Spatial variability of soil properties in red soil and its implications for site-specific fertilizer management

Assessing spatial variability and mapping of soil properties constitute important prerequisites for soil and crop management in agricultural areas. To explore the relationship between soil spatial variability and land management, 256 samples were randomly collected at two depths (surface layer 0–20 cm and subsurface layer 20–40 cm) under different land use types and soil parent materials in Yujiang County, Jiangxi Province, a red soil region of China. The pH, soil organic matter (SOM), total nitrogen (TN), cation exchange capacity (CEC), and base saturation (BS) of the soil samples were examined and mapped. The results indicated that soils in Yujiang were acidified, with an average pH of 4.87 (4.03–6.46) in the surface layer and 4.99 (4.03–6.24) in the subsurface layer. SOM and TN were significantly higher in the surface layer (27.6 and 1.50 g kg–1, respectively) than in the subsurface layer (12.1 and 0.70 g kg–1, respectively), while both CEC and BS were low (9.0 and 8.0 cmol kg–1, 29 and 38% for surface and subsurface layers, respectively). Paddy soil had higher pH (mean 4.99) than upland and forest soils, while soil derived from river alluvial deposits (RAD) had higher pH (mean 5.05) than the other three parent materials in both layers. Geostatistical analysis revealed that the best fit models were exponential for pH and TN, and spherical for BS in both layers, while spherical and Gaussian were the best fitted for SOM and CEC in the surface and subsurface layers. Spatial dependency varied from weak to strong for the different soil properties in both soil layers. The maps produced by selecting the best predictive variables showed that SOM, TN, and CEC had moderate levels in most parts of the study area. This study highlights the importance of site-specific agricultural management and suggests guidelines for appropriate land management decisions.

Variation analysis of growth traits of four poplar clones under different water and fertilizer management

To determine appropriate quantities of water and fertilizer required for early growth of hybrid poplar cuttings,we recorded the growth traits of four clones grown under four factors(irrigation and nitrogen,phosphorus,and potassium fertilizers),each with four levels,using an orthogonal experimental design.A logistic model was used to estimate growth in height.The growth curves for tree height were sigmoid,and the model R^2 values were greater than 0.9,which indicated that the fit was highly significant.ANOVA results for tree height and basal diameter indicated that all sources of variance showed significant differences(p<0.001).The average tree height and basal diameter for all the four clones under the different treatments ranged from 155.39 to 235.04 cm,and from 13.71 to 17.42 mm,respectively.A highly positive correlation between the extreme k value and tree height was observed,suggesting that the k value was an accurate estimation of tree height.For model parameters,the earliest average time point for the onset of the rapid growth period of poplar clones was 131 d,and the highest average increment in tree height during the rapid growth period was 138.78 cm.The highest average tree height for all clones under each factor was 219,210.51,200,and 201 cm when treated with either 1200 mL of water applied every third day,3 g of nitrogen,0 g of phosphorus,or 0 g of potassium,respectively.The most suitable treatment for the early growth of hybrid poplar cuttings,as suggested by the developed logistic model,was 1200 mL of water applied every third day and three applications of 1 g nitrogen(in the form of CH4N2O).

Nitrogen and Phosphorus Loss Law and Emission Reduction Effects Under Water and Fertilizer Management Integrated Mode in Dike Paddy Field

To achieve the purpose of reducing farm non-point source pollution, we integrated site specific nitrogen management precise irrigation, controlled drainage, and wetland eco-repair system in dike area of Taihu basin. During investigation, it had given prominence for the water and fertilizer coupling effects of precise irrigation and site specific nutrient management, the characteristics of integration on controlled irrigation, controlled drainage and wetland ecosystem non-point source pollution control. Then the water and fertilizer integrated management mode of paddy field was put forward in Taihu basin where the water production efficiency increased to 1.64 kg. m-3, water saved 37.8%, fertilizer use efficiency raised 15,4%, yield raised 10%, and N, P load decreased 26%-72%. The modern agricultural and farmland ecosystems that control and cut down the farm non-point source pollution came into being, which can be a reference by Taihu basin to control its agricultural non-point source pollution and eutrophicated water body.

Assessing non-point source pollution in an apple-dominant basin and associated best fertilizer management based on SWAT modeling

Investigating the impact of apple-dominated areas on nitrogen(N)and phosphorus(P)losses at a basin scale was essential for the sustainable development of apple industry in China.This study conducted a survey on fertilizer application and built a Soil and Water Assessment Tool(SWAT)model to quantita-tively analyze the N and P losses in the Qixia apple-dominated area.Additionally,the decreases in N and P losses through adjusting the fertilizer application modes were evaluated.Results showed that average N and P losses in the Wulong River Basin(WRB)were 44.4 and 0.365 kg ha^(-1)in 2011-2017,respectively,and apple orchards accounted for 733%and 51.4%of the total N and P losses in the basin.Under nine fertilizer scheduling scenarios,three fertilizer schedule scenarios,automatic fertilizer application(S-AUTO),"one shot"mode(S1),and regulated fertilizer application(S-BSD),had the lowest N and P losses in apple orchards.The decreases in N loss ranged from 20.6%to 26.1%at the subbasin scale and 14.8%-30.7%at the basin outlet when applying the S-AUTO,S1,and S-BSD fertilizer application modes in Qixia apple orchards and all apple orchards in the WRB.The reductions in P loss varied from 22.0%to 46.1%at the subbasin scale and 14.6%-25.6%at the basin outlet.In orchard-dominated basin,N and P losses can be effectively reduced by optimizing the orchard fertilizer scheduling strategies.

Green High-yield and High-efficiency Cultivation Techniques of Integrated Management of Water and Fertilizer for Maize under Mulch Drip Irrigation

The green high-yield and high-efficiency cultivation techniques of integrated management of water and fertilizer for maize under mulch drip irrigation are described from the aspects of high yield target of maize and its component factor indexes,pre-sowing preparation,sowing,post-sowing management,field management at the seedling stage,integrated management of water and fertilizer for target yield of maize,rational application of micro-fertilizer,comprehensive prevention and control of diseases and pests,timely harvest,etc.,in order to provide a reference for agricultural technicians,maize farmers and maize industry development in northern Xinjiang.

A practical soil management to improve soil quality by applying mineral organic fertilizer

Heavy use of chemical fertilizer causes increasing soil and environmental crisis, and the use of organic fertilizer increases obvious in recent years. In this study,mineral organic fertilizer(MOF) and compound fertilizer(CF) were applied in amaranth culture to explore the effects of these two kinds of fertilizers on soil quality and the potential function for CO_2 fixation. Some soil parameters were tested, e.g. p H value, organic carbon content, microbial biomass, urease activity, and available potassium content. In addition, some parameters of soil infiltration water were also determined, such as p H and HCO_3^- concentration. Experimental results showed that MOF improved soil quality and amaranth biomass and increased possible soil carbon sink.On the contrary, the utilization of CF worsened soil quality and made the soil acidize. These results suggested that MOF can partially replace CF to improve plant growth, soil quality and possible CO_2 sink.

Strategies for improving crop comprehensive benefits via a decision-making system based on machine learning in the rice‒rape,rice‒wheat and rice‒garlic rotation systems in Southwest China

Rice‒rape,rice‒wheat and rice‒garlic rotations are common cropping systems in Southwest China,and they have played a significant role in ensuring ecological and economic benefits(EB)and addressing the challenges of China’s food security in the region.However,the crop yields in these rotation systems are 1.25‒14.73%lower in this region than the national averages.Intelligent decision-making with machine learning can analyze the key factors for obtaining better benefits,but it has rarely been used to enhance the probability of obtaining such benefits from rotations in Southwest China.Thus,we used a data-intensive approach to construct an intelligent decision‒making system with machine learning to provide strategies for improving the benefits of rice-rape,rice-wheat,and rice-garlic rotations in Southwest China.The results show that raising the yield and partial fertilizer productivity(PFP)by increasing seed input under high fertilizer application provided the optimal benefits with a 10%probability in the rice-garlic system.Obtaining high yields and greenhouse gas(GHG)emissions by increasing the N application and reducing the K application provided suboptimal benefits with an 8%probability in the rice-rape system.Reducing N and P to enhance PFP and yield provided optimal benefits with the lowest probability(8%)in the rice‒wheat system.Based on the predictive analysis of a random forest model,the optimal benefits were obtained with fertilization regimes by reducing N by 25%and increasing P and K by 8 and 74%,respectively,in the rice-garlic system,reducing N and K by 54 and by 36%,respectively,and increasing P by 38%in rice-rape system,and reducing N by 4%and increasing P and K by 65 and 23%in rice-wheat system.These strategies could be further optimized by 17‒34%for different benefits,and all of these measures can improve the effectiveness of the crop rotation systems to varying degrees.Overall,these findings provide insights into optimal agricultural inputs for higher benefits through an intelligent decision-making system with machine learning analysis in the rice-rape,rice‒wheat,and rice-garlic systems.

Effects of the fertilizer and water management on amino acids and volatile components in Cabernet Sauvignon grapes and wines

The amino acids and the volatile substances in grapes and wines play important roles in their quality,and the concentrations of these substances can be changed by how a vineyard is managed,e.g.,irrigation and fertigation regimes.This study aimed to evaluate the effect of fertilizer and water management on the distribution of amino acids,the volatile component profiles,and the sensory characteristics of Cabernet Sauvignon grapes and wines.The results showed that the amino acid concentration in grape berries was the highest under the 100%local fertilizer rate(HF)and 100%water irrigation quota(HW)treatment,and the volatile component concentration in wine was the highest under HF and 80%water irrigation quota(MW)treatment.The effect of irrigation on the amino acid content in grapes was greater than that of fertigation.The synergistic effect of fertilizer and water on arginine,serine,and glutamine in grape berries was significant.The interactive effect of fertigation and irrigation on the volatile substance in grapes was greater than that of fertigation and irrigation alone.The influence of irrigation on volatile substances in wines was greater than that of fertigation.In addition,there was also a correlation between the concentrations of multiple amino acids in grapes and volatile components in wines.Principal component analysis showed that the wine from the HFMW treatment had the best quality among all treatments.

Modified fertilization management of summer maize(Zea mays L.) in northern China improves grain yield and efficiency of nitrogen use

Improving the yield of maize grain per unit area is needed to meet the growing demand for it in China, where the availability of fertile land is very limited.Modified fertilization management and planting density are efficient methods for increasing crop yield.Field experiments were designed to investigate the influence of modified fertilization management and planting density on grain yield and nitrogen use efficiency of the popular maize variety Zhengdan 958, in four treatments including local farmer＇s practice（FP）, high-yielding and high efficiency cultivation（HH）, super high-yielding cultivation（SH）, and the control（CK）.Trials were conducted in three locations of the Huang-Huai-Hai Plain in northern China.Compared with FP, SH was clearly able to promote N absorption and dry matter accumulation in post-anthesis, and achieve high yield and N use efficiency by increasing planting density and postponing the supplementary application of fertilizers.However, with an increase in planting density, the demand of N increased along with grain yield.Due to the input of too much N fertilizer, the efficiency of N use in SH was low.Applying less total N, ameliorating cultivation and cropping management practices should be considered as priority strategies to augment production potential and finally achieve synchronization between high yield and high N efficiency in fertile soils.However, in situations where soil fertility is low, achieving high yield and high N use efficiency in maize will likely depend on increased planting density and appropriate application of supplementary fertilizers postpone to the grain-filling stage.

Do Land Characteristics Affect Farmers' Soil Fertility Management?

Soil fertility management （SFM） has important implications for sustaining agricultural development and food self-sufifciency. Better understanding the determinants of farmers’ SFM can be a great help to the adoption of effective SFM practices. Based on a dataset of 315 plots collected from a typical rice growing area of South China, this study applied statistical method and econometric models to examine the impacts of land characteristics on farmers’ SFM practices at plot scale. Main results showed that in general land characteristics affected SFM behaviors. Securer land tenure arrangements facilitated effective practices of SFM through more diversiifed and more soil-friendly cropping pattern choices. Plot size signiifcantly reduced the intensities of phosphorus and potassium fertilizer application. Given other factors, 1 ha increase in plot size might reduce 3.0 kg ha-1 P2O5 and 1.8 kg ha-1 K2O. Plots far from the homestead were paid less attention in terms of both chemical fertilizers and manure applications. Besides, plots with better quality were put more efforts on management by applying more nitrogen and manure, and by planting green manure crops. Signiifcant differences existed in SFM practices between the surveyed villages with different socio-economic conditions. The ifndings are expected to provide important references to the policy-making incentive for improving soil quality and crop productivity.

A Dynamic Knowledge Model for Nitrogen Fertilizationin Wheat Management

By analyzing and extracting the research progress on nitrogen fertilization in wheat, a dynamic knowledge model for management decision-making on total nitrogen rate, ratios of organic to inorganic and of basal to dressing nitrogen under different environments and cultivars in wheat was developed with principle of nutrient balance and by integrating the quantitative effects of grain yield and quality targets, soil characters, variety traits and water management levels. Case studies on the nitrogen fertilization model with the data sets of different eco-sites, cultivars, soil fertility levels, grain yield and quality targets and water management levels indicate a good performance of the model system in decision-making and wide applicability.

Community Soil Resources Management for Sub-Saharan West Africa： Case Study of the Gourma Region in Burkina Faso

A study on community soil fertility management concepts and practices was conducted through rapid and participatory method of research in 15 villages of the Gourma region in Eastern part of Burkina Faso. These investigations aimed at determining farmers＇ knowledge on soil resources： local soil taxonomy and indicators of soil degradation, soil fertility management practices, and capacity for adoption of new technologies in soil fertility management. The results of the study showed that the main parameter for soil classification for all the investigated villages was soil texture composition; soil degradation was evaluated according to crops yield decrease and the development Striga sp. in 100% of the investigated villages; the use of organic manure and long term fellow were the main practices for soil fertility management; concerning the villages where modem technologies of soil fertility management were introduced, the lack of tools and capacity building were the main limiting factors of the adoption of these improved practices at small scale farmers＇ level. Even if discordance between scientific and local soil taxonomy were revealed by our investigations; significant similarities between indigenous and scientific indices of soil degradation were noticed. With regard to the actual magnitude of soil degradation; the local techniques of soil fertility management need to be improved and accessible to a big number of farmers.

Analysis of Chemical and Biological Soil Properties in Organically and Conventionally Fertilized Apple Orchards

We compared chemical and biological properties of soils in organically and conventionally fertilized apple orchards in Nagano Prefecture (one of the major apple producing regions in Japan). Five apple orchards with different fertilizer management systems were used for this study. The total carbon and total nitrogen contents were higher in the organically fertilized orchard, while the total phosphorus and total potassium were at similar levels in both organically and conventionally fertilized orchards. The bacterial biomass did not differ between the two orchards, but the N circulation activity was clearly higher in the organically fertilized orchard from April to December. Total carbon from 50,000 to 60,000 mg/kg, total nitrogen at about 3000 to 4000 mg/kg, and a C/N ratio of 15 - 20 were suggested to be suitable conditions for a high level of apple production under an organic fertilizer management system.

Effects of Interaction of Soil Moisture and Organic Matter on Powdery Mildew Disease and Growth of Heracleum moellendorffii Hance

Taking annual Heracl'eum moellendorffii Hance as the material,this research studied the epidemic dynamics of H.moellendorffii Hance powdery mildew and plant growth by using the interactive methods of soil moisture and soil organic matter.The results showed that the interaction of higher soil moisture content(60%-80%)and soil organic matter content(75-100 g•kg^(-1))had few diseases,dosease index and area under disease progression curve(AUDPC)compared with those of other treatments,thus could effectivley control powdery mildew disease.Moreover,higher soil moisture and organic matter content increased the yield,contents of soluble sugar,soluble protein,vitamin C and coumarin in H.moellendorffii Hance.

Planting Techniques of Pennisetum giganteum in Huanghuai Area

Pennisetum giganteum z. x. lin selected by the National Juncao Center is a high-yielding and high-quality Juncao variety. It is a high-quality horticultural variety that grows upright, and has tall plants with high yield and high value. Planting should be carried out in the right time to ensure the quality of planting and promote the seedlings to be tidy and strong, and according to the row spacing of 80 cm, plant spacing of 40 cm, 2 plants per hole, about 2 000 holes per 667 m2, with the need for furrowing. At the seedling stage, the soil should be kept moist, and watered in time when it is dry and lacking water. P. giganteum is fertilizer-tolerant and sensitive to fertilizers, and requires a reasonable and economical amount of fertilizer.

Effects of Nitrogen Application Rate and Ratio on Lodging Resistance of Super Rice with Different Genotypes

The objective of this study was to determine the morphology mechanism of nitrogen （N） fertilizer rates and ratio on lodging resistance through analying its effects among lodging index （LI）, lodging-related morphological traits and physical strength in basal intemodes by comparing japonica and indica super rice cultivars. Field experiments, with three nitrogen levels （0, 150 and 300 kg ha-L） and two ratios of basal to topdressing （8：2 and 5：5） with two super rice cultivars （Yliangyou 2 and Wuyunjing 23）, were conducted in the Baolin Farm, Danyang Country, Jiangsu Province, China, in 2011 and 2012. Effects of N fertilizer rates and ratios on morphology of whole plant, morphology traits in basal intemodes and culm＇s physical strength parameters were investigated at 20 d after full heading stage. LI of Yliangyou 2 was significant greater than that of Wuyunjing 23 due to larger bending moment by whole plant （WP） with higher plant height and gravity center height. With higher volume of N fertilizer, LI of two super rice cultivars was increased conspicuously. However, no significant effect was detected with increase of panicle fertilizer ratio. The size of breaking strength （M） in basal intemodes was the key factor determining LI among N fertilizer treatments. Correlation analysis revealed that M value was positively related bending stress （BS） of Wuyunjing 23 and section modulus （Z） of Yliangyou 2, respectively. The higher N fertilizer levels induced reduction ofBS of Wuyunjing 23 due to weak culm and leaf sheath plumpness status and reduced Z of Yliangyou 2 owning to small diameter and culm wall thickness, consequently, influencing their M indirectly. These results suggested that breaking strength was the key factor influencing LI with increase of N fertilizer levels. However, the lodging-related morphology mechanism was different with genotypes. Culm wall thickness and diameter in basal internodes of indica super rice and culm and leaf sheath plumpness status of japonica super rice influenced breaking strength, as well as lodging index, respectively.

Optimal nitrogen fertilization of boreal conifer forest

Background： Forest fertilization offers a means to increase the production of renewable resources.Nitrogen is the most common fertilizer in boreal upland forests.There is plenty of research on the effect of nitrogen fertilization on volume growth, but less research on the optimal timing of fertilization and optimal management of fertilized stands.Methods： This study used simulation and optimization to analyze the profitability of fertilization, optimal management of fertilized stands and the effects of fertilization on cash flows and timber yields.The management of 100 stands representing the most common growing sites of Scots pine and Norway spruce was optimized.Results： Fertilization improved profitability in most of the analyzed stands.Profitability improved most in spruce stands growing on mesic site.Improving stem quality increased the economic benefit of fertilization.The timber yields of medium-aged conifer stands can be increased by almost 1 m^3·ha^（-1）·a^（-1）（15%） in sub-xeric pine and mesic spruce sites and about 0.5 m^3·ha^（-1）·a^（-1）（5%） in mesic pine and herb-rich spruce sites when the recommended nitrogen dose（150kg·ha^（-1）） is applied once in 30 years.Conclusions： Nitrogen fertilization of boreal conifer forest should be used mainly in spruce-dominated stands growing on medium sites.The gains are the highest in stands where the mean tree diameter is 16–20 cm and stand basal area is 14–20 m^2·ha^（-1）.

Spatial and temporal variations in nitrogen retention effects in a subtropical mountainous basin in Southeast China

Nitrogen retention within a watershed reduces the amount of N exported to the ocean;however, it worsens environmental problems, including surface water eutrophication, aquifer pollution, acid rain, and soil acidification. Here, we adopted the Soil and Water Assessment Tool(SWAT) model to describe the riverine N output and retention effects in the Shanmei Reservoir Basin, a subtropical mountainous basin located in Quanzhou City, Southeast China. The results revealed that farmlands and orchards in the upstream and central parts of the basin were the dominant land use types, which contributed large N yields. Fertilizer application was the key source of riverine N output and N retention within the basin. On average, approximately 64% of anthropogenic N inputs were retained within the basin, whereas 36% of total N was exported to the downstream and coastal areas. The average N retention efficiency was 80% in a dry year, and within the year, N retention occurred in spring and summer and N release occurred in autumn and winter. The annual variation in N retention within the basin was largely dominated by changes in rainfall and runoff, whereas the seasonal characteristics of N retention were mainly affected by fertilization. Even with a large decrease in fertilizer application, owing to the contributions of the residual N pool and river background, the riverine N output still maintained a certain base value. The effects of precipitation, land use types, and agricultural fertilizer on N retention should be comprehensively considered to implement reasonable N management measures.

Profitability and Farmer Acceptability of Selected Climate Smart Technologies and Practices for Maize-Beans Production in Drought-Prone Areas, Uganda

Climate change is increasingly affecting farm-level decisions on when to plant and which climate smart agriculture (CSA) options to use. This study was conducted to determine the profitability and farmer acceptability of different CSA options for maize-bean production in drought-prone areas of Uganda. It was conducted on-farm in Rakai and Nakasongola districts during 2020 and 2021. Variables included: planting date (early vs late);varieties (common beans: NABE 4 and NAROBEAN 2, and maize: Longe 5 and Bazooka);intercropping versus pure stand;and fertiliser use (manure, Diammonium phosphate (DAP) or combination). The experimental design was split-split plot, replicated six times. Over two years, early planting caused 16% and up to 46% higher yields of maize and beans, respectively, than late planting, resulting in 14% - 28% and 18% - 43% higher Benefit/Cost (B/C) ratio for maize and beans, respectively. Intercropping reduced maize and beans yield by 16% - 25% and 52% - 57%, respectively. The B/C was highest for sole maize;intercropping was more profitable than sole beans. Fertilizer (DAP) was most profitable when Bazooka was early-planted as sole crop followed by intercrop. For late planted-crop, manure was better. These practices were more beneficial when applied simultaneously for both crops excluding bean variety. Farmers’ lessons stressed the importance of early planting and fertilizer use;however, majority indicated they were to adopt more than two of the practices tested.

Application of controlled-release urea increases maize N uptake,environmental benefits and economic returns via optimizing temporal and spatial distributions of soil mineral N

The creation of controlled-release urea (CRU) is a potent substitute for conventional fertilizers in order to preserve the availability of nitrogen (N) in soil,prevent environmental pollution,and move toward green agriculture.The main objectives of this study were to assess the impacts of CRU’s full application on maize production and to clarify the connection between the nutrient release pattern of CRU and maize nutrient uptake.In order to learn more about the effects of CRU application on maize yields,N uptake,mineral N (N_(min)) dynamics,N balance in soil-crop systems,and economic returns,a series of field experiments were carried out in 2018–2020 in Dalian City,Liaoning Province,China.There were 4 different treatments in the experiments:no N fertilizer input (control,CK);application of common urea at 210 kg ha^(-1)(U),the ideal fertilization management level for the study site;application of polyurethane-coated urea at the same N input rate as U (PCU);and application of PCU at a 20% reduction in N input rate (0.8PCU).Our findings showed that using CRU (i.e.,PCU and 0.8 PCU) may considerably increase maize N absorption,maintain maize yields,and increase N use efficiency (NUE) compared to U.The grain yield showed considerable positive correlations with total N uptake in leaf in U and 0.8 PCU,but negative correlations with that in PCU,indicating that PCU caused excessive maize absorption while 0.8 PCU could achieve a better yield response to N supply.Besides,PCU was able to maintain N fertilizer in the soil profile 0–20 cm away from the fertilization point,and higher N_(min)content was observed in the 0–20 cm soil layer at various growth stages,particularly at the middle and late growing stages,optimizing the temporal and spatial distributions of N_(min).Additionally,compared to that in U,the apparent N loss rate in PCU was reduced by 36.2%,and applying CRU (PCU and 0.8 PCU) increased net profit by 8.5% to 15.2% with less labor and fertilization frequency.It was concluded that using CRU could be an effective N fertilizer management strategy to sustain maize production,improve NUE,and increase economic returns while minimizing environmental risks.