[Objective]A long-term paddy-upland experiment was conducted to evaluate the effects of the recommended amount of potassium( K)fertilizer on crop yield,distribution of soil aggregate,and soil available K content. It w...[Objective]A long-term paddy-upland experiment was conducted to evaluate the effects of the recommended amount of potassium( K)fertilizer on crop yield,distribution of soil aggregate,and soil available K content. It was mainly to ascertain the distribution of K in the soil aggregate components in the paddy-upland rotation system,and then to provide theoretical basis for soil structure improvement,K pool management,and reasonable application of K fertilizer. [Method]There were 2 treatments selected,namely,NP(-K) treatment and NPK( + K) treatment in this study. Then the effects of K fertilizer application on the yield,available K content,and aggregate distribution in the middle rice-winter rape rotation system were analyzed. [Result]The results showed that the output of the crop rotation was affected by the year and fertilization. Compared with NP(-K),the average yield increases of rice and winter rape after application of K fertilizer were 0.51 and 0.33 t/hm2,with the increments of 7.5%and 14. 1% respectively. The long-term application of K fertilizer( 7 a) had no significant effects on the distribution of soil aggregates but could significantly increase the water-soluble K content and available K content at depths of 20-30 and 30-40 cm,and available K content of aggregates in each particle size. In addition,the balance of available K at the 10-20 and 30-40 cm of soil layers was the most significant through calculation of surplus-deficit value of available K in agglomerates of different soil layers. [Conclusion]Compared with the initial available K content in the farmland in 2011,the current K fertilizer application could lead to that farmland K content continues to decline. Therefore,we should pay attention to straw returned and supplement of organic K fertilizer,to maintain crop rotation system's productivity and soil K balance.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
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
研究长期施用钾肥对水稻-冬油菜轮作系统作物生产力、钾肥利用率和土壤供钾能力的影响,为水旱轮作区钾肥的统筹分配提供科学依据。2011—2016年在湖北省粮油主要生产区江汉平原布置中稻-冬油菜轮作定位田间试验。共设5个钾肥用量处理,...研究长期施用钾肥对水稻-冬油菜轮作系统作物生产力、钾肥利用率和土壤供钾能力的影响,为水旱轮作区钾肥的统筹分配提供科学依据。2011—2016年在湖北省粮油主要生产区江汉平原布置中稻-冬油菜轮作定位田间试验。共设5个钾肥用量处理,分别为0 kg hm^(-2)(K0),45 kg hm^(-2)(K1),90 kg hm^(-2)(K2),135 kg hm^(-2)(K3)和180 kg hm^(-2)(K4),其中K2处理为当地测土配方推荐钾肥用量(K2O 90 kg hm^(-2))。在土壤供钾能力较高情况下,水稻和油菜年均产量分别为6.87 t hm^(-2)和2.25 t hm^(-2),经过一个轮作周期后施用钾肥具有明显的增产效果,且冬油菜季的产量和地上部吸钾量增幅最为明显,分别为16.9%和63.8%。长期施用推荐钾肥用量后,水稻和冬油菜的钾肥农学利用率年均分别为5.1kg kg–1和3.2 kg kg–1,而钾肥吸收利用率和钾肥贡献率水稻季明显低于冬油菜,这表明水稻吸收的钾素主要来自土壤,而冬油菜则需要较多的外源钾来满足自身对养分的需求。通过线性加平台肥效模型拟合得出,水稻季适宜钾肥用量为70.5~100.9 kg hm^(-2),平均96.6 kg hm^(-2),比推荐用量提高了7.3%;冬油菜季适宜钾肥用量为75.6~118.2 kg hm^(-2),平均107.0 kg hm^(-2),比推荐用量提高18.9%,且冬油菜对钾肥需求高于水稻。因此,在本试验条件下,长期施用年均推荐钾肥用量(180 kg hm^(-2))不仅影响作物产量的稳定性,还导致轮作系统钾素持续亏缺和土壤有效钾含量降低,故钾肥应优先施用于油菜季并且重视作物秸秆还田、归还秸秆钾素,以维持农田钾素平衡和生产力可持续性。展开更多
量化作物生产的碳足迹有助于为农业生态系统温室气体减排提供理论依据。利用生命周期法研究了我国南方地区稻田春玉米 晚稻水旱轮作种植模式和早稻 晚稻连作种植模式下粮食生产的碳足迹,并定量分析粮食生产过程中各种碳排放源的相对贡...量化作物生产的碳足迹有助于为农业生态系统温室气体减排提供理论依据。利用生命周期法研究了我国南方地区稻田春玉米 晚稻水旱轮作种植模式和早稻 晚稻连作种植模式下粮食生产的碳足迹,并定量分析粮食生产过程中各种碳排放源的相对贡献。结果表明,与早稻 晚稻的连作模式相比,春玉米 晚稻轮作模式的单位面积碳排放降低了6724 kg CO2 eq/hm^2,单位产量的碳足迹降低了0.56 kg CO2 eq/kg。春玉米比早稻少排放6228 kg CO2 eq/hm^2;与早稻 晚稻模式中晚稻碳排放相比,春玉米 晚稻轮作模式晚稻碳排放降低了497 kg CO2 eq/hm^2。早稻 晚稻种植模式的碳足迹主要来源于甲烷(CH4),其碳排放为9776 kg CO2 eq/hm^2(54.8%),氮肥生产和施用的碳排放为2871 kg CO2 eq/hm^2(16.1%),灌溉电力消耗的碳排放2849 kg CO2 eq/hm^2(16.0%)。春玉米 晚稻轮作模式的碳足迹主要来源于CH4的碳排放4442 kg CO2 eq/hm^2(39.9%),氮肥生产和施用的碳排放2871 kg CO2 eq/hm^2(25.8%),灌溉电力消耗的碳排放1508 kg CO2 eq/hm^2(13.6%)。该模式中晚稻的碳足迹组成情况与春玉米 晚稻模式的碳足迹相似。但是,对于春玉米而言,其碳足迹主要来源氮肥生产和施用的碳排放1436 CO2 eq/hm^2(50.1%),氧化亚氮(N2O)的碳排放为579 kg CO2 eq/hm^2(20.2%),CH4的碳排放为378 CO2 eq/hm^2(13.2%)。同时,相比于早稻 晚稻中晚稻的产量(6333 kg/hm^2),春玉米 晚稻轮作模式下的晚稻产量(7270 kg/hm^2)提高了14.8%。因此,引入春玉米 晚稻轮作模式有利于提升稻田生产力,降低稻田连作系统碳排放和碳足迹。展开更多
基金Supported by National Key R&D Projects of the 13thFive-Year Plan of the Ministry of Science and Technology(2017YFD0201900)Young and Middle-aged Talents Project of Hubei Provincial Department of Education(Q20181303)Construction Project of National Modern Agricultural Industry Technology System(CAR-13)
文摘[Objective]A long-term paddy-upland experiment was conducted to evaluate the effects of the recommended amount of potassium( K)fertilizer on crop yield,distribution of soil aggregate,and soil available K content. It was mainly to ascertain the distribution of K in the soil aggregate components in the paddy-upland rotation system,and then to provide theoretical basis for soil structure improvement,K pool management,and reasonable application of K fertilizer. [Method]There were 2 treatments selected,namely,NP(-K) treatment and NPK( + K) treatment in this study. Then the effects of K fertilizer application on the yield,available K content,and aggregate distribution in the middle rice-winter rape rotation system were analyzed. [Result]The results showed that the output of the crop rotation was affected by the year and fertilization. Compared with NP(-K),the average yield increases of rice and winter rape after application of K fertilizer were 0.51 and 0.33 t/hm2,with the increments of 7.5%and 14. 1% respectively. The long-term application of K fertilizer( 7 a) had no significant effects on the distribution of soil aggregates but could significantly increase the water-soluble K content and available K content at depths of 20-30 and 30-40 cm,and available K content of aggregates in each particle size. In addition,the balance of available K at the 10-20 and 30-40 cm of soil layers was the most significant through calculation of surplus-deficit value of available K in agglomerates of different soil layers. [Conclusion]Compared with the initial available K content in the farmland in 2011,the current K fertilizer application could lead to that farmland K content continues to decline. Therefore,we should pay attention to straw returned and supplement of organic K fertilizer,to maintain crop rotation system's productivity and soil K balance.
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.
文摘研究长期施用钾肥对水稻-冬油菜轮作系统作物生产力、钾肥利用率和土壤供钾能力的影响,为水旱轮作区钾肥的统筹分配提供科学依据。2011—2016年在湖北省粮油主要生产区江汉平原布置中稻-冬油菜轮作定位田间试验。共设5个钾肥用量处理,分别为0 kg hm^(-2)(K0),45 kg hm^(-2)(K1),90 kg hm^(-2)(K2),135 kg hm^(-2)(K3)和180 kg hm^(-2)(K4),其中K2处理为当地测土配方推荐钾肥用量(K2O 90 kg hm^(-2))。在土壤供钾能力较高情况下,水稻和油菜年均产量分别为6.87 t hm^(-2)和2.25 t hm^(-2),经过一个轮作周期后施用钾肥具有明显的增产效果,且冬油菜季的产量和地上部吸钾量增幅最为明显,分别为16.9%和63.8%。长期施用推荐钾肥用量后,水稻和冬油菜的钾肥农学利用率年均分别为5.1kg kg–1和3.2 kg kg–1,而钾肥吸收利用率和钾肥贡献率水稻季明显低于冬油菜,这表明水稻吸收的钾素主要来自土壤,而冬油菜则需要较多的外源钾来满足自身对养分的需求。通过线性加平台肥效模型拟合得出,水稻季适宜钾肥用量为70.5~100.9 kg hm^(-2),平均96.6 kg hm^(-2),比推荐用量提高了7.3%;冬油菜季适宜钾肥用量为75.6~118.2 kg hm^(-2),平均107.0 kg hm^(-2),比推荐用量提高18.9%,且冬油菜对钾肥需求高于水稻。因此,在本试验条件下,长期施用年均推荐钾肥用量(180 kg hm^(-2))不仅影响作物产量的稳定性,还导致轮作系统钾素持续亏缺和土壤有效钾含量降低,故钾肥应优先施用于油菜季并且重视作物秸秆还田、归还秸秆钾素,以维持农田钾素平衡和生产力可持续性。
文摘量化作物生产的碳足迹有助于为农业生态系统温室气体减排提供理论依据。利用生命周期法研究了我国南方地区稻田春玉米 晚稻水旱轮作种植模式和早稻 晚稻连作种植模式下粮食生产的碳足迹,并定量分析粮食生产过程中各种碳排放源的相对贡献。结果表明,与早稻 晚稻的连作模式相比,春玉米 晚稻轮作模式的单位面积碳排放降低了6724 kg CO2 eq/hm^2,单位产量的碳足迹降低了0.56 kg CO2 eq/kg。春玉米比早稻少排放6228 kg CO2 eq/hm^2;与早稻 晚稻模式中晚稻碳排放相比,春玉米 晚稻轮作模式晚稻碳排放降低了497 kg CO2 eq/hm^2。早稻 晚稻种植模式的碳足迹主要来源于甲烷(CH4),其碳排放为9776 kg CO2 eq/hm^2(54.8%),氮肥生产和施用的碳排放为2871 kg CO2 eq/hm^2(16.1%),灌溉电力消耗的碳排放2849 kg CO2 eq/hm^2(16.0%)。春玉米 晚稻轮作模式的碳足迹主要来源于CH4的碳排放4442 kg CO2 eq/hm^2(39.9%),氮肥生产和施用的碳排放2871 kg CO2 eq/hm^2(25.8%),灌溉电力消耗的碳排放1508 kg CO2 eq/hm^2(13.6%)。该模式中晚稻的碳足迹组成情况与春玉米 晚稻模式的碳足迹相似。但是,对于春玉米而言,其碳足迹主要来源氮肥生产和施用的碳排放1436 CO2 eq/hm^2(50.1%),氧化亚氮(N2O)的碳排放为579 kg CO2 eq/hm^2(20.2%),CH4的碳排放为378 CO2 eq/hm^2(13.2%)。同时,相比于早稻 晚稻中晚稻的产量(6333 kg/hm^2),春玉米 晚稻轮作模式下的晚稻产量(7270 kg/hm^2)提高了14.8%。因此,引入春玉米 晚稻轮作模式有利于提升稻田生产力,降低稻田连作系统碳排放和碳足迹。
