Amount Of Fertilizer Application Research Articles

Nitrogen fertilization affected microbial carbon use efficiency and microbial resource limitations via root exudates

Root exudation and its mediated nutrient cycling process driven by nitrogen (N) fertilizer can stimulate the plant availability of various soil nutrients, which is essential for microbial nutrient acquisition. However, the response of soil microbial resource limitations to long-term N fertilizer application rates in greenhouse vegetable systems has rarely been investigated. Therefore, we selected a 15-year greenhouse vegetable system, and investigated how N fertilizer application amount impacts on root carbon and nitrogen exudation rates, microbial resource limitations and microbial carbon use efficiency (CUEST). Four N treatments were determined: high (N3), medium (N2), low (N1), and a control without N fertilization (N0). Compared to the control (N0), the results showed that the root C exudation rates decreased significantly by 42.9 %, 57.3 % and 33.6 %, and the root N exudation rates decreased significantly by 29.7 %, 42.6 %, and 24.1 % under N1, N2, and N3 treatments, respectively. Interactions between fertilizer and plant roots altered microbial C, N, P limitations and CUEST; Microbial C and N/P limitations were positively correlated with root C and N exudation rates, negatively correlated with microbial CUEST. Random Forest analysis revealed that the root C and N exudation rates were key factors for soil microbial resource limitations and microbial CUEST. Through the structural equation model (SEM) analysis, soil NH4+ content had significant direct effects on the root exudation rates after long-term N fertilizer application. An increase in root exudation rates led to enhanced microbial resource limitations in the rhizosphere soils, potentially due to increased competition. This enhancement may reduce microbial carbon use efficiency (CUE), that is, microbial C turnover, thereby reducing soil C sequestration. Overall, this study highlights the critical role of root exudation rates in microbial resource limitations and CUE changes in plant-soil systems, and further improves our understanding of plant-microbial interactions.

Deep soil desiccation hinders nitrate leaching to groundwater in the global largest apple cultivation area

Massive use of N fertilizer in apple orchards aids China’s Loess Plateau (CLP) to become the largest region of apple production in the world, but it also leads to substantial nitrate accumulation in the vadose zone, posing a potential environmental risk. However, a holistic understanding of the spatial patterns and controls of soil nitrate in the vadose zone of apple orchards remains understudied, which is unfavorable for the formulation of a science-based N application strategy. To this end, we collected a total of 2852 paired data across apple orchards on the CLP from 52 published literature and 1000 paired data from our field sampling. We found that residual nitrate accumulation primarily occurred in the top 4–8.8 m soil layer, and it varied according to mean annual precipitation (MAP) and stand age; the accumulation peaked in sites with MAP of 500–600 mm and declined with a decrease in MAP; and among various stand ages, the highest nitrate content was observed in the 25-yr-old orchard. It was found that MAP and N fertilizer application amounts dominated nitrate accumulation in the soil. Furthermore, the desiccation index of the soil layer below the maximum cumulative depth was identified as the main factor influencing soil nitrate maximum accumulation depth . This means that deep soil desiccation hinders nitrate leaching towards deeper layers and reduces the risk of groundwater contamination. The findings here may provide insights into sustainable nitrogen and water management in apple orchards on the CLP and potentially in other similar regions.

Effects of Organic Fertilizer on Photosynthesis, Yield, and Quality of Pakchoi under Different Irrigation Conditions.

Water scarcity and the overuse of chemical fertilizers present significant challenges to modern agriculture, critically affecting crop photosynthesis, yield, quality, and productivity sustainability. This research assesses the impact of organic fertilizer on the photosynthetic attributes, yield, and quality of pakchoi under varying irrigation water conditions, including fresh water and brackish water. Findings reveal that the modified rectangular hyperbolic model most accurately captures the photosynthetic reaction to organic fertilization, outperforming other evaluated models. The maximum net photosynthesis rate (Pnmax), yield, soluble sugar (SS), and soluble protein content (SP) all exhibited a downward-opening quadratic parabolic trend with increasing amounts of organic fertilizer application. Specifically, under fresh-water irrigation, the optimal Pnmax, yield, SS, and SP were obtained at organic fertilizer rates of 65.77, 74.63, 45.33, and 40.79 kg/ha, respectively, achieving peak values of 20.71 µmol/(m2·s), 50,832 kg/ha, 35.63 g/kg, and 6.25 g/kg. This investigation provides a foundational basis for further research into the intricate relationship between water salinity stress and nutrient management, with the goal of crafting more sophisticated and sustainable farming methodologies. The insights gained could significantly influence organic fertilizer practices, promoting not only higher yields but also superior quality in agricultural outputs.

Optimizing Nitrogen Fertilizer Management Enhances Rice Yield, Dry Matter, and Nitrogen Use Efficiency

Optimizing nitrogen fertilizer management can effectively improve soil ecology, promote agricultural production, and increase the income of farmers and workers. Nitrogen fertilizer is an important factor in the growth and development of rice, and it is important to find out the optimal amount and frequency of fertilizer application for the super-hybrid early rice ‘Zhu LiangYou 819’ in Hunan Province, to give full play to its high quality and high yield characteristics. Various N fertilizer application frequencies (P1, basal–tiller fertilizer = 5:5; P2, basal–tiller–spike fertilizer = 4:3:3; P3, basal–tiller–spike–grain fertilizer = 4:3:2:1) and N application amounts (N1, 90 kg ha−1; N2, 150 kg ha−1; N3, 210 kg ha−1) were applied to the hybrid rice ZLY819. The results show that, under the same frequency of N application, ZLY819 had the highest yield, agronomic efficiency, and physiological utilization rate of N fertilizer with the N2 treatment, averaging 7.53 t ha−1, 18.10 kg kg−1, and 34.34%, respectively, with the yield under N2 being 19.38% higher than that under N1. For the same amount of N application, the yield, agronomic efficiency, partial factor productivity of N (PFPN), N contribution to seed, and N use efficiency (NUE) increased with an increase in the frequency of N application, mainly in the order of P3 > P2 > P1, whereby the yield of P3 was 10.11% higher than that of P1. According to the regression equation, the yield is higher when the amount of nitrogen application is 202.15 kg ha−1 and the fertilization frequency is four times. Appropriate N fertilizer management (P3N2) improved the rice growth characteristics, dry matter accumulation, crop growth rate, dry matter transport rate, dry matter contribution rate, and NUE, thus promoting an increase in the rice yield and efficient use of nitrogen.

Effect of NPS and Zinc Fertilizer Rates on Growth and Yield of Onion (Allium cepa L.) at Shewa Robit, North Shewa, Ethiopia

Onions, a crucial bulb crop cultivated globally, including in Ethiopia, face significant production challenges. These constraints encompass poor soil fertility, inappropriate fertilizer usage, limited availability of improved varieties, disease and insect pests, and the high costs associated with commercial fertilizers. Among these limitations, improper fertilizer application amounts and types play a pivotal role in restricting onion production. To address this, a field experiment was conducted during the 2020-2021 cropping season in the Shewa Robit district of the North Shewa zone. The study assessed the impact of NPS and Zn fertilizer rates on onion growth and yield. The treatments included four NPS fertilizer rates (0, 121, 242, and 363 kg/ha) and four levels of ZnSO4 (0, 0.25, 0.5, and 0.75% w/v). The experiment was laid out as a randomized complete block design in a factorial arrangement and replicated three times. The results demonstrated that the interaction effect of NPS and Zn fertilizers significantly influenced various onion parameters, including days to maturity, plant height, leaf length, marketable bulb yield, unmarketable bulb yield, and total bulb yield. The application of NPS at a rate of 242 kg/ha and 0.75% ZnSO4 led to the highest plant height (65.20 cm), leaf length (51.93 cm), marketable bulb yield (34.87 t/ha), and total bulb yield (35.04 t/ha). In addition, this treatment combination yielded the highest net benefit (908,628.89 ETB/ha) with an acceptable MRR (313.64%) compared to other treatments. Hence, it can be recommended for economical production of onion in the study area and areas with similar agroecologies.

Effects of Organic Substitution on the Yield and Quality of Apples and Residual Nitrate-N Leaching in Soil

The substitution of chemical nitrogen (N) fertilizer with organic fertilizer (organic substitution, OS) is increasingly applied in crop production, due to its environmentally friendly characteristics, low price, and high crop and soil improvement efficacies. Here, we studied the effects of chemical N fertilizer with organic fertilizer treatment at different proportions (no organic substitution (NOS), 20% (OS-20), 40% (OS-40), 60% (OS-60), 100% (OS-100), and 200% (OS-200, double the organic fertilizer application amount of OS-100) on the yield and quality of apples in the Shanxi Province of China. The results revealed that, compared to the NOS, the total apple yields of OS treatments, especially the OS-60 and OS-100 treatments, decreased. However, all OS treatments, except OS-200, increased the yield of large-sized fruits (transverse diameter ≥ 85 mm) and the mean mass of apple fruits, and significantly decreased yield of small-sized fruits (transverse diameter < 75 mm). All OS treatments, especially OS-40, promoted the total sugar and vitamin C (Vc) contents and fruit hardness of apples, and OS-40, OS-60, and OS-200 resulted in significantly decreased titratable acid contents in apples. The influence of organic substitutions on soil quality was further investigated in a two-year field experiment. The results showed that the influence of organic substitution on soil chemical properties differed between the two years. Notably, 40% OS increased the soil organic carbon (SOC) content and the C/N ratio in the upper 20 cm of the soil in both years. Additionally, OS treatments reduced the residual nitrate (NO3−)-N (RN) content in deep soil layers, suggesting that OS has the potential to alleviate N leaching. Moreover, redundancy analysis (RDA) of the soil, fruit yield, and fruit quality parameters revealed that the SOC content in the 0–20 cm soil layer and the RN content in the 0–100 cm soil layer had the greatest impact on the fruit quality and yield variables, respectively. This study showed that the proper substitution (40%) of chemical N fertilizer with organic fertilizer could improve the yield of large-sized fruits, the mean mass and fruit quality of apples, and soil chemical properties. Our study will provide a basis for rational organic substitution in apple orchards.

Development and Optimization of an Offset Spiral Tooth Fertilizer Discharge Device

Due to factors such as a small amount of fertilizer application during rice topdressing and slow machine speed, the ordinary fertilizer discharge device fails to distribute the fertilizer uniformly and accurately as required, making it difficult to meet the needs of precise rice topdressing. This research focuses on the development of an offset spiral tooth fertilizer discharge device suitable for rice topdressing. The study analyzes the amount of fertilizer discharged in one cycle, the fertilizer force, and the motion of the fertilizer particles. In order to enhance the uniformity of the fertilizer discharge device at a low speed and small volume, the discrete element method is employed to conduct experimental research on the key structural parameters that affect the one-cycle amount of discharged fertilizer and the dynamics of the fertilizer discharge device. Through single-factor tests, it was found that the angle, height, number of spiral teeth, and diameter of the fertilizer discharge wheel are closely associated with the fertilizer discharge performance. To further investigate the impact of these four parameters on the fertilizer discharge performance, a regression combination test of the four factors is conducted based on the range optimized by the single-factor tests. A multi-objective mathematical model, considering the key parameters of fertilizer uniformity coefficient, one-cycle amount of fertilizer, and fertilizer discharge torque, is established at three speeds: 20, 55, and 90 rpm. The response surface method is utilized to analyze the influence of the interaction factors on the fertilizer discharge performance. The optimal combination of the key structural parameters was determined as follows: spiral tooth angle of 35.42°, tooth height of 9.02 mm, discharge wheel diameter of 57.43 mm, and tooth amount of 9.37. The bench test results of the device, using the optimal parameter combination and a fertilizer discharge speed of 0–90 rpm, were obtained for four commonly used rice fertilizers. The maximum variation coefficient of fertilizer discharge was found to be 10.42%. The one-cycle amount of fertilizer discharge was measured to be 19.82 ± 0.72 (A Kang), 17.20 ± 0.69 (Ba Tian), 20.34 ± 0.54 (Yaran), and 14.51 ± 0.44 (granular urea). The fertilizer discharge torque remained stable. These results indicate that the achieved optimization meets the precise fertilizer application requirements and can provide technical support for precise topdressing operations.

Analysis of Influencing Factors on Grain Output in Hebei Province Based on Multiple Linear Regression Analysis

Food problem is one of the major problems facing the world today. Only with food can people feel at ease. In this paper, the influence of multiple linear regression analysis on grain output was carried out according to the six indicators of total power of agricultural machinery, effective irrigation area, conversion amount of agricultural fertilizer application, pesticide use, sown area of grain crops and affected area in Hebei Province from 2000 to 2021. Through a series of fitting tests, it was found that the total power of agricultural machinery, the effective irrigated area, the sown area of grain crops and the affected area would all have a significant impact on the grain output of Hebei Province, and the test results were conducive to further guiding the general direction of grain yield increase in Hebei.

Comprehensive evaluation of the water-fertilizer coupling effects on pumpkin under different irrigation volumes.

Compared to conventional irrigation and fertilization, the Water-fertilizer coupling can significantly enhance the efficiency of water and fertilizer utilization, thereby promoting crop growth and increasing yield. Targeting the challenges of poor crop growth, low yield, and inefficient water and fertilizer utilization in the arid region of northwest China under conventional irrigation and fertilization practices. Therefore, a two-year on-farm experiment in 2022 and 2023 was conducted to study the effects of water-fertilizer coupling regulation on pumpkin growth, yield, water consumption (ET), and water and fertilizer use efficiency. Simultaneously the comprehensive evaluation of multiple objectives was carried out using principal component analysis (PCA) methods, so as to propose an suitable water-fertilizer coupling regulation scheme for the region. The experiment was set up as a two-factor trial using water-fertilizer integration technology under three irrigation volume (W1=37.5mm, W2=45.5mm, W3=52.5mm) and three organic fertilizer application amounts (F1=3900-300kg ha-1, F2=4800-450 kg·ha-1, F3=5700-600 kg·ha-1), with the traditional irrigation and fertilization scheme from local farmers as control treatments (CK). The results indicated that irrigation volume and organic fertilizer application significantly affected pumpkin growth, yield, and water and fertilizer use efficiency (P<0.05). Pumpkin yield increased with increasing irrigation volume. Increasing organic fertilizer levels within a certain range benefited pumpkin plant growth, dry matter accumulation, and yield, however, excessive application beyond a certain level had inhibited effects on those. The increased fertilizer application under the same irrigation volume enhanced the efficiency of water and fertilizer utilization. However excessive irrigation only resulted in inefficient water consumption, reducing the water and fertilizer use efficiency. The Comprehensive evaluation by PCA revealed that the F2W3 treatment outperformed all the others, effectively addressing the triple objectives of increasing production, improving efficiency, and promoting green production. Therefore, F2W3 (Irrigation volume: 52.5mm; Fertilizer application amounts: 4800-450 kg/ha-1) as a water and fertilizer management scheme for efficient pumpkin production in the arid region of northwest China.

Effect of Nitrogen Fertilizer Rates on Yield and Yield Related Traits of Durum Wheat (Triticum turgidum L.) Varieties

Low productivity and poor quality of the durum wheat compels Ethiopian pasta industries to import the required raw material; Thus, proper type and amount of nitrogen fertilizer application is the major factor that affects yield and quality components of durum wheat. Hence, field experiment was carried out on farmers’ training center field to determine the effect of nitrogen fertilizerrates in combination with durum wheat varieties on growth, yield and quality components of durum wheat. Factorial combinations of three durum varieties (Mangudo, Ude and Utuba) with six levels of nitrogen (0, 23, 46, 69, 92 and115 kgha-1) were laid out in a randomized complete block design in three replications. The analysis of variance indicated that the interaction effect of nitrogen fertilizer and variety significantly (p&lt; 0.05) influenced 90% days to maturity and spike length. The highest days to 90% maturity (128 days) was recorded from Utuba variety at 115kg N ha-1 application. The longest spike length was recorded from Ude variety at 92 kg N ha- 1 application. However, seed per spike, plant height, productive tiller, grain yield and grain protein content were significantly (p&lt;0.01) influenced by the main effect of nitrogen rates. The highest plant height (85.82cm), productive tiller (7.56), grain yield (4862 kg ha-1), and grain protein content (15.88%) were recorded at the highest N rate (92 kg N ha-1) applied; but, a maximum seed per spike (51.89) was obtained at the rate of 69 N kg ha-1 applied. The analysis of variance also showed that the difference of varieties significantly (p&lt;0.01) influenced the plant height, thousand kernel weight, grain yield, and protein content with highest result obtained from Ude except highest protein content obtained from Utuba. The economic analysis revealed that for a treatment to be considered worthwhile to farmers, application of 92 kg N ha-1to all varieties gave better yields as compared to other N treatments. However, Ude variety is a promising variety for better productivity with profitable economic benefit to the crop at 92 kg N ha-1 application in the study area. However, since the study was done once in single place it is recommended to replicate it spatially and seasonally to have a concrete recommendation on the wheat varieties and nitrogen rates.

Life cycle environmental impact assessment of green tea production in China

Tea is the second most popular beverage in the world after water, and the potential environmental problems during the entire life cycle stages of its production have not been thoroughly discussed. This study aims to investigate the overall environmental impact of green tea production as a typical perennial crop in China with the system boundary from “cradle to gate”. Scenario analysis is carried out to investigate the factors of green tea processing scales and packaging methods on the overall environmental impact level of green tea production in China. Results showed that the average overall global warming potential of procuring 1 kg dry green tea in China ranges from 10.4 to 15.6 kg CO2eq, depending on different processing scales and packaging methods. The processing stage is the dominant contributor to the overall environmental impact of producing 1 kg dry green tea product due to the use of electricity. Electricity consumption in the processing stage and chemical fertilizer application in the planting stage are identified as the environmental hotspots throughout the life cycle of green tea production in China. Optimizing energy structure and improving energy use efficiency in the processing stage, as well as reducing the amount of chemical fertilizer application are the critical measures needed to mitigate the environmental emissions of green tea throughout the life cycle.

Modeling of The Nitrogen Requirement of Winter Wheat for Protein Content Using Optical Sensor in Central Anatolia Region of Türkiye

Chlorophyll meters manage both the amount and duration of nitrogen fertilizer application based on the principle that the chlorophyll or nitrogen content of plants should be maintained throughout their development. For smallholders in developing countries, the use of a hand-held meter to manage nitrogen fertilizer in rice and wheat is the most popular method. The adoption of nitrogen management strategies based on close sensing using chlorophyll meters and optical sensors will largely depend on the inclusion of specific economic analysis in future research. The importance of using sensors and chlorophyll meters for nitrogen fertilizer management depends on how successful current practices have been. In this study, five different nitrogen rates (0, 80, 120, 160, 200 kg N ha-1) were applied to two different wheat varieties, and the effect of these different nitrogen rates on wheat protein content was investigated in a randomized block design. A quadratic polynomial model described the relationship between protein content and nitrogen rates.

The Influence of Organic and Inorganic Fertilizer Applications on Nitrogen Transformation and Yield in Greenhouse Tomato Cultivation with Surface and Drip Irrigation Techniques

Facility agriculture in China is facing the challenge of the excessive use of chemical fertilizers (nitrogen fertilizers), which hinder the development of sustainable and environmentally friendly agriculture. Optimizing nitrogen fertilizer allocation is essential to balance agricultural production and environmental concerns. The aim of this study was to determine the optimal organic fertilizer strategy for tomato cultivation under different irrigation methods. An experiment was conducted in a greenhouse, and two irrigation methods, surface irrigation (SI) and drip irrigation (SDI), were used during tomato growth. The fertilization treatments included urea alone (CK); 30%, 40%, and 50% chicken manure mixed with urea (FC1, FC2, FC3); and 50% cow manure and sheep manure mixed with urea (FB3, FS3). The results showed that the irrigation techniques and fertilization had significant effects on ammonia volatilization accumulation, soil mineral nitrogen content, and tomato yield and quality. Compared with the surface irrigation technique with the same amount of fertilizer application, the drip irrigation technique reduced the ammonia volatilization accumulation by a maximum of 76.40%. The SDIFC3 and SDIFB3 ammonia volatilization accumulation was as low as 5.24 (kg·hm−2) and 7.61 (kg·hm−2); the soil nitrate nitrogen content was reduced, and the tomato yield increased significantly by 17.11%. The SDIFC3 treatment achieved a maximum yield of 13,414 (kg·hm−2), increased the tomato vitamin C and soluble sugar contents by 19.13% and 8.97%, and lowered the titratable acid content by as much as 30.51%. Under drip irrigation fertilization conditions, the SDIFC3 treatment showed lower ammonia volatilization accumulation and the highest tomato yield and quality compared to CK and the same proportion of organic fertilizer substitutes with cow and sheep manure. The increase in the proportion of organic fertilizers replacing chemical fertilizers resulted in a gradual decrease in ammonia volatilization accumulation and a gradual increase in the tomato yield and various qualities. The soil mineral N content, on the other hand, was significantly affected by irrigation, fertilizer application, and water–fertilizer interaction effects, with a tendency for the content to increase and then decrease after each fertilizer application. The mineral N content was lower with drip irrigation compared to surface irrigation, especially in the 10–20 cm soil layer than in the 0–10 cm layer. Increasing drip irrigation and organic fertilizer substitution significantly increased the vitamin C and soluble sugar contents in the tomatoes, while decreasing the titratable acid content.

Characterization of biochar produced from sewage sludge and its potential use as a substrate and plant growth improver

Biochar is a product rich in carbon produced by pyrolysis of different kinds of biomass and it modifies the physical, chemical, and biological properties of soil. In this study, biochar, produced at different pyrolysis temperatures (590 °C, 665 °C, and 765 °C), was physico-chemically characterized. It was explored whether biochar made from sewage sludge can become an alternative solution for future water and phosphorus management in agricultural production. A pot experiment was conducted using Chinese cabbage (Brassica rapa subsp. pekinensis) to investigate the effect of applying different biochars to the substrate, taking into account different growth parameters and the biochemical composition of the plants, as well as the physico-chemical properties of the substrate. According to the results, pyrolysis temperature influences the content of elements in biochar and their availability to plants, with total phosphorus contents in biochar ranging from 4.6% to 4.9%. In addition, applying biochar to the substrate significantly increases the volumetric water content up to 4.5 fold more compared to the control, which indicates a promising application in drought stress conditions and, at the same time, is a source of nutrients and can help to reduce the amount of mineral fertilizer application.

Roles of historical land use/cover and nitrogen fertilizer application changes on ammonia emissions in farmland ecosystem from 1990 to 2020 in China

In the past decades, China has witnessed significant changes in its land use/land cover (LULC) pattern. These changes have led to a direct impact on ammonia (NH3) emissions in soil background, and indirectly affected the total nitrogen fertilizer (N-fertilizer) application, crop planting amount and the resulting straw mass through the changes of cropland area. Great changes have also taken place in the amount and structure of fertilizer application in China, which affects the NH3 emissions from farmland ecosystems caused by N-fertilizer application. The aforementioned changes have led to significant alterations in NH3 emissions from China's farmland ecosystems over the past 30 years. The process of these changes remains to be analyzed, and the contributions of LULC changes and N-fertilizer application in this process are yet to be assessed. This study aims to investigate the NH3 emission changes and spatiotemporal variation characteristics from farmland ecosystems during 1990 and 2020 due to the LULC changes. Additionally, the study employs scenario analysis method to discuss the effects of LULC changes and N-fertilizer application changes on NH3 emissions in farmland ecosystems. Results indicate that there is evident spatiotemporal heterogeneity in China's LULC pattern, particularly in eastern China. The southeast region is predominantly characterized by the conversion of cropland into construction land. Moreover, some regions such as Northwest China and Northeast China have experienced the conversion of other land types into cropland, significantly influenced by national development policies. From 1990 to 2020, the national NH3 emissions from farmland ecosystem range from 3294.75 Gg to 4064.20 Gg. NH3 emissions and their interannual variation in farmland ecosystems exhibit significant differences across various regions. The regions with higher contributions to NH3 emissions in farmland ecosystems are East China, Central China, and North China, accounting for 25.32 %–37.26 %, 18.85 %–22.46 % and 11.24 %–18.50 % of the total emissions, respectively. NH3 emissions in each region are influenced by cropland area, N-fertilizer application, and regional development characteristics. Compared to LULC changes, changes in N-fertilizer application have a more pronounced impact on NH3 emission changes in farmland ecosystems. From 1990 to 2020, the contribution (increase or decrease) of N-fertilizer application changes to NH3 emission changes in farmland ecosystems in China ranges from 0.11 % to 16.61 %, while the contribution (increase or decrease) of LULC changes ranges from 0.47 % to 2.38 %. South China demonstrates a unique situation regarding the influence of LULC changes. This region has a relatively small cropland area, and fluctuations in cropland area significantly affect NH3 emissions in farmland ecosystems. The influence of policies is evident. From the changes in cropland area in Northwest China and Northeast China to changes in N-fertilizer application, policy changes have consistently impacted the changes in NH3 emissions in China's farmland ecosystems. From “soft policies” involving encouragement and guidance to “hard policies” encompassing the establishment of necessary targets, the degree of strictness in policy directly affects the timeliness of policies effectiveness. The results of this study indicate that reducing the application of N-fertilizers is the primary approach to reducing NH3 emissions in China's farmland ecosystems. In terms of policy guidance, compared to implementing structural and pathway adjustments, implementing clear total control of fertilizer usage is a timely and effective choice for reducing NH3 emissions.

Electrical signal of pepper during cropping period affected by different amount of fertilizer

Precision agriculture requires supply of adequate amount of fertilizer application to increase crop yield and prevent environmental contamination. Objective of the study was to evaluate response of pepper under different fertigation method and amount using plant induced electrical signal (PIES) for precision agriculture. Pepper was fertigated 10 times with recommended additional nitrogen fertilizer and set as a control. Low fertilizer treatment did not receive additional urea and high fertilizer received three times higher amount of nitrogen fertilizer. Conventional treatment was fertigated as basal fertilizer and once with additional fertilizer. The PIES decreased during vegetative stage and remained constant at reproductive stage because of reduced nutrient and water uptake. The PIES showed positive relationship with soil NH4+, NO3−, stem NO3− and leaf N, which resulted in highest PIES value during reproductive stage in high fertilizer treated pepper. Plant growth parameters were also related with the PIES although yield was not affected by different fertilizer treatment.

Micro-nano bubble water with potassium fertigation improves strawberry yield and quality by changing soil bacterial community

Aerated drip irrigation can increase the soil oxygen content and improve the utilization efficiency of fertilizer. However, limited information is available on how soluble potassium fertilizer with different aeration levels affects plant yield and quality. Specifically, the underlying mechanism associated with microbial community level has not been reported so far. In this study, a micro-nano bubble water (MNBW) drip irrigation experiment was conducted in a strawberry plantation greenhouse, with three ratios of MNBW and two potassium application amounts and a control treatment (without MNBW). The results showed that compared with the CK (no aeration, 100% traditional potassium fertilizer application, 144 kg hm−2 of potassium sulfate), MNBW irrigation improved the soil oxygen content and changed the structure and functionality of the soil microbial community in the strawberry rhizosphere. The bacterial diversity was reduced, and the microbial co-occurrence patterns were altered. The soil respiration intensity increased by 1.32%–14.22%. The soil temperature increased, and the decomposition of organic matter was enhanced. It was indicated that the increase of soil oxygen had a positive impact on soil fertility, strawberry yield, and quality under the condition of reducing potassium application. The yield and quality of strawberries in MNBW treatments were significantly higher than those treated with CK (p < 0.05), but the carbon dioxide emissions significantly increased. High potassium fertilizer application amount and MNBW ratio did not mean high yield and quality of strawberries. Thus, O20K70 (20% of irrigation water with micro-nano bubbles, 70% of traditional drip irrigation potassium fertilizer level, 101 kg hm−2 of potassium sulfate) and O60K70 (60% of irrigation water with micro-nano bubbles, 70% of traditional drip irrigation potassium fertilizer level, 101 kg hm−2 of potassium sulfate) could be chosen for strawberry plantations with MNBW.

Selenium-Containing Organic Fertilizer Application Affects Yield, Quality, and Distribution of Selenium in Wheat.

This study was designed to investigate the effect on wheat yield of applying organic fertilizers (OF) with five different selenium (Se) concentrations. The mineral nutrients, cadmium (Cd) content, and the distribution of Se in wheat plants were also measured. The results showed that wheat yields reached a maximum of 9979.78 kg ha-1 in Mengcheng (MC) County and 8868.97 kg ha-1 in Dingyuan (DY) County, Anhui Province, China when the application amount of selenium-containing organic fertilizer (SOF) was up to 600 kg ha-1. Among the six mineral nutrients measured, only the calcium (Ca) content of the grains significantly increased with an increase in the application amount of SOF in the two regions under study. Cd content showed antagonistic effects with the Se content of wheat grains, and when the SOF was applied at 1200 kg ha-1, the Cd content of the grains was significantly reduced by 30.1% in MC and 67.3% in DY, compared with under the Se0 treatment. After application of SOF, the Se content of different parts of the wheat plant ranked root > grain > spike-stalk > glume > leaf > stem. In summary, SOF application at a suitable concentration could increase wheat yields and significantly promote the Ca content of the grains. Meanwhile, the addition of Se effectively inhibited the level of toxic Cd in the wheat grains.

Preparation and slow-release performance of modified poly (butyleneadipate-co-terephthalate) melt-coated urea pellets

The current use of environmentally friendly slow-release fertilizers in agriculture is important for solving mitigating environmental pollution caused by the low utilization of fertilizers. In this study, modified biodegradable poly (butyleneadipate-co-terephthalate) (PBAT) based melt coated slow-release urea is prepared, avoiding the use of organic solvents. PBAT is modified with titanium tris(dodecylbenzenesulfonate) isopropoxide (TDBSP), which reduces the molecular weight and crystallinity. The addition of acetyl tributyl citrate (ATBC) as a plasticizer further improves the flowability of the material to satisfy the requirements of melt-coated urea. The ability of TDBSP to affect crystallization and result in branched behaviors in PBAT is demonstrated via differential scanning calorimetry (DSC) and rheological studies. The PBAT coating material is prepared by adding 1 % w/w of TDBSP and 35 % w/w of ATBC (% w/w dry PBAT basis), which constitutes 18 % of the urea mass by weight when coated. Scanning electron microscopy results show that the coating material exhibits the best coating effect on urea pellets. Results of the soil column leaching test show the slow-release performance of the coated area as well as the release of nutrients from the coated urea of 80.09 % after 28 d. By applying a single application of coated slow-release fertilizer in tobacco plant cultivation, the growth data of the tobacco plant is better than that of a topdressing applied after 30 d in conventional cultivation (under the same amount of fertilizer application), while labor cost is saved.

The Status and Stock of Soil Nutrients under Different Land Ownership Management of Rice Fields in Kuranji District Padang West Sumatra

This study aims to determine the status and stock of soil nutrients in three types of land ownership management. This research was conducted on smallholder farmers (SF), tenant farmers (TF), and owner farmers (OF) in Kuranji District, Padang, West Sumatra, and at the Soil Laboratory of the Faculty of Agriculture, Andalas University from March to September 2022. The range of nutrient status in the three types of land ownership is 0.06-0.35% C-organic and 0.06-0.13% N. The concentration ranges of Ca, Mg, K, Na, P, and Si, respectively, were 0.52-0.79; 0.58-1.34; 0.07-0.12; 0.03-0.09 cmol.kg-1and 2.52-12.7; 31.73- 49.33 ppm. The results showed that each management type’s status of organic carbon in soil was deficient. This result was presumably due to miss management of straws. The highest concentrations of Ca, Mg, K, and Na were found in smallholder farmers’ fields (SF), while the lowest concentrations were found in tenant farmers’ fields (TF). The stock of soil nutrients shows a similar trend to the nutrient status of the soil. The dose of fertilizer by SF and TF was 129.5 kg/ha N; 37.5 kg/ha P2O5; 37.7 kg/ha K2O, while OF is 176 kg/ha N, 65 kg/ha P2O5, 45 kg/ha K2O. The soil nutrient status among the farmer groups is not significantly related to the amount of fertilizer application. It is recommended to give a dose of fertilizer following the recommendations that have been set and balanced with the proper management of remaining straw after harvest for sustainable soil fertility and agriculture production.