Coated controlled-release fertilizers （CRFs） have been widely applied in agriculture due to their increased efficiency. However, the widespread and a lot of coated CRFs application may leave undesired coating residu...Coated controlled-release fertilizers （CRFs） have been widely applied in agriculture due to their increased efficiency. However, the widespread and a lot of coated CRFs application may leave undesired coating residues in the soil due to their slow degradation. Limited information is available on the effects of substantial residual coatings on the soil bacterial community. By adding 0, 5, 10, 20, and 50 times quantities of residual coating from conventional application amount of resin and water-soluble coated CRFs, we studied the responses of soil properties and bacterial community composition to these two residual coatings in black soil. The results showed that the resin and water-soluble coatings did not essentially alter the properties of black soil or cause dramatic changes to bacterial diversity within the test concentration range. The residual resin and water-soluble coatings also did not distinctly alter the relative abundance of the top ten bacteria at phylum level. Heatmap results suggested that the treatments were basically clustered into two groups by concentration rather than types of coating material. Pearson correlation analysis showed that the Simpson＇s diversity index of the bacterial community was significantly correlated with microbial biomass carbon （MBC, r=0.394, P〈0.05）, and the richness index abundance-based coverage estimator （ACE） of the bacterial community was significantly correlated with microbial biomass nitrogen （MBN, t=0.407, P〈0.05）. Overall, results of this study suggested that substantial residual resin and water-soluble coatings with 0-50 times quantities of residual coating from conventional application amount of coated CRFs did not generate obviously negative impacts on the bacterial community in black soil.展开更多
Nitrogen(N) fertilizers in agriculture suffer losses by volatilization of N to the air, surface runoff and leaching into the soil, resulting in low N use efficiency(NUE)( 50%) and raising severe environmental pollutio...Nitrogen(N) fertilizers in agriculture suffer losses by volatilization of N to the air, surface runoff and leaching into the soil, resulting in low N use efficiency(NUE)( 50%) and raising severe environmental pollutions. Controlledrelease nitrogen fertilizers(CRNFs) can control the release of N nutrients to NUE in crop production. Different methods were used to develop new CRNFs.However, different CRNF technologies are still underdeveloped due to inadequate controlling on N releasing time and/or unsustainable diffusion. The study on the influences of CRNF processing parameters on microbial conditions are lacking when the CRNFs composed of various bio-ingredients such as biochar, composts, and biowaste. The complexity of processing methods, material biodegradability, and other physical properties make current CRNFs of questionable value in agricultural production. This research aims to develop a novel biochar-compost-based controlled-release urea fertilizer(BCRUF) to preserve microbial properties carried by the compost. The BCRUF was synthesized by pelletizing the 50:50(dry, wt/wt) mixture of biochar and compost. BCRUF was loaded with urea and then spray-coated with polylactic acid(PLA). The releasing time of two types of BCRUFs, coated and uncoated with PLA, for 80% of N release in water was up to 6 h at three different temperatures(4, 23, and 40 °C), compared to conventional urea fertilizer and commercial environmentally smart N(ESN) fertilizer. The releasing time of coated BCRUF for 80% N release in soil was up to 192 h(8 days). Fourier-transform infrared spectroscopy(FTIR) analysis revealed that no new functional groups were found in the release solution, indicating no new chemical hazards generated. The differential scanning calorimetry(DSC)tests also verified that its thermal stability could be up to 160 °C. The microbe populations in the BCRUF pellets were reduced after the pelleting and drying processes in BCRUF fabrication, but a few bacteria can endure in the air-drying process. BCRUF pellets soaked in water for 4 days retained some bacteria. The BCRUF showed very promising characteristics to improve NUE and sustainability in agricultural production.展开更多
Combining nitrification inhibitor and urea can improve crop yield and nitrogen(N)use efficiency(NUE).However,the inhibitor easily gets inactivated in soil,making it difficult to achieve the desired effect.To develop a...Combining nitrification inhibitor and urea can improve crop yield and nitrogen(N)use efficiency(NUE).However,the inhibitor easily gets inactivated in soil,making it difficult to achieve the desired effect.To develop a synergistic urea for increasing the inhibitor action time,soil N supply,and wheat growth,dicyandiamide(DCD)was coated after granulation with epoxy resin and then mixed with urea to develop new resin-coated DCD(RCD)synergistic urea.Scanning electron microscopy(SEM)and hydrostatic release tests were used to evaluate the membrane microstructure and the controlled-release performance of RCD.Five fertilization treatments were set up in the field:zero-N control(CK),urea(U),urea+common DCD particles(SUD1),urea+RCD(SUD2),and urea+both common DCD particles and RCD(3:7,weight/weight)(SUD3)to investigate the effects of the DCD synergistic urea on wheat growth,yield,and NUE and soil available N content.The SEM results showed that RCD had a complete coating,smooth surface,and small and rugged channels for DCD release in the profile.The hydrostatic release test at 25?C showed that the release period of DCD was extended to ten days due to resin coating.In the three DCD synergistic urea treatments,only SUD3 resulted in a significant increase in wheat yield(18.47%)compared with U.The NUE in SUD3 was significantly higher than those in SUD2,U,and SUD1.The treatment SUD3 had higher soil available N content than the other treatments during the key wheat growth stages,while effectively reducing the risk of soil nitrate leaching during wheat maturity.In summary,SUD3,a mixture of urea,DCD particles,and RCD,was the best treatment for significantly increasing wheat growth,yield,and NUE and soil N supply.展开更多
基金supported by the International Scientific and Technological Cooperation Projects of China (2015DFA20790)the National Natural Science Foundation of China (21577172,41501322)the National Basic Research Program (973 program) of China (2013CB127406)
文摘Coated controlled-release fertilizers （CRFs） have been widely applied in agriculture due to their increased efficiency. However, the widespread and a lot of coated CRFs application may leave undesired coating residues in the soil due to their slow degradation. Limited information is available on the effects of substantial residual coatings on the soil bacterial community. By adding 0, 5, 10, 20, and 50 times quantities of residual coating from conventional application amount of resin and water-soluble coated CRFs, we studied the responses of soil properties and bacterial community composition to these two residual coatings in black soil. The results showed that the resin and water-soluble coatings did not essentially alter the properties of black soil or cause dramatic changes to bacterial diversity within the test concentration range. The residual resin and water-soluble coatings also did not distinctly alter the relative abundance of the top ten bacteria at phylum level. Heatmap results suggested that the treatments were basically clustered into two groups by concentration rather than types of coating material. Pearson correlation analysis showed that the Simpson＇s diversity index of the bacterial community was significantly correlated with microbial biomass carbon （MBC, r=0.394, P〈0.05）, and the richness index abundance-based coverage estimator （ACE） of the bacterial community was significantly correlated with microbial biomass nitrogen （MBN, t=0.407, P〈0.05）. Overall, results of this study suggested that substantial residual resin and water-soluble coatings with 0-50 times quantities of residual coating from conventional application amount of coated CRFs did not generate obviously negative impacts on the bacterial community in black soil.
基金funding supports from the South Dakota Governor’s Office of Economic Development (POC2020-04)the USDA NIFA through the North Central Regional Sun Grant Center, and Hatch Projects (3AR652, 3AR689, and 3AH658) of the South Dakota Agricultural Experiment Station。
文摘Nitrogen(N) fertilizers in agriculture suffer losses by volatilization of N to the air, surface runoff and leaching into the soil, resulting in low N use efficiency(NUE)( 50%) and raising severe environmental pollutions. Controlledrelease nitrogen fertilizers(CRNFs) can control the release of N nutrients to NUE in crop production. Different methods were used to develop new CRNFs.However, different CRNF technologies are still underdeveloped due to inadequate controlling on N releasing time and/or unsustainable diffusion. The study on the influences of CRNF processing parameters on microbial conditions are lacking when the CRNFs composed of various bio-ingredients such as biochar, composts, and biowaste. The complexity of processing methods, material biodegradability, and other physical properties make current CRNFs of questionable value in agricultural production. This research aims to develop a novel biochar-compost-based controlled-release urea fertilizer(BCRUF) to preserve microbial properties carried by the compost. The BCRUF was synthesized by pelletizing the 50:50(dry, wt/wt) mixture of biochar and compost. BCRUF was loaded with urea and then spray-coated with polylactic acid(PLA). The releasing time of two types of BCRUFs, coated and uncoated with PLA, for 80% of N release in water was up to 6 h at three different temperatures(4, 23, and 40 °C), compared to conventional urea fertilizer and commercial environmentally smart N(ESN) fertilizer. The releasing time of coated BCRUF for 80% N release in soil was up to 192 h(8 days). Fourier-transform infrared spectroscopy(FTIR) analysis revealed that no new functional groups were found in the release solution, indicating no new chemical hazards generated. The differential scanning calorimetry(DSC)tests also verified that its thermal stability could be up to 160 °C. The microbe populations in the BCRUF pellets were reduced after the pelleting and drying processes in BCRUF fabrication, but a few bacteria can endure in the air-drying process. BCRUF pellets soaked in water for 4 days retained some bacteria. The BCRUF showed very promising characteristics to improve NUE and sustainability in agricultural production.
基金supported by the Major Agricultural Science and Technology Project of China(No.NK202218080315)the Project of Shandong Province Peanut Industry Technology System,China(No.SDAIT-04-06)。
文摘Combining nitrification inhibitor and urea can improve crop yield and nitrogen(N)use efficiency(NUE).However,the inhibitor easily gets inactivated in soil,making it difficult to achieve the desired effect.To develop a synergistic urea for increasing the inhibitor action time,soil N supply,and wheat growth,dicyandiamide(DCD)was coated after granulation with epoxy resin and then mixed with urea to develop new resin-coated DCD(RCD)synergistic urea.Scanning electron microscopy(SEM)and hydrostatic release tests were used to evaluate the membrane microstructure and the controlled-release performance of RCD.Five fertilization treatments were set up in the field:zero-N control(CK),urea(U),urea+common DCD particles(SUD1),urea+RCD(SUD2),and urea+both common DCD particles and RCD(3:7,weight/weight)(SUD3)to investigate the effects of the DCD synergistic urea on wheat growth,yield,and NUE and soil available N content.The SEM results showed that RCD had a complete coating,smooth surface,and small and rugged channels for DCD release in the profile.The hydrostatic release test at 25?C showed that the release period of DCD was extended to ten days due to resin coating.In the three DCD synergistic urea treatments,only SUD3 resulted in a significant increase in wheat yield(18.47%)compared with U.The NUE in SUD3 was significantly higher than those in SUD2,U,and SUD1.The treatment SUD3 had higher soil available N content than the other treatments during the key wheat growth stages,while effectively reducing the risk of soil nitrate leaching during wheat maturity.In summary,SUD3,a mixture of urea,DCD particles,and RCD,was the best treatment for significantly increasing wheat growth,yield,and NUE and soil N supply.
