Excessive 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

BackgroundRice (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.ResultsThe 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: 0 kg/ha (no nitrogen; 0N), 240 kg/ha (moderate nitrogen; MN), and 300 kg/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.ConclusionOur 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.

The contribution of natural and anthropogenic causes to soil acidification rates under different fertilization practices and site conditions in southern China

Excessive application of mineral fertilizers has accelerated soil acidification in China, affecting crop production when the pH drops below a critical value. However, the contributions of natural soil acidification, induced by leaching of bicarbonate, and anthropogenic causes of soil acidification, induced by nitrogen (N) transformations and removal of base cations over acid anions, are not well quantified. In this study, we quantified soil acidification rates, in equivalents (eq) of acidity, by assessing the inputs and outputs of all major cations and anions, including calcium, magnesium, potassium, sodium, ammonium, nitrate, bicarbonate, sulphate, phosphate and chloride, for 13 long-term experimental sites in southern China. The acidification rates strongly varied among fertilizer treatments and with the addition of animal manure. Bicarbonate leaching was the dominant acid production process in calcareous soils (23 keq ha−1 yr−1) and in non-calcareous paddy soils (9.6 keq ha−1 yr−1), accounting for 80 % and 68 % of the total acid production rate, respectively. The calcareous soils were strongly buffered, and acidification led no or a limited decline in pH. In contrast, N transformations were the most important driver for soil acidification at one site with upland crops on a non-calcareous soil, accounting for 72 % of total acid production rate of 8.4 keq ha−1 yr−1. In this soil, the soil pH considerably decreased being accompanied by a substantial decline in exchangeable base cation. Reducing the N surplus decreased the acidification rate with 10 to 54 eq per kg N surplus with the lowest value occurring in paddy soils and the highest in the upland soil. The use of manure, containing base cations, partly mitigated the acidifying impact of N fertilizer inputs and crop removal, but enhanced phosphorus (P) accumulation. Combining mineral fertilizer, manure and lime in integrative management strategies can mitigate soil acidification and minimize N and P losses.

Body size: A hidden trait of the organisms that influences the distribution of antibiotic resistance genes in soil

Body size is a key life-history trait of organisms, which has important ecological functions. However, the relationship between soil antibiotic resistance gene (ARG) distribution and organisms' body size has not been systematically reported so far. Herein, the impact of organic fertilizer on the soil ARGs and organisms (bacteria, fungi, and nematode) at the aggregate level was analyzed. The results showed that the smaller the soil aggregate size, the greater the abundance of ARGs, and the larger the body size of bacteria and nematodes. Further analysis revealed significant positive correlations of ARG abundance with the body sizes of bacteria, fungi, and nematodes, respectively. Additionally, the structural equation model demonstrated that changes in soil fertility mainly regulate the ARG abundance by affecting bacterial body size. The random forest model revealed that total phosphorus was the primary soil fertility factor influencing the body size of organisms. Therefore, these findings proposed that excessive application of phosphate fertilizers could increase the risk of soil ARG transmission by increasing the body size of soil organisms. This study highlights the significance of organisms' body size in determining the distribution of soil ARGs and proposes a new disadvantage of excessive fertilization from the perspective of ARGs.

Effects of Different Organic Fertilizer Substitutions for Chemical Nitrogen Fertilizer on Soil Fertility and Nitrogen Use Efficiency of Foxtail Millet

Conventional fertilizer management can destroy the structure of soil. Replacing chemical fertilizers with organic fertilizers can improve soil quality and nitrogen use efficiency. We aimed to study the effects of organic fertilizer substitutions for chemical nitrogen fertilizer on soil fertility and nitrogen use efficiency in order to clarify the effectiveness of the available nutrient management measures in improving soil quality and increasing foxtail millet yield. A field experiment was carried out over two consecutive years, and a total of six treatments were set up: no fertilizer (CK), chemical nitrogen fertilizer alone (N), the substitution of 25% of chemical nitrogen fertilizer with bio-organic fertilizer (N25A1), the substitution of 25% of chemical nitrogen fertilizer with fermented mealworm manure (N25B1), the substitution of 50% of chemical nitrogen fertilizer with bio-organic fertilizer (N50A2), and the substitution of 50% of chemical nitrogen fertilizer with fermented mealworm manure (N50B2). The results of this study show the following: (1) Compared with chemical nitrogen fertilizer, the substitution of organic fertilizer for nitrogen fertilizer reduced the bulk density and solid phase of the soil, and it increased the total porosity, water content, liquid phase, and gas phase of the soil. (2) Compared with nitrogen fertilizer, the use of an organic fertilizer increased the contents of nitrate nitrogen, ammonium nitrogen, and total nitrogen in the soil by 13.59~52.56%, 4.47~18.27%, and 4.40~12.09%, respectively. The content of alkaline nitrogen increased by 1.70~32.37%, and the contents of soil available potassium, available phosphorus, and organic matter also increased. (3) The activities of sucrase, urease, glutaminase, and asparaginase were improved by replacing chemical nitrogen fertilizer with organic fertilizer. The N25 treatments performed better than the N50 treatments, and fermented mealworm manure performed better than biological organic fertilizer. (4) A moderate application of organic fertilizer (N25) can increase the grain yield, ear weight, grain weight, and 1000-grain weight of foxtail millet, whereas excessive application of organic fertilizer (N50) can reduce foxtail millet yield. (5) Replacing chemical nitrogen fertilizer with organic fertilizer can improve the agronomic use efficiency, physiological efficiency, biased productivity, harvest index, and apparent use efficiency of nitrogen fertilizer. In this study, the substitution of 25% of chemical nitrogen fertilizer with fermented mealworm manure was the best combination for restoring crop productivity and soil quality.

Effects of Water and Nitrogen Control on the Growth Physiology, Yields, and Economic Benefits of Lycium barbarum Plants in a Lycium barbarum + Alfalfa System.

In the production of economic forests, there are common issues such as excessive application of water and fertilizer, redundant plant growth, and low economic benefits. Reasonable water and fertilizer management can not only help address these problems but also improve the absorption and use efficiency of water and fertilizer resources by plants, promoting the green and efficient development of the fruit and forestry industry. In order to explore a suitable water and nitrogen management mode for Lycium barbarum, field experiments were conducted in this study from 2021 to 2022. Specifically, four irrigation modes (according to the proportion ratio of soil moisture content to field moisture capacity θf, 45-55% θf (W1, severe water deficiency), 55-65% θf (W2, moderate water deficiency), 65-75% θf (W3, mild water deficiency), and 75-85% θf (W4, sufficient irrigation)) and four nitrogen application levels (0 kg·ha-1 (N0, no nitrogen application), 150 kg·ha-1 (N1, low nitrogen application level), 300 kg·ha-1 (N2, medium nitrogen application level), and 450 kg·ha-1 (N3, high nitrogen application level)) were set up to analyze the influences of water and nitrogen control on the plant height, stem diameter, chlorophyll content, photosynthetic characteristics and yield, and economic benefits of Lycium barbarum in the Lycium barbarum + Alfalfa system. The study results show that the plant height and stem diameter increment of Lycium barbarum increase with the irrigation amount, increasing first and then decreasing with the increase in the nitrogen application level. Meanwhile, the chlorophyll contents in Lycium barbarum continuously increase throughout their growth periods, with Lycium barbarum treated with W4N2 during all growth periods presenting the highest contents of chlorophyll. In a Lycium barbarum + Alfalfa system, the daily variation curve of the Lycium barbarum net photosynthetic rate presents a unimodal pattern, with maximum values of the daily average net photosynthetic rate and daily carboxylation rate appearing among W4N2-treated plants (19.56 μmol·m-2·s-1 and 157.06 mmol·m-2·s-1). Meanwhile, the transpiration rates of Lycium barbarum plants continuously decrease with the increased degree of water deficiency and decreased nitrogen application level. W1N2-treated plants exhibit the highest leaf daily average water use efficiency (3.31 μmol·s-1), presenting an increase of 0.50-10.47% in efficiency compared with plants under other treatments. The coupling of water and nitrogen has significantly improved the yields and economic benefits of Lycium barbarum plants, with W4N2-treated and W3N2-treated plants presenting the highest dried fruit yield (2623.07 kg·ha-1) and net income (50,700 CNY·ha-1), respectively. Furthermore, compared with other treatment methods, these two treatment methods (W4N2 and W3N2) exhibit increases of 4.04-84.08% and 3.89-123.35% in dried fruit yield and net income indexes, respectively. Regression analysis shows that, in a Lycium barbarum + Alfalfa system, both high yields and economic benefits of Lycium barbarum plants can be achieved using an irrigation amount of 4367.33-4415.07 m3·ha-1 and a nitrogen application level of 339.80-367.35 kg·ha-1. This study can provide a reference for improving the productivity of Lycium barbarum plants and achieving a rational supply of water and nitrogen in Lyciun barbarum + Alfalfa systems in the Yellow River Irrigation Area of Gansu, China, and other similar ecological areas.

Green finance reform and application intensity of chemical fertilizer and pesticide: policy evidence from China.

The environmental hazards resulting from the excessive application of pesticides and fertilizers have been an inevitable agricultural production issue in various countries around the world. New technologies and policies are constantly trying to improve their application efficiency. This paper utilizes panel data of the provincial level in China from 2009 to 2019 to empirically study the effect of green finance reform policies on the chemical fertilizer application intensity (FAI) and pesticide application intensity (PAI). Standard difference-in-differences (DID), synthetic DID, difference-in-difference-in differences (DDD), and spatial DID models are constructed for specific empirical analysis. The findings can be concluded as follows: (1) A unit of the green finance reform policy reduces FAI by 0.0144 and PAI by 1.7921 by promoting green technology innovation. (2) Government financial extractive capacity hinders the reduction effect of green finance on PAI. (3) Coastal geographical location is conducive to reducing PAI through green finance reform. (4) FAI and PAI show positive spatial autocorrelations, and the influence of green finance reform overflows to surrounding areas. The research results can provide policy references for countries around the world to promote the green development of agriculture and reduce environmental pollution.

Soil bacterial community characteristics and its effect on organic carbon under different fertilization treatments.

By implementing small-scale and efficient fertilization techniques, it is possible to enhance the activity of microorganisms, thereby improving soil carbon sequestration and ecological value in agriculture. In this study, field experiments were conducted using various types of fertilizers: organic fertilizer, microbial fungal fertilizer, composite fertilizer, and an unfertilized control (CK). Additionally, different dosages of compound fertilizers were applied, including 0.5 times compound fertilizers, constant compound fertilizers, 1.5 times compound fertilizers and CK. Using advanced technologies such as Illumina MiSeq high-throughput sequencing, PICRUSt2 prediction, Anosim analysis, redundancy analysis, canonical correlation analysis, and correlation matrix, soil organic carbon (SOC) content and components, bacterial diversity, metabolic functions, and interaction mechanisms were examined in different fields. The results showed pronounced effects of various fertilization modes on SOC and the bacterial community, particularly in the topsoil layer (0-20 cm). Organic fertilizer treatments increased the richness and diversity of bacterial communities in the soil. However, conventional doses and excessive application of compound fertilizers reduced the diversity of soil bacterial communities and SOC content. Additionally, different fertilization treatments led to an increase in easily oxidizable organic carbon (EOC) contents. Interestingly, the relationship between SOC components and soil bacteria exhibited inconsistency. EOC was positively correlated with the bacterial diversity index. Additionally, Chloroflexi exhibited a negative correlation with both SOC and its components. The influence of metabolismon primary metabolic functions on the content of SOC components in the soil was more notable. It included seven types of tertiary functional metabolic pathways significantly correlated with SOC components (p < 0.05). These findings enhance the understanding of the relative abundance of bacterial communities, particularly those related to the carbon cycle, by adjusting agricultural fertilization patterns. This adjustment serves as a reference for enhancing carbon sinks and reducing emissions in agricultural soils.

Study on the Effects of Reducing Nitrogen Fertilizer: Stabilizing Yield and Carbon Sequestration by Synergistic Utilization of Chinese Milk Vetch and Rice Straw in Double-Cropping Rice Area

The excessive application of chemical fertilizers in rice fields exacerbates soil degradation and poses a threat to food security. Achieving an increase in rice production and minimizing environmental costs are inevitable requirements for achieving sustainable rice production. The synergistic utilization of rice straw (RS) and Chinese milk vetch (MV) is a sustainable measure to improve soil quality in Southern China. How this management strategy impacts agricultural productivity and soil carbon (C) sequestration under different fertilization conditions is unclear. Several treatments, including only chemical fertilizer (F), F + MV (FM), F + RS (FS), and F + MV + RS (FMS) under a standard rate of nitrogen (N100) and 40% reduced nitrogen (N60) levels were designed to explore changes in rice yields and soil organic carbon (SOC) concentrations, stocks, and soil labile organic C fractions (permanganate oxidizable C) during 2018–2020 in a double-rice-cropping system. The results show that the FMS treatment reduced soil bulk density to alleviate soil compaction and improved the soil carbon management index. The synergistic utilization of MV and RS replacing 40% of the chemical N fertilizer could still maintain the rice yield. Compared to the F treatment, the average annual grain yield was significantly increased by 9.82% and 5.84% in the FMS treatment; SOC concentration was increased by 16.05% and 19.98% on average (p &lt; 0.05), and SOC stock was increased by 1.78 Mg C ha−1 and 2.37 Mg C ha−1 under the N60 and N100 levels, respectively. The random forest regression model and correlation analysis demonstrated that the inputs of chemical N, organic N and C, and appropriate C/N ratio promoted soil C accumulation. Furthermore, the structural equation model analysis exhibited that the C input affects the highly labile organic carbon (HLOC) and total labile organic carbon (LOC); the HLOC had a positive effect on SOC (p &lt; 0.05). N input had a significant effect on LOC and yield. Our results suggest that the synergistic utilization of MV and RS plays an important role in ensuring stable grain production, improving soil C sequestration capacity, and maintaining soil environmental health in Southern China.

Sustainable Economic Impact of Seed Replacement Rate on Production of Mustard Seed: A Case Study on Murshidabad District of West Bengal, India

"Quality Seeds are the critical determinant of different agro-climatic zones for sustainable planning in agricultural production. It is necessary to raise the supply of quality seeds of different crops in sufficient quantity at reasonable prices for farmers at the right time in the state. New seeds are either Certified Seeds (CS) or Hybrid Seeds. A better Seed Replacement Rate (SRR) presents a better application of Certified or Quality Seed or Hybrid Varieties Seeds (HYV). It plays a major role in agriculture to raise the production of crops. In this research paper, we have analysed the impact of Seed Replacement Rate on the production of Mustard Seeds during the period 2022-23 in the Jarur Gram Panchayat (GP) of Block Raghunathganj-I, Murshidabad District, West Bengal. The data have been collected by the stratified random sampling procedure. With the help of collected data, we have formed a Coob-Douglas Type of production function and which is estimated by the Ordinary Least Square Method. From the collected data, it has been observed that the average Seed Replacement Rate is 38.52 percent which is below the state average (53.2%). We have also noticed that 30.43 percent farmers have used farm-saved seeds and only 17.4 percent farmers have used hundred percent new seeds. The estimated result has proved that Seed Replacement Rate is a key determinant to raise both production, productivity and economic benefits. If Seed Replacement increases production also will increase and thereby there would be economic leverage. It has also been found that farm size with Seed Replacement Rate is not a significant factor in increasing the production of Mustard Seeds. Another interesting finding is that seventy percent of farmers have used inorganic fertilizers. They have applied excessive chemical fertilizers which is greater than the government’s prescribed norm. However, from the estimated result we have observed that the Seed Replacement Rate according to different farm sizes with excessive application of fertilizers does not influence both the production and productivity of Mustard Seeds. From an economic standpoint of view, new seeds are better than farm-saved seeds (old seeds) as their gross income increases."

Responses of labile organic carbon fractions and mineralized carbon to straw return combined with fertilizer application in the maize–Melilotus officinalis intercropping system

AbstractMollisol is crucial for solving food security issues, but long‐term excessive application of chemical fertilizers has led to severe Mollisol degradation in Northeast China, especially a rapid decline in soil organic carbon (SOC). In context of the use of crop‐herbage intercropping and straw return as alternatives for some chemical fertilizers, it is important to understand how crop‐herbage intercropping and straw return combined with chemical fertilizers influence labile organic carbon (LOC) fractions that improve SOC. To address this, this study explored how the combined application of maize (Zea mays L.)–Melilotus officinalis intercropping, straw return, and chemical fertilizers affect LOC fractions and mineralized carbon (MC) from the perspective of physical property‐mediated pathways. Thus, a field experiment with six treatments was established in the Songnen Plain of Northeast China: (1) maize monoculture without chemical fertilizers and straw return (CK), (2) maize monoculture with chemical fertilizers and no straw return (CF), (3) maize monoculture with chemical fertilizers and straw return (CFS), (4) maize–M. officinalis intercropping and straw return combined with full application of chemical fertilizers (CFSM), (5) maize–M. officinalis intercropping and straw return combined with half application of chemical fertilizers (1/2CFSM), and (6) maize–M. officinalis intercropping and straw return without chemical fertilizers (SM). The CF and CFS groups had no effect on bulk density and porosity but reduced specific gravity. The CFSM group increased water contents, porosity, LOC fractions, SOC, MC, and CO2 release rate and decreased bulk density and specific gravity. Compared with the CF group, the 1/2CFSM group enhanced water contents, microbial biomass carbon, and water‐soluble organic carbon (WSOC) to 6.36%, 17.91%, and 11.6%, respectively. We found that maize–M. officinalis intercropping, straw return, and reducing chemical fertilizers application improved LOC fractions to increase SOC by positively affecting bulk density, specific gravity, and water contents. Further analysis indicated that WSOC was a key determinant of SOC and maize yields. These findings provide a strategy to increase SOC and rehabilitate degraded soils through crop‐herbage intercropping and straw return combined with reducing chemical fertilizers application, which will contribute to a sustainable and environmentally friendly agriculture.

Different “nongrain” activities affect the accumulation of heavy metals and their source-oriented health risks on cultivated lands

“Nongrain” production on cultivated land is one of the primary environmental issues in China. Different “nongrain” activities may introduce different pollution sources to the local environment, leading to variations in heavy metal contents in soil, which can profoundly impact national food security. In this study, three typical “nongrain” regions (Nanxun (NX), Xiaoshan (XS) and Lin'an (LA)) with intensive aquaculture, tea planting and flower (seedling) growth on cultivated land around the Hangzhou metropolitan area were selected to address the spatial heterogeneity of accumulation levels, sources and source-oriented health risks of heavy metals in soil. The results showed that Hg was the main pollutant in NX and XS, while Cd and As were the major contaminants in LA. Aquiculture and sericultural industries (37.43%), natural sources (23.59%) and industrial activities (38.99%) were the major sources in NX; atmospheric deposition (37.73%), flower and seedling planting (23.49%) and metal-related industries (35.16%) were the major sources in XS; and atmospheric deposition (28.06%), excessive application of fertilizers and pesticides during tea planting (43.47%) and natural sources (28.47%) were the major sources in LA. The major risk population, area, exposure route and hazardous elements were children, LA, ingestion and As and Cr, respectively. From the perspective of source-based health risk assessment, in addition to natural sources that are difficult to intervene in, industrial activities, especially leather and wood process industries, metal-related industries and excessive fertilizer and pesticide application during tea planting contributed the most to the total health risk, which explained 67%, 41% and 42%, respectively, of the total risk in NX, XS and LA. High health risks are present in sources with heavy loadings of hazardous heavy metals (As and Cr); thus, to protect human health, the corresponding high-risk anthropogenic pollution sources in different “nongrain” areas need to be controlled.

Moderate nitrogen application facilitates Bt cotton growth and suppresses population expansion of aphids (Aphis gossypii) by altering plant physiological characteristics.

Excessive application of nitrogen fertilizer in cotton field causes soil and water pollution as well as significant increase of aphid population. Reasonable fertilization is an important approach to improve agricultural production efficiency and reduce agriculture-derived pollutions. This study was aimed to explore the effects of nitrogen fertilizer on the Bt cotton physiological characteristics and the growth and development of A. gossypii, a sap-sucking cotton pest. Five different levels of Ca(NO3)2 (0.0 g/kg, 0.3 g/kg, 0.9 g/kg, 2.7 g/kg and 8.1 g/kg) were applied into vermiculite as nitrogen fertilizer in order to explore the effects of nitrogen fertilizer on the growth and development of Bt cotton and aphids. The results showed that the medium level of nitrogen fertilizer (0.9 g/kg) effectively facilitated the growth of Bt cotton plant and suppressed the population expansion of aphids, whereas high and extremely high nitrogen application (2.7 and 8.1 g/kg) significantly increased the population size of aphids. Both high and low nitrogen application benefited aphid growth in multiple aspects such as prolonging nymph period and adult lifespan, enhancing fecundity, and improving adult survival rate by elevating soluble sugar content in host Bt cotton plants. Cotton leaf Bt toxin content in medium nitrogen group (0.9 g/kg) was significantly higher than that in high (2.7 and 8.1 g/kg) and low (0.3 g/kg) nitrogen groups, but Bt toxin content in aphids was very low in all the nitrogen treatment groups, suggesting that medium level (0.9 g/kg) might be the optimal nitrogen fertilizer treatment level for promoting cotton seedling growth and inhibiting aphids. Overall, this study provides insight into trophic interaction among nitrogen fertilizer levels, Bt cotton, and cotton aphid, and reveals the multiple effects of nitrogen fertilizer levels on growth and development of cotton and aphids. Our findings will contribute to the optimization of the integrated management of Bt cotton and cotton aphids under nitrogen fertilization.

DEVELOPMENT OF THE SOWING SYSTEM OF THE SOWING COMPLEX FORINTERNAL-SOIL DIFFERENTIATED MINERAL FERTILIZER WITH SIMULTANEOUS SOWING OF CEREAL

The issue of increasing the effectiveness of post-sowing intra-soil differentiated application of the main and starting dose of granular mineral fertilizers in the system of precision agriculture is considered. The need to use differential application of granular mineral fertilizer and machines that ensure high-quality performance of this technological process, taking into account the heterogeneity of the content of nutrients in the soil in certain areas of the field, is indicated. It is also indicated the need to develop and introduce into production highly accurate automated information technologies based on the use of high-performance means of mechanization. The indicated shortcomings of modern seeding machines: lack of adaptability for simultaneous differentiated introduction of the main and starting dose, as a result of which they lack highly adapted dispensers, appropriate control and management systems. The construction and technological scheme of the seeding complex is proposed and the pneumatic seeding system of this unit is developed for post-sowing intra-soil differentiated application of the main and starting dose of granular mineral fertilizers in the precision farming system. The proposed seeding complex will make it possible to eliminate the excessive application of mineral fertilizers, which can cause an increase in the activation of microbiological processes in the soil and have negative ecological consequences, leading to the deterioration of the physic-chemical and biological properties of the soil. The use of resource-saving technologies of precision agriculture in the agro-industrial complex of Ukraine will allow to ensure the management of production processes at the expense of information technologies, robotic and automated systems, which will allow to bring domestic agricultural enterprises to a new level.

Effect of tillage, fertilizers and storage structures on quality shelf life of white yam (Dioscorea rotundata Poir) in south west Nigeria

This study examined the effect of tillage, fertilizers and storage structures on quality shelf life of white yam in South West Nigeria. The study was a factorial experiment consisting of Tillage, Fertilizers and Storage Structure. The tillage system involved Heap Tillage (HT) and Ridge Tillage (RT), while Fertilizers involved Poultry Manure (PM), N15P15K15 (NPK) and Control (CLT) and two types of Storage Structures namely; Traditional Barn (TB) and Open Sided Storage Structure (OSSS) were combined to form the treatments. The experiment was a 2x3x2 factorial combination arranged in a Randomised Complete Block Design (RCBD). The treatments were replicated three times for each location respectively. A total of 72 ridges and 144 heaps were used to make a population of 288 plants per location. The tubers were weighed to ensure uniformity before planting. The plot size was 18mx18m square with a pathway of 1.0m between blocks making a total of 324 square metres. At harvest, the tubers were weighed immediately. They were then kept separately in the two storage structures namely: Traditional Barn (TB) and the Open Side Storage Structure (OSSS) for a period of 3 months. After the 3rd months of storage, the tubers were examined and data collected. The weight of each tuber from each storage structure was taken periodically to evaluate the weight loss and assess the keeping quality periodically. The findings of this study demonstrated the significant influence of tillage, fertilizers, and storage structures on the quality, shelf life, nutrient use efficiency, and nutrient composition of white yam. Excessive fertilizer application was found to increase rotting and deterioration levels. Hence, farmers and stakeholders should carefully consider fertilizer application rates to minimize post-harvest losses and enhance food security. Further investigations are needed to explore the underlying mechanisms responsible for the observed effects and to optimize fertilizer management practices for yam storage. Organic fertilization enhances the nutrient use efficiency and nutritional quality of yam, while appropriate storage structures, play a crucial role in preserving the quality and extending the shelf life of the harvested tubers. Based on the result of the study, open sided storage should be considered by producers of yams for storing their harvested tubers due to the facts that, it performed well in minimizing nutrient lost, weight loss and decay to considerable level and prevented pests/rodents attack on yam tubers.

Effects and regulation Mechanisms of Phosphorus Fertilizer on Soil Carbon Cycle

This paper reviews the effects and regulation mechanisms of phosphorus fertilizer on soil carbon cycle, which is an important process for soil fertility, productivity, and climate change and introduces the background, significance, main pathways, mechanisms, influencing factors, research progress and challenges. The paper shows that phosphorus fertilizer can affect soil carbon cycle through various pathways, such as affecting plant productivity and carbon allocation, soil organic matter decomposition and mineralization, soil microbial community and function, and soil aggregate formation and stability. The paper also shows that the effects of phosphorus fertilizer on soil carbon cycle are influenced by many factors, such as the type, amount, application method and time of phosphorus fertilizer, and the soil type, climate condition, vegetation type and management measures. The paper concludes that the effects of phosphorus fertilizer on soil carbon cycle are both positive and negative, direct and indirect, short-term and long-term, local and global, forming a complex impact network. The paper suggests that more research is needed to clarify the mechanisms, interactions and feedbacks of the effects of phosphorus fertilizer on soil carbon cycle, and to develop effective models and indicators to evaluate and predict the effects of phosphorus fertilizer on soil carbon cycle. The paper also suggests that rational application of phosphorus fertilizer and scientific management of soil carbon cycle are important for improving crop phosphorus use efficiency, reducing excessive application of phosphorus fertilizer, protecting water resources and soil quality, and mitigating climate change.

Land management policy shift influenced seasonal variation of erosion-induced nitrogen and phosphorus outputs from intensive agricultural catchment

A shift in policy to intensive agricultural production and land management often leads to excessive fertilizer application and accelerated erosion with consequent detrimental effects to water bodies. We investigated the impact of that shift by quantifying the spatial and temporal change in sediment sources and associated total nitrogen (TN) and total phosphorus (TP) pollutants output loads in an intensive agricultural catchment in North China across one year (November 2021–November 2022). We describe the implications of this work for intensive agriculture elsewhere in China and other countries. Seasonal sediment source apportionment was estimated at the catchment outlet using Berillium-7 (7Be) combined with compound-specific stable isotope (CSSI) signatures from sources and sediments. Diagnostic ‘fingerprints’ in MixSIAR were used to discriminate sediment sources between forest and crop farmland converted from forest (F + C(F)), crop farmland (C), and vegetable farmland (V). Our study identified F + C(F) as the dominant sediment source (mean 55.24 ± 2.91 %), intermediate on V (mean 30.06 ± 2.20 %), and least on C (mean 14.70 ± 2.13 %). Sedimentation ranged from 37.98 ± 3.02 to 89.60 ± 12.68 t·ha−1·event−1 and coincided with shifted land use policy and rainfall distribution. The TN and TP in sediment were both mainly derived from F + C(F) (averaged 22.27 ± 4.26 t·event−1 and 11.62 ± 2.28 t·event−1) and least from V (averaged 1.63 ± 0.29 and 2.09 ± 0.33 t·event−1). Despite being a significant sediment source, V contributed little sediment TN and TP input for eutrophication. Our findings imply that F + C(F) are diffuse sources of catchment pollution over the short term. These results describe the successful use of CSSI and 7Be to cost-effectively quantify the seasonal variation of sediment TN and TP loads from land-use-specific sources in the catchment under shifting land management policy in China with potential for use elsewhere. These findings enable soil conservation strategies and land management practices optimized for implementing targeted pollutant abatement initiatives in intensive agriculture in China and elsewhere.

Intensive agricultural management-induced subsurface accumulation of water-extractable colloidal P in a Vertisol

Abstract. Long-term excessive application of mineral fertilizer leads to phosphorus (P) accumulation, increasing the risk of P migration and loss from the soil profile. The colloids in the soil profile are important carriers for P migration due to their high P adsorption and transport capacity. It is not clearly understood how colloidal P (CP) is distributed in subsoils (&lt;1.2 m) of a Vertisol, contributing to subsurface P loss. Understanding the depth sequence distribution and speciation of colloidal P in the soil profile is critical for a comprehensive assessment of P loss. In this study, water-extractable colloids (WECs) with the size of 0.35–2 µm were obtained from a 0–120 cm soil profile by a sedimentation and centrifugation scheme. The dissolved reactive P (DRP) and dissolved total P (DTP) in soil supernatant with particle sizes &lt;0.35 µm were measured by molybdate blue colorimetry. Solution 31P nuclear magnetic resonance (NMR) and P K-edge XANES (X-ray absorption near-edge structure) were used to characterize the species and distribution of CP in the soil profile of fertilized farmland. Total and available P in bulk soil and colloids decreased with soil depth. The organic P (OP) contained 97–344 mg kg−1 per bulk soil and 110–630 mg kg−1 per WEC. The OP in soil profile consists of orthophosphate mono-esters and diesters primarily according to NMR results. It suggested that OP in WECs from subsoils might be affected by the translocation of CP from surface soils, probably due to soil acidification and preferential flow caused by swelling–shrinkage clays, including montmorillonite and nontronite detected by X-ray powder diffractometer (XRD) results. Additionally, the more negative zeta potential of surface soil colloids suggests the high mobility of colloidal P towards the subsoils. The CP concentration for &lt;2 µm was about 38–93 mg P kg−1 per bulk soil, which is 6–37 times that of DRP, suggesting that CP plays a dominant role in P transport within the soil profile. The relatively small fraction of orthophosphate diesters suggests limited P assimilation by microorganisms for the accumulation of WECs containing organically bound P in subsoils. The P K-edge XANES results indicated that the proportions of Al-P, Fe-P, and inositol hexakisphosphate (IHP) of WECs decreased, but hydroxyapatite (HAP) increased with soil depth. This study showed that inorganic and organic P migrated from the surface to deeper layers along the soil profile, with soil colloids having a significant effect on P migration from both surface and subsurface layers. The findings have an important significance for soil P migration evaluation and agricultural non-point source pollution control in Vertisols.

Physico-Chemical Characteristics of the River Kulik of the Uttar Dinajpur District of West Bengal, India

The river Kulik is an internationally important river between India and Bangladesh. Till date, no work has been done to understand the physico-chemical characteristics as well as the pollution status of the river Kulik at the Raiganj and Hemtabad blocks in the Uttar Dinajpur district, West Bengal, India. The goal of this investigation was to analyse different physico-chemical parameters to understand the present level of pollution in the river Kulik for two years, from November 2019 until October 2021. The investigation was carried out on a monthly basis at five selected sampling sites along the river Kulik. Different physico-chemical parameters were analysed following the methods of APHA, 2017. The pH varied from 5.90 to 7.86, which indicates the slightly acidic to slightly alkaline nature of the water. The lowest dissolved oxygen (DO) value recorded at site 5 (1.60 mgL-1) during the winter season of the first year may have been caused by excessive fertilizer application in agricultural fields close to the river Kulik. The abrupt rise in DO levels from March 2020 to June 2020 at every site might be due to the lesser anthropogenic activities during the lockdown in India because of the COVID-19 Pandemic situation. The highest BOD was found in April 2020 at Site 5, which crossed the limits of the CPCB standard set for drinking and bathing. Public awareness is crucial for river pollution control and revival; further study is needed to understand water quality and productivity.

Dynamics of soil water and nitrate within the vadose zone simulated by the WHCNS model calibrated based on deep learning

Excessive application of water and nitrogen fertilizer during farmland management practices leads to serious groundwater nitrate pollution. A field experiment was conducted during the spring maize growth period in Alxa, Inner Mongolia, China. The soil Water Heat Carbon Nitrogen Simulator (WHCNS) model was calibrated by the ensemble smoother method (ES(DL)) based on the field experiment. Then dynamics of soil water content, soil water percolation flux, soil nitrate concentration and soil nitrate leaching flux were simulated with the calibrated WHCNS model under different water and nitrogen fertilization treatments within the vadose zone. The main conclusions are as follows: ES(DL) is feasible for the calibration of the WHCNS model. RMSE_Maximum a posteriori (RMSE_MAP) of soil water content are 0.0301 cm3 cm−3 and 0.0302 cm3 cm−3 for model calibration and model validation, respectively. RMSE_MAP of soil nitrate concentration are 5.49 mg N kg−1 and 3.86 mg N kg−1 for model calibration and model validation, respectively. Both average soil nitrate concentration and average nitrate leaching flux increase with increasing irrigation amount under the same nitrogen fertilization level for the depths of 1.2 m and 1.8 m. However, average soil nitrate concentration decreased and leaching flux increased with increasing irrigation amount under the same nitrogen fertilization level for the depths of 10 m and 20 m. The study of nitrate dynamics in the deep vadose zone contributes to better understand the procedure of nitrate pollution in groundwater caused by excessive water and nitrogen application.

Pretreatment method standard normal variate (SNV) and baseline shift correction (BSC) on the NIRS-based soil spectrum for rapid prediction of soil nitrogen content

Enhancing agricultural production quality is a crucial role of nitrogen fertilization. Generally, the utilization of nitrogen fertilizer can promote plant growth, impart a more intense green hue to leaves and stems, and significantly augment biomass production. However, excessive application of nitrogen fertilizers can result in substantial cultivation cost increase and serious environmental degradation. Hence, it’s important to regulate the nitrogen content within the soil. The primary goal of this research is to employ the NIRS technique to rapidly and eco-friendly predict soil nitrogen content. Soil samples were obtained from farmlands situated in the Aceh Besar district, with spectral data gathered within a wavelength range of 1000 – 2500 nm at 0.2 nm intervals.. NIRS and Partial Least Square (PLS) spectrum data were used to make a prediction model of the nitrogen harvesting element. The results showed that the PLS method with SNV (R=0,72) and BSC (R=0,73) pretreatment showed predictive model capabilities that were almost the same as the raw data (R=0,75), although there was a slight improvement, this suggested that nitrogen elements in Aceh Besar region have not or can use the model with the suggestion to increase the amount of data and improve the treatment of the soil harvester method so that the nitrous content elements present in the ground do not easily evaporate so as to provide better model prediction results.