On the basis of a long-term(30 years) field experiment that involved four rotation systems, rice-rice-winter fallow(RRF), rice-rice-ryegrass(RRG), rice-rice-rape(RRP), and rice-rice-milk vetch(RRV), this stu...On the basis of a long-term(30 years) field experiment that involved four rotation systems, rice-rice-winter fallow(RRF), rice-rice-ryegrass(RRG), rice-rice-rape(RRP), and rice-rice-milk vetch(RRV), this study described the effects of green manure on the microbial communities in the red paddy soils using 454 pyrosequencing for the 16 S r RNA gene. The Chao1 richness and non-parametric Shannon's index increased in all soil samples that received green manure treatments. The communities' structures with the green manure applications were significantly dissimilar from that under the winter fallow. Using Metastats tests, many genera in the RRG, RRP and RRV soils were significantly different from those in the RRF soil, including a number of genera that functioned in the nitrogen and sulfur cycles. Analyses of the genera with these functions revealed the shifts in microbial ecosystem functions after long-term green manuring. Changes in the microbial communities increased the ammonium supply and decreased the soil acidification in green-manure-amended soils. Together, these data suggested powerful effects of green manure on both the microbial communities and the biogeochemical cycle driven by the shifts in bacterial functional groups.展开更多
Dissimilatory Fe(Ⅲ) reduction is an important process in the geochemical cycle of iron in anoxic environment. As the main products of dissimilatory iron reduction, the Fe(Ⅱ) species accumulation could indicate t...Dissimilatory Fe(Ⅲ) reduction is an important process in the geochemical cycle of iron in anoxic environment. As the main products of dissimilatory iron reduction, the Fe(Ⅱ) species accumulation could indicate the reduction ability. The effects of different green manures on Fe(Ⅲ) reduction in paddy soil were explored based on a 31-year rice-rice-winter green manure cropping experiment. Four treatments were involved, i.e., rice-rice-milk vetch (RRV), rice-rice-rape (RRP), rice-rice-ryegrass (RRG) and rice-rice-winter fallow (RRF). Soils were sampled at flowering stage of milk vetch and rape (S1), before transplantation (S2), at tillering (S3), jointing (S4), and mature (S5) stages of the early rice, and after the harvest of the late rice (S6). The contents of TFeHa (HCI-extractable total Fe), Fe(Ⅱ)HCI (HCI-extractable Fe(Ⅱ) species) and Fe(Ⅲ)HCI (HCI- extractable Fe(Ⅲ) species) were measured. The correlations among those Fe species with selected soil environmental factors and the dynamic characteristics of Fe(Ⅱ)HCI accumulation were investigated. The results showed that TFeHc~ in RRF was significantly higher than those in the green manure treatments at most of the sampling stages. Fe(II)Ha increased rapidly after the incorporation of green manures in all treatments and kept rising with the growth of early rice. Fe(Ⅱ)Ha in RRG was quite different from those in other treatments, i.e., it reached the highest at the S2 stage, then increased slowly and became the lowest one at the S4 and S5 stages. Fe(Ⅲ)Ha showed oppositely, and Fe(Ⅱ)HCI/Fe(Ⅲ)HCI performed similarly to Fe(Ⅱ)HCI The maximum accumulation potential of Fe(Ⅱ)HCI was significantly higher in RRF, while the highest maximum reaction rate of Fe(Ⅱ)Ha accumulation appeared in RRG. Significant correlations were found between the indexes of Fe(Ⅱ)HCI accumulation and soil pH, oxidation-reduction potential (Eh) and total organic acids, respectively. In together, we found that long-term application of green manures decreased the TFeHa in red paddy soils, but promoted the ability of Fe(lll) reduction, especially the ryegrass; Fe(Ⅱ)Ha increased along with the growth of rice and was affected by soil conditions and environmental factors, especially the water and redox ability.展开更多
To ascertain the possibility of cultivating maize using biological nitrogen fixation(BNF)by leguminous green manure crops in maize/leguminous green manure intercropping systems,BNF and nitrogen(N)transfer were studied...To ascertain the possibility of cultivating maize using biological nitrogen fixation(BNF)by leguminous green manure crops in maize/leguminous green manure intercropping systems,BNF and nitrogen(N)transfer were studied in Xining and Wuwei,two typical northwestern Chinese cities.The experimental treatments included monocultured maize,monocultured green manures(hairy vetch and common vetch),and their intercropping systems.The proportions of N derived from the atmosphere(%N_(dfa))in intercropping systems were not significantly different from that in monocultured green manure systems at either experimental site,except for that in hairy vetch(HV)in Xining.The amount of N derived from the atmosphere(N_(dfa))of common vetch(CV)significantly decreased from 1.16 and 1.10 g/pot in monoculture to 0.77 and 0.55 g/pot when intercropped with maize,in Xining and Wuwei,respectively,and the N_(dfa) of HV when intercropped significantly decreased from 1.02 to 0.48 g/pot in Xining.In the intercropping systems in Xining and Wuwei,the amounts of N transferred(N_(transfer))from CV to maize were 21.54 and 26.81 mg/pot,accounting for 32.9 and 5.9%respectively of the N accumulation in maize,and the values of N_(transfer) from HV to maize were 39.61 and 46.22 mg/pot,accounting for 37.0 and 23.3%,respectively,of the N accumulation in maize.Path analysis showed that soil nutrient and green manure biomass were mainly related to N_(dfa),and thatδ^(15) N had a primary relationship with N_(transfer).We found that 5.9-37.0%of N accumulation in maize was transferred from green manures,and that the N transfer ability to maize of HV was higher than that of CV.In conclusion,intercropping with leguminous green manures provided a feasible way for maize to effectively utilize biologicallyfixed N.展开更多
基金supported by the Special Fund for Agro-scientific Research in the Public Interest of China(201103005)the Science and Technology Innovation Project of Chinese Academy of Agricultural Sciences(2013–2017)
文摘On the basis of a long-term(30 years) field experiment that involved four rotation systems, rice-rice-winter fallow(RRF), rice-rice-ryegrass(RRG), rice-rice-rape(RRP), and rice-rice-milk vetch(RRV), this study described the effects of green manure on the microbial communities in the red paddy soils using 454 pyrosequencing for the 16 S r RNA gene. The Chao1 richness and non-parametric Shannon's index increased in all soil samples that received green manure treatments. The communities' structures with the green manure applications were significantly dissimilar from that under the winter fallow. Using Metastats tests, many genera in the RRG, RRP and RRV soils were significantly different from those in the RRF soil, including a number of genera that functioned in the nitrogen and sulfur cycles. Analyses of the genera with these functions revealed the shifts in microbial ecosystem functions after long-term green manuring. Changes in the microbial communities increased the ammonium supply and decreased the soil acidification in green-manure-amended soils. Together, these data suggested powerful effects of green manure on both the microbial communities and the biogeochemical cycle driven by the shifts in bacterial functional groups.
基金supported by the Special Fund for Agroscientific Research in the Public Interest,China(201103005)the Science and Technology Innovation Project of Chinese Academy of Agricultural Sciences(2013–2017)
文摘Dissimilatory Fe(Ⅲ) reduction is an important process in the geochemical cycle of iron in anoxic environment. As the main products of dissimilatory iron reduction, the Fe(Ⅱ) species accumulation could indicate the reduction ability. The effects of different green manures on Fe(Ⅲ) reduction in paddy soil were explored based on a 31-year rice-rice-winter green manure cropping experiment. Four treatments were involved, i.e., rice-rice-milk vetch (RRV), rice-rice-rape (RRP), rice-rice-ryegrass (RRG) and rice-rice-winter fallow (RRF). Soils were sampled at flowering stage of milk vetch and rape (S1), before transplantation (S2), at tillering (S3), jointing (S4), and mature (S5) stages of the early rice, and after the harvest of the late rice (S6). The contents of TFeHa (HCI-extractable total Fe), Fe(Ⅱ)HCI (HCI-extractable Fe(Ⅱ) species) and Fe(Ⅲ)HCI (HCI- extractable Fe(Ⅲ) species) were measured. The correlations among those Fe species with selected soil environmental factors and the dynamic characteristics of Fe(Ⅱ)HCI accumulation were investigated. The results showed that TFeHc~ in RRF was significantly higher than those in the green manure treatments at most of the sampling stages. Fe(II)Ha increased rapidly after the incorporation of green manures in all treatments and kept rising with the growth of early rice. Fe(Ⅱ)Ha in RRG was quite different from those in other treatments, i.e., it reached the highest at the S2 stage, then increased slowly and became the lowest one at the S4 and S5 stages. Fe(Ⅲ)Ha showed oppositely, and Fe(Ⅱ)HCI/Fe(Ⅲ)HCI performed similarly to Fe(Ⅱ)HCI The maximum accumulation potential of Fe(Ⅱ)HCI was significantly higher in RRF, while the highest maximum reaction rate of Fe(Ⅱ)Ha accumulation appeared in RRG. Significant correlations were found between the indexes of Fe(Ⅱ)HCI accumulation and soil pH, oxidation-reduction potential (Eh) and total organic acids, respectively. In together, we found that long-term application of green manures decreased the TFeHa in red paddy soils, but promoted the ability of Fe(lll) reduction, especially the ryegrass; Fe(Ⅱ)Ha increased along with the growth of rice and was affected by soil conditions and environmental factors, especially the water and redox ability.
基金financially supported by the China Agriculture Research System of MOF and MARA(CARS22)the National Natural Science Foundation of China(32072678)+3 种基金the Agricultural Science and Technology Innovation Program of Chinese Academy of Agricultural Sciences(CAAS-ASTIP-2020)the Chinese Outstanding Talents Program in Agricultural Sciencethe Protection and Utilization of Crop Germplasm Resources of China Green Manure(19200393)the Fund Project of Qinghai Academy of Agricultural Sciences(2019-NKY-06)。
文摘To ascertain the possibility of cultivating maize using biological nitrogen fixation(BNF)by leguminous green manure crops in maize/leguminous green manure intercropping systems,BNF and nitrogen(N)transfer were studied in Xining and Wuwei,two typical northwestern Chinese cities.The experimental treatments included monocultured maize,monocultured green manures(hairy vetch and common vetch),and their intercropping systems.The proportions of N derived from the atmosphere(%N_(dfa))in intercropping systems were not significantly different from that in monocultured green manure systems at either experimental site,except for that in hairy vetch(HV)in Xining.The amount of N derived from the atmosphere(N_(dfa))of common vetch(CV)significantly decreased from 1.16 and 1.10 g/pot in monoculture to 0.77 and 0.55 g/pot when intercropped with maize,in Xining and Wuwei,respectively,and the N_(dfa) of HV when intercropped significantly decreased from 1.02 to 0.48 g/pot in Xining.In the intercropping systems in Xining and Wuwei,the amounts of N transferred(N_(transfer))from CV to maize were 21.54 and 26.81 mg/pot,accounting for 32.9 and 5.9%respectively of the N accumulation in maize,and the values of N_(transfer) from HV to maize were 39.61 and 46.22 mg/pot,accounting for 37.0 and 23.3%,respectively,of the N accumulation in maize.Path analysis showed that soil nutrient and green manure biomass were mainly related to N_(dfa),and thatδ^(15) N had a primary relationship with N_(transfer).We found that 5.9-37.0%of N accumulation in maize was transferred from green manures,and that the N transfer ability to maize of HV was higher than that of CV.In conclusion,intercropping with leguminous green manures provided a feasible way for maize to effectively utilize biologicallyfixed N.