Partial substitution of chemical fertilizers by organic amendments is adopted widely for promoting the availability of soil phosphorus(P)in agricultural production.However,few studies have comprehensively evaluated th...Partial substitution of chemical fertilizers by organic amendments is adopted widely for promoting the availability of soil phosphorus(P)in agricultural production.However,few studies have comprehensively evaluated the effects of longterm organic substitution on soil P availability and microbial activity in greenhouse vegetable fields.A 10-year(2009–2019)field experiment was carried out to investigate the impacts of organic fertilizer substitution on soil P pools,phosphatase activities and the microbial community,and identify factors that regulate these soil P transformation characteristics.Four treatments included 100%chemical N fertilizer(4 CN),50%substitution of chemical N by manure(2 CN+2 MN),straw(2 CN+2 SN),and combined manure with straw(2 CN+1 MN+1 SN).Compared with the 4 CN treatment,organic substitution treatments increased celery and tomato yields by 6.9-13.8%and 8.6-18.1%,respectively,with the highest yields being in the 2 CN+1 MN+1 SN treatment.After 10 years of fertilization,organic substitution treatments reduced total P and inorganic P accumulation,increased the concentrations of available P,organic P,and microbial biomass P,and promoted phosphatase activities(alkaline and acid phosphomonoesterase,phosphodiesterase,and phytase)and microbial growth in comparison with the 4 CN treatment.Further,organic substitution treatments significantly increased soil C/P,and the partial least squares path model(PLS-PM)revealed that the soil C/P ratio directly and significantly affected phosphatase activities and the microbial biomass and positively influenced soil P pools and vegetable yield.Partial least squares(PLS)regression demonstrated that arbuscular mycorrhizal fungi positively affected phosphatase activities.Our results suggest that organic fertilizer substitution can promote soil P transformation and availability.Combining manure with straw was more effective than applying these materials separately for developing sustainable P management practices.展开更多
Soil aggregation,microbial community,and functions(i.e.,extracellular enzyme activities;EEAs)are critical factors affecting soil C dynamics and nutrient cycling.We assessed soil aggregate distribution,stability,nutrie...Soil aggregation,microbial community,and functions(i.e.,extracellular enzyme activities;EEAs)are critical factors affecting soil C dynamics and nutrient cycling.We assessed soil aggregate distribution,stability,nutrients,and microbial characteristics within>2,0.25-2,0.053-0.25,and<0.053 mm aggregates,based on an eight-year field experiment in a greenhouse vegetable field in China.The field experiment includes four treatments:100%N fertilizer(CF),50%substitution of N frtilizer with manure(M),straw(S),and manure plus straw(MS).The amounts of nutrient(N,P20,and K20)input were equal in each treatment.Results showed higher values of mean weight diameter in organic amended soils(M,MS,and S,2.43-2.97)vs.CF-amended soils(1.99).Relative to CF treatment,organic amendments had positive effects on nutrient(i.e.,available N,P,and soil organic C(SOC))conditions,microbial(e.g,bacterial and fungal)growth,and EEAs in the>0.053 mm aggregates,but not in the<0.053 mm aggregates.The 0.25-0.053 mm aggregates exhibited better nutrient conditions and hydrolytic activity,while the<0.053 mm aggregates had poor nutrient conditions and higher oxidative activity among aggregates,per SOC,available N,available P,and a series of enzyme activities.These results indicated that the 0.25-0.053 mm(<0.053 mm)aggregates provide suitable microhabitats for hydrolytic(oxidative)activity.Interestingly,we found that hydrolytic and oxidative activities were mainly impacted by fertilization(58.5%,P<0.01)and aggregate fractions(50.5%,P<0.01),respectively.The hydrolytic and oxidative activities were significantly(P<0.01)associated with nutrients(SOC and available N)and pH,electrical conductivity,respectively.Furthermore,SOC,available N,and available P closely(P<0.05)afected microbial communities within>0.25,0.25-0.053,and<0.053 mm aggregates,respectively.These findings provide several insights into microbial characteristics within aggregates under dfferent frilization modes in the greenhouse vegetable production system in China.展开更多
RNA interference(RNAi)technology is a promising crop protection strategy against agricultural pests.The soybean pod borer(SPB),Leguminivora glycinivorella(Mats.),is a serious pest of soybean in northeastern Asia.The n...RNA interference(RNAi)technology is a promising crop protection strategy against agricultural pests.The soybean pod borer(SPB),Leguminivora glycinivorella(Mats.),is a serious pest of soybean in northeastern Asia.The neonate larvae of SPB are endophagous,initially feeding on the inner layer of the pod and then on the immature soybean seeds,a behavior that makes them difficult to rear.Therefore,a suitable artificial diet is desirable to facilitate RNAi research.Seven artificial diets and soybean pods were used for rearing SPB neonate larvae.The survival and mean weight of the larvae reared on artificial diet 6(A6,included 2 g soybean flour and 10 g R3 immature soybean pod powder)were found to be significantly higher than those for larvae reared on all other diets.Subsequently,A6 diet was prepared in DEPC-treated water to obtain a RNase-free artificial diet(RF).The survival and mean weight of the larvae were not significantly different between A6 and RF diets.Feeding neonate larvae with RF-SpbP0 dsRNA(ribosomal protein P0)silenced SpbP0 gene,resulting in arrested development and increased mortality.The results of this study suggested that the newly developed A6 or RF diets could rear SPB neonate larvae and help towards developing an effective method for oral delivery of dsRNA to SPB larvae.展开更多
基金supported by the China Agriculture Research System of MOF and MARA(CARS-23-B04)the National Key Research and Development Program of China(2016YFD0201001)。
文摘Partial substitution of chemical fertilizers by organic amendments is adopted widely for promoting the availability of soil phosphorus(P)in agricultural production.However,few studies have comprehensively evaluated the effects of longterm organic substitution on soil P availability and microbial activity in greenhouse vegetable fields.A 10-year(2009–2019)field experiment was carried out to investigate the impacts of organic fertilizer substitution on soil P pools,phosphatase activities and the microbial community,and identify factors that regulate these soil P transformation characteristics.Four treatments included 100%chemical N fertilizer(4 CN),50%substitution of chemical N by manure(2 CN+2 MN),straw(2 CN+2 SN),and combined manure with straw(2 CN+1 MN+1 SN).Compared with the 4 CN treatment,organic substitution treatments increased celery and tomato yields by 6.9-13.8%and 8.6-18.1%,respectively,with the highest yields being in the 2 CN+1 MN+1 SN treatment.After 10 years of fertilization,organic substitution treatments reduced total P and inorganic P accumulation,increased the concentrations of available P,organic P,and microbial biomass P,and promoted phosphatase activities(alkaline and acid phosphomonoesterase,phosphodiesterase,and phytase)and microbial growth in comparison with the 4 CN treatment.Further,organic substitution treatments significantly increased soil C/P,and the partial least squares path model(PLS-PM)revealed that the soil C/P ratio directly and significantly affected phosphatase activities and the microbial biomass and positively influenced soil P pools and vegetable yield.Partial least squares(PLS)regression demonstrated that arbuscular mycorrhizal fungi positively affected phosphatase activities.Our results suggest that organic fertilizer substitution can promote soil P transformation and availability.Combining manure with straw was more effective than applying these materials separately for developing sustainable P management practices.
基金Fund for China Agriculture Research 3ystem(CAR3-23-B02)the National Key Research and Development Program of China(2016YFD0201001)the Key Research and Development Program of Shandong Province,China(2017CXGC0206).
文摘Soil aggregation,microbial community,and functions(i.e.,extracellular enzyme activities;EEAs)are critical factors affecting soil C dynamics and nutrient cycling.We assessed soil aggregate distribution,stability,nutrients,and microbial characteristics within>2,0.25-2,0.053-0.25,and<0.053 mm aggregates,based on an eight-year field experiment in a greenhouse vegetable field in China.The field experiment includes four treatments:100%N fertilizer(CF),50%substitution of N frtilizer with manure(M),straw(S),and manure plus straw(MS).The amounts of nutrient(N,P20,and K20)input were equal in each treatment.Results showed higher values of mean weight diameter in organic amended soils(M,MS,and S,2.43-2.97)vs.CF-amended soils(1.99).Relative to CF treatment,organic amendments had positive effects on nutrient(i.e.,available N,P,and soil organic C(SOC))conditions,microbial(e.g,bacterial and fungal)growth,and EEAs in the>0.053 mm aggregates,but not in the<0.053 mm aggregates.The 0.25-0.053 mm aggregates exhibited better nutrient conditions and hydrolytic activity,while the<0.053 mm aggregates had poor nutrient conditions and higher oxidative activity among aggregates,per SOC,available N,available P,and a series of enzyme activities.These results indicated that the 0.25-0.053 mm(<0.053 mm)aggregates provide suitable microhabitats for hydrolytic(oxidative)activity.Interestingly,we found that hydrolytic and oxidative activities were mainly impacted by fertilization(58.5%,P<0.01)and aggregate fractions(50.5%,P<0.01),respectively.The hydrolytic and oxidative activities were significantly(P<0.01)associated with nutrients(SOC and available N)and pH,electrical conductivity,respectively.Furthermore,SOC,available N,and available P closely(P<0.05)afected microbial communities within>0.25,0.25-0.053,and<0.053 mm aggregates,respectively.These findings provide several insights into microbial characteristics within aggregates under dfferent frilization modes in the greenhouse vegetable production system in China.
基金Supported by the Harbin Science and Technology Innovation Program(2017RAQXJ122)China National Novel Transgenic Organisms Breeding Project(2016ZX08004-004-006)+2 种基金the Heilongjiang Natural Science Foundation(C2018012)the Chinese National Natural Science Foundation(31201229)Soybean Research&Development Center(CARS-04-PS04)。
文摘RNA interference(RNAi)technology is a promising crop protection strategy against agricultural pests.The soybean pod borer(SPB),Leguminivora glycinivorella(Mats.),is a serious pest of soybean in northeastern Asia.The neonate larvae of SPB are endophagous,initially feeding on the inner layer of the pod and then on the immature soybean seeds,a behavior that makes them difficult to rear.Therefore,a suitable artificial diet is desirable to facilitate RNAi research.Seven artificial diets and soybean pods were used for rearing SPB neonate larvae.The survival and mean weight of the larvae reared on artificial diet 6(A6,included 2 g soybean flour and 10 g R3 immature soybean pod powder)were found to be significantly higher than those for larvae reared on all other diets.Subsequently,A6 diet was prepared in DEPC-treated water to obtain a RNase-free artificial diet(RF).The survival and mean weight of the larvae were not significantly different between A6 and RF diets.Feeding neonate larvae with RF-SpbP0 dsRNA(ribosomal protein P0)silenced SpbP0 gene,resulting in arrested development and increased mortality.The results of this study suggested that the newly developed A6 or RF diets could rear SPB neonate larvae and help towards developing an effective method for oral delivery of dsRNA to SPB larvae.
