting density both enhanced silage maize yield. Nitrogen accumulation and agronomic use efficiency peaked at a planting density of 75,000 hm−2. Structural equation modeling showed that the nitrogen application rate and planting density affected nitrogen accumulation and nutrient properties by influencing chlorophyll fluorescence parameters and nitrogen agronomic efficiency, ultimately resulting in a positive effect on the yield. The A3 × B2 treatments exhibited higher nitrogen accumulation, potentially compensating for any deficiencies in the dry-matter yield. Therefore, the A3 × B2 treatment was evaluated as the optimal treatment to achieve sustainable and economically feasible silage maize production. [ABSTRACT FROM AUTHOR]

Forage maize, with its rich nutrition and high palatability, is an important crop in the develop‐ ment of animal husbandry. With the rapid devel‐ opment of animal husbandry in our country and the continuous advancement of the policy of "changing crop to forage", Chinese forage maize industry has developed rapidly, and the yield and quality have greatly improved. However, the plant‐ ing area of forage maize is limited, and most vari‐ eties are traditional. How to improve the yield and quality of forage maize with limited resources is an urgent problem to be solved in forage maize industry. At present, many in-depth studies have been carried out on the cultivation measures of forage maize. In this paper, the current status of forage maize and the research on its high yield and quality cultivation in recent years are reviewed, including the ef‐ fects of cultivation measures on the yield and quality of forage maize, such as variety selection, planting mode, planting density, nitrogen fertilizer application and harvest time. It also covers the research related to the use of forage maize in cultivating animals. The aim of the paper is to provide important reference for the quality production of forage maize. [ABSTRACT FROM AUTHOR]

Appropriate nitrogen (N) fertilization and planting density management are critical for efficient production of grain maize (Zea mays L.) and for environmental protection. However, the optimal N fertilization and planting density is still not established for forage maize that is cultivated to promote its vegetative growth and utilized for the above-ground vegetative mass. A two-year field experiment was conducted in the rainfed semiarid region of the Chinese Loess Plateau during the 2021 and 2022 growing seasons. The effects of N application rates and planting densities on the dry matter yields and the water- and N-use efficiencies of forage maize were studied. The experiment includes four N application rates (0, 90, 180, and 270 kg ha−1) and three plant densities (70000, 90000, and 110000 plants ha−1), covering the conventional practices of local farmers. The treatments were organized in a randomized complete block design with four replications. Averaged over the three plant densities, N application rate of 180 kg ha−1 resulted in the maximum average aboveground dry matter yield (18.6 t ha−1), crop N accumulation (228.5 kg ha−1), dry matter water productivity (51.9 kg ha−1 mm−1), and dry matter precipitation productivity (62.9 kg ha−1 mm−1) over the two years. Moreover, increasing N application rates significantly increased the soil nitrate-N accumulation (0–200 cm) but reduced the partial factor productivity of applied N fertilizer. Across the three plant densities, the two-year average soil nitrate-N accumulation was 12.6, 32.1, and 75.7 % higher with 90, 180, and 270 kg N ha−1 compared to no N treatment, respectively. The highest soil nitrate accumulation under 270 kg ha−1 N application rate in 2021 (229.5 kg ha−1) and in 2022 (329.7 kg ha−1) may cause severe nitrate leaching loss and potential soil water contamination, driven by intensive rainfalls. Averaged over the four N rates, planting density of 110000 plants ha−1 increased the crop N accumulation and PFP by 21.2 % and 15.8 % in 2021, compared to 70000 plants ha−1, respectively. The interaction of N application and planting density significantly affected the aboveground dry matter yield, crop water consumption, dry matter precipitation productivity, and crop N accumulation in 2021, but the effect was non-significant in 2022. Based on these findings, application of 180 kg N ha−1 and planting density of 110000 plants ha−1 are suggested as an efficient management strategy for improving productivity of forage maize and soil water and N resources utilization in the arid region of the Loess Plateau and similar areas.

To investigate the effects of nitrogen (N) application rate and planting density (D) on the contents of lipid and free fatty acid, fatty acid composition, yield and quality of rice grain, a field experiment was conducted using Koshihikari (japonica) as experimental material from 2021 to 2022 with three N levels (90, 150 and 210 kg ha-1, denoted as N1, N2 and N3, respectively) and three transplanting densities (19.0 × 104, 26.7 × 104 and 40.0 × 104 plants ha-1, denoted as D1, D2 and D3, respectively). The results showed that N application rate and planting density had highly significant impacts only on the contents of free fatty acid and saturated fatty acid, respectively. Increased N and planting density enhanced the contents of lipid (29.41 mg g-1) and free fatty acid (21.47%). The highest values were obtained under N3D3 increasing by 7.02% and 3.23 percentage points, respectively, compared to other treatments. No significant differences in lipid content were found among treatments, whereas free fatty acid exhibited significant differences. The unsaturated fatty acid content increased with increasing N but first decreased and then increased with increasing planting density, while saturated fatty acid content showed the opposite trend. Appropriate N level and planting density improved the relative chlorophyll content and net photosynthetic rate of rice flag leaves, as well as increased grain yield, effective panicle number and spikelete number per panicle, but decreased the seed setting rate. Under N2D2, the relative chlorophyll content and net photosynthetic rate remained relatively high throughout the grain filling stage, resulting in the highest grain yield, with increases of 43.87-47.03% compared to other treatments. A moderate N level improved the milling quality of rice, while increased planting density reduced it. However, both increased N and planting density reduced the appearance quality and cooking and eating quality of rice. Overall, the effects of increasing N application rate and planting density on enhancing rice lipid and free fatty acid contents were limited. A combination of 150 kg ha-1 N application rate and 26.7 × 104 plants ha-1 was recommended for achieving relatively higher yield, lipid content and better grain quality.

Hill number per unit area and seedling number per hill are foundational agrotechnical factors shaping the growth and development of rice plants. This study aimed to determine the effects of decreasing the hill number per unit area combined with increasing the seedling number per hill on grain quality in hybrid rice. Field experiments were performed in Hengyang, Hunan Province, China, in 2022 and 2023 using the hybrid rice variety Huazheyou 261, as well as in Liuyang, Hunan Province, China, in 2023 using the hybrid rice varieties Yueyou 2646 and Zhenliangyouyuzhan. Treatments (combining hill number per unit area and seedling number per hill) encompassed a combination of 24 hills per m2 and one seedling per hill (H24S1) and a combination of 14 hills per m2 and three seedlings per hill (H14S3) in Hengyang, as well as a combination of 28 hills per m2 and two seedlings per hill (H28S2) and a combination of 14 hills per m2 and four seedlings per hill (H14S4) in Liuyang. There were no significant differences in the leaf area index at the heading stage, as well as no significant differences in canopy light transmittance during the grain-filling period between H24S1 and H14S3 in Hengyang, or between H28S2 and H14S4 in Liuyang. The differences in grain quality traits, including milling traits (brown, milled, and head rice rate), appearance traits (rice length, rice length-width ratio, chalky grain rate, and chalkiness degree), amylose and protein content, and pasting characteristics were also not significant between H24S1 and H14S3 in Hengyang, nor between H28S2 and H14S4 in Liuyang. This study indicates that the grain quality in hybrid rice is unaffected by decreasing the hill number per unit area integrated with increasing the seedling number per hill. [ABSTRACT FROM AUTHOR]

Nitrogen (N) application rates and planting density are key factors affecting grain yield and quality. In this experiment, four varieties, Huijing 753 (HJ 753), Huijing 855 (HJ 855), Huijing 866 (HJ 866), and Dangjing 8 (DJ 8), were used to investigate their effects on the yield and quality of japonica rice in Anhui, which has a lower soil N supply capacity. The current study set four levels of N application N1, N2, N3, and N4 (120, 180, 240, and 300) kg ha−1 and three planting densities D1, D2, and D3 (high-density: 45 × 104; medium-density: 37.5 × 104; low-density: 32.2 × 104) hills ha−1 for a total of 12 treatments. The effects of N application and planting density on rice yield, composition, processing quality, appearance quality, and cooking quality were analyzed. The results showed that with the increase in N application rates and planting density, the effective panicle number per plant and grain number per panicle of each rice variety increased, while HJ 753, HJ 855, and HJ 866 reached the highest yield under the N3D1 treatment and then gradually declined, and DJ 8 had the highest yield in the N4D1 treatment. In addition, the processing quality of various varieties can be improved by increasing the N application rate and planting density, but the appearance quality will deteriorate, the amylose content will also decrease, and gel consistency will also be lower. Therefore, under medium-planting density conditions, N at a rate of 240 kg ha−1 was the best for HJ 753, HJ 855, and HJ 866, and using 300 kg ha−1 for DJ 8 resulted in high grain yields and superior rice grain quality. In the next step, physiological, biochemical, and genotypic analyses of these three japonica rice varieties were carried out to provide a scientific basis and technical support for accelerating the breeding of high-yield japonica rice varieties. [ABSTRACT FROM AUTHOR]

In order to clarify the effects of planting density with nitrogen rate on regulation of nitrogen utilization in summer direct seeded cotton, the CCRI 425 were used as the experimental materials in the Key Laboratory of Genetics and Physiology of Yangzhou University in 2019 and 2020. Density were used as the main treatments in 2019 and three levels of density of 60,000 plants hm-2, 90,000 plants hm-2, and 120,000 plants hm-2 were set. Nitrogen application rate as the secondary treatments and four levels of convention nitrogen application rate (0 kg hm-2, 90 kg hm-2, 150 kg hm-2, and 210 kg hm-2) were conducted. Production application (90,000 plants m-2, 180 kg hm-2 nitrogen application rate) was used as the CK. Under the density of 120,000 plants hm-2, there were four levels of convention nitrogen application rate (0 kg hm-2, 90 kg hm-2, 150 kg hm-2, and 210 kg hm-2). The results showed that cotton seed yield was increased, reaching 4147.8-5119.2 kg hm-2, at the density of 12x104 plants hm-2 with nitrogen application of 150 kg hm-2. The dry matter of reproductive organs was 2605.6-2863.6 kg hm-2 and accounted for over 50% of the total dry matter weight. Nitrogen accumulation in reproductive organs was significantly increased, reaching 45.97-60.70 kg hm-2. Nitrogen use efficiency was significantly increased, nitrogen recovery efficiency (NRE) was 42.58%-44.17%, agronomic nitrogen use efficiency (aNUE) was 7.16-21.34 kg (kg N) -1, physiological nitrogen use efficiency (pNUE) was 19.16-24.03 kg (kg N) -1, partial productivity of nitrogen fertilizer (NPP) was 21.12-34.13 kg (kg N) -1. Regression analysis further showed that nitrogen recovery efficiency, nitrogen agronomic efficiency, nitrogen physiological efficiency, and physiological efficiency were linearly positively correlated with yield. The percentage of open bolls reached 43.59%-60.76% before spraying defoliation and ripening agent and the normal flocculation rate could be achieved after spraying defoliation and ripening agent. Therefore, high-density with medium nitrogen rate is beneficial to nitrogen absorption and utilization, which provides the technical support for high yield, high efficient production, and nitrogen reduction in cotton. [ABSTRACT FROM AUTHOR]

Soil dehydrogenase (14.2, 11.3 mg TPF g-1 day-1), alkaline phosphatase (109.5, 86.7 mg PNP g-1 soil h-1), acid phosphatase (69.7, 51.6 mg PNP g-1 soil h-1) and urease activity (60.4, 39.9 mg NH4 g-1 2 h-1) in chickpea at flowering and harvest with seed rate @ 105 kg ha-1. Among, nutrient management the corresponding activity (14.9, 11.7 mg TPF g-1 day-1), (120.7, 96.7 mg g PNP g-1 soil h-1), (70.5, 52.7 mg g PNP g-1 soil h-1) was higher with 75% RDF + microbial consortia (MC). Contrarily, urease activity (62.3, 38.7 mg g NH4 g-1 2 h-1), soil available soil nitrogen (181.3, 179.0 kg ha-1) and phosphorus (78.3, 76.5 kg ha-1) were higher under 125% RDF + MC. PCA indicated that among nutrient management, first principal component explained 71.37% variability to urease activity, available soil potassium and dehydrogenase activity and second component (22.34%) to available soil phosphorus and nitrogen. Among planting density, first component explained variability (66.87%) to acid phosphatase and second component (32.11%) to available phosphorus. [ABSTRACT FROM AUTHOR]

A new maize variety Tianrun 189 was selected as experimental material, and a two-factor split plot design was adopted. Three treat- ments of density level were set up(Al treatment 42 000 plants/hm²; A2 treatment 48 000 plants/hm²; A3 treatment, 54 000 plants/hm²). 4 fertilizer application level treatments were as follows: B1 was treated with conventional fertilizer, 750 kg/hm² compound fertilizer and 150 kg/hm² urea; B2, B3 and B4 treatments were treated with slow-release fertilizer 600,750 and 900 kg/hm², respectively. The main agro- nomic characters, yield and economic benefit of maize variety Tianrun 189 under 3 densities and 4 fertilization levels were studied. Results showed that planting density, fertilizer amount and interaction between fertilizer amount and planting density had significant or extremely signifi- cant effects on plant characters, ear traits and yield. Under different planting densities, A3 had the highest yield of Tianrun 189, was significant or extremely significant higher than treatment Al, but showed no significant differences with A2 treatment. Under different fertilization amount, B4 treatment had the highest yield of Tianrun 189, was extremely higher than B2 treatment, but had no significant differences with B3 and B1. Under the interaction between fertilizer amount and planting density, A3B1 treatment had the highest yield in spring sowing, which reached 8 494.50 kg/hm and was significantly higher than A3B2 treatment. But A3B4 and A3B3 treatments had no significant differences. In autumn sowing, A3B4 treatment had the highest yield (8276.50 kg/hm²) but had no significant differences with A3B1 and A3B3 treatments. Accord- ing to the economic benefits, benefits of B2, B3 and B4 treatments were all higher than normal application treatment B1, and B3 treatment had the highest benefit, reaching 12 353.59 Yuan/hm², was 10.77% higher than B1 treatment. In general, proper density of Tianrun 189 was 48 000-54 000 plants/hm². Under this density, applying 750-900 kg/hm² slow release compound fertilizer (N-P2O5-K2O=24-6-10) could obtain better yield and economic benefit. [ABSTRACT FROM AUTHOR]

[Objective] To study the effects of different planting densities and varieties on the lodging resistance and yield of buckwheat. [Method] A two factor completely randomized block design was adopted with 5 varieties, 3 planting densities, and a total of 15 treatment. The lodging resistance traits of buckwheat under different treatments were measured, including the length and outer diameter of the first, second, and third internodes, center of gravity height, apparent lodging rate and stem snapping resistance. The differences in economic traits, such as plant grain weight, 100-grain weight and plot yield were compared. [Result] The apparent lodging rate of Xinong D4103 was significantly lower than that of other varieties, and the plot yield of treatment P5M3 was significantly higher than those of P1M3 and P3M3. However, there were no significant differences in the apparent lodging rate and yield between the same variety and different planting densities. The correlation analysis results showed that the apparent lodging rate of buckwheat was significantly positively correlated with plant height, center of gravity height, number of main stem nodes and length of the second internode. There was significant positive correlation between length of the third internode, outer diameter of the first internode and the apparent lodging rate of buckwheat. There was a significant positive correlation between plot yield and length of the first and second internodes. [Conclusion] The variety had significant impact on the apparent lodging rate and yield. Xinong D4103 had good lodging resistance and could be used as a material for future research on lodging resistant varieties. The highest yield was obtained with a planting density of 750 000 plants/hm² for the ZiTQ13-05 variety, which was suitable for planting in northern Shaanxi. [ABSTRACT FROM AUTHOR]

Here a dynamic model was developed on the tiller number of the rice population. The double Logistic model was also used to quantitatively analyze the dynamic process of the tiller occurrence and the extinction. A set of indicators was defined to describe the tillering dynamics, including the total number of growing tillers(Ng ), the total number of dead tillers(Nd ), the number of retained tillers(Nr ), the start time of tillering(Tst), the peak time of tillering(Tpt), the end time of tillering(Tet), the start time of tillers death(Tsd), the peak time of tillers death(Tpd), the end time of tillers death(Ted), the duration of tillering(Dt ), the duration of tillers death(Dd ), the inherent rate of tillering(Rit), the inherent rate of tillers death(Rid), the maximum tillering rate(Rmt), the maximum tillers death rate(Rmd). According to the temporal characteristics of the rice tillering, the formula was derived to calculate the indicators of the tillering dynamics. The goodness and adaptability of the model were tested with the dynamic datasets of the rice tillers under different genotypes, transplanting, sowing time, and transplanting density. The model and the indicators were used to explore the dynamic tillering response to the cultivation density. The results were as follows. (1) The model shared the better fitting for the dynamic dataset of rice tillers under different genotypes, transplanting, planting time, and transplanting density. The standard root mean square error (SRMSE) was followed by the Gamma distribution with the mean was less than 5% and and 99% SRMSE less than 10%. (2) The dynamic indicators and model parameters of tillers after calculation showed a better response to the cultivation density. Taking the planting density test of Huiliangyou 898 as an example, the number of tillers per unit area was accelerated and then slowed down after transplanting at 15 to 33.75 hills/m². The number of tillers per unit area reached the peak at 45-50 d after transplanting. After the peak, the number of tillers per unit area decreased rapidly and then slowed down slowly. There was no change in the number of tillers per unit area about 70 d after transplanting. Tpt and Tpd were about (26±3) d and (54±3) d after transplantation, respectively. An outstanding trend was achieved in the response of the tillering characteristic index to planting density. Except for Tpt and Tsd, the tillering characteristic index followed the power function. Ng, Rit, Nr, Ted, Dd, Rmt, and Rmd showed a power function increase with the increase of planting density, and the exponent of the power function was less than 1, indicating the slow-down trend. Tpt, Rid, Tst, Tet, and Dt also decreased as a power function with the increase of planting density. The exponent of the power function was greater than -1, that is, the decreasing rate gradually decreased with the increase in planting density. Nd increased as a power function with the increase of planting density, where the exponent of the power function was greater than 1, indicating the accelerated increase. Tpd and Tsd decreased with the increase of planting density and then increased gradually after reaching the minimum. (3) A better prediction was achieved, where the R² between the observed and simulated values were all 0.96. Therefore, the model can accurately describe the evolution in the number of rice tillers, indicating the better goodness of fitting, adaptability, and interpretability. The model can be applied to the dynamic regularity of the tiller number under the genotypic varieties and the agronomic measures. The tillering dynamic indicators can be expected to serve as the important phenotype in the interaction between genes and environments. [ABSTRACT FROM AUTHOR]

[Objective] The dry matter accumulation and distribution of Angelica pubescens were studied, to provide theoretical basis for rational close planting and scientific fertilization. [Method] The dry matter of aerial part ( stems and leaves) and root were measured in different growth periods, then create fit curve to predict and analyze. [Result] The dry matter accumulation could be fitted curve well with the increase of the number of days after transplant. Under different planting density, the dry matter accumulation variation trends were similar. With the increase of density, the individual average accumulation got smaller and smaller, the area yield was more and more big, and the profit increased first and then decreased. [Conclusion]On the cultivation of Angelica pubescens, the density should be used 75 933 plants/ hm². The fertilization should be divided into parts and applied in small quantities and several times, and a proper increase in nitrogen fertilizer, to help you get a higher yield. [ABSTRACT FROM AUTHOR]

To explore the optimum planting density and fertilizer application rate for buckwheat production in Baicheng. A randomized block design with 4 planting densities and 5 fertilization rates was used to study the effects of different planting densities and fertilization rates on agronomic traits and yield of buckwheat. Results showed that under the low planting density, plant height enhanced with the increase of fertilizer application amount. The number of main stem nodes among treatments had no obvious difference. The number of branches enhanced with the increase of fertilizer application amount at the low planting density of 750 000 plants/ hm², but the differences between treatments were not obvious. Under different densities, grain number per plant, grain weight per plant and 1 000-grain weight enhanced with the increase of fertilizer application under M1 treatment. The plant height enhanced with the increase of density at no fertilizer application, and decreased with the increase of density at 400 kg / hm² of fertilizer application. The number of branches did not change significantly among treatments. Thus, the optimum planting density of buckwheat in Baicheng was 1. 25 million plants/ hm² and the optimum fertilization amount was 300 kg / hm². [ABSTRACT FROM AUTHOR]

【Objective】To screen the suitable maize planting density and varieties in Hetao irrigation district of Inner Mongolia, and provide reference for the improvement of maize yield per unit area based on this.【Methods】The experiment was carried out in Bayannur City, Inner Mongolia from 2022 to 2023. A two-factor randomized block design was adopted, and the main treatment was plant density (D1: 90 000 plants/hm², D2: 97 500 plants/hm², D3: 105 000 plants/hm², D4: 112 500 plants/hm², D5: 120 000 plants/hm²), and varieties were sub-treated (Sitai 112, Lilong 170, Mingyu 268, Jinyuan 118). The effects of different densities on agronomic traits, yield components and yield of each maize variety were analyzed, and their economic benefits were calculated.【Results】At 5 densities, the reproductive growth of Sitai 112 was 3 days earlier than that of other varieties. At D3 density, Mingyu 268 plant height and ear height both were the highest, which were 3.18 and 1.33 cm, respectively. At D5 density, the lodging rate and hollow bar ratio of Mingyu 268 both were the highest, which were 30.40% and 14.21%, respectively. With the increase of density, the ear length of each variety gradually decreased and the values of Sitai 112, Lilong 170, Mingyu 268 and Jinyuan 118 reached the maximum at the density of D1, which were 20.10, 21.55, 18.75 and 20.85 cm, and there was no significant difference in ear diameter among varieties (P>0.05). At the density of D1 and D2, the yield and net income of Sitai 112 were highest, which were 14.68, 15.01 t/hm² and 27 394, 28 017 yuan/hm². At the density of D3 and D4, the yield and net income of Lilong 170 were highest, which were 17.09, 17.00 t/hm² and 32 504, 32 206 yuan/hm². At the density of D5, the yield and net income of Jinyuan 118 were highest, which were 13.13 t/hm² and 23 585 yuan/hm².【Conclusion】In Hetao irrigation district of Inner Mongolia, the high-yield cultivated varieties were Sitai 112 at 90 000 and 97 500 plants/hm², Lilong 170 at 105 000 and 112 500 plants/hm², and Jinyuan 118 at 120 000 plants/hm². [ABSTRACT FROM AUTHOR]

To explore the correlation mechanism of mung bean planting density and root morphology and photosynthetic characteristics in arid areas in northern Shaanxi, in this study, taking a characteristic mung bean variety Yulü1 in Hengshan district of Yulin city of Shaanxi province as the tested material, the random group design was applied to set up 3 planting densities including 5.70(D1), 6.60(D2), and 79 500 strains/ha(D3), and the influence of planting density on root morphology and leaf photosynthetic characteristics was analyzed. The results indicated that compared with the D2 and D3 treatments, the root length and root surface area of mung bean in the D1 treatment increased by 29% and 2% respectively. The net photosynthetic rate and transpiration rate of mung bean were generally W-shaped throughout the growth period, there was no significant differences between the 3 treatments. Intercellular CO2 concentration reached its maximum during the bulge phase, D2 and D3 treatment increased the intercellular CO2 concentration by 14% and 27% respectively compared with D1 treatment. Under 3 treatments, plant height, stem diameter, and biomass all showed a slight decrease with the increase of planting density, there was no significant differences between the treatments. Compared with the D2 and D3 treatments, D1 treatment increased yield of mung bean by 5% and 32%, respectively. Correlation analysis found that net photosynthetic rate and stomatal conductivity were extremely significantly positively correlated with transpiration rate, respectively, and yield was significantly positively correlated with root mass and was extremely significantly positively correlated with stem mass, respectively. In conclusion, different planting densities could regulate the root morphology, which could significantly optimize and regulate the photosynthetic physiological characteristics at the flower pod stage, change the accumulation and distribution of dry matter in roots, stems, and leaves, promote the transfer of dry matter to grains, and then promote the increase of mung bean yield. Therefore, after comprehensive comparison, when the planting density of the mung bean variety Yulü 1 was 5.70 10 000 plants/ha, it was the most suitable for planting in the arid areas in northern Shaanxi. [ABSTRACT FROM AUTHOR]

Cotton photosynthetic efficiency and the root–shoot relationship are two important physiological indexes affecting the final yield, but the interactive effects of plastic film mulching and planting density on the cotton photosynthetic efficiency and root–shoot relationship have rarely been reported. We aimed to investigate the optimal plant density with or without plastic film mulching for improved seed cotton yield in southern Xinjiang. Therefore, a two-year field experiment was conducted to investigate the effects of plastic film mulching (with or without plastic film mulching) and planting density (D1: 9 × 104 plants ha−1; D2: 18 × 104 plants ha−1; D3, 22 × 104 plants ha−1, local conventional planting density; D4, 27 × 104 plants ha−1) on the cotton root–shoot relationship, photosynthetic parameters, and seed cotton yield. Our results showed that the seed cotton yield was improved under plastic film mulching at all planting densities, but economic income was significantly lower in comparison to without plastic film mulching in 2023. Compared with D3, seed cotton yield and economic income at D2 increased by 6.9% and 12.2%, either with or without plastic film mulching, respectively. The highest increase in the seed cotton yield in D2 under plastic film mulching was due to the greatest improvements in the root production capacity and photosynthesis. The boll capacity of the root system (BCR) and boll loading of the root system (BLR) in D2 were the highest among all treatments with film mulching, being 9.0% and 16.9% higher than that in D3 in 2022 and 2023. However, the root–shoot ratio (R/S) was 7.1% and 6.9% lower in D2 than D3, under film mulching, in 2022 and 2023. Moreover, moderate plant density (D2) improved the SPAD value, chlorophyll fluorescence (Fv/Fm and PIabs), and photosynthetic parameter (Pn, Tr, and Gs) and decreased Ci compared with other planting density treatments in both years. Further analyses with correlation analysis showed that the seed cotton yield was highly positive correlated with BLR, BCR, and the photosynthetic parameter. In summary, suitable planting density (18 × 104 plants ha−1) combined with plastic film mulching has the potential to obtain high yields by enhancing the efficiency of photosynthetic assimilates, improving the capacity of cotton root production, providing a reference for suitable planting density under plastic film mulching. [ABSTRACT FROM AUTHOR]