Efficiency Of Fertilizer Use Research Articles

Climatic threshold of crop production and climate change adaptation: A case of winter wheat production in China

Global climate change has adversely affected agricultural production. Identifying the climatic threshold is critical to judge the impact and risk of climate change and proactively adapt agriculture. However, the climatic threshold of agriculture, especially crop production, remains unclear. To bridge this gap, taking winter wheat production from 1978 to 2017 in China as an example, this study clarified the definition of the climatic threshold of crop production and calculated it based on a mechanism model considering multiple factors and their synergies. The results showed that (1) the climate presented a warmer and wetter trend from 1978 to 2017, especially after 1996. (2) Water, fertilizer, and winter wheat yields increased significantly (22.4 mm/decade, 96.4 kg/ha·decade, and 674.2 kg/ha·decade, respectively, p < 0.01). (3) The average optimal temperature and water thresholds for winter wheat were 7.3°C and 569 mm, respectively. The temperature rise was unfavorable for winter wheat production, and the water supply increase was beneficial to winter wheat production. (4) Increasing irrigation and fertilization could raise the optimal temperature threshold and adapt to climate warming in most provinces, while Shandong and Shaanxi both needed to reduce fertilization. We established a generalized method for calculating the climatic threshold of agricultural production and found that multifactor synergistic effects could influence the climatic threshold. The climatic threshold of winter wheat changed with different adaptation levels. However, considering the limitations in resource availability and environmental capacity, increasing the use efficiency of water and fertilizer is more important for adapting to climate change in the future.

Managing nitrogen environmental impacts to improve green technical efficiency in Philippines rice cultivation

The efficient use of nitrogen fertilisers is a global priority to optimise the economic and environmental outcomes of farming. This paper is the first to consider pollution in the form of nitrous oxide emissions and excess nitrogen to analyse technical efficiency (TE) in farming. This is done by extending the two-stage double bootstrap Data Envelopment Analysis to explicitly model nitrogen pollutants as undesirable outputs. We compared green TE (when undesirable pollutants are considered) and conventional TE (without pollutants) using a case study of 33 rice-producing provinces in the Philippines. Provinces in Mindanao, Luzon, and Visayas islands experienced improvements in green TE but stagnant conventional TE from 2006 to 2017. Although transplanting rice seedlings (rather than direct sowing of seeds) improved both green and conventional TE, seed quality was also identified as an important factor for green TE but not for conventional TE. Our analysis has implications for sustainable rice production and such analysis can be extended to other crops. To advance the effective green transformation of rice production, future research should analyse farm-level data to understand farmers’ decisions regarding seed quality, crop establishment method and nitrogen fertiliser application to devise comprehensive farm integrated management plans.

Synergistic Fertilizers Improved Chemical Properties of Soil in Wheat (Triticum aestivum L.) Field

ABSTRACT In this study, the efficiency of fertilizers was improved by coating the fertilizers with a hydrogel formed by the polymerization of itaconic acid (IA), maleic acid (MA), acrylic acid (AA), and potassium persulfate (KPS) to form a synergistic fertilizer and improve its slow-release performance. The effect of synergistic fertilizers on the changes in soil nutrients in wheat fields was studied through field and soil column experiments using ordinary and commercial synergistic fertilizers as controls and different application rates of `synergistic fertilizers as treatments. The results revealed that the alkali-hydrolyzed nitrogen (N) and total N contents were significantly higher in T1 than that in CK, and the treatments were ranked as T3 > T2 > T5 > T1 > CK > T4. The difference in the alkali-hydrolyzed N and total N contents between CK and T3 was significant. In terms of available phosphorus (P) and potassium (K) contents, the treatments were ranked as T1 > T4 > T2 > CK > T3 in all soil layers and T3 > T2 > T5 > T1 > CK > T4 in the soil column. The treatments were ranked as T4>CK>T3>T1>T2 in terms of soil organic matter (SOM) content. Compared with ordinary fertilizers, synergistic fertilizers could significantly increase the soil total N, alkali-hydrolyzed N, available P, and available K contents. Compared with ordinary slow-release fertilizers in the market, the effect of synergistic fertilizers is better in improving the use efficiency of fertilizers. By slowly releasing nutrients, synergistic fertilizers can continuously provide nutrients for the growth and development of wheat and improve the use efficiency of fertilizer.

Potassium Determines Sugar Beets’ Yield and Sugar Content under Drip Irrigation Condition

Sugar beet is one of the main sugar crops and an important cash crop in the three northern regions of China (Northeast China, North China, and Northwest China). As an arid region, Xinjiang lacks water resources. The establishment of a reasonable drip-irrigation system for sugar beet in Xinjiang can not only achieve the goal of high quality and high yield, but is also crucial for the efficient utilization of water and fertilizer. This research was implemented in the experimental field of the Xinjiang Academy of Agricultural Sciences’ Sugar Beet Improvement Center in Manas County, Xinjiang, from the year 2019. Taking ST 15140 sugar beet as the experimental variety, a field study was conducted to investigate the effects of different irrigation and fertilization methods on the yield and sugar content of sugar beets. Ten treatments of two irrigation levels (W1: 4500 m3 ha−1, W2: 5400 m3 ha−1) and five fertilization methods (F1, F2, F3, F4, and F5) were carried out in a randomized block design with three replications. The yield and sugar content; growth indicators such as leaf photosynthetic rate, stomatal conductance, chlorophyll content and intercellular CO2 concentration; and fertilizer-use efficiency (nitrogen-use efficiency (NUE), phosphorus-use efficiency (PUE), and potassium-use efficiency (KUE)) during the sugar beet growing seasons were determined. The results indicated that the W1F3 (4500 m3 ha−1, N 229.5 kg ha−1 + P2O5 180 kg ha−1 + K2O 202.5 kg ha−1 + hydroquinone 229.5 g ha−1) treatment had the highest yield and sugar content of 132.20 Mg ha−1 and 15.61%, respectively. For crop growth indicators, the photosynthetic rate (33.27 μmol m−2 s−1) and the stomatal conductance (252.67 mmol m−2 s−1) under W1F3 were both the highest among all of the treatments. The fertilizer-use efficiency in W1F3 was in the following order: KUE > NUE > PUE. The highest KUE (128.10%) and NUE (65.49%) occurred under W1F3 at the sugar accumulation stage of the crop growing season. In addition, K determined the yield and sugar content of sugar beet by influencing growth factors such as the photosynthetic rate, chlorophyll content, intercellular CO2 concentration, along with the KUE, which explained 30.2%, 5.1%, 10%, and 14.7% of the variation in yield and sugar content, respectively. The results of this study indicated that the application of an inhibitor with optimized-minus-N fertilization under lower irrigation (W1F3) was the optimal treatment. Above all, K determined the yield and sugar contents of sugar beets, emphasizing the pivotal role of K in the growth, physiological processes, and output of sugar beets.

Global Food Security and Fundamental Role of Fertilizer Part 2. Fundamental Role of Fertilizer in Food Production

The article shows the fundamental role of mineral fertilizers in solving the problems of global food security. Due to a number of reasons, primarily the increase in the cost of fertilizers and restrictions on their supply, as well as sanctions restrictions on the supply of raw materials, techniques for more efficient use of fertilizers are given. The role of precision agriculture is characterized, including issues of increasing the efficiency of fertilizer use. The results of agrochemical experiments with various crops and in various soil and environmental conditions are presented, their agronomic and economic efficiency is shown. Further directions of work on the evaluation of the effectiveness of the use of fertilizers, in particular nitrogen, are given. The risk assessment and management measures are also noted.

Inhibitory Effect of Neem Seed Extract on Soil Nitrogen Mineralization under Chemical and Organic Amendments

Background: Improvement of nitrogen use efficiency (NUE) of chemical fertilizers and N-rich-organic amendments using natural mineralization inhibitors, like neem extract, was recommended to minimize nitrogen (N) loss. This study hence aimed to evaluate the effects of combined uses of neem seed extract with cricket feces on soil N mineralization and plant NUE. Methods: The treatment combinations included i) amending materials involving unamended (Un), chemical fertilizer at a recommended rate of 312.5 kg N ha-1, 100 kg P ha-1 and 100 kg K ha-1 (CF) and three rates of cricket feces (CrF) [3.125 (CrFlow), 6.25 (CrFmedium) and 12.5 (CrFhigh) Mg ha-1], ii) in combination without (-Nm) and with (+Nm) neem seed extract. Amaranth (Amaranthus tricolor) was employed to assay the plant’s NUE. Result: Neem seed extract inhibited the N mineralization under the Un (74%) and CF (84%) treatments, but not in any of the CrF treatments (-102%, -99% and -2% for CrFlow, CrFmedium and CrFhigh, respectively. In addition, the neem extract significantly decreased NUE parameters, including N recovery efficiency and agronomy NUE, only in CF treatment. Neem seed extract could only function as an N inhibitor in unamended and chemically fertilized soils.

Principles of Nutrient and Water Management for Indoor Agriculture

Mass balance principles are a cornerstone of efficient fertilizer use and can be utilized to optimize plant nutrition without discarding or leaching solution. Here, we describe the maintenance of closed hydroponic and soilless substrate systems based on mass balance. Water removed by transpiration is restored with solution that replaces the nutrients that were taken up with the water. The concentration of nutrients in this refill/irrigation solution is determined by multiplying the optimal concentration of each nutrient in plant tissue by the water-use efficiency (WUE; ratio of dry mass to water transpired). Optimal leaf nutrient concentrations are well established, but WUE in controlled environments varies widely and is less well characterized. Elevated CO2 increases photosynthesis and demand for nutrients, but partially closes stomata and reduces transpiration; so high CO2 dramatically increases WUE. The concentration of the refill/irrigation solution must be adjusted to account for a two-fold range of WUE, from 3 g L−1 in ambient CO2 in lower humidity, to 6 g L−1 in elevated CO2 in higher humidity. WUE and nutrient requirements vary during the vegetative and reproductive stages of growth, and adjustment of the solution over the lifecycle can be beneficial. Measurement of solution electrical conductivity (EC) is helpful, but if the solution is appropriate, low EC usually means healthy plants and active nutrient uptake. The ammonium to nitrate ratio is critical to pH management. We have applied these principles across multiple species and environments to achieve long-term, steady-state nutrient concentrations with no discharge or leaching of solution.

Effect of Compost and Synthetic Fertilizer on Soil Fertility, Yield and Nitrogen Use Efficiency of Broccoli Crop in Arid Region of Morocco

Background: Soils in arid regions like Morocco are becoming increasingly degraded and polluted because of the high use of synthetic chemical fertilizers linked to population growth. Organic fertilizers such as compost remain a good alternative to improve soil quality and crop yields. Broccoli is a crop that is beginning to develop in Morocco. It is very nitrogen demanding crop; therefore, it is necessary to know nitrogen use efficiency in broccoli. Methods: In this field experimental conducted during 2015 at the horticultural complex of Agadir - Agronomy and Veterinary Institute Hassan II, different treatments were tested on broccoli as follows:TC8t/ha: compost, 8 t/ha (equivalent 200 kgN /ha), TC12t/ha: compost, 12 t/ha (equivalent 300 kg N /ha), TSYN: Synthetic chemical fertilizer (200kg N/ha), TC+SYN: 50% compost, 4t/ha+50% Synthetic fertilizer (equivalent 200 kg N/ha) and T0: control, in order to optimize nitrogen use efficiency of compost and synthetic fertilizer. Result: Our research showed that the combination of compost and synthetic fertilizer: TC+SYN improved the growth and yield parameters of broccoli; the best main head yield of broccoli was 13.5 t/ha for TC+SYN. Compost improved the chemical properties of soil. Total N content was 266 kg/ha for TC+SYN, 253 kg/ha for TSYN, 244 kg/ha for TC8 t/ha and 234 kg/ha forTC12 t/ha. For Nitrogen use efficiency, apparent recovery efficiency (ARE) was higher with TSYN: 0.91 followed by TC+SYN: 0.88 followed by TC8t/ha with 0.77and T C12 t/ha: 0.48.

Effects of Potassium Deficiency on the Growth of Tea (Camelia sinensis) and Strategies for Optimizing Potassium Levels in Soil: A Critical Review

Potassium is among the three essential macronutrients for tea plants, along with nitrogen and phosphorous, and plays important roles in growth and stress response. Potassium is absorbed by plants in larger amounts than any other mineral element except nitrogen and, in some cases, calcium. At present, more than 59% of China’s tea gardens are in a state of potassium deficiency, which negatively affects tea quality and yield. This paper reviews the effects of potassium deficiency on tea plant growth and stress response, details factors affecting potassium supply and demand in tea gardens, examines the interactions between potassium and other elements in soils, and provides strategies for optimizing potassium levels in soils. Potassium is positively correlated with the elements nitrogen, copper, and zinc. Sufficient potassium dramatically improves the yield and quality of tea: it accelerates metabolism, promotes synthesis of catechins, and strengthens biotic and abiotic resistance by activating and regulating different enzymes. Moderate application of potassium fertilizers, along with potassium-solubilizing bacteria, can regulate the ratio of different forms of potassium and increase available potassium in soils of tea gardens. We suggest that research on potassium occurring in soils and its interaction with other elements be strengthened, so as to improve the efficient use of potassium fertilizers in tea gardens and maintain the balance of elements in soils.

Pendistribusian Pupuk Bersubsidi Dengan Acuan Rencana Definitif Kebutuhan Kelompok (RDKK) Perspektif Etika Bisnis

Subsidized fertilizers are goods under supervision whose procurement and distribution receive subsidies from the Government. Subsidized fertilizers are used to meet the needs of farmer groups and farmers in the agricultural sector which is regulated through the Definitive Plan for Group Needs (RDKK). RDKK is the calculation of the plan for subsidized fertilizer needs prepared by farmer groups based on the use of fertilizers that are higher or less than the recommendation to reduce the efficiency and effectiveness of fertilizer use. Based on the problem formulation, this study aims to explore the distribution channel system for subsidized fertilizers in Cumedak Village, Sumberjambe District, Jember Regency according to the perspective of business ethics. This research uses a qualitative approach with a case study type in Cumedak Village, Sumberjambe District, Jember Regency. The results of the study show that basically subsidized fertilizers have the potential to improve people's welfare. However, the underlying problem that actually occurs is that the distribution of subsidized fertilizers tends to be lower than the distribution of non-subsidized fertilizers.
 Keywords: Subsidized Fertilizer, RDKK, Business Ethics

Fertilizers and Fertilization Strategies Mitigating Soil Factors Constraining Efficiency of Nitrogen in Plant Production.

Fertilizer Use Efficiency (FUE) is a measure of the potential of an applied fertilizer to increase its impact on the uptake and utilization of nitrogen (N) present in the soil/plant system. The productivity of N depends on the supply of those nutrients in a well-defined stage of yield formation that are decisive for its uptake and utilization. Traditionally, plant nutritional status is evaluated by using chemical methods. However, nowadays, to correct fertilizer doses, the absorption and reflection of solar radiation is used. Fertilization efficiency can be increased not only by adjusting the fertilizer dose to the plant’s requirements, but also by removing all of the soil factors that constrain nutrient uptake and their transport from soil to root surface. Among them, soil compaction and pH are relatively easy to correct. The goal of new the formulas of N fertilizers is to increase the availability of N by synchronization of its release with the plant demand. The aim of non-nitrogenous fertilizers is to increase the availability of nutrients that control the effectiveness of N present in the soil/plant system. A wide range of actions is required to reduce the amount of N which can pollute ecosystems adjacent to fields.

Seasonal rainfall distribution drives nitrogen use efficiency and losses in dryland summer sorghum

Nitrogen (N) fertiliser inputs represent one of the largest variable costs in dryland cropping systems, and a key determinant of water-limited yield. Despite extensive research into microbial N losses via intermediate denitrification products such as N2O, limited research exists on total N losses, and the effect of increasing soil N surplus has on fertiliser use-efficiency is not clear. In this study, the fate of banded urea fertiliser N across crop uptake, soil residual N and N losses was determined using the 15N recovery technique over nine trials with four N rates (0, plus low, medium and high industry rates) across N responsive and non-N responsive sites over 3 years in dryland sorghum (Sorghum bicolor). On average, crop uptake efficiency ranged from 50% at the low and medium N rate (80 kg N ha−1) to < 38% at the highest N rate, and was as low as 5%. Nitrogen losses averaged 26.5% across all rates and trials. At the medium N rate, losses exceeded 18% in all trials, despite relatively dry seasons, and in some trials exceeded 34%. Losses of N were driven by large cumulative rain events and high early-season rainfall. In dryland systems, the inability of crops to acquire banded N fertiliser can potentially leave fertiliser stranded in the topsoil, leaving it vulnerable to losses.Download : Download high-res image (141KB)Download : Download full-size image

Fine Soil Texture Is Conducive to Crop Productivity and Nitrogen Retention in Irrigated Cropland in a Desert-Oasis Ecotone, Northwest China

Agricultural production in oases requires extensive irrigation and nitrogen (N) inputs, which result in a high incidence of non-point-source pollution. Information on how soil texture affects crop productivity and water and N use efficiency is needed to improve N management in oases. A two-year field study with six free-draining leaching pits was set up to quantify soil water content (SWC), drainage, yield, N uptake, soil residual N, N leaching, water-use efficiency (WUE), and N fertilizer-use efficiency (NFUE) on sandy-textured soils in a young oasis field (24 years, YOF) and loam-textured soils in an old oasis field (&gt;60 years; OOF) within an intensive oasis agricultural zone in Northwest China. The results showed that sand content in the YOF was significantly higher than that in the OOF (p &lt; 0.01), while both clay and silt contents in the YOF were significantly lower than those in the OOF (p &lt; 0.01). Soil water storage (SW) in the 0–100 cm soil layer, evapotranspiration water-use efficiency (WUEET) and irrigation water-use efficiency (WUEIrrig) in the OOF were, respectively, 87.1, 23.5, and 24.1% higher than those in the YOF (p &lt; 0.05), and deep drainage in the YOF was 6.2 times higher than that in the OOF (p &lt; 0.01). Maize N uptake and soil N accumulation in the OOF in the 0–100 cm soil layer were, respectively, 33.4 and 10.3% higher than those in the YOF (p &lt; 0.05), and N leaching loss in the YOF was 1.65 times higher than that in the OOF (p &gt; 0.01). Crop yield and NFUE in the OOF were, respectively, 23.9 and 27.2% higher than those in the YOF (p &lt; 0.05). These results indicated that sandy-textured soils with high sand content were not conducive to water and N retention, resulting in lower crop yields and water- and fertilizer-use efficiency in YOF. Therefore, it is imperative that management practices in sandy-textured land promote improvements in soil structure and maintain the long-term productivity of the young cultivated fields.

Table-Grape Cultivation in Soil-Less Systems: A Review

Table grape (Vitis vinifera L.) is considered to be one of the most popular fruit crops in the world. Italy is the leading table-grape producer in the EU and is the main European exporting country. However, to stay competitive, new solutions and perspectives, including varietal renovation, are now needed in addition to the already well-established Italian table-grape production lines consisting of conventional open-field cultivation and greenhouse cultivation. One of these new perspectives is represented by the development of table-grape soil-less cultivation systems (TGSC) under greenhouse. In fact, TGSC systems are alleged to offer many advantages in terms of the advancement of berry maturity, extreme varietal flexibility, easier manipulation of the vegetative–reproductive cycle, higher yields of high quality extra-seasonal production, higher sustainability for reduced pesticides application, and higher use efficiency of water and fertilizers than conventional (soil-grown) cultivation. They can be also useful for overcoming soil- and rootstock-related problems. In this review, the opportunities offered by the recently developed table-grape soil-less cultivation systems are thoroughly examined and updated to the latest experimental and application findings of the sector’s research activity. A special emphasis is given to the evolution of the applied technical solutions, varietal choice, and environmental conditions for the aims of table-grape soil-less cultivation.

Efficacy of neem and zinc coated urea on productivity and economics of wheat (Triticum aestivum)

Nitrogen (N) fertilizer-use efficiency (20 − 50%) is low in wheat fields in India. Coated urea can increase N-use efficiency in wheat, but a desirable coating for use with urea is not widely accepted yet. Therefore, to study the efficacy of coated urea on productivity and economics of wheat, an experiment was conducted at Research Farm of SKUAST-J, India, during winter season of 2017 − 2018 and 2018 − 2019. The experiment was laid out in a randomized block design with 11 treatment combinations, replicated thrice. The treatments comprised of various doses of different types of coated urea viz prilled urea, Neem coated urea (NCU), Zinc coated urea (ZnCU), and Neem + Zinc coated urea (NCU + ZnCU). Different doses of coated urea fertilizers showed significant effect on the growth, yield, economics, and nutrient uptake of wheat crop. Application of 100% of recommended (Rec.) nitrogen (N) through ZnCU + Rec. Phosphorus (P), Potassium (K) and Zinc (Zn) (T8) showed significantly better growth, yield attributing characters and grain and straw yield, during both the years of study and remained statistically at par with the application of 85% of Rec. N through ZnCU + Rec. P, K, & Zn (T7), 100% of Rec. N through NCU + ZnCU + Rec. P, K, & Zn (T11), 85% of Rec. N through NCU + ZnCU + Rec. P, K, & Zn(T10) and 100% of Rec. N through NCU + Rec. P, K, & Zn (T5).Similarly, nutrient uptake (N, K and Zn), net returns, and B:C ratio were also observed to be significantly higher with the application of 100% of Rec. N through ZnCU + Rec. P, K, & Zn than other treatments. However, maximum mean Agronomic use efficiency (AUE) and Recovery use efficiency (RUE) of 36.2% and 30.0%, respectively, were found with the application of 85% of Rec. N through ZnCU + Rec. P, K, & Zn (T7) over the application of100% of Rec. N through urea + Rec. P, K, & Zn(T2).

EFISIENSI PENGGUNAAN PUPUK FOSFOR PADA TANAMAN JAGUNG DENGAN APLIKASI EKSTRAK PELARUT FOSFAT

Increasing corn production by minimizing the use of fertilizers, especially phosphorus (P) fertilizers can be done by maximizing the release of phosphorus nutrients bound in the soil. This study aims to make efficient use of phosphorus fertilizer by utilizing phosphate solvent extract (EPF) in increasing the growth and production of maize. The study was conducted from November 2018 to March 2019, which was arranged in a randomized block design with package treatments: EPF 100 mL/L + P 50 kg/ha (0.7 g/plant), EPF 150 mL/L water + P 100 kg /ha (1.4 g/plant), EPF 200 mL/L water + P 150 kg/ha (2.1 g/plant), EPF 150 mL/L water + P 50 kg/ha (0.7 g/ plants) and EPF 200 mL/L water + P 100 kg/ha (1.4 g/plant). Each treatment combination was repeated three times. The results showed that 1) The availability of P in the soil increased after being treated with a combination of EPF and P reaching 8.61 ppm compared to only 1.15 ppm before treatment. 2) The combination of treatment with EPF 100 mL/L water + P 0.7 g/plant has a very good effect on the level of P uptake. 3) The combination of Phosphate Solvent Extract 200 mL/L water + P 1.4 g/plant has a good effect on growth and maize production of Srikandi Putih Variety with Phosphorus Use Efficiency of 0.82%.

Used Wisely, Fertilizers Will Feed Africa and Protect its Unique Biodiversity

The balanced and efficient use of fertilizers is critical for improving food security, reducing malnutrition and protecting biodiversity in Africa. The next Africa Fertilizer Summit must result in concrete targets, commitments and actions by governments and industry to, within the next 10-20 years, at least triple the nutrient input rates on cropland. Otherwise hunger and malnutrition will persist, and more natural ecosystems will be destroyed.

Genetic Diversity in Nitrogen Fertiliser Responses and N Gas Emission in Modern Wheat.

Crops assimilate nitrogen (N) as ammonium via the glutamine synthetase/glutamate synthase (GS/GOGAT) pathway which is of central importance for N uptake and potentially represents a bottle neck for N fertiliser-use efficiency. The aim of this study was to assess whether genetic diversity for N-assimilation capacity exists in wheat and could be exploited for breeding. Wheat plants rapidly, within 6 h, responded to N application with an increase in GS activity. This was not accompanied by an increase in GS gene transcript abundance and a comparison of GS1 and GS2 protein models revealed a high degree of sequence conservation. N responsiveness amongst ten wheat varieties was assessed by measuring GS enzyme activity, leaf tissue ammonium, and by a leaf-disc assay as a proxy for apoplastic ammonia. Based on these data, a high-GS group showing an overall positive response to N could be distinguished from an inefficient, low-GS group. Subsequent gas emission measurements confirmed plant ammonia emission in response to N application and also revealed emission of N2O when N was provided as nitrate, which is in agreement with our current understanding that N2O is a by-product of nitrate reduction. Taken together, the data suggest that there is scope for improving N assimilation capacity in wheat and that further investigations into the regulation and role of GS-GOGAT in NH3 emission is justified. Likewise, emission of the climate gas N2O needs to be reduced, and future research should focus on assessing the nitrate reductase pathway in wheat and explore fertiliser management options.

Biochar Optimizes Wheat Quality, Yield, and Nitrogen Acquisition in Low Fertile Calcareous Soil Treated With Organic and Mineral Nitrogen Fertilizers.

Crop quality and nutrient uptake are considerably influenced by fertilizers inputs and their application rate. Biochar (BC) improves nitrogen uptake and crop productivity. However, its interaction with synthetic and organic fertilizers in calcareous soil is not fully recognized. Therefore, we inspected the role of biochar (0, 10, 20, and 30 t ha–1) in improving N uptake and quality of wheat in a calcareous soil under integrated N management (90, 120, and 150 kg N ha–1) applied each from urea, farmyard manure (FYM) and poultry manure (PM) along with control) in 2 years field experiments. Application of 20 t BC along with 150 kg N ha–1 as poultry manure considerably improved wheat grain protein content (14.57%), grain (62.9%), straw (28.7%), and biological (38.4%) yield, grain, straw, and total N concentration by 14.6, 19.2, and 15.6% and their uptake by 84.6, 48.8, and 72.1%, respectively, over absolute control when averaged across the years. However, their impact was more pronounced in the 2nd year (2016–2017) after application compared to the 1st year (2015–2016). Therefore, for immediate crop benefits, it is recommended to use 20 t BC ha–1 once in 50 years for enhancing the nitrogen use efficiency of fertilizers and crop yield.

Farmer Motivations for Excess Nitrogen Use in the U.S. Corn Belt

Improving the use efficiency of nitrogen fertilizer is one of the most effective ways to mitigate agriculture’s contributions to climate change and water-quality degradation. However, studies suggest that many farmers worldwide are exceeding annual-profitable nitrogen rates and thus “overapplying” nitrogen. This paper utilizes a case study to understand overapplication at the individual level, focusing on (1) prevalence and severity of overapplication as defined by maximum profitable thresholds and (2) gaining an understanding of what factors limit overapplying farmers’ desire and capacity to lower their rates. Using a sample of 132 interviews with row-crop farmers in three states in the Midwestern United States, I find that 37% of interviewed farmers overapplied nitrogen by 5 lbs./acre or more, with few farmers adjusting rates annually and the largest farmers being most likely to overapply. When asked what prevented them from reducing their rates, overapplying farmers felt their current rates were appropriate or profitable, and thus, they did not desire to reduce them. Of these farmers, some assumed they could not be overapplying, some used more N to achieve maximized production, while others intentionally overapplied as a risk-mitigation strategy. I conclude by offering recommendations for policy and future research to build on this case study.