Manure substitution improves maize yield by promoting soil fertility and mediating the microbial community in lime concretion black soil

Synthetic nitrogen(N)fertilizer has made a great contribution to the improvement of soil fertility and productivity,but excessive application of synthetic N fertilizer may cause agroecosystem risks,such as soil acidification,groundwater contamination and biodiversity reduction.Meanwhile,organic substitution has received increasing attention for its ecologically and environmentally friendly and productivity benefits.However,the linkages between manure substitution,crop yield and the underlying microbial mechanisms remain uncertain.To bridge this gap,a three-year field experiment was conducted with five fertilization regimes:i)Control,non-fertilization;CF,conventional synthetic fertilizer application;CF_(1/2)M_(1/2),1/2 N input via synthetic fertilizer and 1/2 N input via manure;CF_(1/4)M_(3/4),1/4 N input synthetic fertilizer and 3/4 N input via manure;M,manure application.All fertilization treatments were designed to have equal N input.Our results showed that all manure substituted treatments achieved high soil fertility indexes(SFI)and productivities by increasing the soil organic carbon(SOC),total N(TN)and available phosphorus(AP)concentrations,and by altering the bacterial community diversity and composition compared with CF.SOC,AP,and the soil C:N ratio were mainly responsible for microbial community variations.The co-occurrence network revealed that SOC and AP had strong positive associations with Rhodospirillales and Burkholderiales,while TN and C:N ratio had positive and negative associations with Micromonosporaceae,respectively.These specific taxa are implicated in soil macroelement turnover.Random Forest analysis predicted that both biotic(bacterial composition and Micromonosporaceae)and abiotic(AP,SOC,SFI,and TN)factors had significant effects on crop yield.The present work strengthens our understanding of the effects of manure substitution on crop yield and provides theoretical support for optimizing fertilization strategies.

Application of organic manure as a potential strategy to alleviate the limitation of microbial resources in soybean rhizospheric and bulk soils

The development and vigor of soil microorganisms in terrestrial ecosystems are frequently constrained by the limited availability of essential elements such as carbon(C),nitrogen(N),and phosphorus(P).In this study,we investigated the impact of long-term application of varying levels of organic manure,low(7.5 Mg ha^(−1)yr^(−1)),moderate(15.0 Mg ha^(−1)yr^(−1)),and high(22.5 Mg ha^(−1)yr^(−1)),on the stoichiometry of enzymes and the structures of the microbial communities in soybean rhizospheric and bulk soils.The main goal of this research was to examine how soil microbial resource limitations in the rhizosphere respond to different long-term fertilization strategies.The soil enzymatic activities were quantified,and the structure of the microbial community was assessed by analyzing phospholipid fatty acid profiles.When compared to the bulk soil,the rhizospheric soil had significant increases in microbial biomass carbon(MBC),nitrogen(MBN),and phosphorus(MBP),with MBC increasing by 54.19 to 72.86%,MBN by 47.30 to 48.17%,and MBP by 17.37 to 208.47%.Compared with the unfertilized control(CK),the total microbial biomasses of the rhizospheric(increased by 22.80 to 90.82%)and bulk soils(increased by 10.57 to 60.54%)both exhibited increases with the application of organic manure,and the rhizospheric biomass was higher than that of bulk soil.Compared with bulk soil,the activities of C-,N-and P-acquiring enzymes of rhizospheric soil increased by 22.49,14.88,and 29.45%under high levels of organic manure,respectively.Analyses of vector length,vector angle,and scatter plots revealed that both rhizospheric and bulk soils exhibited limitations in terms of both carbon(C)and phosphorus(P)availability.The results of partial least-squares path modelling indicated that the rhizospheric soil exhibited a more pronounced response to the rate of manure application than the bulk soil.The varying reactions of rhizospheric and bulk soils to the extended application of organic manure underscore the crucial function of the rhizosphere in mitigating limitations related to microbial resources,particularly in the context of different organic manure application rates.

Excessive manure application stimulates nitrogen cycling but only weakly promotes crop yields in an acidic Ultisol:Results from a 20-year field experiment

Population growth and growing demand for livestock products produce large amounts of manure,which can be harnessed to maintain soil sustainability and crop productivity.However,the impacts of excessive manure application on crop yields,nitrogen(N)-cycling processes and microorganisms remain unknown.Here,we explored the effects of 20-year of excessive rates(18 and 27 Mg ha^(–1)yr^(–1))of pig manure application on peanut crop yields,soil nutrient contents,N-cycling processes and the abundance of N-cycling microorganisms in an acidic Ultisol in summer and winter,compared with none and a regular rate(9 Mg ha^(–1)yr^(–1))of pig manure application.Long-term excessive pig manure application,especially at the high-rate,significantly increased soil nutrient contents,the abundance of N-cycling functional genes,potential nitrification and denitrification activity,while it had a weaker effect on peanut yield and plant biomass.Compared with manure application,seasonality had a much weaker effect on N-cycling gene abundance.Random forest analysis showed that available phosphorus(AP)content was the primary predictor for N-cycling gene abundance,with significant and positive associations with all tested N-cycling genes.Our study clearly illustrated that excessive manure application would increase N-cycling gene abundance and potential N loss with relatively weak promotion of crop yields,providing significant implications for sustainable agriculture in the acidic Ultisols.

The combined effects of farm yard manure and boron application on growth,and oil quality of Canola grown under newly reclaimed soils

Two field experiments were conducted during the main seasons of 2021/2022 at the Research and Production Station of National Research Centre in Egypt to investigate the effects of farmyard manure(FYM)and boron on Canola growth,yield,oil yield,and quality.The results unequivocally demonstrated that the combined application of FYM at a rate of 14.4 ton ha^(-1)with a foliar spray of boron at 100 ppm positively influenced plant characteristics,leading to enhanced growth rates and higher yields compared to the control group.Moreover,this integrated approach significantly improved nutrient content by enhancing levels of oil content,carbohydrates,proteins,phenolics,flavonoids,and total soluble sugars.These findings provide compelling evidence that utilizing farm manure along with boron can effectively enhance Canola properties in newly reclaimed soils while promoting sustainable agricultural practices.

Legume Green Manure and Intercropping for High Biomass Sorghum Production

Before the advent of cheap, synthetic fertilizers, legumes were commonly used as green manure crops for their ability to fix atmospheric nitrogen (N). A three-year study at Overton, TX examined legume integration into high-biomass sorghum (Sorghum bicolor L.) production systems on a Lilbert loamy fine sand recently cultivated after a fertilized bermudagrass [Cynodon dactylon (L.) Pers.] pasture. In this split-split plot design, ‘Dixie’ crimson clover (Trifolium incarnatum L.) and ‘Iron and Clay’ cowpea (Vigna unguiculata L.) were integrated into a high-biomass sorghum production system to evaluate impacts on N concentration, C concentration, and yield of high-biomass sorghum and their impacts on soil total N and soil organic carbon (SOC). Main plots were split into crimson clover green manure (CLGM) and winter fallow (FALL) followed by three sub-plots split into warm-season crop rotations: cowpea green manure (CPGM), cowpea-sorghum intercrop (CPSR), and sorghum monocrop (SORG). Three N fertilizer treatments (0, 45, 90 kg N∙ha−1) were randomized and applied as sub-sub plots. The CLGM increased (P sorghum biomass yield (16.5 t DM∙ha−1) 28% in year three but had no effect in the first two years. The CPSR treatment reduced sorghum yield up to 62% compared to SORG;whereas CPGM increased sorghum yield 56% and 18% the two years following cowpea incorporation. Rate of N fertilizer had no effect on sorghum biomass yield. Decrease in SOC and soil N over time indicated mineralization of organic N and may explain why no N fertilizer response was observed in sorghum biomass yield. Cowpea showed strong potential as a green manure crop but proved to be too competitive for successful intercropping in high-biomass sorghum production systems.

Impact on Soil Organic C and Total Soil N from Cool- and Warm-Season Legumes Used in a Green Manure-Forage Cropping System

Annual forage legumes are important components of livestock production systems in East Texas and the southeastern US. Forage legumes contribute nitrogen (N) to cropping systems through biological N fixation, and their seasonal biomass production can be managed to complement forage grasses. Our research objectives were to evaluate both warm- and cool-season annual forage legumes as green manure for biomass, N content, ability to enhance soil organic carbon (SOC) and soil N, and impact on post season forage grass crops. Nine warm-season forage legumes (WSL) were spring planted and incorporated as green manure in the fall. Forage rye (Secale cereale L.) was planted following the incorporation of WSL treatments. Eight cool-season forage legumes (CSL) were fall planted in previously fallow plots and incorporated as green manure in late spring. Sorghum-sudangrass (Sorghum bicolor x Sorghum bicolor var. sudanense) was planted over all treatments in early summer after forage rye harvest and incorporation of CSL treatments. Sorghum-sudangrass was harvested in June, August and September, and treatments were evaluated for dry matter and N concentration. Soil cores were taken from each plot, split into depths of 0 to 15, 15 to 30 and 30 to 60 cm, and soil C and N were measured using combustion analysis. Nylon mesh bags containing plant samples were buried at 15 cm and used to evaluate decomposition rate of above ground legume biomass, including change in C and N concentrations. Mungbean (Vigna radiata L. [Wilczek]) had the highest shoot biomass yield (6.24 t DM ha-1) and contributed the most total N (167 kg∙ha-1) and total C (3043 kg∙ha-1) of the WSL tested. Decomposition rate of WSL biomass was rapid in the first 10 weeks and very slow afterward. Winter pea (Pisum sativum L. spp. sativum), arrow leaf clover (Trifolium vesiculosum Savi.), and crimson clover (Trifolium incarnatum L.) were the most productive CSL in this trial. Austrian winter pea produced 8.41 t DM ha-1 with a total N yield of 319 kg N ha-1 and total C production of 3835 kg C ha-1. The WSL treatments had only small effects on rye forage yield and N concentration, possibly due to mineralization of N from a large SOC pool already in place. The CSL treatments also had only minimal effects on sorghum-sudangrass forage production. Winter pea, arrow leaf and crimson clover were productive cool season legumes and could be useful as green manure crops. Mungbean and cowpea (Vigna unguiculata [L.] Walp.) were highly productive warm season legumes but may include more production risk in green manure systems due to soil moisture competition.

Carbon sequestration rate,nitrogen use efficiency and rice yield responses to long-term substitution of chemical fertilizer by organic manure in a rice–rice cropping system

Combined application of chemical fertilizers with organic amendments was recommended as a strategy for improving yield,soil carbon storage,and nutrient use efficiency.However,how the long-term substitution of chemical fertilizer with organic manure affects rice yield,carbon sequestration rate(CSR),and nitrogen use efficiency(NUE)while ensuring environmental safety remains unclear.This study assessed the long-term effect of substituting chemical fertilizer with organic manure on rice yield,CSR,and NUE.It also determined the optimum substitution ratio in the acidic soil of southern China.The treatments were:(i)NPK0,unfertilized control;(ii)NPK1,100%chemical nitrogen,phosphorus,and potassium fertilizer;(iii)NPKM1,70%chemical NPK fertilizer and 30%organic manure;(iv)NPKM2,50%chemical NPK fertilizer and 50%organic manure;and(v)NPKM3,30%chemical NPK fertilizer and 70%organic manure.Milk vetch and pig manure were sources of manure for early and late rice seasons,respectively.The result showed that SOC content was higher in NPKM1,NPKM2,and NPKM3 treatments than in NPK0 and NPK1 treatments.The carbon sequestration rate increased by 140,160,and 280%under NPKM1,NPKM2,and NPKM3 treatments,respectively,compared to NPK1 treatment.Grain yield was 86.1,93.1,93.6,and 96.5%higher under NPK1,NPKM1,NPKM2,and NPKM3 treatments,respectively,compared to NPK0 treatment.The NUE in NPKM1,NPKM2,and NPKM3 treatments was higher as compared to NPK1 treatment for both rice seasons.Redundancy analysis revealed close positive relationships of CSR with C input,total N,soil C:N ratio,catalase,and humic acids,whereas NUE was closely related to grain yield,grain N content,and phenol oxidase.Furthermore,CSR and NUE negatively correlated with humin acid and soil C:P and N:P ratios.The technique for order of preference by similarity to ideal solution(TOPSIS)showed that NPKM3 treatment was the optimum strategy for improving CSR and NUE.Therefore,substituting 70%of chemical fertilizer with organic manure could be the best management option for increasing CSR and NUE in the paddy fields of southern China.

Black soldier fly: A new vista for livestock and poultry manure management

The corresponding author and editor express their thanks to Dr.Dave Mangindaan(Bina Nusantara University,Indonesia)forpointingoutthemisuse.

Chitin, Biochar, and Animal Manures Impact on Eggplant and Green Pepper Yield and Quality

The global obligation for food requires soil and plant management practices that provide valuable effects on the physical, chemical, and organic properties of soils. The use of animal manure, in agricultural production systems as alternative to synthetic elemental fertilizers has potential application to improve crop yield and fruit quality. A randomized complete block design (RCBD) was established to investigate the impact of nine soil treatments on yield and quality of bell pepper, Capsicum annuum and eggplant, Solanum melongena. The nine soil treatments included: chitin CH, biochar Bio, sewage sludge SS, chicken manure CM, SS mixed with biochar (SSBio), SS mixed with CH (SSCH), CM mixed with biochar (CMBio), CM mixed with CH (CMCH), and unamended (UN) native soil used as control treatment. At maturity, fruits from each treatment, were counted, weighed, and classified according to the USDA grades to U.S. Fancy, U.S. No.1, U.S. No.2, and culls. Overall number and weight of green pepper fruits collected from plants grown in SSCH were significantly greater (26.2 and 3.14 kg 5 plants-1) compared to fruits of plants grown in unamended control treatment (17.1 and 1.98 kg 5 Plants-1, respectively). Whereas CH alone was superior in increasing the number and weight of eggplant fruits compared to the control treatment. Average weight and number of eggplant fruits of plants grown in soil amended with chitin (4.46 kg and 11.5, respectively) were significantly (P ≤ 0.05) greater than weight and number of fruits obtained from plants grown in other soil treatments. Results also revealed a positive correlation coefficient (r) and high probability of significance (P) between number of fruits and weight of fruits among the nine soil treatments. Utilization of animal manures in agricultural systems is an inexpensive means for limited-resource farmers looking for improvements in crop yield and quality at affordable costs.

Production of Biogas from Olive Mill Waste Waters Treated by Cow Manure

The olive mill waste waters (OMWW) generated from olive oil extraction is a major environmental concern since they are characterized by their role as a pollutant (high organic and mineral matters) and their pH acid. The aim of this study was to valorize (OMWW) by anaerobic fermentation in the presence of cow manure in order to produce biogas and reduce their toxic load. Many tests were carried out by fermenting (OMWW) with polyphenols in the presence of cow manure in thermophile temperatures. The performance of this treatment was valuated through measurements of biogas production and by the determination of different parameters of fermented media (pH, volume of the biogas and polyphenols).

Maize response to nitrogen and phosphorus starter fertilisation in mineral-fertilised or manured systems

Phosphorus(P)is an essential nutrient for maize production,but in temperate areas the P uptake during early growing stages can be limited due to low soil temperature,even though the soil was tested high in P.The objective of this study was to assess the effects of nitrogen and phosphorous(NP)starter fertilisation during early growth stages and its carryover until maize harvest,in mineral-fertilised or manured systems.A field experiment was carried out in north-west Italy during the 2019 and 2020 growing seasons.The trial compared sub-surface placement of NP(diammonium phosphate)or N alone(ammonium nitrate)in bands close to the maize seed furrows,in differing long-term(LT)fertilisation managements:two doses of urea(Min-L and Min-H),two doses of bovine slurry(Slu-L and Slu-H)or two doses of farmyard manure(Fym-L and Fym-H).The two rates,low(L)and high(H),corresponded to 170 and250 kg N ha^(-1)year^(-1) respectively.Compared to N fertilisation,NP starter fertilisation improved early maize growth assessed by leaf area index(LAI)and shoot dry weight(SDW)in all systems.The effects differed between the two years(2019:LAI+63%,SDW+67%;2020:LAI+36%,SDW+38%),as 2019was cool during the first growth.Higher LAI and SDW values were confirmed at crop flowering in the mineral-fertilised systems only.As shoot growth was enhanced by NP starter fertilisation,anthesis occurred 1 day earlier in all systems.However,a response to NP starter fertilisation at harvest was recorded in mineral-fertilised systems only(+1.3 and+3.2 t ha^(-1) in Min-L and Min-H,respectively).The uptake of P,used as a true indicator of soil nutrient availability,increased with increasing soil Olsen P until 39 mg kg^(-1).These results suggest that soil test thresholds should be revised for points above which P fertilisation should be suspended.

The potential of green manure to increase soil carbon sequestration and reduce the yield-scaled carbon footprint of rice production in southern China

Green manure(GM)has been used to support rice production in southern China for thousands of years.However,the effects of GM on soil carbon sequestration(CS)and the carbon footprint(CF)at a regional scale remain unclear.Therefore,we combined the datasets from long-term multisite experiments with a meta-analysis approach to quantify the potential of GM to increase the CS and reduce the CF of paddy soils in southern China.Compared with the fallow-rice practice,the GM-rice practice increased the soil C stock at a rate of 1.62 Mg CO_(2)-eq ha^(-1) yr^(-1) and reduced chemical N application by 40%with no loss in the rice yield.The total CF varied from 7.51 to 13.66 Mg CO_(2)-eq ha^(-1) yr^(-1) and was dominated by CH_(4) emissions(60.7-81.3%).GM decreased the indirect CF by 31.4%but increased the direct CH_(4) emissions by 19.6%.In the low and high CH_(4) emission scenarios,the CH_(4) emission factors of GM(EF_(gc))were 5.58 and 21.31%,respectively.The greater soil CS offset the increase in GM-derived CF in the low CH_(4) scenario,but it could not offset the CF increase in the high CH_(4) scenario.A trade-off analysis also showed that GM can simultaneously increase the CS and reduce the total CF of the rice production system when the EF_(gc) was less than 9.20%.The variation in EF_(gc) was mainly regulated by the GM application rates and water management patterns.Determining the appropriate GM application rate and drainage pattern warrant further investigation to optimize the potential of the GM-rice system to increase the CS and reduce the total CF in China.

An Evaluation of Manure Management Strategies, Phosphorus Surface Runoff Potential and Water Usage at an Arkansas Discovery Dairy Farm

Manure management is an essential component of dairy production. Nutrient-laden, field-applied dairy manure often serves as a fertilizer source, but can also pose environmental threats if not properly managed. The Haak dairy farm, located in Decatur, Arkansas, was granted a permit by the Arkansas Department of Environmental Quality (ADEQ) to employ a unique method in treating and storing cattle manure generated during the milking process. This method includes minimizing water use in wash water, dry scraping solids to combine with sawdust for composting and pumping effluent underground into a sloped concrete basin that serves as secondary solid separator before transporting the manure effluent into an interception trench and an adjacent grassed field to facilitate manure nutrient uptake and retention. The Arkansas Discovery Farm program (ADF) is conducting research to evaluate the environmental performance of the dairy’s milk center wash water treatment system (MCWW) by statistical analysis, characterization of phosphorus (P) migration in soil downslope from the inception trench, temperature measurements, and nutrient analysis of a stored dry stack manure/sawdust mixture. Goals included determining possible composting effectiveness along with comparisons to untreated dairy manure and quantifying the use of on-farm water. Results from this research demonstrated that: 1) The MCWW was effective at retaining manure-derived nutrients and reducing field nutrient migration as the MCWW interception trench had significantly higher total nitrogen (TN) (804.2 to 4.1), total phosphorus (TP) (135.6 to 1.5), and water extractable phosphorus (WEP) (55.0 to 1.0) concentrations in milligrams per liter (mg⋅L-1) than the downhill freshwater pond respectively;2) temperature readings of the manure dry stack indicated heightened levels of microbial and thermal activity, but did not reach a standard composting temperature of 54°C;3) manure dry stack nutrient content was typically higher than untreated dairy manure when measured on a “dry basis” in ppm, but was lower on an “as is basis” in ppm and kg/metric ton;and 4) water meter readings showed that the greatest use of on-farm water was for farm-wide cattle drinking (18.77), followed by water used in the milking center (3.45) and then followed by human usage (0.02) measured in cubic meters per day (m3⋅d-1). These results demonstrate that practical innovations in agricultural engineering and environmental science, such as the Haak dairy’s manure treatment system, can effectively reduce environmental hazards that accompany the management of manure at this dairy operation.

Investigates of substrate mingling ratio and organic loading rate of KOH pretreated corn stover and pig manure in batch and semi-continuous system:Anaerobic digestion performance and microbial characteristics

The effects of substrate mingling ratio(SMR)(1:1,1:2,1:3,3:1,and 2:1)and organic loading rate(OLR)(50-90 g total solids per liter per day)on anaerobic co-digestion performance and microbial characteristics were investigated for pig manure(PM)and pretreated/untreated corn stover in batch and semicontinuous anaerobic digestion(AD)system.The results showed that SMR and pretreatment affected co-digestion performance.The maximum cumulative methane yield of 428.5 ml·g^(-1)(based on volatile solids(VS))was obtained for PCP13,which was 35.7%and 40.0%higher than that of CSU and PM.In the first 5 days,the maximum methane yield improvement rate was 378.1%for PCP13.The daily methane yield per gram VS of PCP13 was 11.4%-18.5%higher than that of PC_(U)13.Clostridium_sensu_stricto_1,DMER64,and Bacteroides and Methanosaeta,Methanobacterium,and Methanospirillum had higher relative abundance at the genus level.Therefore,SMR and OLR are important factor affecting the AD process,and OLR can affect methane production through volatile fatty acids.

Evaluation of the Productivity of Intercropping Plantain Cultivar (PITA 3) Fertilized with Two Types of Manure, under Coconut Tree Based (Cocos nucifera L.), on the Tertiary Sands of Côte d’Ivoire

Pressure on land tenure is having a negative impact on the coconut sector, reducing farmers’ incomes. Intercropping cultivars plantain under coconut based has been considered as a solution to this problem. The aim of this work is to diversify the sources of income for coconut growers. The plantain variety PITA 3, popularised by the CNRA, was grown in coconut inter-rows (PB113+), with two types of manure (chemical, organic). Six (06) treatments D1, D2, D3, D4, D5 and D6 were studied. In the tenth month after planting, treatment D3, which included banana plants fertilised with 9 kg of manure/plant, got the best agromorphological performance: height (264.08 cm), neck circumference (57.68 cm) and 12 leaves. In terms of production parameters, D3 banana plants had a shorter production cycle (347 days) and the highest diet mass (9.3 kg). However, the plants that received no fertiliser (D6) showed stunted growth and were unable to produce brunch. The fertilization of plantain with 10 t/ha of laying hen droppings permitted good development and production of plantains on tertiary sands.

Garden Egg (Solanum melongena L.) Performance under Different Sources of Animal Manure as a Sustainable Alternative Fertilizer for Farmers

To ensure food security, continuous intensive farming systems with limited fallowing periods and other farming systems like crop rotation have led to poor soil health with extremely low organic matter, especially in tropical regions with high organic matter mineralization. Small-scale farmers in developing countries cannot afford intensive agricultural systems with heavy chemical inputs, which have not improved soil health. Inorganic fertilizers are harmful to the environment, so farmers should use cheap, locally available organic fertilizers like animal manure, which supports organic agricultural systems and soil health. Animal manure is used as a soil amendment to improve soil health, fertility, and crop yields, but data on how different manures affect specific crops is scarce. Poultry, cattle, and goat manure were compared to no fertilizer and mineral fertilizer on garden egg phenology, vegetative growth, and yield. Poultry manure improved garden egg vegetative growth, phenology, yield, and yield components compared to the negative control and the other treatments. Poultry manure yielded the most fruit at 0.921 kg∙ha-1, followed by cattle and goat manure at 0.709 kg∙ha-1 and 0.698 kg∙ha-1. In conclusion, poultry manure may be a better alternative to synthetic NPK with yield performance similar to garden eggs and long-term soil health benefits similar to other manure sources.

应用Manure-DNDC模型模拟畜禽养殖氮素污染

畜禽养殖是重要的农业面源氮素污染源头,大量的畜禽粪便施入农田后,会加大农田氮素径流和淋溶损失强度。畜禽养殖废弃物氮素污染过程复杂,涉及到动物自身营养循环以及废弃物通过不同途径进入环境的过程,目前大多通过排放系数法估算畜禽养殖过程产生的氮素污染负荷。该文选用最新版Manure-DNDC模型,以山东小清河流域为例,模拟畜禽养殖及废弃物处理的生物地球化学过程,分析氮素在动物、畜禽粪便、农田之间的迁移转化,探讨该过程中氮素的主要损失途径以及污染物负荷的时空变化特征。模拟结果表明,小清河流域2008年畜禽养殖及粪便处理场所氮素径流损失4.66万t,粪便施入农田后的氮素径流和淋溶损失分别为0.1、0.51万t。

Heavy metals pollution in poultry and livestock feeds and manures under intensive farming in Jiangsu Province, China

The heavy metals pollution in poultry and livestock feeds and manures under intensive farming in Jiangsu Province was investigated. 97 feed and manure samples were sampled from 31 farming plants in 10 major cities of Jiangsu. 14 metals, including Zn, Cu, Pb, Cd, Cr, Ni, Mo, Mn, Ba, Co, Sr, Ti, As and Hg, were analyzed after samples acid digestion. The results showed that the most feed samples contained high concentration of metals exceeding National Hygienical Standard for Feeds. Meanwhile, it was found that Cu, Zn, Pb, Cd and Cr concentrations in animal manures were also high, for example, Cu concentration in a manure sample reached to as much as 1726 3 mg/kg. Heavy metals loading quantities in soil per year were then calculated when metals contaminated organic fertilizers were applied, and its effects on soil environmental quality were further evaluated.

Long-Term Application of Organic Manure and Mineral Fertilizer on N_2O and CO_2 Emissions in a Red Soil from Cultivated Maize-Wheat Rotation in China

A long-term field experiment was established to determine the influence of mineral fertilizer and organic manure on soil fertility. A tract of red soil （Ferralic Cambisol） in Qiyang Red Soil Experimental Station （Qiyang County, Hunan Province, China） was fertilized beginning in 1990 and N20 and CO2 were examined during the maize and wheat growth season of 2007-2008. The study involved five treatments： organic manure （NPKM）, fertilizer NPK （NPK）, fertilizer NP （NP）, fertilizer NK （NK）, and control （CK）. Manured soils had higher crop biomass, organic C, and pH than soils receiving the various mineralized fertilizers indicating that long-term application of manures could efficiently prevent red soil acidification and increase crop productivity. The application of manures and fertilizers at a rate of 300 kg N ha-1 yr-1 obviously increased NzO and CO2 emissions from 0.58 kg N20-N ha-~ yr-~ and 10565 kg C ha-~ yr-~ in the CK treatment soil to 3.0l kg N20-N ha-~ yr-~ and 28 663 kg C ha-~ yr-I in the NPKM treatment. There were also obvious different effects on N20 and CO2 emissions between applying fertilizer and manure. More N20 and CO2 released during the 184-d maize growing season than the 125- d wheat growth season in the manure fertilized soils but not in mineral fertilizer treatments. N20 emission was significantly affected by soil moisture only during the wheat growing season, and CO2 emission was affected by soil temperature only in CK and NP treatment during the wheat and maize growing season. In sum, this study indicates the application of organic manure may be a preferred strategy for maintaining red emissions than treatments only with mineral fertilizer. soil productivity, but may result in greater N20 and CO2

Effects of Long-Term Winter Planted Green Manure on Physical Properties of Reddish Paddy Soil Under a Double-Rice Cropping System

Soil physical properties are important indicators of the potential for agricultural production.Our objective was to evaluate the effects of long-term inputs of green manures on physical properties of a reddish paddy soil（Fe-Typic Hapli-Stagnic Anthrosols） under a double cropping system.The common cropping pattern before the study was early-late rice-fallow（winter）.The field treatments included rice-rice-fallow（R-R-WF）,rice-rice-rape（R-R-RP）,rice-rice-Chinese milk vetch（RR-MV）,and rice-rice-ryegrass（R-R-RG）.The rape,Chinese milk vetch and ryegrass were all incorporated as green manures 15 d before early rice transplanting during the following year.The soil bulk density in all green manure treatments was significantly reduced compared with the winter fallow treatment.Soil porosity with green manure applications was significantly higher than that under the winter fallow.The green manure treatments had higher 0.25-5 mm water stable aggregates and aggregates stabilities in the plow layer（0-15 cm depth） compared with the fallow treatment.The mean weight diameter（MWD） and normalized mean weight diameter（NMWD） of aggregates in the green manure treatment were larger than that with the winter fallow.Soil given green manure retained both a higher water holding capacity in the plow layer soil,and a larger volume of moisture at all matric potentials（-10,-33 and-100 kPa）.We conclude that the management of double-rice fields in southern central China should be encouraged to use green manures along with chemical fertilizers to increase SOC content,improve soil physical properties and soil fertility.