| Based on the long-term experiment in 2009-2010 wheat growing season,the effects of cultivation modes on winter wheat yield and sustainable yield index(SYI),nitrogen absorption and utilization of winter wheat,nitrogen nutrition index of plant,nitrogen supply and demand balance in the wheat field,soil physical structure,soil carbon sequestration rate,soil organic matter quality,and soil quality area index were studied to provide theoretical support for further optimizing the soil-crop system integrated management mode and achieving a high and stable yield of winter wheat at a higher level.Four cultivation modes were set up in the experiment: local farmer mode(T1);improvement mode based on farmers(T2);high-yield and higher-yield mode regardless of production cost(T3)and integrated soil-crop system management mode(T4).The main results are as follows:1 Effects of cultivation modes on dry matter accumulation,grain yield and SYI of winter wheatThere were significant differences in dry matter accumulation and grain yield at maturity and sustainable yield index among the four cultivation modes in the growing season of2020-2022.The dry matter accumulation and grain yield at maturity stage showed T3>T4>T2>T1.The SYI showed T4>T3=T2>T1.2 Effects of cultivation modes on nitrogen absorption and utilization of winter wheat and nitrogen supply and demand balance in wheat fieldThere were significant differences in nitrogen absorption and utilization among the four cultivation modes.The aboveground nitrogen accumulation of the four cultivation modes was T3>T4>T2>T1,the nitrogen use efficiency and nitrogen recovery efficiency were T2>T4>T3>T1,the apparent nitrogen loss was T1>T3>T4>T2,and the apparent nitrogen loss rate was the highest in T1,T2 and T4 are lower.The whole plant at the anthesis stage and the spikes at the maturity stage of T4 mode were in the balance of nitrogen supply and demand.3 Effects of cultivation modes on soil physicochemical properties in winter wheat fieldAfter 13 wheat-maize growing seasons,the bulk density of winter wheat in T1,T2,T3 and T4 decreased by 6.21%,9.80%,12.25% and 13.56%,respectively,and the organic matter content increased by 21.88%,26.80%,32.05% and 36.39%,respectively.The total nitrogen content increased by 34.16%,12.38%,39.60% and 20.79%,respectively,and the alkali-hydrolyzable nitrogen content increased by 47.85%,48.87%,74.49% and 62.21%,respectively.The content of available phosphorus increased by 62.73%,36.56%,297.93% and68.68% respectively,and the content of available potassium increased by 14.36%,40.00%,221.20% and 59.60% respectively.The accumulation of inorganic nitrogen in 0-100 cm soil layer increased by 33.96%,10.32%,52.77% and 19.49%,respectively.The p H decreased from 7.50 to 6.28,6.68,5.35 and 6.64,respectively.There were significant differences in the particle size distribution and stability index of soil air-dried and water-stable aggregates at the maturity stage of winter wheat among the four cultivation modes.The proportion of large macroaggregates in air-dried and water-stable aggregates in 0-20 cm and 20-40 cm soil layers was T4>T2>T1>T3,the proportion of silt and clay was T3>T1>T2>T4,and percentage of > 0.25 mm aggregates,mean weight diameter and geometric mean diameter were T4>T2>T1>T3.The structure deterioration rate of soil aggregates was the highest in T1 and T3,and the lowest in T2 and T4.4 Effects of cultivation modes on soil carbon and nitrogen in wheat fieldThe total carbon input of the four cultivation modes in 13 years showed T3 > T4 > T2 =T1.Compared with T1 mode,the total carbon input of T2,T3 and T4 modes increased by2.11%,23.08% and 7.53%.The carbon sequestration rate of T4 mode was significantly higher than that of other modes.There were significant differences in the content,proportion and C: N ratio of bulk soil and its fractionations in 0-20 cm and 20-40 cm soil layers of winter wheat at maturity stage among the four cultivation modes.The content and proportion of light fraction and particle fraction organic carbon in 0-40 cm soil layer of T4 mode were the highest,and the proportion of light fraction and particle fraction total nitrogen was the highest.The C: N ratio of bulk soil and its fractionations in 0-40 cm soil layer of T2 and T4 modes was higher.The content of easily oxidized organic carbon and carbon pool management index in 0-40 cm soil layer of T4 mode were the highest.The soil quality area index of 0-20 cm and 20-40 cm soil layers at the maturity stage of winter wheat was the highest in T4 mode,and the soil health was the best.Comprehensive analysis showed that compared with the other three modes,T4 mode with wide range sowing with higher planting density,reduced nitrogen application and appropriate delayed sowing as salient features could achieve high yield,stable yield,nitrogen absorption and utilization of winter wheat and synergistic improvement of soil health in winter wheat field. |
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