The efficient cultivation technique of "rice-rice-potato" triple cropping rotation pattern is summarized by analyzing its characteristics and cultivation techniques in Yangjiang region of Guangdong Province,...The efficient cultivation technique of "rice-rice-potato" triple cropping rotation pattern is summarized by analyzing its characteristics and cultivation techniques in Yangjiang region of Guangdong Province,China,and machine-transplanted cultivation technique of double cropping rice and cultivation techniques of winter potato black film mulching are emphatically introduced,in order to promote the development of potato industry in Yangjiang City.The results will provide a scientific basis for the popularization and application of the "rice-rice-potato" triple cropping rotation pattern.展开更多
To evaluate the effects of various rotation systems on rice grain yield and N use efficiency, a paddy–upland cropping experiment(2013–2016) was conducted in southeastern China. The experiment was designed using six ...To evaluate the effects of various rotation systems on rice grain yield and N use efficiency, a paddy–upland cropping experiment(2013–2016) was conducted in southeastern China. The experiment was designed using six different rice––winter crop rotations: rice–fallow(RF),rice–wheat(RW), rice–potato with rice straw mulch(RP), rice–green manure(Chinese milk vetch; RC–G), rice–oilseed rape(RO), and rice–green manure crop(oilseed rape with fresh straw incorporated into soil at flowering; RO–G) and three N rates, N0(0 kg N ha-1), N1(142.5 kg N ha-1), and N2(202.5 kg N ha-1). Average rice yields in the RF(5.93 t ha-1) rotation were significantly lower than those in the rotations with winter crops(7.20–7.48 t ha-1)under the N0 treatment, suggesting that incorporation of straw might be more effective for increasing soil N than winter fallow. The rice yield differences among the rotations varied by year with the N input. In general, the grain yields in the RP and RO–G rotations –were respectively 11.6–28.5% and 14.80–37.19% higher than those in the RF in plots with N applied. Increasing the N rate may have tended to minimize the average yield gap between the RF and the other rotations; the yield gaps were 18.55%, 4.14%, and 0.23% in N0, N1, and N2, respectively. However, the N recovery efficiency in the RF was significantly lower than that in other rotations, except for 2015 under both N1 and N2 rates, a finding that implies a large amount of chemical N loss. No significant differences in nitrogen agronomic efficiency(NAE) and physiological efficiency(NPE) were found between the rotations with legume(RC–G) and non–legume(RO and RW) winter crops, a result that may be due partly to straw incorporation. For this reason, we concluded that the return of straw could reduce differences in N use efficiency between rotations with and without legume crops. The degree of synchrony between the crop N demand and the N supply was evaluated by comparison of nitrogen balance degree(NBD) values. The NBD values in the RP and RW were significantly lower than those in the other rotations under both N1 and N2 rates. Thus,in view of the higher grain yield in the RP compared to the RW under the N1 rate, the RP rotation might be a promising practice with comparable grain yield and greater N use efficiency under reduced N input relative to the other rotations. The primary yield components of the RF and RP were identified as number of panicles m-2 and numbers of kernels panicle-1, respectively. The NAE and NPE were positively correlated with harvest index, possibly providing a useful indicator for evaluating N use efficiency.展开更多
Cover crops can provide changes in soil chemical and physical properties, which could allow a sustainable development of soybean and upland rice rotation in Brazilian Cerrado. The objective of this study was to determ...Cover crops can provide changes in soil chemical and physical properties, which could allow a sustainable development of soybean and upland rice rotation in Brazilian Cerrado. The objective of this study was to determine the effects of cover crops(cultivated in the offseason) in the soybean-upland rice rotation(cultivated in the summer season) on the soil chemical and physical properties, yield components and grain yield of the cash crops. The experimental design was a randomized block design in factorial scheme 4 × 2 with six replications. Treatments were composed by four cover crops: fallow, millet(Pennisetum glaucum) + Crotalaria ochroleuca, millet + pigeon pea(Cajanus cajans), and millet + pigeon pea + Urochola ruziziensis in the offseason with one or two cycles of cover crops, with rice(Oryza sativa)or soybean(Glycine max) in the summer season. Cover crops alone provided no changes in soil chemical properties. However, the rotation cover crops/cash crops/cover crops/cash crops reduced p H, Al and H + Al and increased Ca, Mg, K and Fe contents in the soil. The cover crops millet + pigeon pea and millet + pigeon pea + U. ruziziensis improved soil physical properties in relation to fallow,especially in the 0–0.10 m soil layer. In spite of the improvement of the soil physical properties after two years of rotation with cover crops and cash crops, the soil physical quality was still below the recommended level, showing values of macroporosity, S index and soil aeration capacity lower than 0.10 m3/m3, 0.035 and 0.34, respectively. Upland rice production was higher under mixtures of cover crops than under fallow, mainly because of soil physical changes done by these mixtures of cover crops.Soybean grain yield was similar under all cover crops tested, but was higher after the rotation cover crops/upland rice/cover crops than after only one cycle of cover crops.展开更多
Field measurements were made from June 2001 to May 2002 to evaluate the effect of crop residue application and temperature on CO2, CH4, and N2O emissions within an entire rice-wheat rotation season. Rapeseed cake and ...Field measurements were made from June 2001 to May 2002 to evaluate the effect of crop residue application and temperature on CO2, CH4, and N2O emissions within an entire rice-wheat rotation season. Rapeseed cake and wheat straw were incorporated into the soil at a rate of 2.25 t hm(-2) when the rice crop was transplanted in June 2001. Compared with the control, the incorporation of rapeseed cake enhanced the emissions of CO2, CH4, and N2O in the rice-growing season by 12.3%, 252.3%, and 17.5%, respectively, while no further effect was held on the emissions of CO2 and N2O in the following wheat-growing season. The incorporation of wheat straw enhanced the emissions of CO2 and CH4 by 7.1% and 249.6%, respectively, but reduced the N2O emission by 18.8% in the rice-growing season. Significant reductions of 17.8% for the CO2 and of 12.9% for the N2O emission were observed in the following wheat-growing season. A positive correlation existed between the emissions of N2O and CO2 (R-2 = 0.445, n = 73,p < 0.001) from the rice-growing season when N2O was emitted. A trade-off relationship between the emissions of CH4 and N2O was found in the rice-growing season. The CH4 emission was significantly correlated with the CO2 emission for the period from rice transplantation to field drainage, but not for the entire rice-growing season. In addition, air temperature was found to regulate the CO2 emissions from the non-waterlogged period over the entire rice-wheat rotation season and the N2O emissions from the nonwaterlogged period of the rice-growing season, which can be quantitatively described by an exponential function. The temperature coefficient (Q(10)) was then evaluated to be 2.3+/-0.2 for the CO2 emission and 3.9+/-0.4 for the N2O emission, respectively.展开更多
In rice–wheat rotation systems, crop straw is usually retained in the field at land preparation in every, or every other, season. We conducted a 3-year-6-season experiment in the middle–lower Yangtze River Valley to...In rice–wheat rotation systems, crop straw is usually retained in the field at land preparation in every, or every other, season. We conducted a 3-year-6-season experiment in the middle–lower Yangtze River Valley to compare the grain qualities of rice under straw retained after single or double seasons per year. Four treatments were designed as: both wheat and rice straw retained(WR), only rice straw retained(R), only wheat straw retained(W), and no straw retained(CK). The varieties were Yangmai 16 wheat and Wuyunjing 23 japonica rice. The results showed contrasting effects of W and R on rice quality. Amylopectin content, peak viscosity, cool viscosity, and breakdown viscosity of rice grain were significantly increased in W compared to the CK, whereas gelatinization temperature,setback viscosity, and protein content significantly decreased. In addition, the effect of WR on rice grain quality was similar to that of W, although soil fertility was enhanced in WR due to straw being retained in two cycles. The differences in protein and starch contents among the treatments might result from soil nitrogen supply. These results indicate that wheat straw retained in the field is more important for high rice quality than rice straw return, and straw from both seasons is recommended for positive effects on soil fertility.展开更多
The objective of this study is to evaluate the performance of three models for estimating daily evapotranspiration(ET) by employing flux observation data from three years(2007, 2008 and 2009) during the growing season...The objective of this study is to evaluate the performance of three models for estimating daily evapotranspiration(ET) by employing flux observation data from three years(2007, 2008 and 2009) during the growing seasons of winter wheat and rice crops cultivated in a farmland ecosystem(Shouxian County) located in the Huai River Basin(HRB), China. The first model is a two-step model(PM-Kc);the other two are one-step models(e.g., Rana-Katerji(R-K) and advection-aridity(AA)). The results showed that the energy closure degrees of eddy covariance(EC) data during winter wheat and rice-growing seasons were reasonable in the HRB, with values ranging from 0.84 to 0.91 and R2 of approximately 0.80. Daily ET of winter wheat showed a slow decreasing trend followed by a rapid increase, while that of rice presented a decreasing trend after an increase. After calibrating the crop coefficient(Kc), the PM–Kc model performed better than the model using the Kc recommended by the Food and Agricultural Organization(FAO). The calibrated key parameters of the R-K model and AA model showed better universality. After calibration, the simulation performance of the PM-Kc model was satisfactory. Both the R-K model and AA model underestimated the daily ET of winter wheat and rice. Compared with that of the R-K model, the simulation result of the AA model was better, especially in the simulation of daily ET of rice. Overall, this research highlighted the consistency of the PM-Kc model to estimate the water demand for rice and wheat crops in the HRB and in similar climatic regions in the world.展开更多
The rice and wheat cropping pattern is one of the main cropping systems in the world. A large number of research results showed that successive cropping of rice and wheat resulted in a series of problems such as hinde...The rice and wheat cropping pattern is one of the main cropping systems in the world. A large number of research results showed that successive cropping of rice and wheat resulted in a series of problems such as hindering nutrition absorption, gradual degeneration of soil fertility, decline of soil organic matter, and increased incidence of diseases and pests. In China, especially in the Chengdu plain where rice-wheat cropping system is practiced, productivity and soil fertility was enhanced and sustained. This paper reviews the relevant data and experiences on rice-wheat cropping in the Chengdu Plain from 1977 to 2006. The principal sustainable strategies used for rice-wheat cropping systems in Chengdu Plain included: 1) creating a favorable environment and viable rotations; 2) balanced fertilization for maintenance of sustainable soil productivity; 3) improvement of crop management for higher efficiency; and 4) use the newest cultivars and cultivation techniques to upgrade the production level. Future research is also discussed in the paper as: 1) the constant topic: a highly productive and efficient rice-wheat cropping system for sustainable growth; 2) the future trend: simplified cultivation techniques for the rice-wheat cropping system; 3) the foundation: basic research for continuous innovation needed for intensive cropping. It is concluded that in the rice-wheat cropping system, a scientific and reasonable tillage/cultivation method can not only avoid the degradation of soil productivity, but also maintain sustainable growth in the long run.展开更多
A two-year on-farm study was carried out at Eglime in the moist savanna (MS) and Ouake in the dry savanna (DS) of Benin to evaluate the contribution of inoculation of dual-purpose soybean varieties to grain yield ...A two-year on-farm study was carried out at Eglime in the moist savanna (MS) and Ouake in the dry savanna (DS) of Benin to evaluate the contribution of inoculation of dual-purpose soybean varieties to grain yield of upland NERICA rice fertilized with low N level. In 2005, four dual-purpose, promiscuous soybean varieties (cv. TGx1440-IE; TG×1448-2E; TG×1019-2EB; and TG×1844-18E), and a popular improved variety (cv. Jupiter) were sown in 12 farmer fields with and without Bradyrhizobium japonicum inoculation. There was also land which was left fallow that acted as the control. In 2006, upland interspecific rice (NERICA 1) was sown in all the plots and supplied with 15 kg N haL. Dry matter yield, N accumulation, and net N-balance were significantly enhanced by over 40% with inoculation of cv. TG× 1844-18E than non-inoculation in the DS in comparison to other cultivars. There were no significant effects of inoculation of previous soybean cultivars on soybean grain yield and on the succeeding NERICA rice yield. Averaged over inoculation, previous cv. TG× 1019-2EB plots supplied with only 15 kg N hal gave the highest grain yield, more than twice the yield of control plots in the DS, possibly because of significant production of higher tillers, panicles and harvest index than the other cultivars; and it could be recommended for upland rice-based system for NERICA production.展开更多
Soil siderophores are important for crop growth,benefit ferric iron absorption of root,and are affected by cropping patterns.The objective of this study was to evaluate the quantity of siderophores in soil of 2 contin...Soil siderophores are important for crop growth,benefit ferric iron absorption of root,and are affected by cropping patterns.The objective of this study was to evaluate the quantity of siderophores in soil of 2 continuous crop rotation patterns over 30 years in Anren country,China.Quantity and siderophore-producing capability of microorganisms in rice-riceoilseed rape(DDY)rotation and rice-rice(DD)rontinuous cropping rhizosphere soil were tested and analyzed by chrome azurol S method.Isolated strains were used to identify siderophore-producing microorganism(SPM)by PCR amplification and DNA sequencing.Results showed that 9 siderophore-producing bacteria strains were isolated from DDY rhizosphere soil while 7 strains were identified from DD rhizosphere soil.The mean solubility index which representing siderophore-producing capability of strains was 3.05.PCR amplification results indicated that bacterial were the major SPM in soil.This research indicates that crop rotation systems could drive microorganisms to produce siderophores and enrich them in bacterial communities.展开更多
基金Supported by Guangdong Provincial Special Fund for Modern Agriculture Industry Technology Innovation Teams (2019KJ111)。
文摘The efficient cultivation technique of "rice-rice-potato" triple cropping rotation pattern is summarized by analyzing its characteristics and cultivation techniques in Yangjiang region of Guangdong Province,China,and machine-transplanted cultivation technique of double cropping rice and cultivation techniques of winter potato black film mulching are emphatically introduced,in order to promote the development of potato industry in Yangjiang City.The results will provide a scientific basis for the popularization and application of the "rice-rice-potato" triple cropping rotation pattern.
基金The National Key Research and Development Program of China(2016YFD0300108,2016YFD0300208-02)the National Natural Science Foundation of China(31671638)+1 种基金the China Agriculture Research System(CARS-01-04A)the Special Fund for Agro-scientific Research in the Public Interest(201203096)partly supported this study
文摘To evaluate the effects of various rotation systems on rice grain yield and N use efficiency, a paddy–upland cropping experiment(2013–2016) was conducted in southeastern China. The experiment was designed using six different rice––winter crop rotations: rice–fallow(RF),rice–wheat(RW), rice–potato with rice straw mulch(RP), rice–green manure(Chinese milk vetch; RC–G), rice–oilseed rape(RO), and rice–green manure crop(oilseed rape with fresh straw incorporated into soil at flowering; RO–G) and three N rates, N0(0 kg N ha-1), N1(142.5 kg N ha-1), and N2(202.5 kg N ha-1). Average rice yields in the RF(5.93 t ha-1) rotation were significantly lower than those in the rotations with winter crops(7.20–7.48 t ha-1)under the N0 treatment, suggesting that incorporation of straw might be more effective for increasing soil N than winter fallow. The rice yield differences among the rotations varied by year with the N input. In general, the grain yields in the RP and RO–G rotations –were respectively 11.6–28.5% and 14.80–37.19% higher than those in the RF in plots with N applied. Increasing the N rate may have tended to minimize the average yield gap between the RF and the other rotations; the yield gaps were 18.55%, 4.14%, and 0.23% in N0, N1, and N2, respectively. However, the N recovery efficiency in the RF was significantly lower than that in other rotations, except for 2015 under both N1 and N2 rates, a finding that implies a large amount of chemical N loss. No significant differences in nitrogen agronomic efficiency(NAE) and physiological efficiency(NPE) were found between the rotations with legume(RC–G) and non–legume(RO and RW) winter crops, a result that may be due partly to straw incorporation. For this reason, we concluded that the return of straw could reduce differences in N use efficiency between rotations with and without legume crops. The degree of synchrony between the crop N demand and the N supply was evaluated by comparison of nitrogen balance degree(NBD) values. The NBD values in the RP and RW were significantly lower than those in the other rotations under both N1 and N2 rates. Thus,in view of the higher grain yield in the RP compared to the RW under the N1 rate, the RP rotation might be a promising practice with comparable grain yield and greater N use efficiency under reduced N input relative to the other rotations. The primary yield components of the RF and RP were identified as number of panicles m-2 and numbers of kernels panicle-1, respectively. The NAE and NPE were positively correlated with harvest index, possibly providing a useful indicator for evaluating N use efficiency.
基金the National Council for Scientific and Technological Development (CNPq)Foundation for Research Support of the State of Goiás for their support
文摘Cover crops can provide changes in soil chemical and physical properties, which could allow a sustainable development of soybean and upland rice rotation in Brazilian Cerrado. The objective of this study was to determine the effects of cover crops(cultivated in the offseason) in the soybean-upland rice rotation(cultivated in the summer season) on the soil chemical and physical properties, yield components and grain yield of the cash crops. The experimental design was a randomized block design in factorial scheme 4 × 2 with six replications. Treatments were composed by four cover crops: fallow, millet(Pennisetum glaucum) + Crotalaria ochroleuca, millet + pigeon pea(Cajanus cajans), and millet + pigeon pea + Urochola ruziziensis in the offseason with one or two cycles of cover crops, with rice(Oryza sativa)or soybean(Glycine max) in the summer season. Cover crops alone provided no changes in soil chemical properties. However, the rotation cover crops/cash crops/cover crops/cash crops reduced p H, Al and H + Al and increased Ca, Mg, K and Fe contents in the soil. The cover crops millet + pigeon pea and millet + pigeon pea + U. ruziziensis improved soil physical properties in relation to fallow,especially in the 0–0.10 m soil layer. In spite of the improvement of the soil physical properties after two years of rotation with cover crops and cash crops, the soil physical quality was still below the recommended level, showing values of macroporosity, S index and soil aeration capacity lower than 0.10 m3/m3, 0.035 and 0.34, respectively. Upland rice production was higher under mixtures of cover crops than under fallow, mainly because of soil physical changes done by these mixtures of cover crops.Soybean grain yield was similar under all cover crops tested, but was higher after the rotation cover crops/upland rice/cover crops than after only one cycle of cover crops.
文摘Field measurements were made from June 2001 to May 2002 to evaluate the effect of crop residue application and temperature on CO2, CH4, and N2O emissions within an entire rice-wheat rotation season. Rapeseed cake and wheat straw were incorporated into the soil at a rate of 2.25 t hm(-2) when the rice crop was transplanted in June 2001. Compared with the control, the incorporation of rapeseed cake enhanced the emissions of CO2, CH4, and N2O in the rice-growing season by 12.3%, 252.3%, and 17.5%, respectively, while no further effect was held on the emissions of CO2 and N2O in the following wheat-growing season. The incorporation of wheat straw enhanced the emissions of CO2 and CH4 by 7.1% and 249.6%, respectively, but reduced the N2O emission by 18.8% in the rice-growing season. Significant reductions of 17.8% for the CO2 and of 12.9% for the N2O emission were observed in the following wheat-growing season. A positive correlation existed between the emissions of N2O and CO2 (R-2 = 0.445, n = 73,p < 0.001) from the rice-growing season when N2O was emitted. A trade-off relationship between the emissions of CH4 and N2O was found in the rice-growing season. The CH4 emission was significantly correlated with the CO2 emission for the period from rice transplantation to field drainage, but not for the entire rice-growing season. In addition, air temperature was found to regulate the CO2 emissions from the non-waterlogged period over the entire rice-wheat rotation season and the N2O emissions from the nonwaterlogged period of the rice-growing season, which can be quantitatively described by an exponential function. The temperature coefficient (Q(10)) was then evaluated to be 2.3+/-0.2 for the CO2 emission and 3.9+/-0.4 for the N2O emission, respectively.
基金financial supported by the National Key Technology R&D Program of China (2012BAD04B08, 2011BAD16B14)
文摘In rice–wheat rotation systems, crop straw is usually retained in the field at land preparation in every, or every other, season. We conducted a 3-year-6-season experiment in the middle–lower Yangtze River Valley to compare the grain qualities of rice under straw retained after single or double seasons per year. Four treatments were designed as: both wheat and rice straw retained(WR), only rice straw retained(R), only wheat straw retained(W), and no straw retained(CK). The varieties were Yangmai 16 wheat and Wuyunjing 23 japonica rice. The results showed contrasting effects of W and R on rice quality. Amylopectin content, peak viscosity, cool viscosity, and breakdown viscosity of rice grain were significantly increased in W compared to the CK, whereas gelatinization temperature,setback viscosity, and protein content significantly decreased. In addition, the effect of WR on rice grain quality was similar to that of W, although soil fertility was enhanced in WR due to straw being retained in two cycles. The differences in protein and starch contents among the treatments might result from soil nitrogen supply. These results indicate that wheat straw retained in the field is more important for high rice quality than rice straw return, and straw from both seasons is recommended for positive effects on soil fertility.
基金supported by the National Natural Science Foundation of China (41905100)the Anhui Provincial Natural Science Foundation, China (1908085QD171)+3 种基金the Anhui Agricultural University Science Foundation for Young Scholars, China (2018zd07)the Anhui Agricultural University Introduction and Stabilization of Talent Fund, China (yj2018-57)the National Key Research and Development Program of China (2018YFD0300905)the Postgraduate Research and Practice Innovation Program of Jiangsu Province, China (KYCX17_0885)。
文摘The objective of this study is to evaluate the performance of three models for estimating daily evapotranspiration(ET) by employing flux observation data from three years(2007, 2008 and 2009) during the growing seasons of winter wheat and rice crops cultivated in a farmland ecosystem(Shouxian County) located in the Huai River Basin(HRB), China. The first model is a two-step model(PM-Kc);the other two are one-step models(e.g., Rana-Katerji(R-K) and advection-aridity(AA)). The results showed that the energy closure degrees of eddy covariance(EC) data during winter wheat and rice-growing seasons were reasonable in the HRB, with values ranging from 0.84 to 0.91 and R2 of approximately 0.80. Daily ET of winter wheat showed a slow decreasing trend followed by a rapid increase, while that of rice presented a decreasing trend after an increase. After calibrating the crop coefficient(Kc), the PM–Kc model performed better than the model using the Kc recommended by the Food and Agricultural Organization(FAO). The calibrated key parameters of the R-K model and AA model showed better universality. After calibration, the simulation performance of the PM-Kc model was satisfactory. Both the R-K model and AA model underestimated the daily ET of winter wheat and rice. Compared with that of the R-K model, the simulation result of the AA model was better, especially in the simulation of daily ET of rice. Overall, this research highlighted the consistency of the PM-Kc model to estimate the water demand for rice and wheat crops in the HRB and in similar climatic regions in the world.
基金funded by the National Key Technologies Research and Development Program of China(2006BAD02A05)the Science and Technology Project for Public (Agriculture)the Ministry of Agriculture, China (200903050-4)
文摘The rice and wheat cropping pattern is one of the main cropping systems in the world. A large number of research results showed that successive cropping of rice and wheat resulted in a series of problems such as hindering nutrition absorption, gradual degeneration of soil fertility, decline of soil organic matter, and increased incidence of diseases and pests. In China, especially in the Chengdu plain where rice-wheat cropping system is practiced, productivity and soil fertility was enhanced and sustained. This paper reviews the relevant data and experiences on rice-wheat cropping in the Chengdu Plain from 1977 to 2006. The principal sustainable strategies used for rice-wheat cropping systems in Chengdu Plain included: 1) creating a favorable environment and viable rotations; 2) balanced fertilization for maintenance of sustainable soil productivity; 3) improvement of crop management for higher efficiency; and 4) use the newest cultivars and cultivation techniques to upgrade the production level. Future research is also discussed in the paper as: 1) the constant topic: a highly productive and efficient rice-wheat cropping system for sustainable growth; 2) the future trend: simplified cultivation techniques for the rice-wheat cropping system; 3) the foundation: basic research for continuous innovation needed for intensive cropping. It is concluded that in the rice-wheat cropping system, a scientific and reasonable tillage/cultivation method can not only avoid the degradation of soil productivity, but also maintain sustainable growth in the long run.
文摘A two-year on-farm study was carried out at Eglime in the moist savanna (MS) and Ouake in the dry savanna (DS) of Benin to evaluate the contribution of inoculation of dual-purpose soybean varieties to grain yield of upland NERICA rice fertilized with low N level. In 2005, four dual-purpose, promiscuous soybean varieties (cv. TGx1440-IE; TG×1448-2E; TG×1019-2EB; and TG×1844-18E), and a popular improved variety (cv. Jupiter) were sown in 12 farmer fields with and without Bradyrhizobium japonicum inoculation. There was also land which was left fallow that acted as the control. In 2006, upland interspecific rice (NERICA 1) was sown in all the plots and supplied with 15 kg N haL. Dry matter yield, N accumulation, and net N-balance were significantly enhanced by over 40% with inoculation of cv. TG× 1844-18E than non-inoculation in the DS in comparison to other cultivars. There were no significant effects of inoculation of previous soybean cultivars on soybean grain yield and on the succeeding NERICA rice yield. Averaged over inoculation, previous cv. TG× 1019-2EB plots supplied with only 15 kg N hal gave the highest grain yield, more than twice the yield of control plots in the DS, possibly because of significant production of higher tillers, panicles and harvest index than the other cultivars; and it could be recommended for upland rice-based system for NERICA production.
基金supported by the Natural Science Foundation of China (No. 31272248)the project of graduate innovation in Hunan Province (No. CX2017B364)
文摘Soil siderophores are important for crop growth,benefit ferric iron absorption of root,and are affected by cropping patterns.The objective of this study was to evaluate the quantity of siderophores in soil of 2 continuous crop rotation patterns over 30 years in Anren country,China.Quantity and siderophore-producing capability of microorganisms in rice-riceoilseed rape(DDY)rotation and rice-rice(DD)rontinuous cropping rhizosphere soil were tested and analyzed by chrome azurol S method.Isolated strains were used to identify siderophore-producing microorganism(SPM)by PCR amplification and DNA sequencing.Results showed that 9 siderophore-producing bacteria strains were isolated from DDY rhizosphere soil while 7 strains were identified from DD rhizosphere soil.The mean solubility index which representing siderophore-producing capability of strains was 3.05.PCR amplification results indicated that bacterial were the major SPM in soil.This research indicates that crop rotation systems could drive microorganisms to produce siderophores and enrich them in bacterial communities.