Nitrogen Fertilizer Application Research Articles

Comparative transcriptome analysis reveals major genes, transcription factors and biosynthetic pathways associated with leaf senescence in rice under different nitrogen application.

Rice (Oryza sativa L.) is one of the most important food crops in the world and the application of nitrogen fertilizer is an effective means of ensuring stable and high rice yields. However, excessive application of nitrogen fertilizer not only causes a decline in the quality of rice, but also leads to a series of environmental costs. Nitrogen reutilization is closely related to leaf senescence, and nitrogen deficiency will lead to early functional leaf senescence, whereas moderate nitrogen application will help to delay leaf senescence and promote the production of photosynthetic assimilation products in leaves to achieve yield increase. Therefore, it is important to explore the mechanism by which nitrogen affects rice senescence, to search for genes that are tolerant to low nitrogen, and to delay the premature senescence of rice functional leaves. The present study was investigated the transcriptional changes in flag leaves between full heading and mature grain stages of rice (O. sativa) sp. japonica 'NanGeng 5718' under varying nitrogen (N) application: 0kg/ha (no nitrogen; 0N), 240kg/ha (moderate nitrogen; MN), and 300kg/ha (high nitrogen; HN). Compared to MN condition, a total of 10427 and 8177 differentially expressed genes (DEGs) were detected in 0N and HN, respectively. We selected DEGs with opposite expression trends under 0N and HN conditions for GO and KEGG analyses to reveal the molecular mechanisms of nitrogen response involving DEGs. We confirmed that different N applications caused reprogramming of plant hormone signal transduction, glycolysis/gluconeogenesis, ascorbate and aldarate metabolism and photosynthesis pathways in regulating leaf senescence. Most DEGs of the jasmonic acid, ethylene, abscisic acid and salicylic acid metabolic pathways were up-regulated under 0N condition, whereas DEGs related to cytokinin and ascorbate metabolic pathways were induced in HN. Major transcription factors include ERF, WRKY, NAC and bZIP TF families have similar expression patterns which were induced under N starvation condition. Our results revealed that different nitrogen levels regulate rice leaf senescence mainly by affecting hormone levels and ascorbic acid biosynthesis. Jasmonic acid, ethylene, abscisic acid and salicylic acid promote early leaf senescence under low nitrogen condition, ethylene and ascorbate delay senescence under high nitrogen condition. In addition, ERF, WRKY, NAC and bZIP TF families promote early leaf senescence. The relevant genes can be used as candidate genes for the regulation of senescence. The results will provide gene reference for further genomic studies and new insights into the gene functions, pathways and transcription factors of N level regulates leaf senescence in rice, thereby improving NUE and reducing the adverse effects of over-application of N.

Reducing Soil-Emitted Nitrous Acid as a Feasible Strategy for Tackling Ozone Pollution.

Severe ozone (O3) pollution has been a major air quality issue and affects environmental sustainability in China. Conventional mitigation strategies focusing on reducing volatile organic compounds and nitrogen oxides (NOx) remain complex and challenging. Here, through field flux measurements and laboratory simulations, we observe substantial nitrous acid (HONO) emissions (FHONO) enhanced by nitrogen fertilizer application at an agricultural site. The observed FHONO significantly improves model performance in predicting atmospheric HONO and leads to regional O3 increases by 37%. We also demonstrate the significant potential of nitrification inhibitors in reducing emissions of reactive nitrogen, including HONO and NOx, by as much as 90%, as well as greenhouse gases like nitrous oxide by up to 60%. Our findings introduce a feasible concept for mitigating O3 pollution: reducing soil HONO emissions. Hence, this study has important implications for policy decisions related to the control of O3 pollution and climate change.

Effects of Maize/Peanut Intercropping and Nitrogen Fertilizer Application on Soil Fungal Community Structure

Maize/peanut intercropping may improve soil health through reducing nitrogen (N) fertilization. However, the effects of maize/peanut intercropping combined with reduced N fertilization on the soil fungal community structure have not been well reported. Using a long-term localized micro-zone experiment, we investigated the combined effects of intercropping and N fertilizer application on soil fungal community diversity and composition. Three cropping patterns (maize/peanut intercropping, maize monoculture, and peanut monoculture) and three N application levels (0 kg·hm−2, 150 kg·hm−2, and 300 kg·hm−2) were assessed. The results showed that the total numbers of fungal species and unique species (operational taxonomic units, OTUs) in both maize and peanut soils tended to first increase and then decrease with increasing N application. Compared with monoculture, the numbers of total OTUs and unique OTUs in intercropped maize soil decreased by 4.14% and 12.79%, respectively, but the total numbers of OTUs and unique OTUs in peanut soil increased by 1.08% and 3.78%, respectively. With increasing N application, the soil fungal Ace and Chao indices of maize soil first increased and then decreased, while the fungal Shannon, Ace, and Chao indices of peanut soil decreased. Compared with the monoculture system, intercropping significantly reduced the maize soil fungal Ace and Chao indices but increased the peanut soil fungal Shannon, Ace, and Chao indices. Nitrogen application and intercropping significantly altered the fungal community structure of maize soil, while N application had no significant effect on the fungal community structure of peanut soil, though intercropping significantly changed the fungal community structure of peanut soil. At the phylum level, Ascomycota, Basidiomycota, Mortierellomycota, unclassified_k_Fungi, and Chytridiomycota were the dominant taxa. Redundancy analysis (RDA) showed that soil nitrate (NO3−) content was the main environmental factor shaping the soil fungal community. In conclusion, excessive N fertilization (300 kg·hm−2) can reduce soil fungal community diversity; maize/peanut intercropping reversed the negative effect of N application on fungal community of peanut soil, but not that of maize soil. Soil NO3− content is the primary environmental driver of soil fungal communities.

Method for Monitoring Wheat Growth Status and Estimating Yield Based on UAV Multispectral Remote Sensing

An efficient and accurate estimation of wheat growth and yield is important for wheat assessment and field management. To improve the accuracy and stability of wheat growth and yield estimation, an estimation method based on a genetic algorithm-improved support vector regression (GA-SVR) algorithm was proposed in this study. The correlation analysis between vegetation indices calculated from spectral data and wheat growth phenotypes and yields was performed to obtain the optimal combination of vegetation indices with high correlation and good estimation performance. At the same time, the optimal model for wheat growth monitoring was screened and constructed in experiments with 12 wheat varieties and 3 gradient nitrogen fertilizer application levels. Then, the yield estimation model was established and its applicability was verified under different nitrogen fertilizer application levels. The results showed that the constructed models for the leaf area index, plant height, and yield estimation performed well, with coefficients of determination of 0.82, 0.71, and 0.70, and root mean square errors of 0.09, 2.7, and 68.5, respectively. This study provided an effective UAV remote sensing technique for monitoring wheat growth status and estimating yield. This study provides an effective unmanned aerial remote sensing technique for monitoring wheat growth and estimating yield, and provides technical support for wheat yield assessment and field management.

Enhancing root physiology for increased yield in water-saving and drought-resistance rice with optimal irrigation and nitrogen

ObjectivesWater-saving and drought-resistance rice (WDR) plays a vital role in the sustainable development of agriculture. Nevertheless, the impacts and processes of water and nitrogen on grain yield in WDR remain unclear.MethodsIn this study, Hanyou 73 (WDR) and Hyou 518 (rice) were used as materials. Three kinds of nitrogen fertilizer application rate (NFAR) were set in the pot experiment, including no NFAR (nitrogen as urea applied at 0 g/pot), medium NFAR (nitrogen as urea applied at 15.6 g/pot), and high NFAR (nitrogen as urea applied at 31.2 g/pot). Two irrigation regimes, continuous flooding cultivation and water stress, were set under each NFAR. The relationships between root and shoot morphophysiology and grain yield in WDR were explored.ResultsThe results demonstrated the following: 1) under the same irrigation regime, the grain yield of two varieties increased with the increase of NFAR. Under the same NFAR, the reduction of irrigation amount significantly reduced the grain yield in Hyou 518 (7.1%–15.1%) but had no substantial influence on the grain yield in Hanyou 73. 2) Under the same irrigation regime, increasing the NFAR could improve the root morphophysiology (root dry weight, root oxidation activity, root bleeding rate, root total absorbing surface area, root active absorbing surface area, and zeatin + zeatin riboside contents in roots) and aboveground physiological indexes (leaf photosynthetic rate, non-structural carbohydrate accumulation in stems, and nitrate reductase activity in leaves) in two varieties. Under the same NFAR, increasing the irrigation amount could significantly increase the above indexes in Hyou 518 (except root dry weight) but has little effect on Hanyou 73. 3) Analysis of correlations revealed that the grain yield of Hyou 518 and Hanyou 73 was basically positively correlated with aboveground physiology and root morphophysiology, respectively.ConclusionThe grain yield could be maintained by water stress under medium NFAR in WDR. The improvement of root morphophysiology is a major factor for high yield under the irrigation regime and NFAR treatments in WDR.

Comparing combined application of biochar and nitrogen fertilizer in paddy and upland soils: Processes, enhancement strategies, and agricultural implications

Recently, biochar and N fertilizers have been used to tackle low N use efficiency (NUE) in crops across diverse environmental conditions. The coupling of biochar and N fertilizer may impact crop N utilization through different pathways in various soil types. However, there is currently a lack of comprehensive assessment of how coupling effects specifically influence N utilization in paddy and upland crops. We conducted a meta-analysis of 175 peer-reviewed studies to assess the responses of soil properties and crop traits in paddy and upland fields under coupling effects. The results indicate that NUE (+26.1 %) and N uptake (+15.0 %) in paddy fields increase more than in upland fields (+23.7 % and +8.0 %, respectively), with the coupling effect providing NH4+ predominantly for rice and NO3− for upland crops. NH4+ increases in paddy fields (+6.9 %) but decreases in upland fields (−0.7 %), while microbial biomass carbon (MBC) decreases in paddy fields (−2.9 %) and increases in upland fields (+36.0 %). These findings suggest that coupling effects supply soil inorganic nutrients in paddies and affect microbes in uplands, thereby positively affecting crop N utilization. Specifically, the greatest increase in paddy crop yield and N use efficiency occurs when the ratio of N fertilizer to biochar exceeds 1.5 %, and in uplands, it manifests when applying 10–20 t·ha−1 of biochar and <150 kg·ha−1 N fertilizer. In conclusion, this meta-analysis explores the differential effects of biochar and N fertilizer coupling in different arable land types, offering novel insights into the utilization strategies of biochar in agricultural fields.

Regulation of photoassimilate transportation and nitrogen uptake to decrease greenhouse gas emissions in ratooning rice with higher economic return by optimized nitrogen supplies

Mechanized harvesting of the main crop rice, with low stubble height in rice ratooning is scaling up, especially in Southeast China with a higher population density and less cultivated land. Currently, the common nitrogen fertilization for ratoon rice is concentrated within 20 days before and after the harvest of the main crop. However, this fertilization pattern may not be suitable for low stubble regenerative rice due to its extended growth period, leading to diminished nitrogen utilization efficiency and heightened greenhouse gas emissions, particularly nitrous oxide (N2O) emissions. It is imperative to explore a nitrogen fertilizer management model for clean production of low stubble ratoon rice (RR). In this study, we examined the effects of nitrogen fertilizer application rates and methods (single or split application) on yield and greenhouse gas emissions during the regrowth season. We employed a multi-criteria assessment approach combined with field measurements, energy analysis, environmental assessment, and economic evaluation on ratoon rice under various nitrogen fertilizer treatments. The results showed that the ratoon rice produced the highest total energy output under 67.5N+22.5N (Fertilize with 67.5kg nitrogen ha-1 and 22.5kg nitrogen ha-1 3 days after main season rice harvesting and during the heading stage of ratoon rice) treatment compared to the 90N+0N (conventional fertilization, apply 90kg nitrogen ha-1 fertilizer 3 days after harvesting at once) treatment. It was also found that reducing nitrogen application during the tillering stage reduced CH4 emissions, fertilization during the heading stage of the ratoon rice did not increase CH4 emissions, Since fertilization during the heading stage of ratoon rice did not lead to an increase in the partitioning of photoassimilates (photosynthetic product assimilates) to the rhizosphere soil, significant differences in sugar and acetic acid levels were not observed in the rhizosphere soil. As a result, no change was found in the expression of the methanogenic mcrA gene in the microbial community. The study also demonstrated that the 67.5N+22.5N treatment was able to promote the absorption of nitrogen nutrients, reduction in N2O emissions by 16.61%, subsequently increasing resource use efficiency, final yield and net ecosystem economic benefit by 5.96%, 7.19% and 5.57%, respectively, thereby decreasing carbon and nitrogen footprints by 6.64% and 3.50% compared with the 90N+0N treatment in the ratoon rice. These results suggest that a reasonable ratoon rice cultivation scheme is a promising farming system that can simultaneously improve resource use efficiency and economic profits, reduce greenhouse gas emissions and environmental footprint, while still maintaining the high productivity in ratoon rice.

Optimization of irrigation (ETc) and nitrogen levels under drip fertigation in okra (Abelmoschus esculentus L.) using response surface methodology (RSM)

A comprehensive field investigation was conducted to enhance the productivity, profitability, and water use efficiency (WUE) of summer okra through the optimization of irrigation and nitrogen fertilizer application. The study involved 3 irrigation levels – 0.75 Epan (pan evaporation) as I1, 1.00 Epan as I2, and 1.25 Epan as I3 – as the main plot factors, and 4 nitrogen concentrations – 75% recommended nitrogen dose (RDN) as N1, 100% RDN as N2, 125% RDN as N3, and 150% RDN as N4 – as the subplot variables. The results of the study revealed a significant influence of irrigation and nitrogen levels on various key parameters. Above-ground dry matter, yield, plant height, WUE, net returns, and benefit-to-cost ratio (B:C) exhibited an incremental trend with increasing irrigation and nitrogen levels, up to a certain threshold. Beyond this threshold, further increments in irrigation and nitrogen led to diminishing returns. The models developed for estimating crop yield, above-ground dry matter, plant height, WUE, net returns, and B:C demonstrated impressive accuracy, with high coefficients of determination (R2) and satisfactory precision. The optimized irrigation level (crop evapotranspiration, ETc) ranged from 418.39–441.23 mm. At the same time, the ideal nitrogen application rate was found to be in the range of 167.04–176.13 kg N/ha. These optimal conditions resulted in peak crop yield of 28 295 kg/ha, above-ground dry matter of 6 709.1 kg/ha, plant height of 66.3 cm, WUE of 5.26 kg/m3, B:C of 4.54, and net returns amounting to 441 133 INR/ha. In conclusion, the application of response surface methodology facilitated the identification of the impact of each factor on individual responses, as well as the determination of optimal conditions that simultaneously maximize multiple desirable outcomes. These findings hold significant promise for improving the cultivation of summer okra while optimizing resource use and economic returns.

Blended controlled-release nitrogen fertilizer increases rice post-anthesis nitrogen accumulation, translocation and nitrogen-use efficiency.

One-time application of blended controlled-release nitrogen fertilizer (CRN) has the potential to solve the difficulty of top-dressing fertilizer in the cultivation of rice and reduce the cost of CRN fertilizer application. However, its effects on rice dry matter and nitrogen (N) accumulation and translocation, yield and N-use efficiency (NUE) remain uncertain. Field experiments were carried out at three sites (Mingguang, Chaohu, and Guichi) in the Yangtze River Delta in China to compare the effects of the conventional split applications of urea and the blended CRN and on post-anthesis dry matter and N accumulation and translocation, yield, and NUE in rice at 0, 60, 120, 180, and 240kg N ha-1. The results showed that at the equal N application rates, compared under the conventional N fertilizer treatment, the blended CRN application significantly increased the rice yield by an average of 0.9-6.9%, mainly due to increase the number of spikelets per panicle. The highest yield achieved with blended CRN treatment occurred at 200kg N ha-1, with an NUE of 45.9%. Moreover, in comparison to the conventional N fertilizer, the blended CRN treatment increased pre-anthesis N translocation (Pre-NT) by 1.0-19.8%, and the contribution of pre-NT to grain N by 0.2-8.7%, and NUE by 3.2-28.4%. Meanwhile, the blended CRN treatment reduced labor costs by 1800 Yuan ha-1 and enhanced the economic gains by 21.5-68.8%. Therefore, one-time application of blended CRN ≤ 200kg N ha-1 application rate improved rice yield, NUE, and economic profit compared to equivalent rates of split applied conventional N fertilizers.

Comparative analysis of the effects of microplastics and nitrogen on maize and wheat: Growth, redox homeostasis, photosynthesis, and AsA-GSH cycle

Microplastics (MPs) pose a significant threat to the function of agro-ecosystems. At present, research on MPs has mainly focused on the effects of different concentrations or types of MPs on a crop, while ignoring other environmental factors. In agricultural production, the application of nitrogen (N) fertilizer is an important means to maintain the high yield of crops. The effects of MPs and N on growth parameters, photosynthetic system, active oxygen metabolism, nutrient content, and ascorbate-glutathione (AsA-GSH) cycle of maize and wheat were studied in order to explicit whether N addition could effectively alleviate the effects of MPs on maize and wheat. The results showed that MPs inhibited the plant height of both maize and wheat, and MPs effects on physiological traits of maize were more severe than those of wheat, reflecting in reactive oxygen metabolism and restriction of photosynthetic capacity. Under the condition of N supply, AsA-GSH cycle of two plants has different response strategies to MPs: Maize promoted enzyme activity and co-accumulation of AsA and GSH, while wheat tended to consume AsA and accumulate GSH. N application induced slight oxidative stress on maize, which was manifested as an increase in hydrogen peroxide and malonaldehyde contents, and activities of polyphenol oxidase and peroxidase. The antioxidant capacity of maize treated with the combination of MPs + N was better than that treated with N or MPs alone. N could effectively alleviate the adverse effects of MPs on wheat by improving the antioxidant capacity.

Effects of Nitrogen Fertilizer Doses and Application Methods on the Yield of Syr Suluy Rice in the Kyzylorda Region

Effects of Nitrogen Fertilizer Doses and Application Methods on the Yield of Syr Suluy Rice in the Kyzylorda Region

Inhibitory effect of ammonium conversion by deep nitrogen application effectively reduces gaseous nitrogen losses

Increasing the depth of nitrogen (N) fertilizer application is an effective agronomic management measure for mitigating NH3 volatilization and N2O emissions. However, the information about reasons for the reduction of gaseous N loss and the responses of soil N transformation processes to deep N fertilization is limited. This field experiment monitored NH3 volatilization, N2O emission, and soil NH4+/NO3- dynamics under three N application depths (8, 16, and 24 cm) in the typical soil of Loess Plateau (Cumulic Anthrosol) during 2021–2022 and 2022–2023. The N transformation rate under different soil depths was determined by laboratory 15N tracing experiments, and driving contributions of soil physicochemical properties and biological characteristics to gaseous N emissions were considered comprehensively. Our field results verified that increasing N fertilization depth effectively reduces NH3 volatilization and N2O emission by 20.7–55.6% and 17.9–45.8%; Simultaneously, deep N fertilization delayed the peak time of NH3 or N2O and retained a higher concentration of NH4+ in deep soil (37.3–46.4 mg kg−1). The 15N tracing experiments revealed that the lower soil enzymatic activity and microbial abundance in deep soil significantly decreased N mineralization, NH4+ consumption, and nitrification rates by 30.6–44.1%, 37.1–44.9%, and 22.5–31.1% (P < 0.05), compared with the shallow soil. Random forest analysis explored that the predictive factors of NH3 volatilization were soil urease activity, NH4+ consumption rate, soil NH4+, and TOC (P < 0.01). Interestingly, N2O emission was also mainly affected by soil urease activity, hydroxylamine oxidoreductase (HAO) activity, soil NH4+, and NO3- (P < 0.01); Through partial least squares path models (PLS-PMs), deep N fertilization mainly reduced risk of gaseous N loss by changing the environmental conditions required for N transformation and affecting the N mineralization and nitrification processes to limit NH4+ generation and consumption. This study provides a theoretical foundation for the demonstration and promotion of deep fertilization in the Loess Plateau.

Integration of anaerobic co-digestion of grass silage and cattle slurry within a livestock farming system in Ireland: Quantification of greenhouse gas emission reduction and nutrient flow

Pasture-based beef systems can provide cattle slurry and grass silage for anaerobic digestion (AD). However, sustainable production of these feedstocks within a livestock farm presents challenges. This study examined the farmland area required to provide slurry and grass silage for a 40 GWh biomethane plant, quantified greenhouse gas (GHG) emissions reduction and analyzed digestate management. Results indicated that 130 farms of 50 ha and a livestock unit (LU) of 2.1 LU/ha were required to meet the feedstock requirements of the AD plant. Assigning 15 % of the farmland to produce grass silage for AD decreased GHG emissions by 24 % compared to conventional beef farming. Depending on soil nutrient status, returning digestate to the farmland reduced the application of nitrogen, phosphorus and potassium fertilizers by up to 65 %, 33 % and 56 %, respectively. Future research should analyze the economic implication of biomethane production from these feedstocks at farm and supply chain scales.

NRT1.1B mediates rice plant growth and soil microbial diversity under different nitrogen conditions

Interactions between microorganisms and plants can stimulate plant growth and promote nitrogen cycling. Nitrogen fertilizers are routinely used in agriculture to improve crop growth and yield; however, poor use efficiency impairs the optimal utilization of such fertilizers. Differences in the microbial diversity and plant growth of rice soil under different nitrogen application conditions and the expression of nitrogen-use efficiency-related genes have not been previously investigated. Therefore, this study investigates how nitrogen application and nitrogen-use efficiency-related gene NRT1.1B expression affect the soil microbial diversity and growth indices of two rice varieties, Huaidao 5 and Xinhuai 5. In total, 103,463 and 98,427 operational taxonomic units were detected in the soils of the Huaidao 5 and Xinhuai 5 rice varieties, respectively. The Shannon and Simpson indices initially increased and then decreased, whereas the Chao and abundance-based coverage estimator indices decreased after the application of nitrogen fertilizer. Nitrogen fertilization also reduced soil bacterial diversity and richness, as indicated by the reduced abundances of Azotobacter recorded in the soils of both rice varieties. Nitrogen application initially increased and then decreased the grain number per panicle, yield per plant, root, stem, and leaf nitrogen, total nitrogen content, glutamine synthetase, nitrate reductase, urease, and root activities of both varieties. Plant height showed positive linear trends in response to nitrogen application, whereas thousand-grain weights showed a negative trend. Our findings may be used to optimize nitrogen fertilizer use for rice cultivation and develop crop-variety-specific strategies for nitrogen fertilizer application.

Effect of high frequency subsurface drip fertigation on plant growth and agronomic nitrogen use efficiency of red cabbage

High emissions of nitrogen to the environment are one of the major drawbacks of modern agriculture. Subsurface drip fertigation (SDF) is a technology to apply fertilizer in small amounts continuously and directly into the root zone with the potential of mitigating deep percolation losses when accurately managed. Our study was established to analyze possible benefits of SDF, i.e. nitrate losses reduction without decrease in yield, as alternative to the conventional application of nitrogen fertilizer. In this five-year field study, effects of SDF on red cabbage (Brassica oleracea) growth, yield, root distribution and nitrogen uptake were evaluated. The experiments took place in northern Germany. Application of fertilizer in a solution with water was managed to match the needs of crops and placed directly in the root zone through permanently buried driplines. The outcomes of crop growth under SDF were compared with a control crop receiving fertilizer at one or two dates by surface broadcasting. Yield and agronomic nitrogen use efficiency were higher for crops grown under SDF. Total dry mass increase was especially high under dry conditions (34%) but as well under wet conditions with efficient management (20%). Head dry mass of crops grown under SDF had a stronger reaction to the available nitrogen than crops under conventional application, with values of 0.19 and 0.1 Mg ha-1 per kg N ha-1 respectively. Moreover, SDF treatment resulted on average ca. 14 kg ha−1 higher nitrogen uptake. In SDF plots, yield formation and nitrogen uptake was higher for plants grown directly above drip lines. Effect of the distance to nitrogen source was supported with numerical simulations. The root structure showed different distributions for the two treatments, particularly in years with low rainfall. Overall, the results showed the potential of SDF to effectively control nitrogen supply, thereby increasing yield formation of marketable plant organs.

Determining the Profitability of Different NPSB and Nitrogen Fertilizer Rates on Yield and Yield Attributes of SweetPotato (Ipomoea batatas L.) in the Midland Areas of Guji Southern Oromia, Ethiopia

Sweet potato is a crucial crop for food security and income generation. Sweet potato vine length, number of stems, average number of roots per plant, average root weight, marketable root yield, non-marketable root yield, and total sweet potato root yield were determined by the NPSB and nitrogen fertilizer application rates (p&lt;0.01). Using the right fertilizer recommendations can improve crop growth and yield while minimizing resource use. Both NPSB and Nitrogen fertilizer rates had a highly significant impact on root number, root weight, marketable root yield, unmarketable root yield, and total root yield. The combination of 100 kg ha-1 NPSB fertilizer and 69 kg ha-1 of Nitrogen fertilizer gave the highest marketable root yield (553.09 qt ha-1). The treatment with 100 kg ha-1 NPSB fertilizer and 46 kg ha-1 Nitrogen fertilizer demonstrated the best result in terms of marginal rate of returns, with a marginal revenue of 17872%. To optimize sweet potato productivity in the Adola rede region, it is recommended to apply 100 kg ha-1 NPSB and 46 kg ha-1 nitrogen fertilizer. In general, cultivation in the Adola rede region can be optimized by applying a combination of 100 kg ha-1 of NPSB fertilizer and 46 kg ha-1 of nitrogen, resulting in improved plant growth and marketability, higher root yields and cost efficiency.

Optimizing irrigation and nitrogen fertilizer management to improve apple yield, quality, water productivity and nitrogen use efficiency: A global meta-analysis

Inappropriate strategies in water use and nitrogen (N) fertilizer application in apple production can decrease apple yield, water productivity (WP), nitrogen use efficiency (NUE), and quality, leading to severe environmental pollution. However, there is a lack of systematic analysis on the effects of water use and N fertilizer inputs on apple yield, quality, WP, and NUE at the global scale. Therefore, we conducted a comprehensive meta-analysis with 1834 observations from 72 published studies across 18 countries to assess the effects of water use and N inputs on apple yield, quality, WP, and NUE. We aim to quantify the potential for water-saving and N-saving for global apple production. Our results showed that the global average apple yield, organic acids (OA), total soluble solids (TSS), vitamin C (VC), firmness (FN), WP, and NUE were 34.7 t ha−1, 0.51 %, 13.9 %, 4.7 mg 100 g−1, 7.4 kg cm−2, 6.8 kg m−3, and 214.5 kg kg−1, respectively. Reducing above-optimal water input to optimal water input may increase apple yield by 19.4 %, WP by 36.1 %, OA by 12.5 %, TSS by 8.4 %, VC by 17.5 % and FN by 9.8 %, respectively. Reducing above-optimal N inputs to optimal N inputs may increase apple yield by 8.9 %, NUE by 48.1 %, OA by 10.7 %, TSS by 6.1 %, VC by 13.3 % and FN by 5.2 %, respectively. The overall global mean water-saving and N-saving potentials for apple production were 20.4 % (136 mm less water irrigated) and 37 % (203 kg ha−1 less N fertilizer used), respectively. Our findings provide guidance for water use and N fertilizer management of apple production and can thus help to improve/ maintain yield and quality for greatly saving water and N fertilizer.

Overexpression of rice OsNRT1.1A/OsNPF6.3 enhanced the nitrogen use efficiency of wheat under low nitrogen conditions.

Overexpression of OsNRT1.1A promotes early heading and increases the tolerance in wheat under nitrogen deficiency conditions. The application of inorganic nitrogen (N) fertilizers is a major driving force for crop yield improvement. However, the overuse of fertilizers significantly raises production costs and leads to environmental problems, making it critical to enhance crop nitrogen use efficiency (NUE) for the sake of sustainable agriculture. In this study, we created a series of transgenic wheat lines carrying the rice OsNRT1.1A gene, which encodes a nitrate transporter, to investigate its possible application in improving NUE in wheat. The transgenic wheat exhibited traits such as early maturation that were highly consistent with the overexpression of OsNRT1.1A in Arabidopsis and rice. However, we also observed that overexpression of the OsNRT1.1A gene in wheat can facilitate the growth of roots under low N conditions but has no effect on other aspects of growth and development under normal N conditions. Thus, it may lead to the improvement of wheat low N tolerance,which is different from the effects reported in other plants. A field trial analysis showed that transgenic wheat exhibited increased grain yield per plant under low N conditions. Moreover, transcriptome analysis indicated that OsNRT1.1A increased the expression levels of N uptake and utilization genes in wheat, thereby promoting plant growth under low N conditions. Taken together, our results indicated that OsNRT1.1A plays an important role in improving NUE in wheat with low N availability.

Insights into CO2 and N2O emissions driven by applying biochar and nitrogen fertilizers in upland soil

Biochar and soil carbon sequestration hold promise in mitigating global warming by storing carbon in the soil. However, the interaction between biochar properties, soil carbon-nitrogen cycling, and nitrogen fertilizer application's impact on soil carbon-nitrogen balance remained unclear. Herein, we conducted batch experiments to study the effects and mechanisms of rice straw biochar application (produced at 300, 500, and 700 °C) on net greenhouse gas emissions (CO2, N2O, CH4) in upland soils under different forms of nitrogen fertilizers. The findings revealed that (NH4)2SO4 and urea significantly elevated soil carbon dioxide equivalent emissions, ranging from 28 to 61.7 kg CO2e/ha and 8.2 to 37.7 kg CO2e/ha, respectively. Conversely, KNO3 reduced soil CO2e emissions, ranging from 2.2 to 13.6 kg CO2e/ha. However, none of these three nitrogen forms exhibited a significant effect on CH4 emissions. The pyrolysis temperature of biochar was found negatively correlated with soil CO2 and N2O emissions. The alkaline substances presented in biochar pyrolyzed at 500–700 °C raised soil pH, increased the ratio of Gram-negative to Gram-positive bacteria, and enhanced the relative abundance of Sphingomonadaceae. Moreover, the co-application of KNO3 based nitrogen fertilizer and biochar increased the total carbon/inorganic nitrogen ratio and reduces the relative abundance of Nitrospirae. This series of reactions led to a significant increase in soil DOC content, meanwhile reduced soil CO2 emissions, and inhibited the nitrification process and decreased the emission of soil N2O. This study provided a scientific basis for the rational application of biochar in soil.

DESCOMPOSICIÓN Y LIBERACIÓN DE NITRÓGENO DE LOS RESIDUOS DE CAÑA DE AZÚCAR (Saccharum officinarum L.) COMBINADOS CON EL FOLLAJE DE PLANTAS LOCALES

&lt;p&gt;&lt;strong&gt;Background&lt;/strong&gt;: Green post-harvest sugarcane residues (&lt;em&gt;Saccharum officinarum&lt;/em&gt;) present low rates of decomposition and N release in the short term when integrated into the production system. Combining &lt;em&gt;S. officinarum&lt;/em&gt; residues with the foliage of local plants rich in nitrogen could be an alternative to accelerate the decomposition process of residues with a positive impact on soil conservation. &lt;strong&gt;Objective&lt;/strong&gt;: To evaluate and compare the decomposition patterns and potential release of N to the soil of the residues of &lt;em&gt;S. officinarum&lt;/em&gt; variety MEX 69-290, with the addition of different foliage such as &lt;em&gt;Clitoria ternatea&lt;/em&gt;, &lt;em&gt;Leucaena leucocephala&lt;/em&gt; and &lt;em&gt;Tithonia diversifolia&lt;/em&gt;, in southern Quintana Roo. &lt;strong&gt;Methodology&lt;/strong&gt;: The treatments evaluated were the following: Clitoria + MEX 69-290, Leucaena + MEX 69-290, Tithonia + MEX 69-290, and MEX 69-290 (control). The materials were placed in decomposition bags and incubated on the ground in four periods (15, 30, 60 and 120 days), in a completely randomized design. The contents of dry matter, nitrogen and lignin were determined for the initial and remaining material in each period. &lt;strong&gt;Results&lt;/strong&gt;: With the integration of local plants, a significant increase in the percentage of decomposition and release of N was obtained. After 120 days of evaluation, the decomposition values were 71.3, 50.4, 48.1 and 33.5%, for the Tithonia + MEX 69-290, Clitoria + MEX 69-290, Leucaena + MEX 69-290, and MEX 69-290 control, respectively. Likewise, the potential N release values were 98.2, 95.3, 92.9 and 58.7%, for Tithonia + MEX 69-290, Leucaena + MEX 69-290, Clitoria + MEX 69-290, and MEX 69-290 control. The Tithonia + MEX 69-290 treatment had the highest relative decomposition rate (0.009 g g&lt;sup&gt;-1&lt;/sup&gt; day&lt;sup&gt;-1&lt;/sup&gt;) and a high potential N release rate (0.053 g g&lt;sup&gt;-1&lt;/sup&gt; day&lt;sup&gt;-1&lt;/sup&gt;), compared to the other treatments. &lt;strong&gt;Implications&lt;/strong&gt;: The integration of N-rich plants can increase the decomposition and release of N from sugarcane residues, with potential in plant assimilation from the first crop cycle, reduce the application of nitrogen fertilizer and increase sugarcane yields. in the region. &lt;strong&gt;Conclusion&lt;/strong&gt;: The combination of &lt;em&gt;S. officinarum&lt;/em&gt; residues with foliage of local plants, particularly &lt;em&gt;T. diversifolia&lt;/em&gt;, could be considered a viable strategy to accelerate the decomposition process and release of N in residues on the edaphoclimatic conditions of southern Quintana Roo.&lt;/p&gt;