Manure Substitution Research Articles

Long-term green manuring enhances crop N uptake and reduces N losses in rice production system

Green manuring is a potential method for reducing chemical N fertilizer input and reactive N losses to the environment that can achieve dual goals of food security and green development of agriculture. In this study, three long-term field experiments in south China and process-based model (WHCNS_LIXIM model) were combined to examine effects of long-term green manure substitution on soil N supply, crop N uptake, and N losses in rice production system. Results showed that green manure substitution significantly improves soil mineral N by 27.4–94.9% and 1.0–45.0% at jointing and maturity stages, respectively, compared with the use of chemical N alone. Moreover, 18.4–62.2% of crop N uptake increased at the maturity stage at Xinyang and Yujiang sites. The model demonstrated satisfactory performance in modeling dynamics of soil mineral N, crop N uptake, crop dry matter, and grain yield of the rice–green manure system with a determination coefficient (R2) > 0.967 and slope of linear regression equation (β) close to 1.0. Simulated N budgets presented that green manure reduces 20–40% of the chemical N fertilizer input and decreased 5.5%, 25.1%, and 30.6% of N losses by ammonia volatilization, leaching, and runoff, respectively, when green manure application rates (fresh matter) are less than 30 t ha−1. However, the total N loss increased with the increase of green manure application amounts when application amounts are larger than 30 t ha−1. These findings indicated that the further reduction of chemical N fertilizer was needed when the application amount of milk vetch was higher than 30 t ha−1. A milk vetch application of 15–30 t ha−1 was recommended to substitute 20–40% of chemical N fertilizer to improve crop N uptake and reduce N losses, and develop green rice production system in the study areas.

Reducing greenhouse gas emissions and increasing yield through manure substitution and supplemental irrigation in dryland of northwest China

Achieving carbon neutrality is a global goal, and increasing crop yield while reducing agriculture-related greenhouse gas (GHG, including CO2, CH4, and N2O) emissions is an urgent challenge. In the dryland of northwest China, the high input of nitrogen (N) fertilizer drives high GHG emissions. Replacement of part of the N fertilizer with manure (NM) and adding supplemental irrigation water (NMW) to NM can significantly increase crop yields. However, it is still unknown whether the increased yield would induce more GHG emissions. In this study, the change in GHG emissions were investigated under conventional farmer N application (FN), NM and NMW in winter wheat cropping systems. The two-year study showed that the global warming potential, greenhouse gas intensity and carbon footprint of NM and NMW were 3–25%, 21–42% and 9–18% lower, respectively, than those of FN, owing to the lower N fertilizer and the associated N2O emissions under NM and NMW. In addition, compared with FN, CO2 emissions during the growing season were higher under NM and NMW; however, due to the 23–40% higher biomass productivity, NM and NMW neutralized and fixed more CO2 (21–39% higher net ecosystem productivity) than FN. Therefore, NM and NMW could be favorable agronomic practices in the Loess Plateau when considering the dual goal of maintaining acceptable yields while reducing GHG emissions.

Effects of manure substituting chemical nitrogen fertilizer on rubber seedling growth and soil environment.

The substitution of manure for chemical nitrogen fertilizers has great impacts on the growth of rubber seedlings and soil environment, with implications for rubber cultivation and transplantation and soil environment improvement. In this study, rubber seedlings of thermal research '7-33-97' strain were cultivated under four treatments: No fertilizer application (CK), only application of chemical fertilizer (N), manure replacing 50% chemical fertilizer (M+N), and manure replacing 100% chemical fertilizer (M). Plants parameters (including plant height, basal diameter, biomass, and chlorophyll), soil physicochemical properties (including pH, soil organic carbon and nitrogen, soil enzyme activities), and their relationships were investigated. The results showed that plant height, basal diameter, biomass, and chlorophyll content in the M+N and M treatments were significantly higher, while underground biomass and root-shoot ratio were significantly lower than those of in N treatment. Compared with CK, soil pH was significantly increased in the M treatment, decreased in the N treatment, and was not changed in the M+N treatment. Soil ammonium and nitrate content in the M+N and M treatments were significantly lower, while soil organic carbon content, the activity of β-1,4-glucosidase (BG), β-1,4-N-acetylglucosaminidase (NAG) and leucine aminopeptidase (LAP) were significantly higher than those of in N treatment. Results of correlation analysis showed that soil pH was negatively correlated with soil ammonium and nitrate content, but positively correlated with BG and NAG activities. The structural equation model analysis showed that soil pH had significant positive effects on seedling quality index, while nitrate content had significant negative effects, and soil enzyme activities had no significant effect. Those results indicated that soil pH and nitrate content were the important driving factors on the growth of rubber seedlings. The manure replacing of 50% and 100% chemical nitrogen fertilizer could promote rubber seedlings growth, improve soil environment, and promote sustainable development of rubber production in Danzhou City, Hainan Province.

A sustainable agricultural supply chain considering substituting organic manure for chemical fertilizer

Promoting organic manure utilization and increasing soil carbon sequestration is essential to develop sustainable agriculture, and has become a critical issue in agricultural planting. This study addresses a substitute organic manure for chemical fertilizer problem from the perspective of supply chain network with consideration of subsidy policy, social responsibility and quality preference. The supply chain network equilibrium methodology is adopted to investigate the optimal transaction prices and volumes among various decision-makers in the network with the objectives of maximizing economic profits and environmental benefits simultaneously. A production function based on experimental data of organic manure substitution is introduced into the agri-product supply chain network with multiple layers and participants. A table grape supply chain case is carried out in this work and the results show that: (1) Increasing subsidies is efficient to improve organic manure utilization, while excessive subsidies are not conducive to long-term sustainable agriculture development. (2) Social responsibility benefits the environment, while it would bring additional economic pressure for farmers. (3) High-quality preferences could inspire farmers to make green planting decisions. This study provides effective organic manure promotion strategies for different participants in the agri-product supply chain network, which could promote green planting and sustainable agricultural development.

Reactive nitrogen releases and nitrogen footprint during intensive vegetable production affected by partial human manure substitution.

Evaluating the sustainability of vegetable production is crucial to secure future food supply. A 2-year field study of four different vegetable crops was performed to investigate the effects of inorganic fertilizer and human manure at different ratios on vegetable yields, reactive gaseous nitrogen emissions (GNrEs), reactive nitrogen (Nr) footprint, and net ecosystem economic income (NEEI) by using life cycle analysis. Four fertilization strategies were studied, including CK (no fertilization); CF (inorganic fertilization); CHF1 (human manure /inorganic fertilizer, N ratio = 1:7); and CHF2 (human manure /inorganic fertilizer, N ratio = 1:3). Results showed that compared with CF treatment, both CHF1 and CHF2 treatments increased the N2O + NO emissions by 11.8% and 32.4% on average, while decreased the vegetable yields by 6.7% and 7.4%, respectively. Moreover, the addition of human manure increased the proportions of Nr footprint by 6.6% (CHF1) and 2.9% (CHF2) in comparison with CF treatment. However, although CHF2 treatment significantly increased the values of GNrEs and reactive gaseous nitrogen intensity (GNrI) by 8.4% and 12.5%, respectively, in relation to those in CF treatment, it still increased farmers' income by 16,404 CNY ha-1. These findings suggest that although human manure incorporation could not mitigate Nr releases, the appropriate ratio of inorganic fertilizer and human manure (CHF2) is able to improve net economic income (NEI) and NEEI during intensive vegetable production. Nevertheless, it should be further explored about the relationship between combinatorial treatment of inorganic fertilizer and human manure on Nr release mitigation in intensive vegetable production.

How does partial substitution of chemical fertiliser with organic forms increase sustainability of agricultural production?

To ensure global food security, agriculture must increase productivity while reducing environmental impacts associated with chemical nitrogen (N) fertilisation. This necessitates towards more sustainable practices such as recycling organic waste to substitute chemical fertiliser N inputs. However, hitherto how such strategy controls the succession of microbial communities and their relationship with crop yields and environmental impacts have not been comprehensively investigated. We conducted a field experiment with vegetable production in China examining partial substitution (25–50%) of chemical fertiliser with organic forms (pig manure or municipal sludge compost) considering key sustainability metrics: productivity, soil health, environmental impacts and microbial communities. We demonstrate that partial organic substitution improved crop yields, prevented soil acidification and improved soil fertility. Treatments also reduced detrimental environmental impacts with lower N2O emission, N leaching and runoff, likely due to reduced inorganic nitrogen surplus. Microbial communities, including key genes involved in the N cycle, were dynamic and time-dependent in response to partial organic substitution, and were also important in regulating crop yields and environmental impacts. Partial organic substitution increased bacterial diversity and the relative abundance of several specific microbial groups (e.g. Sphingomonadales, Myxococcales, Planctomycetes, and Rhizobiales) involved in N cycling. Additionally, partial organic substitution reduced the number of bacterial ammonia oxidizers and increased the number of denitrifiers, with the proportion of N2O-reducers being more pronounced, suggesting a mechanism for reducing N2O emissions. Comprehensive economic cost-benefit evaluation showed that partial organic substitution increased economic benefit per unit area by 37–46%, and reduced agricultural inputs and environmental impacts per unit product by 22–44%. Among them, 50% substitution of pig manure was the most profitable strategy. The study is crucial to policy-making as it highlights the potential advantages of shifting towards systems balancing chemical and organic fertilisers with economic benefits for farmers, reduced environmental damage and an efficient way for organic waste disposal.

Nitrogen use efficiency exhibits a trade-off relationship with soil N2O and NO emissions from wheat-rice rotations receiving manure substitution

Nitrogen (N) fertilizer has shown to affect soil nitrous oxide (N2O) and nitric oxide (NO) emissions that contribute to global warming and stratospheric ozone depletion. However, soil N2O and NO emissions with a linkage to crop N use efficiency (NUE) under different fertilization strategies in winter wheat-summer rice rotation systems remain yet to be further examined. Here, we carried out a two-year field study to assess the response of soil N2O and NO emissions as an interplay with NUE to different fertilization strategies in a typical winter wheat-summer rice rotation cropland of subtropical China. Three fertilizer treatments were established consisting of phosphorus (P) and potassium (K) fertilizer application (PK), NPK fertilizer application (NPK), and NPK fertilizer application with N partially replaced with manure (NPKM). Annual N2O, NO and N2O + NO emissions averaged 0.96, 0.24 and 1.19 kg N ha−1 yr−1 for the PK plots and 6.54, 1.48 and 8.03 kg N ha−1 yr−1 for the NPK plots, respectively. Relative to the NPK plots, partially replacing chemical N fertilizer with manure decreased annual N2O and NO emissions and their combined emissions by 13–15%, while it significantly enhanced crop NUE as compared to the NPK plots. Annual mean emission factors (EFs) of N fertilizer for N2O and NO were estimated to be 1.17% and 0.26% for the NPK plots, and 0.99% and 0.22% for the NPKM plots, respectively. Both N2O and NO emissions were positively correlated with N surplus, while yield-scaled N2O + NO emissions and the fertilizer N-induced combined EF for N2O + NO were negatively related to crop NUE. Together, our results highlight that improving crop NUE while reducing soil N surplus constitutes an effective strategy to mitigate soil gaseous N loss through N2O and NO in the wheat-rice rotation cropping systems.

Low N2O emissions from wheat in a wheat-rice double cropping system due to manure substitution are associated with changes in the abundance of functional microbes

Fertilization has been shown to affect nitrogen (N) cycling and its related functional microbes in agricultural soils. However, the linkage between soil N2O emissions and N-related functional genes under different fertilization strategies from wheat in a wheat-rice double cropping system is rarely examined. Here, we carried out a two-year field study to examine the response of soil N2O emissions driven by N cycling functional genes [archaeal and bacterial amoA (AOA + AOB), nirS, nirK and nosZ] to different fertilization strategies in a wheat cropland of subtropical China. Three fertilizer treatments were established consisting of chemical phosphorus (P) and potassium (K) fertilizer application (PK), chemical N (urea) and PK fertilizer application (NPK), and chemical NPK fertilizer application with chemical N partially replaced with manure (composted pig manure) (NPKM). Over the two wheat seasons, seasonal total N2O emissions averaged 0.66, 3.60 and 3.11 kg N ha−1 for PK, NPK and NPKM plots, respectively. Relative to the NPK treatment, the NPKM treatment significantly decreased N2O emissions by 14 % without compromising grain yield, with a lowered combined fertilizer-induced emission factor (EF) of 1.02 %. Compared with the PK treatment, N fertilization consistently and significantly increased the abundance of ammonium-oxidation bacteria (AOB), nirS, nirK and nosZ genes. The nosZ gene, which drives N2O reduction during denitrification, showed a greater extent under NPKM with manure N combination. The AOB had a more sensitive response than ammonium-oxidation archaea (AOA) to chemical N fertilization. Seasonal N2O emissions showed significant positive correlations with AOB gene abundance and the ratio of (nirK+nirS)/nosZ, while had a negative correlation with nosZ gene abundance across N fertilized treatments. The N2O-related microbial composition of functional genes was significantly changed by N fertilizer application and also showed contrasting patterns between treatments of chemical N fertilizer with and without manure N substitution. Together, partially replacing chemical N fertilizer with manure reduced N2O emissions from wheat in a wheat-rice double cropping system, mainly through decreasing AOB associated-nitrifying potential, and particularly stimulating N2O reduction.

Using manure for improving nitrogen fertilization and maize yield

AbstractManure and chemical fertilizers have different effects on soil properties, the nitrogen cycle, and crop yield. This study aimed to investigate the effects of different fertilizer applications under the same N input on soil physicochemical properties and soil bacterial communities and to explain the contributions of soil properties to grain yield. Manure substitution of chemical fertilizer was conducted in leaching monitoring systems. The study began in 2009 and sampling was carried out in 2014 and 2016. Three fertilizer treatments with the same total N, P, and K application rates and one control treatment were designed as follows: (1) CK, without nitrogen fertilizer; (2) 100%U, whole nitrogen coming from urea; (3) 100%M, whole nitrogen coming from composted cattle manure; and (4) 50%U + 50%M, half nitrogen from composted cattle manure and half nitrogen from urea. Soil organic carbon (SOC) content was positively correlated with total N (TN), NO3−–N, and NH4+–N contents, the mean weight diameter of soil aggregates, and the Shannon diversity index of bacteria, whereas SOC content was not significantly correlated with grain yield. NO3−–N content was positively correlated with grain yield. Substituting half the amount of chemical fertilizer with manure as a nitrogen source improved soil stability, increased bacterial diversity, and enhanced nitrogen supply, while reducing nitrogen loss from ammonia volatilization and nitrogen leaching. Substituting half the amount of chemical fertilizer with manure as a nitrogen source was a more sustainable way to increase grain yield through a sustainable nitrate supply and to reduce N loss.

Evaluation of carbon, nitrogen footprint and primary energy demand under different rice production systems

Abstract Ground cover rice production system (GCRPS) has been widely proved to enhance rice yield and save irrigation water. However, information on the environmental impacts and energy consumption of GCRPS remains unknown. In this study, a two-year field experiment was conducted in Hubei Province of China including conventional paddy (W1) and GCRPS (W2, maintaining saturated soil water content; W3, maintaining 80% of the field capacity), factorially combined with different N management practices (N1, zero-N application; N2, single urea application; N3, split application of urea for W1 treatments; manure substitution for W2 and W3 treatments). By combining a soil-crop model simulation with a footprint analysis method, a life cycle inventory was built to evaluate yield-scaled carbon footprint (CF), nitrogen footprint (NF), and primary energy demand (PED) of different rice production systems. Results showed that, compared to conventional flooding paddy, GCRPSs significantly reduced CF, NF, and PED by 31%–35%, 37%–40%, and 17%–18% respectively. Across different N treatments under GCRPS, manure substitution reduced the CF (20%–22%), NF (11%–37%), and PED (25%–27%) compared to the single urea treatments. The hotspot’s contribution of N2O to CF, NH3 to NF, and N-fertilizer production to PED under GCRPS can be reduced by 77%, 33%, and 51% respectively compared to the single urea treatments. Therefore, W3N3 was recommended as the best management practice achieving less CF of 541.4 kg CO2 eq t−1, NF of 2.4 kg N eq t−1, and PED of 2440.0 MJ t−1 meanwhile maintaining high rice yield of 8526 kg ha−1 in the study region.

Crop yield and N2O emission affected by long-term organic manure substitution fertilizer under winter wheat-summer maize cropping system

Application of organic manure combined with synthetic fertilizer can maintain crop yield and improve soil fertility, but the long-term effects of substituting different proportions of synthetic fertilizers with organic manure on N2O emission remain unclear. In this study, field experiments and DNDC model simulations were used to study the long-term effects of substituting synthetic fertilizers with organic manure on crop yield and N2O emission. The field experiment was conducted at Guanzhong Plain, northern China, under a wheat-maize cropping system. Six treatments were included: no fertilization (CK); synthetic nitrogen (N), phosphorus (P) and potassium (K) fertilizers (NPK); and 25%, 50%, 75% and 100% of the synthetic N substituted by dairy manure (25%M, 50%M, 75%M, and 100%M), respectively. The DNDC model was calibrated using the field data from the NPK treatment from 2014 to 2017 and was validated for the other treatments. The results showed that the DNDC model can successfully simulate the crop yield (e.g. nRMSE < 5%) and annual N2O emission (nRMSE < 20%). In addition, a 30-year simulation found that organic manure substitution treatments could maintain wheat yield well, and the yield variation between different years was small. However, relative to the NPK treatment, the maize yields for the first 6 and 7 years were lower under 50%M and 75%M, and under 100%M maize yields were reduced for the first 15 years. The long-term simulation showed that N2O emission of fertilized treatment had an increasing trend over time, especially the 75%M treatment where the N2O emission was higher than that of NPK treatment after 25 years of fertilization. The annual mean N2O emission under different treatments was, in decreasing order, NPK > 25%M > 50%M > 75%M > 100%M > CK. The yield-scale N2O emission and emission factor were highest for the NPK treatment. Considering crop yield, yield stability and N2O emission, substitution of 25% synthetic fertilizer by organic manure can simultaneously ensure crop productivity and environmental protection under the tested environment.

Providing azolla and goat manure to increase nutrient N and growth of lowland rice (Oryza sativa L.)

One of the problems in the paddy field is the lack of availability of nutrient N in paddy soil, it can be overcome by giving azolla and goat manure. The aimis to determine the effect of giving azolla and goat manure for increasing the nutrient N and the growth of rice plants. This research used factorial Random Group Design (RAK) with two treatment factors and three replications. The first factor is azolla dose (0, 7 tons / ha) and the second factor is goat manure dose (0, 5, 10, 15 tons / ha). This research is implemented in the greenhouse of the Faculty of Agriculture, University of North Sumatra, Medan. The result of the study indicated giving of azolla increased C-organic, N-total, N content, and N uptake of plant. Giving goat manure at a dose of 15 tons/ha increased C-organic, number of tillers, canopy dry weight, root dry weight, N content of N uptake. Providing azolla and goat manure 5 tons/ha the highest increased N uptake of plants and growth of lowland rice plants. REFERENCES Abu R.L.A., Z. Basri, U. Made. 2017. Response of Growth and Yield of Rice (Oryza sativa L.). Of Nitrogen Needs Using Leaf Color Bgn. Faculty of Agriculture's Agrotechnology Study Program. Tadulako University. BPS North Sumatra. 2018. Harvested Area and Rice Production in North Sumatra. BPPP. 2006. Organic fertilizers and biological fertilizers. Center for Research and Development of Agricultural Land Resources. West Java. Handayani, M. 2011. Utilization of Goat Manure and Rice Husk Ash to Reduce the Use of Urea and KCl Fertilizers and Their Effects on the Growth of Rice Plants and the Chemical Properties of Paddy Soils. Faculty of Agriculture, University of North Sumatra. Field. Nurmayulis, U. P, F. Dewi, Y. Hasnan, and C. Ania.2011. The Response of Nitrogen and Azolla to Mira I Varieties Rice Plant Growth with SRI Method. Scientific Journal of Isotope and Radiation Applications .ISSN 1907-0322. Rauf, A. W., Syamsuddin., S. R. Sihombing. 2000. Role of NPK Fertilizers in Rice Plants. Agriculture department. Agricultural Research and Development Agency. West Koya Agricultural Technology Study Workshop. Irian Jaya. Setiawati M. R. 2014. Increased N and P Content of Soil and Paddy Rice Results Due to Application of Azolla and Biotertilizer Azotobacter chroococcum and Pseudomonas cepaceae. Faculty of Agriculture. Padjadjaran University. Bandung. Setyorini, D ,. Sri, R, .and Irsal, L. 2010. Agriculture in Wetland Ecosystems in Reversing the Degradation of Land Resources and Water Degradation. Agricultural Research and Development Agency. Ministry of Agriculture. Suharyanto and J. Rinaldi, 2002. Estimation of the Potential and Economic Value of Manure in Bali. Institute for Agricultural Technology Assessment (BPTP), Bali. Sudjana, B ,. 2014. Use of Azolla for Sustainable Agriculture. Singapore University of Krawang. Bandung. Scientific Journal of Solutions 1 (2) 72-81 April-June 2014. Soedharmono, G.G., S.Y. Tyasmoro and H.T., Sebayang. 2016. The effect of giving azolla fertilizer and N fertilizer on rice (Oryza sativa L.) Inpari rice varieties, Faculty of Agriculture, Brawijaya University, East Java. Journal of crop production 4 (2) 145: 152 March 2016. Syamsiah, J., Hendro., B.S., and Mujiyo. 2016. Potential of Azolla as Substitution of Manure on Organk Rice Cultivation. Soil Science Study Program, Faculty of Agriculture, Sebelas Maret University. Surakarta

The reactive nitrogen loss and GHG emissions from a maize system after a long-term livestock manure incorporation in the North China Plain

The use of livestock manure as a substitution for synthetic nitrogen (N) fertilizers is recommended to improve the sustainable use of manure nutrients and alleviate the adverse impacts of synthetic N fertilizers on the environment. A thorough understanding of how such substitutions affect reactive N losses and greenhouse gas (GHG) emissions in cereal production systems in the North China Plain (a main livestock production region in China), is needed to achieve an environmental friendly and sustainable production. Based on a long-term field experiment, different manure/chemical fertilizer treatments were designed, i.e., non-fertilization control (CK), chemical fertilizers alone (NPK), and manure substitution for chemical N fertilizers (with equivalent N rate; NPKP, 50% N from pig manure; NPKC, 50% N from chicken manure). Crop yield, nitrogen use efficiency (NUE), soil fertility, N losses, and GHG emissions were chosen as prominent indicators to evaluate the consequences of manure substitutions for N-based fertilizers. The replacement of synthetic fertilizers by livestock manure decreased NO3-N leaching and NH3 volatilization by 46.2% and 5.61–22.2%, respectively, while sustained the crop yields and improved NUE. However, both NPKP and NPKC treatments did not have any impact on N2O and CO2 mitigation. Compared with NPK, NPKC and NPKP meaningfully increased SOC by 9.56% and 19.6%, respectively. More specifically, NPKC increased TN content by 14.7% (P < 0.05) compared to NPK treatment. The results showed that 50% substitution of manure for synthetic N fertilizers is a potential option in maize production systems to decrease N losses (including NH3, N2O emissions and N leaching) by approximately 45% (42.8–48.1%). However, only 1.81% of the total farmers surveyed (i.e., 16,595) have being applied livestock manure for maize cultivation in the North China Plain. Therefore, famers in this plain should be encouraged to use manure to improve ecological aspects of cereal cultivation and decrease the associated environmental pollutions.

Substitution of manure for chemical fertilizer affects soil microbial community diversity, structure and function in greenhouse vegetable production systems.

Soil microbial communities and enzyme activities together affect various ecosystem functions of soils. Fertilization, an important agricultural management practice, is known to modify soil microbial characteristics; however, inconsistent results have been reported. The aim of this research was to make a comparative study of the effects of different nitrogen (N) fertilizer rates and types (organic and inorganic) on soil physicochemical properties, enzyme activities and microbial attributes in a greenhouse vegetable production (GVP) system of Tianjin, China. Results showed that manure substitution of chemical fertilizer, especially at a higher substitution rate, improved soil physicochemical properties (higher soil organic C (SOC) and nutrient (available N and P) contents; lower bulk densities), promoted microbial growth (higher total phospholipid fatty acids and microbial biomass C contents) and activity (higher soil hydrolase activities). Manure application induced a higher fungi/bacteria ratio due to a lower response in bacterial than fungal growth. Also, manure application greatly increased bacterial stress indices, as well as microbial communities and functional diversity. The principal component analysis showed that the impact of manure on microbial communities and enzyme activities were more significant than those of chemical fertilizer. Furthermore, redundancy analysis indicated that SOC and total N strongly influenced the microbial composition, while SOC and ammonium-N strongly influenced the microbial activity. In conclusion, manure substitution of inorganic fertilizer, especially at a higher substitution rate, was more efficient for improving soil quality and biological functions.

Nitrous oxide emission and the related denitrifier community: A short-term response to organic manure substituting chemical fertilizer.

Partially substituting chemical fertilizer with organic manure can aid in the disposal of agricultural wastes via recycling into agricultural land, reduce chemical fertilizer application, and influence nitrogen (N) transformation. However, relatively few studies have investigated the association between soil physicochemical properties, denitrifier communities and N2O emission after short-term substitution of organic manure in vegetable fields. We conducted a short-term vegetable field experiment which included one control treatment (CT, no fertilizer) and three fertilization treatments containing equal amount of total N, phosphorus and potassium (CF, chemical fertilizer only; CMR, chemical fertilizer plus mushroom residue; COM, chemical fertilizer plus cattle manure). The results showed that partial substitution of chemical fertilizer with organic manure greatly increased cumulative N2O emissions, N2O emission factors and yield-scaled N2O emissions by 122-203%, 238-600% and 128-181%, respectively. Compared with the CF treatment, short-term substitution with organic manure reduced the abundance of nirS- and nosZ-type denitrifiers, and increased that of nirK-type denitrifiers. Modeling indicated that nirS abundance, together with soil available N, NIR activity, nirK abundance, SOC, NH4+, and NO3- were the primary factors associated with cumulative N2O emissions. The denitrifier community composition of the CF- treated soil was separated from that of soils treated with CMR and COM, and was primarily influenced by soil NH4+ concentration. NIR activity showed a significant correlation with denitrifier community composition. Overall, short-term substitution of chemical fertilizer with cattle manure (lower C/N ratio) reduced the abundance of nirS- and nosZ-type denitrifiers, but stimulated N2O emission.

Mechanisms of mitigating nitrous oxide emissions from vegetable soil varied with manure, biochar and nitrification inhibitors

A clear understanding of the effects of manure, biochar and nitrification inhibitors (NI, nitrapyrin-SNI and Sorghum bicolor L.-BNI) amendment on nitrous oxide (N2O) production pathways and consumption remains elusive under field conditions. A field experiment using an isotopocule mapping approach (δ15NSPN2O and δ18ON2O/H2O map) in conjunction with molecular techniques were conducted to understand the mechanisms of these options for N2O mitigation in a Tung choy (Ipomoea aquatic Forssk.) vegetable soil. The manure substitution and biochar not only decreased nitrification/fungal denitrification and bacterial denitrification/nitrifier denitrification-derived N2O emission, but also stimulated N2O reduction to N2 during the denitrification process as evidenced from the decrease of ammonia-oxidizing bacteria (AOB) amoA and the increase of nirS, nosZⅠ, nosZⅡ and fungal nirK transcripts. Biochar had a greater potential to enhance this reduction with decrease of ammonia-oxidizing archaea (AOA) amoA transcripts. NIs mitigated the N2O derived from nitrification and/or bacterial denitrification/nitrifier denitrification demonstrated from the simultaneous decrease of soil NO2− and NO3− and increase of soil NH4+ intensity together with the lower AOB amoA transcripts in NIs than in the urea. These results helped explain the observed differences in N2O emissions among these mitigation options, and laid the foundation for a better understanding of N2O production and reduction under field conditions.

Economic Aspects of Manure Management and Practices for Sustainable Agriculture in Turkey

Abstract Turkish livestock sector plays very important role in the Turkish GDP and the use of manure affects the environment but the farming sector want the farmers to employ the use of more integrated manure practice. The study assessed the economic impacts of integrated manure and chemical fertilizer used and the manure management practices sustainable for Turkish agriculture. Turkey is dependent on foreign countries not only for energy but for chemical fertilizers raw materials. High price of chemical fertilizers is one of the negative impact, manure substitution will lead to stable macro-economy, and environmental friendly economy and agricultural productivity will also impacts. To achieve these impacts, some manure practices suitable for sustainable rural development in Turkey was assessed.

Ecosystem services of partial organic substitution for chemical fertilizer in a peri-urban zone in China

Chemical nitrogen fertilizer application in the peri-urban zone has benefited food supply, but excess nitrogen input has altered multiple ecosystem services and caused an array of ecosystem dis-services that have degraded air and water quality. Using sewage sludge compost and pig manure to partially substitute chemical fertilizer nitrogen may promote sustainable ecosystem services. However, few studies have been conducted to evaluate the values of associate ecosystem services with a unified standard. To comprehensively understand the effect of partial organic substitution on ecosystem services (supporting vegetable production and sequestering soil organic carbon) and ecosystem dis-services (greenhouse gas emissions and reactive nitrogen release), we attempted to evaluate the ecosystem service from the perspective of economic assessment. A field experiment was conducted in a peri-urban zone in eastern China, including the following six treatments at equal total nitrogen application rates: (1) no fertilizer nitrogen applied; (2) 25% sewage sludge compost substitution; (3) 25% pig manure substitution; (4) 50% sewage sludge compost substitution; (5) 50% pig manure substitution and (6) chemical fertilizer nitrogen only. The results showed that partial organic substitution significantly increased annual vegetable yield by 27.8%–35.3% and annual soil organic carbon sequestration rate by 129.2%–213.8%. Moreover, greenhouse gas emissions (methane and nitrous oxide) were significantly decreased by 28.6%–43.2%; nitrogen leaching and runoff were significantly decreased by 39.0%–49.5% and 26.8%–62.0%, respectively; and ammonia volatilization was increased by 2.4%–27.8%. Overall, partial substitution with organic fertilizer decreased total reactive nitrogen losses by 19.9%–39.8% compared with the 100% chemical fertilizer nitrogen treatment. Although additional labor and higher input costs were required, partial organic substitution could obtain a higher net economic benefit of 25198–90670 ¥ ha−1 yr−1 compared with the sole application of chemical fertilizer nitrogen. The results suggest that partial substitution of chemical fertilizer with organic fertilizer can sustain ecosystem services and reduce ecosystem dis-services in the peri-urban zone and increase economic profits for farmers.

Utilization Azollapinnata as substitution of manure to improve organic rice yield and paddy soil health

Organic rice has become the champion program of the Department of Agriculture in several districts in Indonesia, it is related to increasing awareness of consuming healthy foods which free from inorganic contaminants. Organic farming requires organic fertilizer supply in large quantities as a source of nutrition plants. Azollapinnata water fern is alternative organic matter in organic rice fields because of higher nutritional value compared to manure and can be cultivated in situ that reduces transportation costs. This research was conducted in the fields which first planted organic rice. The randomized block design was used, repeated three times with the treatment: cow manure 100% and the combination of Azolla + manure 25%, 50%, and 75% up to 100%. The results showed that Azolla 50% + cow manure 50% could increase plant height and tillers number, but the organic C content, total N, and C/N of soil was not different than the application of 100% cow manure. Although the yield of all treatments showed similarly,it could increase the dry grain rice weight as much as 19.17% compared with the 100% manure treatment. TheAzolla 50% + cow manure 50% treatment could increase the soil organic C content ranging from 1.3% to 1.7% which indicates the restoration of sick soil leads to healthy soil.

A synthetic analysis of livestock manure substitution effects on organic carbon changes in China's arable topsoil

Application of livestock manure has been recognized as an important strategy for enhancing soil organic carbon (SOC) stocks. However, the magnitude of manure application impacts on SOC changes as compared with conventional mineral fertilizers still needs to be better assessed. In this study, we conducted a meta-analysis to address the effects of various fertilization practices on SOC changes in China's arable topsoil. The analysis was based on 148 peer reviewed articles reporting 69 sites and 729 observations with an average experimental duration of 18 years across China. We compared the response of SOC content to application of manure alone (M) or manure plus mineral fertilizers (NPKM) with the SOC response to NPK or no fertilizers (Control). We systematically analyzed how SOC responses were influenced by different environmental and management factors (land use, climate and soil properties, etc.). First, the retention coefficient of manure was used to present the percentage of C input from manure “converted” to SOC. Compared to Control, on average, manure had C-retention coefficients of 31% ± 12% (95% Confidence Interval, CI) and 18% ± 2% for the experimental duration of ≤10 years and >10 years, respectively. When compared to NPK, manure had C-retention coefficients of 29% ± 13% and 9% ± 3% for the experimental duration of ≤10 years and >10 years, respectively. In addition, compared to Control and NPK, application of manure increased SOC content by 0.23–0.26 and 0.18–0.19 g kg−1 yr−1, respectively. The results also indicated that the mean differences of SOC change between the treatments with or without manure application were mainly controlled by soil properties (28–43%) and anthropogenic farming practices (21–27%). Our results highlight the significance of improving or maintaining SOC stocks by manure applications, and provide insights for making manure application recommendations or guidelines to improve SOC stocks of China's cropland based on soil properties, climatic conditions and management practices.