Prediction Model of Soil Nutrients Loss Based on Artificial Neural Network

On the basis of Artificial Neural Network theory, a back propagation neural network with one middle layer is building in this paper, and its algorithms is also given, Using this BP network model, study the case of Malian-River basin. The results by calculating show that the solution based on BP algorithms are consis- tent with those based multiple - variables linear regression model. They also indicate that BP model in this paper is reasonable and BP algorithms are feasible.

Impact of nutrient losses from agricultural lands on nutrient stocks in Dianshan Lake in Shanghai, China

Abstract： The water quality of Dianshan Lake in Shanghai Municipality, China, is impacted by nutrient losses from agricultural lands around the lake. In this study, nine types of agricultural land use were monitored in 2010 and 2011, and a correlation analysis between nutrient losses from agricultural non-point sources （NPS） and nutrient stocks in the lake was conducted over monthly and seasonal time periods. The results indicate that the monthly average concentration of total nitrogen （TN） ranged from 1.41 to 7.34 mg/L in 2010 and from 1.52 to 5.90 mg/L in 2011, while the monthly average concentration of total phosphorous （TP） ranged from 0.11 to 0.26 mg/L in 2010 and from 0.13 to 0.30 mg/L in 2011. The annual loss of TN from agricultural NPS was 195.55 tons in 2010 and 208.40 tons in 2011. The cultivation of water oat made the largest contribution to the loss of TN. The annual loss of TP was 44.58 tons in 2010 and 48.12 tons in 2011, and multi-vegetable cultivation made the largest contribution to the loss of TP. The results of correlation analysis show that the monthly stocks of TN and TP in the lake have a positive correlation with the monthly losses of TN and TP from agricultural NPS. According to the seasonal data, the stocks of TN and TP in the lake both have a much stronger correlation with the losses of TN and TP from agricultural NPS in summer than in other seasons. Agricultural NPS pollution control should be the main focus for the water resource conservation in this area.

Soil nutrient loss due to tuber crop harvesting and its environmental impact in the North China Plain

Soil loss due to crop harvesting （SLCH） is a soil erosion process that signiifcantly contributes to soil degradation in crop-lands. However, little is known about soil nutrient losses caused by SLCH and its environmental impacts. In the North China Plain area, we measured the losses of soil organic carbon （SOC） and nitrogen as wel as phosphorus due to SLCH and assessed their relationship with soil particle size composition, agronomic practices and soil moisture content. Our results show that the losses by harvesting potato of SOC, total nitrogen （TN）, available nitrogen （AN）, available phosphorus （AP） and total phosphorus （TP） were 1.7, 1.8, 1.8, 15.9 and 14.1 times compared by harvesting sweet potato, respectively. The variation of SOC, N and P loss by SLCH are mainly explained by the variation of plant density （PD） （17–50%）, net mass of an individual tuber （Mcrop/p） （16–74%）, soil clay content （34–70%） and water content （19–46%）. Taking into account the current sewage treatment system and the ratio of the nutrients adhering to the tubers during transportation from the ifeld （NTRP/SP）, the loss of TN and TP by harvesting of potato and sweet potato in the North China Plain area amounts to 3% N and 20% P loads in the water bodies of this region. The fate of the exported N and P in the sewage treatment system ultimately controls the contribution of N and P to the polution of lakes and rivers. Our results suggest that a large amount of SLCH-induced soil nutrient export during transportation from the ifeld is a potential polutant source for agricultural water for vast planting areas of tuber crops in China, and should not be overlooked.

Effects of riparian vegetation patterns on the distribution and potential loss of soil nutrients： a case study of the Wenyu River in Beijing

A riparian ecosystem is an ecological transition zone between a river channel and terrestrial ecosystems. Riparian ecosystems play a vital role in maintaining stream health and bank stabilization. The types of riparian vegetation have changed greatly because of human activities along the Wenyu River. This study examines the impact of riparian vegetation patterns on water pollution due to soil nutrient loss. Four riparian vegetation patterns from the river channel to the upland were chosen as the focus of this study： grassland, cropland, grassland- cropland, and grassland-manrnade lawn. The different distributions of soil nutrients along vegetation patterns and the potential risk of nutrient loss were observed and compared. The results showed that riparian cropland has the lowest value of total nitrogen （TN）, total phosphorus （TP）, available nitrogen （AN）, available phosphorus （AP）, and organic matter （OM）, but it has the highest soil bulk density （BD）. The distributions of soil TN, TP, AN, AP, and OM exhibited a declining trend from the upland toward the river channel for riparian cropland, whereas a different trend was observed for the riparian grassland. The vegetation patterns of grassland-cropland and grassland- manmade lawn show that the grassland in the lower slope has more nutrients and OM but lower soil BD than the cropland or manmade lawn in the upper slope. So, the lower-slope grassland may intercept and infiltrate surface runoff from the upland. The lower-slope grassland has higher levels of soil TN, TP, AN, and AP, and thus it may become a new source of nutrient loss. Our results suggest that the management of the riparian vegetation should be improved, particularly in densely populated areas, to control soil erosion and river pollution.

Impact of Different Contour Hedgerows on Runoff,Nutrient and Soil on Sloping Farmland in Danjiangkou Reservoir Region of China

Soil and water loss has been a major environmental problem in the Danjiangkou Reservoir Region.A study of 14°sloping farmland was performed on impact of different contour hedgerows on runoff,losses of soil and nutrients during 2008 and 2011,with five treatments and three replications.The winter wheat and summer maize were used as the test crops.Treatments consisted of four hedgerows:Amorpha(Amorpha fruticosa L.),Honeysuckle(Lonicera japonica Thunb.),Day-lily flower(Hemerocallis citrina Baroni.),and Sabaigrass(Eulaliopsis binata),and a control without hedgerow.Result showed that the runoff under the control treatment was much higher than that of hedgerows.Amorpha could reduce the runoff by 35.2%compared with the control.Soil losses in four hedgerows showed significant reduction in four years(e.g.,Amorpha:78.3%;Honeysuckle:77.1%).Nutrient losses in winter were much higher than that in summer,especially total nitrogen,total phosphorus and total potassium,even though there was an abundant precipitation in summer.Hedgerows greatly affected the soil and nutrient losses on slopping farmland compared with the control treatment,especially Amorpha treatment.The present study found that the Amorpha could be used as the hedgerow species for reducing soil and water loss in the Danjiangkou Reservoir Region.

Variation of Nutrient Value in Selected Composted Farm Wastes

Smallholder farming is promoted for its environmental friendliness, assurance of food security sovereignty and conservation of indigenous knowledge. However, in actual practice, Smallholder farmers recycle farm plant waste to improve soil fertility. By so doing, they contribute to environmental pollution, emissions, and global warming. This situation is a Smallholder farmers’ challenge worldwide. One of these challenges is the inability to find cheaper sources of plant nutrients. These sources of nutrients are associated with environmental pollution, such as the release of Methane. This study focused on farm wastes (bean trash, maize trash, banana trash, cattle slurry, goat slurry, and pig slurry) commonly produced by smallholder farmers in two farming systems of Masaka and Lyantonde Districts to explore the effects of composting and surface decomposition on nutrients contained in farm wastes by specifically: estimating baseline nutrient contents in farm wastes before disposal, determining the variation of nutrients of farm wastes managed by composting and surface decomposition and the potential source of major nutrients among selected farm wastes. Through carbon analysis, Calorimetric determination of Nitrogen and Phosphorus analysis using a block digester and UV-Visible spectrometer, Carbon, Nitrogen, Potassium and Phosphorus were determined from bean trash, maize trash, banana trash, cattle slurry, goat slurry, and pig slurry. Results revealed that goat slurry, chicken waste, maize trash and pig slurry contained more and retained more P, K, C and N, respectively, as compared to other farm wastes. Significant volumes of N and P were retained in composted materials as compared to those managed by surface decomposition.

Effects of tillage practices on nutrient loss and soybean growth in red-soil slope farmland

Field experiments were conducted to examine the effect of tillage practices on sediment and nutrient loss and soybean growth under natural rainfall conditions.Three tillage practices were applied:downslope ridge(check),downslope ridge+contour living hedgerow,and cross ridge.Cross ridge tillage reduced surface runoff by 69%and sediment yield by 86%,compared to the check treatment.The downslope ridge with a contour living hedgerow reduced surface runoff by 24%and sediment yield by 53%.Additionally,compared to the check plot,nutrient losses carried by runoff were reduced by over 68%and that carried in the sediment was reduced more than 85%in the cross ridge plot.Nutrient losses in runoff were reduced by 20%to 30%in the downslope ridge and contour living hedgerow plot and those carried in the sediment were reduced by 44%to 57%.Cross ridge tillage soybean yields exceeded those of the downslope ridge and downslope ridge+contour living hedgerow treatments by 16%-18%.Cross ridge tillage could contribute to the prevention sediment and nutrient loss and could improve crop yield,and thus it is recommended to be applied to mild slopes in the red soil region.

Runoff and nutrient losses in alfalfa(Medicago sativa L)production with tied-ridge-furrow rainwater harvesting on sloping land

Ridge-furrow rainwater harvesting(RFRH)is known to be effective in controlling water loss and soil erosion,and increasing soil moisture and crop yield in semiarid regions.However,it can cause water-logging,ridge overtopping,and harvest failure if not properly designed.A four consecutive-year field trial was carried out to assess the impacts of various slope gradients and tillage practices on soil moisture,runoff,sediment yield,associated soil nutrient losses,fodder yield,and water use efficiency(WUE)of alfalfa in the Loess Plateau,China.The trial adopted a split-plot design,taking slope gradient(5and 10)as main plot treatment and tillage practice(traditional tillage,open-ridging,and tied-ridging)as split-plot treatment,from 2015 to 2018.There were greater variations in runoff,sediment yield,and associ-ated soil nutrient losses than in fodder yield and WUE.Tied-ridging and open-ridging resulted in decreased runoff and reduced sediment transport and associated soil nutrient losses,and increased soil moisture,fodder yield,and WUE.Runoff,sediment transport,and associated soil nutrient losses inclined with increasing slope;while fodder yield and the WUE declined.For slopes of 5and 10,the average decrease in runoff,sediment yield,total nitrogen,total phosphorus,and organic matter losses for open-ridging were 47.7e56.2%,91.0e92.7%,90.4e93.1%,90.1e92.2%,and 88.9e90.2%,respectively,while these for tied-ridging were 62.4e68.4%,94.5e96.4%,93.6e95.5%,93.9e95.9%,and 93.0e94.9%,over 4 years as compared with traditional tillage.The mean annual runoff,sediment,total nitrogen,total phosphorus,and organic matter losses for slopes of 10were 1.31,1.96,1.87,1.99,and 1.64 times greater than the corresponding values for slopes of 5,respectively.The increase of fodder yield and WUE for open-ridging and tied-ridging was 40.1e45.6%and 16.0e17.5%,and 3.66e5.99 and 1.35e2.50 kg ha^(-1)mm^(-1),respectively,for slopes of 5and 10.The average fodder yield and WUE for slopes of 5were 1.19 and 1.23 times greater than corresponding values for slopes of 10,respectively.The disparities in fodder yield and WUE of alfalfa between slopes of 5and 10were not clear in dry years,but were evident in wet years.Tied-ridging was recommended for water and soil conservation,while open-ridging was recommended for increase of fodder yield and WUE of alfalfa.The implementation of RFRH in crop production should be evaluated by the use of a model in accordance with climatic conditions,soil type,and plant species.

Effects of nano carbon on soil erosion and nutrient loss in a semi-arid loess region of Northwestern China

Since 2005,the application of nano carbon(NC)in agriculture and environmental remediation has received considerable attention with most of the research focusing on plant growth and heavy metal absorption.However,little is known about the potential effects of NC on soil erosion and nutrient loss.In this study,rainfall simulation tests were conducted on a soil plot(1 m×1 m,located in a semi-arid loess region of northwestern China),in which a mixture(5-cm below the soil surface)of NC(0,0.1%,0.5%,0.7% and 1.0% on a mass base)and sandy soil(same as the one in the plot)was embedded as three bands(5 cm wide,1 m long and 5 cm thick)at the three positions(top,middle and bottom of the plot),respectively.Before the rainfall simulation test,a mixed solution of potassium bromide(1.0 mol/L KBr),potassium nitrate(1.0 mol/L KNO_(3)),monopotassium phosphate(1.0 mol/L KH_(2)PQ_(4))was sprayed on the soil surface.Results showed that the sandy soil on the Loess Plateau with 0.7%NC addition(36.47 kg/hm^(2) on a mass basis)could improve soil water runoff,sediment yield,and nutrient loss in the semi-arid loess region of northwestern China,in addition to preventing soil water from deep percolation.Therefore,NC may have a great potential in soil erosion control on the Loess Plateau of China.

Recent advances in the chemistry of nitrogen,phosphorus and potassium as fertilizers in soil:A review

The advent of civilization has made humans dependent on plants for food and medicine,leading to the intensification of agricultural production.The intense cultivation of crops has resulted in the depletion of available nutrients from soil,thereby demanding the application of excess nutrients to soil to improve yield.Thus,mineral fertilizer discovery and application have,in many ways,contributed greatly to meeting global food demands.However,aside from the positive effects of mineral fertilizers,their excessive application to soil produces large amounts of pollutants that affect environmental sustainability.This necessitates the study of the major mineral fertilizer elements(nitrogen(N),phosphorus(P),and potassium(K)),the forms in which they are applied to soil,and their chemistry/reactions in soil.Here,we reviewed the forms of different N,P,and K mineral fertilizers to provide current knowledge on their constituents,the chemistry of N,P,and K in soil to understand the reactions they undertake in soil,the efficient methods of fertilizer application for environmental sustainability,the effects of mineral fertilizer loss to the environment,and improved fertilization technologies for environmental sustainability.Nanofertilizers are a promising technology for sustainable agricultural production and are discussed in detail in this review.

Strategies to reduce nutrient pollution from manure management in China

As the demand for livestock products continues to increase in China,so too does the challenge of managing increasing quantities of manure.Urgent action is needed to control point source(housing,storage and processing)and diffuse(field application)pollution and improve the utilization of manure nutrients and organic matter.Here,we review strategies to improve management at each stage of the manure management chain and at different scales.Many strategies require infrastructure investment,e.g.,for containment of all manure fractions.Engineering solutions are needed to develop advanced composting systems with lower environmental footprints and design more efficient nutrient stripping technologies.At the field-scale,there is an urgent need to develop a manure nutrient recommendation system that accounts for the range of manure types,cropping systems,soils and climates throughout China.At the regional scale,coordinated planning is necessary to promote recoupling of livestock and cropping systems,and reduce nutrient accumulation in regions with little available landbank,while minimizing the risk of pollution swapping from one region to another.A range of stakeholders are needed to support the step change and innovation required to improve manure management,reduce reliance on inorganic fertilizers,and generate new business opportunities.

Ecological intensification of cropping systems enhances soil functions,mitigates soil erosion,and promotes crop resilience to dry spells in the Brazilian Cerrado

Water scarcity threatens global food security and agricultural systems are challenged to achieve high yields while optimizing water usage.Water deficit can be accentuated by soil physical degradation,which also triggers water losses through runoff and consequently soil erosion.Although soil health in cropping systems within the Brazilian Cerrado biome have been surveyed throughout the years,information about soil erosion impacts and its mitigation are still not well understood;especially concerning the role of cropping system diversification and its effects on crop yield.Thus,the aim of this study was to assess whether ecological intensification of cropping systems-inclusion of a consorted perennial grass and crop rotation-could promote soil coverage and consequently decrease water erosion and soil,water,and nutrient losses.This work studied the effects of crop rotation and consorted Brachiaria,along with different levels of investment in fertilization on soil physical quality and on soil,water,and nutrient losses,and crop yields.Results proved that soybean monoculture(SS)is a system of low sustainability even under no-till in the Brazilian Cerrado conditions.It exhibited high susceptibility to soil,water,and nutrient losses,causing low crop yields.Our results showed that water losses in SS cropping system were approximately 10%of the total annual rainfall,and total K losses would require an additional 35%of K application.Conversely,ecological intensification of cropping systems resulted in enhanced soil environmental and agronomic functions,increased grain yield,and promoted soil and water conservation:high soil cover rate,and low soil,water and nutrient losses.Ecological intensification proved to be an adequate practice to boost crop resilience to water deficit in the Brazilian Cerrado.

Sugarcane bagasse amendment mitigates nutrient leaching from a mineral soil under tropical conditions

Large quantities of organic by-products are generated by the sugarcane industry during sugar extraction process.These by-products may be used as soil amendments to improve soil quality,as nutrient leaching is common in mineral soils of Florida in USA due to their sandy texture and frequent rain events.A soil column study was designed to evaluate the effects of bagasse application at 85 t ha^(-1) of fresh bagasse,170 t ha^(-1) of fresh bagasse,and 170 t ha^(-1) of fresh bagasse+nitrogen(N)on the leaching potential of carbon(C),N,phosphorus(P),and potassium(K).Bagasse was incorporated within the topsoil(0-15 cm)in outdoor soil columns exposed to natural conditions,with periodical irrigation during the experiment.After approximately 57 weeks,the distributions of C,N,P,and K were evaluated at three soil depths(i.e.,0-15,15-30,and 30-53 cm)within the soil columns.Total organic C(TOC),N,and P in leachates decreased significantly from the soils amended with bagasse compared with the control with no bagasse and no N.Based on K content changes in the columns,bagasse could also be utilized as a potential source of K for plants.Overall,application of bagasse as a soil amendment might be an effective way to sustainably reutilize organic by-products while reducing concerns regarding major nutrients entering groundwater resources.The results of this study could assist in developing nutrient management plans of using sugarcane bagasse as a potential soil amendment in mineral soils.

Mulching as a mitigation agricultural technology against land degradation in the wake of climate change

The sloping topography of the island of Rodrigues(an outer island dependency of the Republic of Mauritius)makes it very prone to soil erosion,and loss of fertile topsoil.Climate variability and climate change in the form of increasing temperatures,long periods of drought followed by short periods of torrential rains are exacerbating this situation.Mulching is a cheap,affordable,sustainable agricultural technology for sustainable soil and land management and reducing soil erosion,which can be adopted by small as well as large farmers.The present work on mulching was carried out in Rodrigues in farmers'fields that were prone to severe soil erosion(8%slope)Banana(Musa sp)leaves,coconut(Cocos nucifera)leaves,and vetiver(Vetiveria zizanoides)grass,at 0 t ha^(-1),10 t ha^(-1),20 t ha^(-1)and 40 t ha^(-1),were used as natural organic mulches after seeding the plots with maize in a randomised block design with four replicates.Runoff and sediment were collected from the treated and control plots,and analysed for total sediments,total runoff,and nutrient content(N,P,K).Results showed that all the mulches tested contributed to lowering of soil and nutrient losses,albeit in varying amounts.Coconut leaves mulch was found to be the most efficient,followed by vetiver and then banana leaves.Percentage mitigation in soil and nutrient erosion was found to be 28.9%for banana leaves at 10 t ha-',and 57.3%for coconut leaves at 40 t ha-'.The reduction of soil and nutrient losses was attributed to the mechanical barrier provided by the mulches,and also to the reduction in the momentum of raindrops acting on the soil aggregates.Mulching also contributed to increasing infiltration rate,lowering temperature and therefore lowering evaporation.