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【Background】 Excessive application of nitrogen fertilizer is often used by farmers in China as an insurance to guarantee winter wheat yield despite its detrimental impact on the environments such as leaching to groundwater and development of eutrophication. Breeding new varieties with improved nitrogen use efficiency is an alternative to sustain wheat production without compromising the environment. 【Objective】 The objective of this paper is to experimentally compare the difference in nitrogen uptake and translocation between different varieties of winter wheat in response to nitrogen fertilization in the loess plateau of China. 【Method】 The experiment was conducted from 09/2018 to 07/2019 at Taigu experimental station of Shanxi Agricultural University. We compared six cultivars: Liangxing 99, Hanmai 13, Shannong 22, Liangxing 77, Yannong 999 and Shannong 29. Added to each cultivar was two nitrogen fertilizations: 150 kg/hm2 and 270 kg/hm2. In each treatment, we analyzed the relationship between wheat yield and N use efficiency (NUE) as well as N translocation. 【Result】 The varieties Shannong-29, Hanmai-13 and Yannnong-999 were more N-use efficient. Compared with other three varieties, they saw a significant increase in N accumulation in grains and pre-anthesis N translocation and post-anthesis N accumulation; their grain yield and NUE thus increased by 17.85%~22.35% and 9.20%~12.31%, respectively, due to the increased N uptake from the 20~200 cm soil. Fertilization also affected N translocation and accumulation. For the three N-efficient varieties, increasing N application from 150 kg/hm2 to 270 kg/hm2 significantly reduced N accumulation in stem, sheath, leaves and the grains, but boosted pre-anthesis N translocation in stem, sheath and leaves, and post-anthesis N accumulation in the grains. These combined to increase average grain yield and NUE by 11.98% and 4.89%, respectively. For the varieties with low N use efficiency, increasing N application also boosted N accumulation in their grains though not as significant as in other varieties. For the same variety, its yield, NUE and N content in the grains were all positively correlated with pre-anthesis N translocation, especially for the varieties with high NUE. 【Conclusion】 Wheat varieties with high NUE gave high yield because they are more efficient to translocate N from organs to the grains. Pre-anthesis N translocation in stem, sheath and leaves can be used as a proxy for NUE. In terms of fertilization, increasing N fertilizer application from 150 kg/hm2 to 270 kg/hm2 can promote yield and NUE, especially the varieties with high NUE.

The application of nitrogen (N) improves the winter wheat yield. Excessive N application affects winter wheat yields, leading to low net incomes and negative environmental impacts, therefore, optimizing N application is essential. In this study, the effects of N rates on crop growth yield, net income (NI), water use efficiency (WUE), and nitrogen use efficiency (NUE) in the irrigated districts of the eastern loess plateau, China, were investigated using seven N application rates (N0, N90, N180, N210, N240, N270, and N300 kg ha−1) during the 2016–2017 and 2017–2018 seasons. N application significantly increased the total water consumption at 0–200 cm during the growth period, the aboveground dry matter at maturity, the grain nitrogen accumulation, yield, NI, and WUE. However, N exceeding 240 kg ha−1 did not favor dry matter and nitrogen accumulation or translocation from the anthesis stage to the maturity stage, thus leading to reduced yield, NI, and WUE. The transpiration rate and stomatal conductance N240 was highest 21–28 day after anthesis, at 187–276 kg ha−1, which can achieve a high yield and profitability with relatively low environmental costs. [ABSTRACT FROM AUTHOR]

Precipitation is the major cause of crop yield variation in rainfed agriculture production in the Loess Plateau. As over fertilization is economically and environmentally undesirable, and crop yield and the resulting returns for N input are uncertain when rainfall variability is high, optimizing N management according to precipitation during fallow season is vital for efficient crop water use and high yield in dryland rainfed farming systems. Results show that the nitrogen treatment rate of 180 treatment significantly increased the tiller percentage rate, and the leaf area index at anthesis, the jointing anthesis, anthesis maturity dry matter, and nitrogen accumulation was closely related to yield. N150 treatment compared to N180 treatment significantly increased the percentage of ear-bearing tiller by 7%, dry substance accretion from jointing to anthesis by 9%, and yield by 17% and 15%, respectively. Our study has important implications for the assessment of the effects of fallow precipitation, as well as for the sustainable development of dryland agriculture in the Loess Plateau. Our results indicate that adjusting N fertilizer inputs based on summer rainfall variation could enhance wheat yield in rainfed farming systems. [ABSTRACT FROM AUTHOR]

This study aims to understand the influence of chlorophyll fluorescence parameters on the yield of winter wheat in some areas of China. Nitrogen (N) application is believed to improve photosynthesis in flag leaves, ultimately increasing the final yield. The results from different parameters of research showed that the grain number per spike improved by 12.2% and the 1000-grain weight by 7.3%, respectively. At 20–30 days after anthesis, the activities of superoxide dismutase (SOD), peroxidase (POD), and soluble protein in flag leaves of N150 were found to be the most effective. The grain yield under N manure partial substitution for N fertilizer treatment increased by 23 and 15%, respectively. The important implications of photosynthetic characteristics of variable fluorescence yield of the light-adapted state are that the contents of clear, ball, alcohol soluble, gluten, protein, and flour quality showed an increasing trend, while the contents of amylose, amylopectin, total starch, and direct/branch ratio were decreased of wheat. The net photosynthetic rate, transpiration rate, and relative chlorophyll content of wheat. The outcome of the present investigation suggests that chlorophyll fluorescence parameters could be a valuable insight into understanding yield stability under stress conditions. Moreover, the investigated parameters could be useful criteria for the selection of photosynthetic energy under varying nitrogen application levels. [ABSTRACT FROM AUTHOR]

The current study was designed to investigate the best sowing method that encourages dry matter accumulation to increase dryland wheat yield, grain quality, and protein content. Three different seeding methods were applied: (I) wide-space sowing (WSS), (II) furrow sowing, and (III) drill sowing. Two nitrogen levels, namely low nitrogen (N1) and high nitrogen (N2), were also applied, and the pure nitrogen was 150 kg ha−1 and 210 kg ha−1, respectively. Wide-space sowing significantly increased the ears and yield production, the maximum, and average grain-filling rate while furrow sowing delayed the disappearance of the population after anthesis, increased the duration of grain filling, and then significantly increased the number of spikes and the 1000-grain weight increased, respectively. Drill sowing compared to wide-space sowing significantly increased the content of nitrogen in the grain of the nitrogen harvest index, and it increased the content of protein and the yield of protein, respectively. In addition, the grain yield and protein yield of wide-precision sowing were significantly higher than that of trench sowing. Our findings suggest that wide-space sowing was beneficial for increasing water consumption during the growth period, increasing the tiller dynamics, improving the plant dry matter quality, and increasing the grain protein. [ABSTRACT FROM AUTHOR]

This study aims to understand the influence of chlorophyll fluorescence parameters on the yield of winter wheat in some areas of China. Nitrogen (N) application is believed to improve photosynthesis in flag leaf, which ultimately increases the final yield. The experiment was conducted in the wheat experimental base of Shanxi Agricultural University in Taigu, Shanxi Province, China; before sowing, four N application rates were set—N0, N120, N150, and N210 kg ha–1 of the Yunhan-20410 variety from 2019 to 2022. The results from different parameters of research showed that the organic manure partial substitution for chemical fertilizer increased post-anthesis N uptake by 16.4 and 81.4%, thus increasing the post-anthesis photosynthetic capacity and delaying leaf senescence. N150 treatment can improve dry matter (DM) accumulation, thus promoting the increase of the yield. The maximum net photosynthesis PN value of the booting stage and flowering stage indicated that nitrogen application could significantly improve the photosynthetic rate of wheat leaves, among which medium nitrogen treatment had the most significant promoting effect. The single-photon avalanche diode (SPAD) value of the leaf of wheat in each treatment increased rapidly in a small range from the jointing stage to the booting stage, respectively. The grain yield under N fertilizer partial substitution for N fertilizer treatment increased by 23%. According to the different significance test, the effects of nitrogen application rate on net photosynthesis PN of winter wheat were extremely significant at all growth stages, indicating that changing the population distribution mode and nitrogen level could effectively improve leaf photosynthetic performance and that N150 level was the best. [ABSTRACT FROM AUTHOR]

To evaluate the effects of long-term fallow tillage on soil microbial community structure in different soil layers and winter wheat yield, we conducted a 5-year long-term field experiment in the Loess Plateau, China, using three fallow tillage methods: no-tillage (NT), subsoiling tillage (ST), and deep plowing (DP). The soil physical and chemical properties, community structure, and composition of soil bacteria and fungi in the 0–20 cm and 20–40 cm soil layers, and winter wheat yield were analyzed. The results showed that, compared with DP, NT and ST significantly increased soil moisture content (SWC), soil organic carbon (SOC) content, and dissolved organic carbon (DOC) contents in 0–20 cm soil layer (p < 0.05), and significantly increased soil microbial community Shannon and Simpson index in 0–40 cm soil layer (p < 0.05). Compared with NT, ST and DP significantly increased SWC and SOC contents in 20–40 cm soil layer (p < 0.05). Actinobacteria and Ascomycota were the most abundant bacteria and fungi in the soil of the experimental site. Redundancy analysis further showed that soil physicochemical properties (SWC, SOC, DOC, and DON) were closely related to the microbial community. PICRUSt2 prediction results showed that DP increased the metabolic functional diversity of bacteria and fungi. ST and DP significantly increased the yield of winter wheat, and DP had the best effect. In conclusion, subsoiling tillage and deep plowing were beneficial to the accumulation and utilization of natural precipitation and the improvement of soil microbial community structure. Deep plowing was beneficial to the decomposition and metabolism of straw and organic fertilizer, and improved the catabolic ability of microbial community, thus increasing the yield of winter wheat. [ABSTRACT FROM AUTHOR]

Background: About 60% of the annual precipitation in the Loess Plateau occurs during the summer fallow season, and does not align with the wheat growing season. In addition, the nitrogen use efficiency is low in this area because nutrient availability is affected by drought. As a result, rainwater storage during the summer fallow season is very important to increasing nitrogen use efficiency, and to the stable production of dryland wheat in the Loess Plateau. Methods: A 3-year field experiment in the eastern part of the Loess Plateau was conducted with two tillage methods (no tillage (NT) and deep ploughing (DP)) and five N rates (0, 120, 150, 180, and 210 kg N ha-1) to study the effect of tillage on soil water utilization, plant nitrogen utilization, and wheat yield. Result: Compared to NT, DP showed a larger increase in soil water storage (SWSf) and precipitation storage efficiency (PSEf) during the two dry summer fallow seasons than in the normal summer fallow season. DP substantially increased the pre-anthesis soil water consumption (SWCpre) and N translocation. The average yield under DP was 12.46% and 14.92-18.29% higher than under NT in the normal and dry seasons, respectively. A 1 mm increase in SWCpre could increase grain yield by 25.28 kg ha-1, water use efficiency (WUE) by 0.069 kg ha-1 mm-1, and nitrogen utilization efficiency (NUtE) by 0.029 kg kg-1. DP could reduce the N rate by 11.49-53.34% in the normal seasons and 40.97-65.07% in the dry seasons compared to the same highest point of yield, WUE, and NUtE under NT. Conclusion: Deep ploughing in the summer fallow season, paired with optimized N application, could help increase wheat yield and nitrogen efficiency in dryland. [ABSTRACT FROM AUTHOR]