Enhancing Nitrogen Use Research Articles

Role of integrated nutrient management for enhancing nitrogen use efficiency in crop

Role of integrated nutrient management for enhancing nitrogen use efficiency in crop

Effect of nitrogen-starvation on growth pattern and expression of nitrogen assimilation genes

Studying plant response and adaptation under low nitrogen stress condition is pre-requisite to enhance nitrogen use efficiency in crops. The present study investigated the physiological and molecular responses of maize (Zea mays L.) to nitrogen stress during early vegetative stage. Maize seedlings were grown hydroponically under controlled environmental conditions in phytotron. One set of plants were nutritionally stressed by eliminating nitrogen source in hydroponic culture while the other set was provided with nitrogen (2 mM KNO3). Under nitrogen-starvation condition, plant growth and physiological parameters changed dramatically. Significant reduction in chlorophyll content, total soluble proteins and nitrate reductase activity was observed. Further, nitrogen-starvation resulted into differential expression of genes related to nitrogen-assimilation and metabolism. The present study might be useful to improve our understanding towards plants adaptive response under nitrogen-starvation conditions.

Effect of Long-Term Nitrogen Addition on Wheat Yield, Nitrogen Use Efficiency, and Residual Soil Nitrate in a Semiarid Area of the Loess Plateau of China

Nitrogen (N) fertilizer plays an important role in wheat yield, but N application rates vary greatly, and there is a lack of data to quantify the residual effects of N fertilization on soil N availability. A 17-yr experiment was conducted in a semiarid area of the Loess Plateau of China to assess the effects of N fertilization on spring wheat (Triticum aestivum L.) grain yield, N uptake, N utilization efficiency, and residual soil nitrate. Treatments included a non-N-fertilized control and annual application of 52.5, 105.0, 157.5, and 210.0 kg N ha−1 in the first two years (2003 and 2004). In the third year (2005), the four main plots with N fertilizer application were split. In one subplot, N fertilization was continued as mentioned previously, while in the other subplot, N fertilization was stopped. The concentration of NO3-N in the 0–110 cm depth soil layers was significantly affected by N application, with higher N rates associated with greater soil NO3-N concentration. With the annual application of N over 17 years, residual soil NO3-N concentration in the 100–200 cm soil layer in the last study year was significantly greater than that in the non-N-fertilized control and was increased with rate of N application. There was a significant positive relationship of soil NO3-N in the 0–50 cm and 50–110 cm soil layers at wheat sowing with wheat grain N content and yield. Wheat grain yield in the third year (2005) was significantly, i.e., 22.57–59.53%, greater than the unfertilized treatment after the N application was stopped. Nitrogen use efficiency decreased in response to each increment of added N fertilizer, and was directly related to N harvest index and grain yield. Therefore, greater utilization of residual soil N through appropriate N fertilizer rates could enhance nitrogen use efficiency while reducing the cost of crop production and risk of N losses to the environment. For these concerns, optimum N fertilizer application rate for spring wheat in semiarid Loess Plateau is about 105 kg N ha−1, which is below the threshold value of 170 kg N ha−1 per year as defined by most EU countries.

Theanine transporters are involved in nitrogen deficiency response in tea plant (Camellia sinensis L.)

ABSTRACTNitrogen in soil directly influences the production and quality of tea. However, high nitrogen application in tea plantation leads to soil acidification and environmental pollution. Studies in model plants showed that plasma membrane localized amino acid transporter can regulate the distribution of amino acids to enhance nitrogen use efficiency. Our recent study identified six CsAAPs as transporters for theanine, a unique and most abundant non-proteinaceous amino acid in tea plant. In this work, we found these theanine transporters can also transport Glutamine, Glutamate, aspartate, alanine and γ-aminobutyric acid. Tissue-specific expression analyses showed that CsAAP1, CsAAP5 and CsAAP6 mainly expressed in leaves, CsAAP8 in root, CsAAP4 and CsAAP2 in stem. Furthermore, the expression of these CsAAPs was induced by nitrogen deficiency in a tissue-specific manner. Subcellular localization analyses showed that CsAAP1, CsAAP2 and CsAAP6 location were in the plasma membrane and endoplasmic reticulum. Taken together, these results suggested theanine transporters are involved in nitrogen deficiency response probably by mediating amino acid transport from roots to new shoots and from source to sink tissues in tea plants.

Chemical Composition of High Organic Carbon Soil Amendments Affects Fertilizer-Derived N2O Emission and Nitrogen Immobilization in an Oxic Sandy Loam

Nitrous oxide (N2O) emission is a negative side effect of modern agriculture and a serious issue for global climate change. The combined application of nitrogen (N) fertilizer and high organic carbon soil amendments (HCA) has been regarded as an alternative to promote fertilizer-related N immobilization and enhance nitrogen use efficiency. The effect of HCA on N2O emission and N immobilization highly depends on its chemical composition, as it controls carbon (C) supply to soil microbes and reactivity of lignin-derived phenols to fertilizer-derived N species. Here we present a 127-d laboratory incubation study to explore the N2O emission and N immobilization after combined application of N fertilizer and HCA (wheat straw, spruce sawdust, and commercial alkali lignin) differing in their chemical composition. The 15N labelling technique was used to trace the transformation of fertilizer-N in ammonium (NH4+), NO3-, soil organic nitrogen (SON), and N2O. The amendment of wheat straw and spruce sawdust greatly promoted N immobilization and N2O emission, while lignin amendment enhanced the immobilization of fertilizer N. The chemical composition of HCA explained 26% of the total variance of fertilizer-derived N2O emission and N retention via soil microbial biomass, composition of lignin-derived phenols, and nitrification. The holocellulose/lignin ratio of HCA could be used as an indicator for predicting HCA decomposition, microbial N immobilization and N2O emission. In addition, the composition of lignin-derived phenols was affected by HCA amendment and significantly related to N2O emission and N retention. The varying chemical composition of HCA could thus be a promising tool for controlling N2O emission and N immobilization in environment-friendly and climate-smart agriculture.

Integrated soil-cotton management system enhances nitrogen use efficiency under different soil fertility levels

ABSTRACT An integrated soil-cotton management system integrated with optimal management practices is projected to replace the conventional management system for enhancing nitrogen use efficiency. Field experiment was conducted in the more and less fertile soil with two treatments. Results showed that compared with conventional management system, integrated soil-cotton management system increased 9.5–21.2% soil-available nitrogen during the middle and later growth stages, in addition, improved average and maximum accumulation rate of nitrogen by 30.4–36.2% and 39.9–45.1%, and postponed the start time of the fast nitrogen accumulation phase by 3–6d, resulting in 32.5–38.3% higher final nitrogen accumulation. Furthermore, the increased nitrogen accumulation improved leaf area index, leaf area duration and boll number, finally enhanced agronomic nitrogen use efficiency and recovery nitrogen use efficiency. We suggest the nitrogen-based fertilizer of integrated soil-cotton management system could be omitted completely in the more fertile soil to enhance physiological nitrogen use efficiency ultimately by optimizing leaf area index. In addition, the decrement of nitrogen use efficiency was diminished under integrated soil-cotton management system. These results demonstrate ISMS might be a more profitable pattern for nitrogen use efficiency of cotton, especially to meet the challenge of soil degradation in future.

Omeprazole Treatment Enhances Nitrogen Use Efficiency Through Increased Nitrogen Uptake and Assimilation in Corn.

Omeprazole is a selective proton pump inhibitor in humans that inhibits the H+/K+-ATPase of gastric parietal cells. Omeprazole has been recently shown to act as a plant growth regulator and enhancer of salt stress tolerance. Here, we report that omeprazole treatment in hydroponically grown maize improves nitrogen uptake and assimilation. The presence of micromolar concentrations of omeprazole in the nutrient solution alleviates the chlorosis and growth inhibition induced by low nitrogen availability. Nitrate uptake and assimilation is enhanced in omeprazole treated plants through changes in nitrate reductase activity, primary metabolism, and gene expression. Omeprazole enhances nitrate assimilation through an interaction with nitrate reductase, altering its activation state and affinity for nitrate as a substrate. Omeprazole and its targets represent a novel method for enhancing nitrogen use efficiency in plants.

Deep placement of controlled-release urea effectively enhanced nitrogen use efficiency and fresh ear yield of sweet corn in fluvo-aquic soil

Application of controlled-release urea (CRU) improves crop yield and nitrogen use efficiency (NUE) compared with conventional urea. However, the effectiveness of CRU differs with fertilization placement. A two site-year field experiment was carried out in fluvo-aquic soil in central China to study the effects of two N sources (CRU and urea) and three fertilization placements (band application between two corn rows at 0, 5, and 15 cm soil depths) on fresh ear yield and NUE of sweet corn. The soil inorganic N (NO3−-N and NH4+-N) concentrations at the soil layers of 0–20 cm and 20–40 cm, root morphology characteristics and leaf physiological functions were also measured during the sweet corn growth period. Results showed that the deep placement of CRU at 15 cm soil depth significantly increased the sweet corn fresh ear yield, total N uptake, and NUE by 6.3%–13.4%, 27.9%–39.5%, and 82.9%–140.1%, respectively compared with CRU application at 0 cm depth. Deep placement of CRU at 15 cm also increased the root morphology traits, gas exchange attributes, and soil NO3−-N and NH4+-N concentrations in 0–20 cm and 20–40 cm layer, especially during later crop growth stages. However, the different N placements exerted non-significant effects on NUE and fresh ear yield when urea was applied as the N source. In crux, deep CRU placement instead of urea at 15 cm depth can effectively improve fresh ear yield and NUE of sweet corn in fluvo-aquic soil because of higher root growth, better leaf physiological functions and increased availability of soil NO3−-N and NH4+-N.

Combined application of nitrogen and phosphorus to enhance nitrogen use efficiency and close the wheat yield gap on varying soils in semi‐arid conditions

AbstractA primary driver of the wheat yield gap in Australia and globally is the supply of nitrogen (N) and options to increase N use efficiency (NUE) are fundamental to closure of the yield gap. Co‐application of N with phosphorus (P) is suggested as an avenue to increase fertiliser NUE, and inputs of N and P fertiliser are key variable costs in low rainfall cereal crops. Within field variability in the response to nutrients due to soil and season offers a further opportunity to refine inputs for increased efficiency. The response of wheat to N fertiliser input (0, 10, 20, 40 and 80 kg N ha‐1) under four levels of P fertiliser (0, 5, 10 and 20 kg P ha−1) was measured on three key low rainfall cropping soils (dune, mid‐slope and swale) across a dune‐swale system in a low rainfall semi‐arid environment in South Australia, for three successive cropping seasons. Wheat on sandy soils produced significant and linear yield and protein responses across all three seasons, while wheat on a clay loam only produced a yield response in a high rainfall season. Responses to P fertiliser were measured on the sandy soils but more variable in nature and a consistent effect of increased P nutrition leading to increased NUE was not measured.

English

Study was carried out to evaluate the supplementary nitrogen requirement of tef to enhance nitrogen use efficiency of tef grown under chickpea-tef rotation cropping. On-farm, experiment was conducted during the 2015 main cropping season at Tahtay Koraro District of the Tigray regional State, Ethiopia on tef after preceding chickpea. The experiment was set in a randomized complete block design with three replications. Seven treatments: Six N levels (0, 11.5, 23, 34.5, 46, and 69 kg N ha-1) under the chickpea-tef rotation and the seventh one negative control (0 kg N ha-1) under the continuous tef cropping were tested. Surface soil samples were collected before tef sowing and after harvesting. They were analyzed for selected soil properties. Clay sized particles dominate the soil of the experimental site and the textural class of the soil is clayey. There was a difference in the bulk density of the same soil between the chickpea-tef and tef-tef sequence. Nitrogen and organic carbon were higher in soil under chickpea-tef cropping sequence than in soil under continuous tef cropping. Application of different N rates under chickpea-tef rotation statistically significantly affected grain (GNU), straw (SNU) and total nitrogen uptake (TNU) (kg ha-1). The highest total tef nitrogen uptake (59 kg N ha-1) was obtained in response to application of 34.5 kg N ha-1. The highest apparent nitrogen recovery (81%), agronomic efficiency (10.48 kg kg-1) and physiological N use efficiency were obtained in response to the lower N rate (11.5 kg N ha-1), 23 kg N ha-1 rate and 34.5 kg N ha-1 respectively. The highest grain protein content (7.78%) was recorded for grain harvested from plots fertilized with 23 kg N ha-1. Hence, it could be concluded that, under chickpea-tef rotation cropping system some supplementary nitrogen is needed to fulfill the nitrogen requirement and nitrogen use efficiency of tef crop at the study area. Key words: Chickpea, tef, nitrogen uptake, nitrogen use efficiency, protein content.      &nbsp

Adaptive traits do not mitigate the decline in bread wheat quality under elevated CO2

Increased levels of atmospheric CO2 levels (eCO2) have been shown to decrease Grain Protein Concentration (GPC) and alter wheat composition (both protein and carbohydrate components). Lower GPC and altered composition under eCO2 conditions have deleterious impacts on end-product processing, dough rheology and bread loaf volume. To determine if the decline in GPC in wheat under eCO2 could be circumvented, traits hypothesised to improve grain protein were assessed in the Australian Grains Free Air CO2 Enrichment (AGFACE) facility. Wheat genotypes were selected with enhanced nitrogen use efficiency, water use efficiency, root vigour and grain quality, and were exposed to eCO2 (550 μmol mol−1) to determine if grain quality could be retained. Results showed that these trait strategies were not able to prevent the significant decline in GPC or grain quality (P ≤ 0.001). The decline in loaf volume (P ≤ 0.001) was greater under eCO2 across the selected cultivars and environments is likely associated with reduced GPC, changes in gluten protein composition, and significant increases in arabinoxylan content. Larger quantities (increased yield, P > 0.05) of lower quality grain will be produced in the future climates (eCO2), unless crop breeding efforts focus on grain-nitrogen translocation traits so that wheat can retain high quality grain under eCO2.

Maize production and field CO<sub>2</sub> emission under different straw return rates in Northeast China

In order to understand and clarify the impacts of straw return on maize production and field CO<sub>2</sub> emission in Northeast China, the most important agricultural base of the nation, a field experiment was conducted in 2012–2015, including no straw return (CK), straw amendment at 4000 kg/ha (S<sub>4</sub>), and at 8000 kg/ha (S<sub>8</sub>). The average grain yield was found significantly promoted by the two straw treatments, with comparably increased magnitudes of 11.0% and 12.8% for S<sub>4</sub> and S<sub>8</sub>, respectively, and the benefits were gradually enlarged with increasing experimental duration. Although straw return tends to reduce slightly the harvest index, it was detected that it exerted significantly positive impacts on nitrogen harvest index. These results implied that added straw could lead to raising grain yield and enhancing nitrogen use efficiency simultaneously. In 2015, our monitoring showed that CO<sub>2</sub> emission was elevated with intensified use of straw, and S<sub>4</sub> and S<sub>8</sub> decreased carbon emission efficiency by 7.3% and 13.6%, respectively. However, there was no statistical difference between S<sub>4</sub> and CK. Overall, straw addition at the rate of 4000 kg/ha accompanied with inorganic fertilizer was recommended to be adopted in Northeast China, which was considered as a sustainable and relatively environment-friendly agricultural technique during maize production.

Approach in Nitrogen Fertilizer Technology for Enhanced Nitrogen Use Efficiency: Review

Nitrogen (N) fertilizer has made a substantial contribution to the tripling of global food production over the past 50 years. During this period the main goal of applying fertilizer was to provide nutrient to plants to increase or sustain optimal crop yield. However, any fertilizer, whether in the natural, inorganic, or organic form, can harm the environment if misused. Nitrogen, the most widely applied plant nutrient, has until recently often been singled out for its adverse effects on the environment, as well as on human and animal health. The large increase in N fertilizer use resulted in steep decrease in N use efficiency. The low use efficiency of N fertilizer in general shows unsustainable N fertilizer use which resulted negative effect on the environment and economic benefit from farming. To ensure that proper use of nitrogen fertilizer that maintain beneficial to both crop production and the environment, researchers and fertilizer producers have tried to find ways to achieve the newly defined Enhanced fertilizer efficiency. Therefore, the objective of this seminar is to review achievements so far made in the area of Nitrogen fertilizers technology. The fate of applied fertilizer nitrogen in agricultural ecosystems is dependent on the immobilization and mineralization of nitrogen by various biotic and abiotic factors. When N-fertilizer is applied to crops under very distinct agricultural systems, plants rarely recover more than 50% of the fertilizer-N. The remainder is lost from the soil-plant system by mechanisms like volatilization, denitrification, leaching out of the root zone and being carried out by soil or water erosion. NUE in plants is a function of capacity of soil to supply levels of nutrients and ability of plant to acquire, transport in roots and shoots and remobilize to other parts of the plant. Different methods have been proposed in recent years to reduce loss of N from agriculture field. One of the methods is enhanced efficiency of fertilizer. Enhanced efficiency of fertilizer includes additives, physical barrier and chemical formulation. Therefore considering both the economic and environmental challenge represented by reducing both the cost and application of N fertilizers is critical. Keywords: Efficiency, Enhanced, Fertilizers, Nitrogen, Nutrient DOI : 10.7176/JBAH/9-8-04 Publication date : April 30 th 2019

Conjunctive use of composted leguminous shrub Caragana microphylla-straw and Bacillus cereus reduces nitrogen input but enhances nitrogen use efficiency and cucumber yields in alkaline soils

Fertilizer N use efficiency (NUE) is relatively low in most regions of the world, especially when a relatively large proportion of synthetic N fertilizer is used. To protect both the environment and crops, it is essential to improve NUE by reducing N input but maintaining or enhancing crop yields. In this study, we estimated the effects of composted leguminous shrub Caragana microphylla-straw (CM), Bacillus cereus (BC) and their combination on soil properties, cucumber plant growth, fruit yield, NUE and fruit quality under variable N-input rate conditions, through a study of four successive cropping seasons (CSs). The soil treatments considered were (i) traditional chicken manure applied as basal (control), (ii) CM plus 100% N from basal (CM-100%N), (iii) CM plus 75% N from basal (CM-75%N) and (iv) CM plus 50% N from basal (CM-50%N). The control and the CM-100%N treatment received the same amount of total N input according to local recommendations. Cucumber plants were inoculated without or with BC to create plant treatments that included (i) no inoculation (−BC) and (ii) inoculation with BC (+BC). Finally, a total of eight treatments (4 soil treatments × 2 plant treatments) were created. In general, CM application and BC inoculation enhanced soil quality (expressed by soil quality index (SQI)) mainly through reducing secondary salinization and autotoxin accumulation, both of which had detrimental effects on crop growth, and by increasing the utilization potential of amino acids, which had beneficial effects on crop growth. The SQI exhibited strong positive relationships with both fruit yield and NUE. The highest fruit yield was generally found under the CM-75%N + BC treatment in the first CS and under the CM-50%N + BC treatment in other three CSs, while the highest NUE was found under the CM-50%N + BC treatment in all four CSs. Our results infer that conjunctive use of CM and BC could enhance both crop yields and NUE under conditions with reduced N input.

Response of Two Potato Varieties to Irrigation Methods in the Dry Mediterranean Area

Abstract Due to water scarcity and dry Mediterranean conditions, improving water use efficiency is a major challenge for sustainable crop production and environment protection. Field experiments were conducted for two consecutive years (2010 and 2011) to assess the effects of variety and irrigation method on potato crop, following a 2 × 4 factorial experiment type arranged in a split plot design with two spring potato varieties (Spunta and Marfona), and four irrigation methods (drip irrigation with two modes of dripper spacing/dripper flow: 30 cm at 4 l/h and 60 cm at 8 l/h, sprinkle irrigation, and furrow irrigation), with three replicates. Potato was irrigated when soil moisture in the active root depth was within the range of 75-80% of field capacity as determined by the neutron probe technique. Results did not show any differences between both varieties. Moreover, no differences in marketable yield, total dry matter, and harvest index were found between irrigation methods. However, results showed that sprinkle irrigation significantly enhanced nitrogen use efficiency. Furthermore, both water productivity and irrigation water use efficiency were significantly increased under drip irrigation compared with the other irrigation methods. They were about twice those under furrow irrigation, indicating that the employment of drip irrigation method can effectively address water shortage and sustainable potato production, in the dry Mediterranean region.

Modelling reactive nitrogen fluxes and mitigation scenarios on a landscape in Central France

The intensification of agriculture has been made possible by increasing the supply of synthetic mineral nitrogen to crops. That has led to increased losses of reactive nitrogen (Nr e.g. ammonia NH3, nitrous oxide N2O, nitrogen oxides NOx, nitrate NO3−, ammonium NH4+) in the environment that may produce negative impacts on agroecosystems: soil, water or air pollution, greenhouse gas emission, biodiversity loss. The nitrogen losses result from a cascade of a large number of processes that interact spatially and temporally in agroecosystems. Integrated models are very useful to investigate such complex systems.We used the NitroScape model that couples an agroecosystem model, a cattle farm model, an atmospheric model of dispersion, transport and deposition, and a hydrological model. It made it possible to simulate processes of the nitrogen cascade at the landscape scale (i.e. a domain from a few square metres to a few tens of square kilometres). The model was applied on an agricultural site of 427 ha in Central France to simulate nitrogen flows for years 2014 and 2015. It used data from measurement campaigns and farm surveys that provided soil characteristics, meteorological data and crop management for the two years of simulation. The simulation results were compared to nitrogen fluxes and concentrations measured in the air, the soil and plants.The simulated Nr fluxes were consistent with the observed fluxes (i.e. low root mean square error, coefficients of regression significant at a 5% level). The coupled NitroScape model that integrates numerous related-nitrogen processes was therefore able to reproduce the main Nr fluxes. However, there were discrepancies between simulated and observed values for N2O emissions resulting from denitrification and for NH3 volatilisation. The model showed that the main Nr losses were due to NO3− leaching, which accounted for 11% of the nitrogen outflows (29 kg N ha−1 yr−1). Total losses of Nr (emissions of NH3, NO and N2O, and NO3− leaching) in the environment accounted for 13% of the nitrogen outflows.Two alternative scenarios aiming at enhancing nitrogen use efficiency and mitigating losses of Nr in the environment were built and assessed with the model. Simulations showed that changing nitrogen fertilisation and including catch crops and buffer strips led to a 18% decrease of NO3− losses. They also showed that including pea in crop rotation led to a 25% decrease of mineral fertilisation and a reduction of NO3− losses of 2 kg N ha−1 yr−1. The NitroScape model is a valuable tool to assess the effect of nitrogen management at the landscape scale on mitigation of nitrogen losses in the environment.

Evaluation of Nitrogen Fertilization Patterns Using DSSAT for Enhancing Grain Yield and Nitrogen Use Efficiency in Rice

ABSTRACTTemporal variation of rice growth and nitrogen (N) uptake generally follow a sigmoid curve and may respond positively to the N-fertilizer application at critical growth stages. In this study, it was hypothesized that the amount of N-fertilizer applied at critical growth stages possibly follows a geometric pattern such as line, parabola, and sinusoidal to attain maximum yield and nitrogen use efficiency. To test and identify the best pattern, short-term modeling-field testing-long-term modeling strategy was followed. The patterns with the highest simulated yield and nitrogen use efficiency from short-term modeling were tested in the field. Finally, long-term evaluation of N-fertilization patterns was performed using 25 years of historical weather data, resulting in the line pattern with 14% more yield and 25% less NO3− leaching in comparison to the conventional N-Fertilization pattern. Therefore, line pattern may be adopted to enhance the yield and nitrogen use efficiency in rice.

Effect of Epichloë gansuensis Endophyte on the Nitrogen Metabolism, Nitrogen Use Efficiency, and Stoichiometry of Achnatherum inebrians under Nitrogen Limitation.

The systemic fungal endophyte of the grass Achnatherum inebrians, Epichloë gansuensis, has important roles in enhancing resistance to biotic and abiotic stresses. In this work, we first evaluated the effects of E. gansuensis on nitrogen metabolism, nitrogen use efficiency, and stoichiometry of A. inebrians under varying nitrogen concentrations. The results demonstrated that E. gansuensis significantly improved the growth of A. inebrians under low nitrogen conditions. The fresh and dry weights, nitrogen reductase, nitrite reductase, and glutamine synthetase activity, NO3-, NH4+, N, and P content, and also the total N accumulation, N utilization efficiency, and N uptake efficiency were all higher in leaves of A. inebrians with E. ganusensis (E+) plants than A. inebrians plants without this endophyte (E-) under low nitrogen availability. In conclusion, E. gansuensis has positive effects on improving the growth of A. inebrians under low-nitrogen conditions by modulating the enzymes of nitrogen metabolism and enhancing nitrogen use efficiency.

How to enhance crop production and nitrogen fluxes? A result-oriented scheme to evaluate best agri-environmental measures in Veneto Region, Italy

ABSTRACTThe cost-effectiveness of adopting agri-environmental measures (AEMs) in Europe, which combine agricultural productions with reduced N losses, is debated due to poorly targeted site-specific funding that is allocated regardless of local variability. An integrated DAYCENT model-GIS platform was developed combining pedo-climatic and agricultural systems information. The aim was to evaluate best strategies to improve N fluxes of agro-ecosystems within a perspective of sustainable intensification. Indicators of agronomic efficiency and environmental quality were considered. The results showed that agronomic benefits were observed with a continuous soil cover (conservation agriculture and cover crops), which enhanced nitrogen use efficiency (+17%) and crop yields (+34%), although in some cases these might be overestimated due to modelling limitations. An overall environmental improvement was found with continuous soil cover and long-term change from mineral to organic inputs (NLeach < 10 kg ha−1 a−1, N-N2O emissions < 1 kg ha−1 a−1, soil C stock > 45 Mg ha−1), which were effective in the sandy soils of western and eastern Veneto with low SOM, improving the soil-water balance and nutrients availability over time. Results suggest that AEM subsidies should be allocated at a site-specific level that includes pedo-climatic variability, following a result-oriented approach.

Combined effects of straw-derived biochar and bio-based polymer-coated urea on nitrogen use efficiency and cotton yield

ABSTRACTThe interactive effects of straw-derived biochar and bio-based polymer-coated urea (BPCU) was examined with a pot experiment conducted in 2014 and 2015. Using a split-plot design, the main plot factor was the form of straw use and the sub-plot factor was the type of N fertilizer. The soil inorganic nitrogen (N), organic carbon and lint yield of biochar treatments were significantly higher than for straw treatments. Meanwhile, the BPCU treatments enhanced nitrogen use efficiency (NUE) and yield over urea treatments. Biochar combined with BPCU resulted in the highest lint yield, 14.3–108.2% increasing over the other treatments, with NUE 27.1–63.5% increased. We attributed this superior performance to the interactive effects between BPCU’s controlled supply of N according to cotton’s N requirements and biochar’s functionalities in enhancing soil quality. Thus, the application of biochar and BPCU is a sustainable strategy to improve soil quality and increase cotton yield.