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Reasoned fertilization practices promote fertilizers formula adjusted to the crop's needs and increase production and income. In this study, two agronomic tests were carried out on two sites named Tabligbo (site 1) and Djikame (site 2) on degraded sandy loam soils situated in the south of Togo using inorganic and organic fertilizer quantities obtained from reasoned fertilization. An indigenous variety of Abelmoschus esculentus was used and five treatments were applied: T2: mineral fertilizer (667 kg/ha), T3: waste compost (6126 kg/ha at Tabligbo and 7260 kg/ha at Dzikame), T4: mineral (333.50 kg/ha) + compost fertilizers (3063 kg/ha for site 1 and 3630 kg/ha for site 2), control (T0) and smallholder farmers' old fertilization practices (T1). At Tabligbo, treatments T2 and T4 stimulated quick growth (74,5 ± 03.50 cm) and the highest number of fruit was obtained on T4 treatment (102 ± 09). At Djikame, treatments T2 and T3 presented the highest growth (65.82 ± 2.51 cm) and the T4 treatment gave the best number of fruits (72 ± 4.00). Economic Efficiency and Cost-Value Ratio were high on the T4 formula on Tabligbo soil (53.48% and 1.85). At Djikame, treatment T2 presents the highest value of economic parameters (24.52% and 01.35). Among treatments tested, T4 (compost + mineral fertilizer) is the effective treatment on Tabligbo sandy loam soil for okra production while the T2 (mineral fertilizer) option is the best for okra production on site 2 due to the low content in nitrogen increasing C/N ratio. The effective fertilizer formulas discovered in this study will be shared with farmers in the study areas in order to improve market garden crop production in South Togo. [ABSTRACT FROM AUTHOR]

Controlled release fertilizers (CRFs) mitigate negative effects of high nitrogen (N) fertilization rates, such as N toxicity and soil N loss. However, it is unknown if potentially toxic rates of CRF and quick release fertilizer differentially affect soil bacterial communities. To examine potential N toxicity effects on soil microbial communities, we grew tomato (Solanum lycopersicum "Rutgers") for eight weeks in soils that were fertilized with high levels of quick release or controlled release urea and in soils with either low or high initial microbial N competitor populations. In both soils, we observed N toxicity in urea-fertilized tomatoes, but toxicity was ameliorated with CRF application. Controlled release fertilization increased soil N retention, thereby reducing soil N loss. While N toxicity symptoms manifested in the plant, the soil microbiome was only minorly affected. There were subtle differences in soil bacterial populations, in which nitrifying bacteria accumulated in soils fertilized at high N rates, regardless of the type of N fertilizer used. Ultimately, CRF reduced plant N toxicity symptoms but did not change the soil microbiome compared to quick release urea. These results show that while there are clear benefits of CRF regarding N toxicity tolerance on crops, the soil microbiome is resilient to this abiotic stressor. [ABSTRACT FROM AUTHOR]

In a field experiment from 2020-2023 on the southern chernozems of the Odessa region of Ukraine, we studied the effect of the doses and timing of mineral nitrogen application when growing winter peas on the tuberization process and crop productivity. Mineral nitrogen in doses of 30, 45 and 60 kg/ha in the form of ammonium nitrate was applied in different development phases of winter peas under seedbed cultivation: foliar top dressing with urea solutions during the resumption of spring vegetation, the budding phase and the beginning of grain filling. Winter pea of the Enduro variety was sown annually on October 20, with a row spacing of 15 cm and a rate of 1.2 million germinating seeds per hectare. The previous crop was winter wheat. The conditions of the Southern Steppe of Ukraine for winter sown peas were shown for the first time. The introduction of mineral nitrogen at a rate of 30-60 kg/ha into the soil during sowing inhibited the formation of nodules from the active spring growth phase. The mass of nodules on the roots of pea plants decreased by 30-50% compared to the control variant without nitrogen application. The same norms of mineral nitrogen introduced in early spring during the resumption of vegetation on the leaf in the form of aqueous solutions did not have a negative impact on tuberization. The correlation coefficient between the dose of mineral nitrogen and the number and weight of nodules did not exceed 0.37, indicating a weak relationship between these indicators. The share of influence of mineral nitrogen norms did not exceed 13.7%. With this method of application, the nitrogen content in the vegetative mass of winter peas exceeded the control variant by 18-27%. [ABSTRACT FROM AUTHOR]

The second half of the nineteenth century was marked by the concomitant and entangled processes of the rise of agricultural chemistry and that of the fertiliser trade. Yet, while the two were undoubtedly related, the work of agricultural chemists was not necessarily characterized by the uniform and unequivocal promotion of fertilisers. This article looks at some of the complex ways in which chemists participated in the development of the fertiliser trade by studying how their work was used to ascribe a commercial price to a chemical element. It analyses the contested development of the idea that nitrogen, in particular, could be given a price, and shows how the rise of this quotation lay at the intersection of scientific and commercial considerations. More broadly, it argues that the importance of the new artificial fertilisers primarily lay not so much in yield increases as in inaugurating a new regime marked by a more comprehensive quantitative assessment of inputs and outputs, thereby playing a key role in the industrialisation of agriculture. [ABSTRACT FROM AUTHOR]

A field experiment was conducted at College of Agriculture, Hassan during kharif 2018 to study the growth, yield and quality parameters of fodder oats (Avena sativa L.) under varied dates of sowing and nitrogen application. The experiment was conducted on red sandy loam soil and the experiment was laid out in a factorial RCBD with 10 treatment combinations, which consisted of five different dates of sowing and two nitrogen levels replicated thrice. The results revealed that sowing during first fortnight of June recorded significantly higher plant height (133.42 cm), number of tillers (93.80) 0.5 m-1 row length, leaf to stem ratio (0.76), leaf area (3,766 cm2 0.5 m-1 row length), dry matter accumulation (97.73 g 0.5 m-1 row length) and SPAD readings (29.83), green fodder yield (28.88 t ha-1), dry fodder yield (5.79 t ha-1) crude protein (6.39%), B:C ratio (2.32) as compared to other dates of sowing. Application of 125 kg N ha-1 recorded significantly higher leaf to stem ratio (0.57), SPAD readings (25.46), leaf area (3,151 cm2 0.5 m-1 row length) green fodder yield (23.57 t ha-1), uptake of nitrogen, phosphorous and potassium (96.80 kg ha-1, 16.86 kg ha-1 and 82.11 kg ha-1, respectively) gross returns (Rs.47156/- ha-1) and net returns (Rs.22279/- ha-1) as compared to 100 kg N ha-1. [ABSTRACT FROM AUTHOR]

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Copyright of Cientifica is the property of Fundacao de Apoio a Pesquisa e Extensao 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.)

Core Ideas: The milpa marceña is an ancient maize agrosystem on herbaceous wetlands "popals" in the dry season.Three improved maize cultivars and the traditional cultivar mején were evaluated.The mején cultivar showed the highest performance.The milpa marceña is compatible with the hydrological dynamics of wetlands and without the use of industrial inputs. Although herbaceous wetlands are one of the most productive ecosystems and their functions provide benefits to humankind, they have been subjected to a number of disturbances over the past 65 yr. Wetlands have been drained to convert them into permanent agricultural land and urban areas, or used by the oil industry or for construction of hydroelectric dams. Moreover, little has been done to innovate the milpa marceña, an ancient maize (Zea mays L.) agrosystem on herbaceous wetlands dominated by hojilla (Thalia geniculata f. rheumoides) named popals in the dry season (March–June). From an agroecological perspective for improving milpa marceña, in a popal soil (Eutric Molic Gleysol), three improved maize cultivars (CP‐560, CP‐561, and CP‐562) and the traditional cultivar mején were evaluated under three planting densities (50,000, 53,000, and 60,000 plants ha–1) with no use of mineral fertilizers, herbicides, or pesticides. The results show that precipitation during the milpa marceña growth cycle was 50% lower than the amount required for a successful maize crop (>1 Mg ha–1), hence avoiding the risk of flooding. Maize cultivars take groundwater and nutrients from popal soil; however, these results suggest that cultivars were subject to N deficiency and water stress in the flowering stage. We concluded that the mején cultivar showed the highest performance, with 3.3 Mg ha–1, i.e., it has attributes not previously considered (e.g., plant × microbe interactions) in plant breeding programs for drought‐tolerant or flood‐tolerant cultivars. There is a need for further research and conservation on the use of popals. [ABSTRACT FROM AUTHOR]

Core Ideas: Decreased atmospheric deposition has led to increased S consumption in winter wheat.Sulfur did not increase yield or grain N concentration at any site.Use of recommended soil testing guides are encouraged. Decreased atmospheric S deposition in the past 20 yr has led to increased S fertilizer consumption in winter wheat (Triticum aestivum L.). Producers often apply S without any soil test information. Experiments were conducted at Lahoma, Lake Carl Blackwell, and Perkins, OK (2011–2013) to assess the effect of N and S applied preplant and foliar on grain yield and grain N for winter wheat. In 2011–2012, urea ammonium nitrate (UAN) was applied preplant at rates of 40 and 80 kg N ha−1 additionally; UAN and urea‐triazone (NSURE) were foliar‐applied at rates of 10 and 20 kg N ha−1. Sulfur was foliar‐applied as gypsum (CaSO4⋅2H2O) at 6 kg S ha−1. In 2013, trials were altered to apply 40 kg N ha−1 as UAN preplant, and 20 kg N ha−1 foliar‐applied. Gypsum rates were adjusted at 0, 3, and 6 kg S ha−1 preplant, and S (MAX‐IN‐S) at 3 and 6 kg S ha−1 was foliar‐applied. Sulfur did not increase grain yield or grain N concentration at any site. The interaction between foliar S and N and preplant S and N was not significant. Sulfur fertilizer application is less likely to benefit this region unless low levels of soil test S are identified before planting. Use of recommended soil‐testing guides are encouraged. Although S applications are encouraged commercially, no response was observed in these trials, and all were on sites where soil organic carbon was low (<8.5 g kg−1), where the possibility of seeing S deficiency was greater. [ABSTRACT FROM AUTHOR]

Core Ideas: Cereal N use efficiency was estimated at 35, 41, 30, and 21% for the world, the United States, China, and India, respectively.There was a trend for increased N fertilizer consumption for agricultural use.Best N fertilizer management practices could improve N use efficiency. Two decades ago, world cereal nitrogen use efficiency (NUE) was documented at 33%. Since then, research addressing NUE has advanced. However, there are no current estimates to communicate whether or not research efforts and recent advances have contributed to improved NUE. With the apparent trends for increasing greenhouse gases, NUE values could be used as a management tool for agronomic and environmental sustainability. Our objective was to provide current estimates and trends of NUE for the world and selected countries for cereal crops cultivated in relatively large quantities. Data from the Food and Agriculture Organization (www.fao.org/faostat) website were used to compute NUE. The difference method was employed to derive NUE and trends. Results indicated that cereal NUE in 2015 was 35, 41, 30, and 21% for the world, the United States, China, and India, respectively. Compared with 33% reported in 1999, there was insignificant trend of increase (r2 = 0.01) from 2002 to 2015 for cereal world NUE (p > 0.05). Low NUE for China and India was due to high N consumption. A slight improvement for the United States from 31% in 2002 to 41% in 2015 (r2 = 0.20) could be a result of using improved cultivars and precision crop management. Increasing cereal NUE in the United States echoes the value of new technologies and the heightened importance of the environment. Recognizing year‐to‐year variability in N fertilizer requirement and implementing a systematic approach that combines agronomic recommendations with improved crop varieties could further improve NUE. [ABSTRACT FROM AUTHOR]

Core Ideas: Grassland is a widespread agroecosystem in the globe; however, not enough attention has been given to link grazing management to soil health.Grazing management practices greatly impact soil quality.Moderate stocking rate are more adequate to keep grassland stability. Pasture management affects soil physical–chemical properties and root depth distribution. Adjusting grazing pressure and N fertilization are key management tools affecting these responses. This study evaluated the effect of N fertilization and stocking rate (SR) on soil physical and chemical attributes and root depth distribution in grazed elephantgrass (Pennisetum purpureum Schum. cv. 381) pastures (2009 and 2010). Treatments consisted of three SR (2.0, 3.9, and 5.8 AU ha−1; 1 AU = animal unit = 450 kg body weight) and three N doses (0, 150, and 300 kg N ha−1 yr−1) on elephantgrass pastures. Response variables included soil bulk density (BD), particle density (PD), total porosity (TP), aggregate stability (AS), water infiltration rate (WIR), light fraction of soil organic matter (LF‐SOM), soil fertility, root length density (RLD), and root biomass. Increased SR resulted in greater BD. Soil bulk density ranged from 1.42 to 1.58 g cm−3 for SR ranging from 2.0 to 5.8 AU ha−1, respectively. The C concentration of the LF‐SOM decreased with increasing SR, ranging from 383 to 174 mg C kg−1 soil. Soil fertility, RLD, and the stock of C and N in the root system varied among soil layers. At the end of 2 yr, SR and N fertilization did not affect TP, WIR, and AS nor influenced soil fertility and root system distribution. Overgrazing led to soil compaction and reduced LF‐SOM, indicating a trend of pasture degradation. Moderate SR resulted in greater LF‐SOM, indicating a positive trend for C accumulation in the long term. [ABSTRACT FROM AUTHOR]

Core Ideas: Limited information is available concerning the effects of nitrogen (N) and golf cart traffic rates on buffalograss roughs.Increasing the N rate, especially from 0 to 1 or 1 to 2 lb N/1000 ft2/year, will increase the ability of buffalograss to better withstand traffic stress from golf carts in traffic situations.Increased late season percent green turfgrass cover and turfgrass quality were observed when applying 2 lb to 3 lb N/1000 ft2/year on buffalograss roughs.Buffalograss was able to maintain adequate green cover and acceptable quality with traffic rates up to 4 traffic passes/week. Buffalograss [Buchloë dactyloides (Nutt.) Engelm.] is increasing in popularity for use in golf course roughs in semiarid climates of the transitional climatic zone due to its low water requirements. Limited information is available concerning the effects of nitrogen (N) and golf cart traffic rates on buffalograss roughs. The objective of this study was to determine the influence of N rate and repeated simulated golf cart traffic on buffalograss maintained at golf course rough mowing height. Three field trials were initiated in July 2014 and 2015 in Manhattan, KS on 'Cody' buffalograss. Treatment factors were four N application rates (0, 1, 2, and 3 lb N/1000 ft2) and five traffic application rates (0, 2, 4, 8, and 16 passes/week) with a custom‐built golf cart traffic simulator. Regardless of traffic rate, as N rate increased, percent green cover (PGC), visual turf quality (VQ), and turf color increased. Results from this study indicate that an increase in N rate, especially from 0 to 1 lb N/1000 ft2/year and from 1 to 2 lb N/1000 ft2/year will increase the ability of buffalograss to better withstand traffic stress during the summer. Although, there may be minimal benefits of applying above 2 lb N/1000 ft2/year on buffalograss roughs. As traffic rate increased, regardless of N rate, buffalograss PGC, VQ, and turf color decreased, especially at 8 and 16 passes/week. Generally, buffalograss was able to maintain adequate PGC and acceptable VQ with traffic rates up to 4 traffic passes/week. We recommend that buffalograss turf managers carefully monitor traffic on buffalograss, especially in high traffic areas in the rough. Results show trafficked buffalograss can maintain adequate PGC and VQ when maintained at varying N levels. [ABSTRACT FROM AUTHOR]

Core Ideas: Soybean leaf senescence and maturation, yield, and seed quality were minimally impacted by soil and foliar‐applied nitrogen.Cultivar differences in maturation, yield, and seed quality were evident.The use of NDVI is an effective technique to describe soybean leaf senescence during maturation. Ohio producers often question whether fertilizing soybeans [Glycine max (L.) Merr.] with nitrogen (N) will increase yield. Foliar‐ and soil‐applied N have been evaluated throughout the Midwestern US, but few studies have compared the response of commercially available foliar N applications to soil‐applied N within the same environments. Additionally, there is limited information on the impacts of N application on soybean maturation and leaf senescence. The objectives of this study were to: (i) evaluate the effect of various rates of soil‐ and foliar‐applied N at different growth stages on the maturation of soybeans; and (ii) quantify the effect on soybean yield and quality (protein and oil) of soil and foliar N application. A field study was conducted in 2017 at two Ohio locations using a randomized complete block design with full factorial of soybean cultivar (one Maturity Group II and one Maturity Group III) and N application treatment (unfertilized control and four N applications varying in source, rate, and timing). The maturity date, yield, and quality varied among cultivars. Leaf senescence was impacted by weather conditions to a greater extent than N application. Maturity date was impacted by N application, but all treatments matured within 1 day of one another and were similar to the untreated control. The N treatments had minimal effects on leaf senescence, yield, seed protein, and seed oil. Future studies should focus on expanding these results in additional environments and with more N application treatments. [ABSTRACT FROM AUTHOR]

High ozone (O3) can cause great damage to plants. However, the effect of high O3 on nitrogen (N) absorption, distribution, and utilization in rice at different growth stages under different planting densities is poorly understood. In the present study, a conventional cultivar (Yangdao 6) and a hybrid cultivar (II You 084) with different planting densities were exposed to an elevated amount of O3 (E-O3; 50% higher than that of the control, C-O3) under a freeair gas concentration enrichment (FACE) system. N absorption, distribution, and utilization of the green leaves, stems, and shoots at tillering, jointing heading, and maturity were investigated. Results showed that E-O3 significantly increased the N content in the shoots of Yangdao 6 by 7.5%, 12.7%, and 19.6%, respectively, at jointing, heading, and maturity. Also, the N content in the shoots of II You 084 increased by 5.4%, 6.5%, and 8.4% at the corresponding growth stage upon E-O3 application. E-O3 significantly decreased N accumulation of II You 084 by 8.3%, 4.9%, 4.7%, and 19.2%, respectively, at tillering, jointing, heading, and maturity. Further, E-O3 had a decreasing effect on the N distribution in green leaves (p ≤ 0.05) of both cultivars, but exerted an increasing effect on that in the stems of both cultivars (p ≤ 0.05). In addition, E-O3 significantly decreased the N use efficiency (NUE) for biomass of the two cultivars in all growth stages. These results revealed that E-O3 could increase the N content in rice plants but decrease the N accumulation and utilization in both cultivars. The effects of E-O3 on N absorption, distribution, and utilization were not affected by planting density. [ABSTRACT FROM AUTHOR]

Abstract Indirect N 2 O emissions from agricultural nitrogen (N) leaching and runoff in water bodies contribute significantly to the global atmospheric N 2 O budget. However, considerable uncertainty regarding this source remains in the bottom-up N 2 O inventory. Indirect N 2 O emission factor associated with N leaching and runoff (EF 5 ; kg N 2 O N per kg of NO 3 −−N) incorporate three components for groundwater and surface drainage (EF 5g), rivers (EF 5r), and estuaries (EF 5e). The 2006 IPCC default EF 5 value was based on a small number of studies available at the time. Here we present the synthesis of 254 measurements of EF 5 , dissolved N 2 O, and nitrate from 106 studies. Our results do not support the further downward revision of EF 5g by the IPCC and suggest an upward revision of EF 5g of 0.0060. The emission factors for groundwater and springs (0.0079) was higher than that for surface drainage (0.0040). The emission factor for lakes, ponds, and reservoirs was 0.0012, whereas that for rivers was 0.0030, and a combined EF 5r was 0.0026. Estimated EF 5r and EF 5e (0.0026) values from the study were close to the current IPCC default values (0.0025 each). We estimated an updated default EF 5 value of 0.01 for the refinement of IPCC guidelines. Graphical abstract Image 1 Highlights • We summarized 254 field data on indirect emission factor from N leaching and runoff. • Mean emission factor (EF) for ground water and surface drainage (EF 5g) was 0.0060. • Mean EF for lakes, ponds & reservoirs, and rivers (EF 5r) was 0.0026. • Mean EF for estuaries (EF 5e) was 0.0026. • Combined EF (EF5) was 0.01, higher than IPCC 2006 default EF (0.0075). We summarized 254 field datasets and estimated indirect N 2 O emission factor from leaching and runoff of agricultural N (EF 5) of 0.01, higher than IPCC 2006 default EF (0.0075). [ABSTRACT FROM AUTHOR]

Herbivore damage by chewing insects activates jasmonate (JA) signalling that can elicit systemic defense responses in rice. Few details are known, however, concerning the mechanism, whereby JA signalling modulates nutrient status in rice in response to herbivory. (15NH4)2SO4 labelling experiments, proteomic surveys, and RT‐qPCR analyses were used to identify the roles of JA signalling in nitrogen (N) uptake and allocation in rice plants. Exogenous applications of methyl jasmonate (MeJA) to rice seedlings led to significantly reduced N uptake in roots and reduced translocation of recently‐absorbed 15N from roots to leaves, likely occurring as a result of down‐regulation of glutamine synthetase cytosolic isozyme 1–2 and ferredoxin–nitrite reductase. Shoot MeJA treatment resulted in a remobilization of endogenous unlabelled 14N from leaves to roots, and root MeJA treatment also increased 14N accumulation in roots but did not affect 14N accumulation in leaves of rice. Additionally, proteomic and RT‐qPCR experiments showed that JA‐mediated plastid disassembly and dehydrogenases GDH2 up‐regulation contribute to N release in leaves to support production of defensive proteins/compounds under N‐limited condition. Collectively, our results indicate that JA signalling mediates large‐scale systemic changes in N uptake and allocation in rice plants. Exogenous methyl jasmonate applications significantly inhibited N uptake in rice roots and N‐assimilating enzymes, mediated plastid disassembly, and reduced N translocation from roots to leaves. Jasmonate signalling mediates large‐scale systemic changes in N uptake and allocation in rice plants. [ABSTRACT FROM AUTHOR]

For 50 years, UC Agriculture and Natural Resources (UC ANR) has contributed to dairy water quality policy in California and helped, with partner organizations, to implement it in the dairy industry. When conditional waivers for waste discharge requirements expired in 2003, UC ANR shared research and best professional practices as regional water quality control boards developed new orders. UC ANR academics then worked with water quality control boards' staff and dairy industry representatives to develop feasible, staged implementation plans. Collaboratively, more than 50 hours of workshop curriculum were developed and disseminated, helping dairy producers to accept scientifically sound management practices that are more protective of groundwater. Research by UC ANR to better understand system dynamics, nitrogen management and practices to minimize the impact of manure application on groundwater quality continues, as does a program in environmental stewardship. [ABSTRACT FROM AUTHOR]

Field experiments were conducted to investigate the influence of varying levels of water and nitrogen at grain filling stage on 2-acetyl-1-pyrroline (2-AP) content, enzymes activities and grain yield of fragrant rice (Oryza sativa L.). Two fragrant rice cultivars i.e., 'Basmati 385' and 'Nongxiang 18', were grown under two water treatments i.e., W1: well-watered (water layer 4-6 cm) and W2: mild soil drought, (the soil water potential was ?(25 ± 5 kPa)) from full heading stage to maturity during early and late season, 2014 at South China Agricultural University, Guangzhou, China. Two nitrogen levels i.e., N1: 15 kg hm-2 and N2: 30 kg hm-2 were applied at heading stage. Results showed that the W2 and N1 treatment improved 2-AP content in brown rice for both cultivars. Higher 2-AP content was observed in the W2N1 treatment in 'Basmati 385' (26.22 and 136.29 ng g-1) and 'Nongxiang 18' (23.47 and 66.48 ng g-1). Moreover, 2-AP content in brown rice showed positive correlation with proline dehydrogenase (PDH) activity whilst showed negative correlation with proline content in grains during both seasons. In addition, 2-AP content in brown rice showed significantly negative correlation with proline for early season, but significant and positive correlation with PDH activity in grains for late season. During early season, all treatments were found no statistically difference for grain yield of both rice cultivars, whereas the highest grain yield i.e., 7.39 and 8.07 t hm-2 was obtained under W2N1 treatment in 'Basmati 385' and 'Nongxiang 18', respectively during late season. In conclusion, mild drought conditions in combination with the N application at 15 kg hm-2 at grain filling stage could promote grain yield and 2- AP content in brown rice. [ABSTRACT FROM AUTHOR]

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Potassium (K) as a macro nutrient governs important physiological mechanisms ensuring optimum plant growth and produce quality. An experiment was conducted during the summer of 2017 to study the effects of potassium application on maize under high nitrogen (N) nutrition with optimum and reduced irrigations. The experiment was comprised of three factors, viz. two irrigation levels (optimum, reduced), three potassium levels (80, 120 and 160 kg ha-1) and four nitrogen levels (100, 150, 200 and 250 kg ha-1). Two separate trials were carried out in randomized complete block design (RCBD), one under optimum (five irrigations) and another under reduced irrigation (three irrigations). One control plot (0K, 0N) was used under each replication for both trials. Optimum irrigation had resulted in maximum days of tasseling, silking, physiological maturity, crop growth rate (CGR), net assimilation rate (NAR), absolute growth rate (AGR), plant height, grains ear-1, thousand grains weight, biological yield, grain yield, chlorophyll contents and shelling percentage. High N (250 kg ha-1) delayed tasseling, silking and physiological maturity and resulted in maximum growth, physiological traits and biological yields. However, 150 kg N ha-1 had resulted in maximum number of ears m-2, number of grains ear-1, thousand grains weight and grain yield. While 100 kg N ha-1 had resulted in early tasseling, silking and physiological maturity. Potassium fertilization at the rate of 160 kg ha-1 delayed phenology and recorded with maximum growth rates, improved physiology and maximum yield traits and grain yield. However, the treatment 120 kg K ha-1 remained almost statistically similar to the 160 kg K ha-1 for most of the parameters. In the case of control vs rest, generally the performance of the control plot was poor. Hence, 150 kg N ha-1 with 120 kg K ha-1 under optimum irrigation is recommended for optimum productivity of maize crop. [ABSTRACT FROM AUTHOR]

Nutrient loss reduction strategies have recently been developed in the U.S. Midwest to decrease the environmental footprint associated with nitrogen (N) fertilizer use. Although these strategies generally suggest decreasing N rates and shifting the timing of N application from fall to spring, the spatiotemporal impacts of these practices on maize yield and fertilizer N use efficiency (NUE, kg grain yield increase per kg N applied) have not been assessed at the watershed scale using crop simulation models. We simulated the effects of N fertilizer rate (0, 168, 190, 224 kg N ha-1) and application timing [fall-applied N (FN): 100% N applied on 1 December; spring-applied N (SN): 100% N applied 10 days before planting; split N: 66% N applied on 1 December + 34% N applied 10 days before planting] on maize grain yield (GY) across 3042 points in Illinois during 2011–2015 using the DSSAT-CERES-Maize model. When simulations were scaled up to the watershed level, results suggest that increases in average maize GY for SN compared to FN occurred in years with higher than average winter rainfall (2011, 2013), whereas yields were similar (+/- 4%) in 2012, 2014, and 2015. Accordingly, differences in NUE for SN compared to FN were small (0.0–1.4 kg GY/kg N) when cumulative winter rainfall was < 300 mm, but increased to 0.1–9.2 kg GY/kg N when winter rainfall was > 500 mm at both 168 kg N ha-1 and 224 kg N ha-1. The combined practice of reducing N fertilizer amounts from 224 kg N ha-1 to 190 kg N ha-1 and shifting from FN to SN resulted in a wide range of yield responses during 2011–2015, with the probability of increasing yields varying from <10% to >70% of simulation points within a watershed. Positive impacts on both GY and NUE occurred in only 60% of simulations for this scenario, highlighting the challenge of simultaneously improving yield and NUE with a 15% N rate reduction in this region. [ABSTRACT FROM AUTHOR]

The effects of different nitrogen application rate on the physical characteristics and anatomic structure of rice stems were investigated with rice cultivars Guangliangyou 1128 (with high resistance) and Zhunliangyou 527 (with low resistance) as materials. The results showed that, firstly, plant height, gravity center height and basal internode length of the 2 rice cultivars increased with the increase of nitrogen application rate, while wall thicknees and internode fiiling degree decreased. The breaking-resistance strength per stem and thrust-resistance strength of plants declined with the increase of nitrogen application rate. Secondly, as nitrogen input increased, the number of vascular bundles and the area of vascular bundles increased between the 2 rice cultivas. Thirdly, with the increase of nitrogen application rate, the stem section area of Guangliangyou 1128, which had strong lodging resistance, graduHy increased, while that of Zhunliangyou 527 increased firstly and then decreased. The maximum application amount of nitrogen was 240 kg/hm2. Nitrogen fertilizer mainly affected the relative gravity center height, stem WXI thicknees and internode fiiling degree of the 2 cultivars, thereby reducing the basal stem breaking resistance and plant thrust-resistance strength. [ABSTRACT FROM AUTHOR]

Copyright of Dyna is the property of Universidad Nacional de Colombia, Medellin, Facultad de Minas 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.)

Agriculture in the semi-arid is often challenged by overuse of nitrogen (N), inadequate soil water and heavy carbon emissions thereby threatening sustainability. Field experiments were conducted to investigate the effect of nitrogen fertilization levels (N0 - 0, N100 - 100, N200 - 200, N300 -300 kg N/ha) on soil water dynamics, soil respiration (Rs), net ecosystem production (NEP), and biomass yields. Zero nitrogen soils decreased Rs by 23% and 16% compared to N300 and N200 soils, respectively. However, biomass yield was greatest under N300 compared with N0, which therefore translated into increased net primary production by 89% and NEP by 101% compared to N0. To a lesser extent, N200 increased net primary production by 69% and net ecosystem production by 79% compared to N0. Grain yields were greatest under N300 compared with N100 and N0, which therefore translated into increased carbon emission efficiency (CEE) by 53, 39 and 3% under N300 compared to N0, N100 and N200 treatments, respectively. There appears potential for 200 kg N/ha to be used to improve yield and increase CEE. [ABSTRACT FROM AUTHOR]

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.)

1. Compared to other plant life-forms, epiphytes remain understudied. Understanding the responses of epiphytes to changing environmental conditions is necessary to predict changes in ecosystem functioning especially in subtropical and tropical regions. 2. We investigated the functional traits of epiphytes along a large elevation gradient on Mount Kilimanjaro, Tanzania. We measured traits of co-occurring trees and terrestrial non-tree life-forms and compared changes in community-weighted means (CWM) of traits and trait spread, the range of observed trait values. We chose traits linked to growth and persistence: leaf area, specific leaf area, leaf dry matter content, stem specific density, plant height, leaf carbon, leaf nitrogen and leaf phosphorus. 3. For most traits, differences in CWM between life-forms exceeded differences within life-forms along the elevation gradient. Many CWM showed linear changes with elevation, but no response and unimodal patterns were also frequent. This was best explained by temperature, or a combination of temperature with precipitation or humidity, indicating effects of these factors on the distribution of epiphytic and non-epiphytic species. Trait spread did not change with elevation in nearly half of the traits, but hump-shaped patterns were also common, probably a result of weaker environmental filtering in the gradient centre. The magnitude of trait spread, that is, the variability between species of the same life-form within communities, was highest for terrestrial non-trees (TNT). Excluding ferns from the analyses lead to marked differences in trait patterns for epiphytes, as ferns made up 59% of the epiphytic species, while playing a minor role in the other groups. 4. The observed differences can be explained by a dichotomy in epiphytic life strategies, with tough-leaved xerotolerant species on one side and succulent soft-leaved species on the other. However, the influence of phylogeny was lower than expected from the taxonomic composition of the three life-form groups. 5. Our results emphasize that environmental constraints act upon functional traits of epiphytes, trees and TNT. The differences in trait expressions, arguably adaptations of the different life-forms, need to be taken into account in conservation contexts as well as when modelling the effects of global change on ecosystems. [ABSTRACT FROM AUTHOR]

Soybean, an important legume crop, serves as a good source of protein and oil with tremendous ability to fix atmospheric nitrogen for soil improvement. To study the genetic variability, genotypic, phenotypic and environmental coefficient of variation, broad sense heritability and genetic advance in soybean, a field experiment was conducted during Kharif 2013. The experiment, laid out in a randomized block design (RBD) with three replications, comprised of 24 genotypes and observations on 9 traits of soybean were recorded. In this experiment, analysis of variance indicated that significant variation were present among the different genotypes of the soybean for all the traits under study. The highest genotypic (GCV) and phonotypic coefficient of variation (PCV) were exhibited by the test weight, number of pods per plant, harvest index and plant height. The PCV was found higher than GCV which indicates the important role of environment in the expression of the characters. High heritability and high genetic advance were observed in the test weight, number of pods per plant, harvest index and plant height. The combination of the high heritability and high genetic advance provide the clear image of the trait in the selection process for crop improvement programme. [ABSTRACT FROM AUTHOR]

In order to clarify the response characteristics of tillering and nitrogen (N) uptake and utilization under micronano bubble aeration irrigation and nitrogen fertilizer level, the nitrogen uptake and utilization characteristics, tillering and yield of early rice under different irrigation methods and nitrogen levels were investigated. The results showed that micro-nano bubble aerated irrigation and nitrogen fertilizer have substantial influence on tillering of early rice, and the effect of N fertilizer was greater than the effect of oxygen. Nitrogen accumulation increased by 6.75-10.79% in micro-nano bubble aerated irrigation treatment compared with the conventional irrigation. The application of N in treatment of micro-nano bubble aerated irrigation and 160 kg N/ha fertilizer used (W1N1) was 90% of the treatment of micro-nano bubble aerated irrigation and 180 kg N/ha fertilizer used (W1N2), while the yield decreased by only 0.31%. The study indicated that the adoption of an appropriate deficit N rate combine with micro-nano bubble aerated irrigation can be an effective means to reduce non-beneficial N consumption, achieve higher crop yield and N utilization efficiency. [ABSTRACT FROM AUTHOR]

Abstract: Phosphorus (P) often limits the biomass of primary producers in freshwater lakes. However, in unproductive northern lakes, where anthropogenic nitrogen (N) deposition is low, N instead of P can limit primary producers. In addition, light can be limiting to primary producers at high concentrations of coloured dissolved organic matter (cDOM), as cDOM is the major determinant of light penetration in these lakes. To address resource limitation of epilithic algal biomass, we repeatedly sampled epilithon (periphyton on stony substrata) in 20 lakes covering a large, correlated cDOM and N‐deposition gradient across boreal and subarctic Sweden. Across these lakes, pelagic total N (TN) and total P (TP) were positively correlated, and benthic light supply was negatively correlated, with cDOM. Microscopically determined algal biovolume and epilithic carbon (C), N and P were subsequently regressed against benthic light supply and pelagic TN and TP. Patterns in epilithic biovolume were driven by N2‐fixing cyanobacteria, which accounted for 2%–90% of total epilithic biovolume. Averaged over the growing season, epilithic algal biovolume, C and N were negatively related to TP and positively to TN, and were highest in the clearest, most phosphorus‐poor lakes, where epilithon was heavily dominated by potentially N2‐fixing cyanobacteria. A structural equation model supports the hypothesis that cDOM had two counteracting effects on total epilithic algal biovolume: a positive one by providing N to algae that depend on dissolved N for growth, and a negative one by shading N2‐fixing cyanobacteria, with the negative effect being somewhat stronger. Together, these findings suggest that (1) light and N are the main resources limiting epilithic algal biomass in boreal to subarctic Swedish lakes, (2) epilithic cyanobacteria are more competitive in high‐light and low‐nitrogen environments, where their N2‐fixing ability allows them to reach high biomass, and (3) epilithic N increases with N2 fixer biomass and is—seemingly paradoxically—highest in the most oligotrophic lakes. [ABSTRACT FROM AUTHOR]

Copyright of Diyala Agricultural Sciences Journal is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) 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.)