| Rice is the primary crop in the province of Jiangsu.The decrease in arable land and the increase in population have intensified the need to enhance the yield per unit area,rendering it a fundamental method to tackle this issue.Researchers posit enhancing the absorption and efficient utilization of nitrogen in rice as a promising means of stimulating plant development and realizing the crop’s potential yield.In recent times,farmers have resorted to elevated application of nitrogen fertilizers to maximize rice yield but faced a decline in nitrogen fertilizer absorption utilization.Nitrogen and other vital nutrients from the fertilizers are carried off through tailwater runoff from the rice field,polluting the surrounding rivers and lakes with excess nutrient concentration and causing eutrophication.Presently,there is scant research on the effects of varied cultivation practices on rice yield development,nutrient uptake and utilization,and tailwater nutrient content in rice production.Consequently,this study undertook multiple interactive tests in Jiangsu’s Changzhou and Yangzhou cities between 2020 to 2022,to investigate the impact of several farming strategies,such as straw mulching,cultivation techniques,fertilizing tactics,and fertilizer types,on rice yield development,plant and soil nutrient uptake and utilization,and tailwater nutrient content.The findings are presented below:1.Compared with the treatment without straw mulching:Rice with straw mulching:1)Had significantly higher grain yield,on average by 5.42%;2)Had an average of 3.37%higher dry weight at maturity,and an average increase of 4.72%and 9.34%in dry matter growth before and after heading,respectively;the economic coefficient was on average 2.35%higher;3)Had an average lower nitrogen content of 0.15 percentage point in the plants at maturity,with an average increase of 3.34%in nitrogen accumulation and an average increase of 12.62%and 17.49%in nitrogen absorption before and after heading,respectively.The nitrogen grain production efficiency,nitrogen harvest index,and nitrogen fertilizer partial productivity were on average increased by 1.79%,2.97%,and 5.2%,respectively.The nitrogen utilization rate was on average increased by 2 percentage points and nitrogen requirement per 100 kg of grain was on average reduced by 1.4%;4)Had an average increase of 3.33%,1.1%,10.58%,and 0.18%in total nitrogen,total phosphorus,available nitrogen,and available phosphorus content in the soil at maturity,respectively;5)Had an average increase of 4.83%and 39.28%in total nitrogen and total phosphorus content in the tailwater from the tillering to heading stage.2.In comparison to conventional and slow-release fertilizers:Rice treated with slow-release fertilizers:1)Had significantly lower grain yield,with an average decrease of 13.09%and 4.12%,respectively;2)The dry weight at maturity was,on average,5.88%and 0.22%respectively,lower,and the average decrease of dry matter growth before heading was 14.15%and 6.25%.After heading,the average increase of dry matter growth was 15.35%and 16.92%,respectively.Additionally,the economic coefficient was 10%and 4.79%lower on average;3)At maturity,the nitrogen content in the plants was on average 0.09 and 0.07 percentage points higher,with an average increase of 1.08%and 9.66%in nitrogen accumulation.Additionally,nitrogen absorption before heading was on average 20.15%and 7.11%lower whereas nitrogen absorption after heading was 10.36%and 17.12%higher,respectively.The nitrogen grain production efficiency,nitrogen harvest index,and nitrogen fertilizer partial productivity were lower on average by 13.07%and 11.79%,3.57%and 1.67%,and 11.99%and 2.97%,respectively.Moreover,nitrogen requirement per 100 kg of grain was,on average,higher by 15.19%and 13.61%,while nitrogen utilization rate was,on average,higher by 0.9 and 6.6 percentage points,respectively;4)In comparison to conventional fertilizer treatment,slow-release fertilizer treatment had an average increase of soil total nitrogen,total phosphorus,available nitrogen,and available phosphorus content at maturity,with an average of 5.56%,1.76%,2.37%,and 2.27%,respectively;5)During the tillering and heading period,rice paddies treated with slowrelease fertilizers had lower total nitrogen content in the tailwater by an average of 18.95%and 8.36%,and lower total phosphorus content by an average of 13.2%and 10.61%,respectively.3.In comparison to shallow tillage treatment:Rice treated with deep tillage:1)Had significantly higher grain yield,with an average increase of 14.1%;2)The dry weight at maturity was on average 4.16%higher,with an average increase of 10.17%and 10.44%in dry matter growth before and after heading,respectively.The economic coefficient was also significantly higher,with an average increase of 6.95%;3)At maturity,the nitrogen content in the plants was on average 0.02 percentage points lower,however,nitrogen accumulation was on average 3.61%higher.The nitrogen absorption before heading and after heading was on average 6.17%and 10.91%higher,respectively.The nitrogen grain production efficiency and nitrogen fertilizer partial productivity was on average higher by 9.31%and 9.01%,respectively.Additionally,nitrogen harvest index and nitrogen requirement per 100 kg of grain were on average lower by 0.05%and 7.34%,respectively,while nitrogen utilization rate was on average higher by 5.6 percentage points;4)In comparison to shallow tillage treatment,the soil total nitrogen,total phosphorus,available nitrogen,and available phosphorus content at maturity were lower on average by 1.17%,3.64%,4.31%,and 0.27%,respectively;5)During the tillering and heading period,the total nitrogen and total phosphorus content in the tailwater of rice paddies treated with deep tillage were on average 12.55%and 46.52%lower,respectively.4.In comparison to tillage-based with lateral fertilizer application(tillage+base fertilization+lateral deep fertilizer application)and tillage-based conventional fertilizer application(tillage+base fertilization+conventional fertilizer application):Rice treated with base fertilization followed by deep lateral fertilizer application(base fertilization+tillage+lateral deep fertilizer application)had the following results:1)Significantly higher grain yield compared to tillage-based with lateral fertilizer application and tillage-based conventional fertilizer application,with an average increase of 3.86%and 7.52%,respectively;2)During the tillering to jointing stage,the leaf area index and plant height were higher on average by 13.48%,3.8%,and 28.06%,8.9%,respectively;3)The dry weight at maturity was higher on average by 4.42%and 8.46%,respectively,with an average increase of 12.34%and 32.38%,3.56%and 10.04%in dry matter growth before and after heading.The economic coefficient was higher by 1.96%and 10.64%,respectively;4)At maturity,nitrogen content was found to be higher on average by 0.02 and 0.08 percentage points,and there was an average increase of 6.58%and 16.3%in nitrogen accumulation.Before and after heading,nitrogen absorption was higher on average by 7.18%and 8.74%,24.32%and 53.6%,respectively.Additionally,nitrogen requirement per 100 kg of grain and nitrogen fertilizer partial productivity was higher on average by 7.48%and 3.85%,10.1%and 7.51%,respectively,while nitrogen utilization rate was higher on average by 4.9 and 11.2 percentage points.However,nitrogen grain production efficiency was on average lower by 2.53%and 7.55%,and nitrogen harvest index was higher on average by 2.13%and lower by 9.05%compared to tillage-based with lateral fertilizer application and tillage-based conventional fertilizer application,respectively;5)At maturity,the soil total nitrogen,total phosphorus,available nitrogen,and available phosphorus content were lower by 3.87%,3.7%,7.51%,and 5.29%,respectively;6)During the tillering and heading period,the total nitrogen,total phosphorus,and ammoniacal nitrogen content in the tailwater of rice paddies decreased on average by 5.39%,8.57%,and 8.33%,respectively,while nitrate nitrogen content increased by 37.38%.5.Compared to slow-release fertilizer with a release period of 90 days:Rice treated with 60-day slow-release fertilizer had the following results:1)Significantly higher grain yield than treatment with 90-day slow-release fertilizer,with an average increase of 3.13%;2)During the tillering to jointing stage,the leaf area index and plant height were higher on average by 4.86%and 2.6%,respectively;3)The dry weight at maturity was on average lower by 3.35%,with an average increase of 17.81%in dry matter growth before heading and an average decrease of 7.46%in dry matter growth after heading.The economic coefficient was significantly higher by 6.81%;4)At maturity,nitrogen content was on average lower by 0.05 percentage points,while nitrogen accumulation was on average higher by 0.67%.Before heading,nitrogen absorption was higher on average by 45.54%,while after heading it was lower on average by 21.98%.Nitrogen grain production efficiency,nitrogen harvest index,and nitrogen fertilizer partial productivity were on average higher by 2.41%,3.17%,and 3.14%,respectively.Nitrogen utilization rate was higher by 0.45 percentage points,while nitrogen requirement per 100 kg of grain was on average lower by 0.26%;5)At maturity,the soil total nitrogen,total phosphorus,available nitrogen,and available phosphorus content were lower by 3.87%,3.7%,7.51%,and 5.29%,respectively;6)During the tillering to heading stage,the total nitrogen,total phosphorus,and ammoniacal nitrogen content in the tailwater of rice paddies decreased on average by 5.39%,8.57%,and 8.33%,respectively,while nitrate nitrogen content increased by 37.38%.Conclusion:Under the planting mode of using conventional quick-acting fertilizer,returning straw to the field,and applying fertilization with the base tillage lateral method and deep tillage method,it is beneficial to increase rice yield and nitrogen fertilizer utilization and reduce nutrient content in tailwater of rice paddies.Under the planting mode of using slow-release fertilizer,treating with 60-day slow-release fertilizer can achieve higher yields and nitrogen fertilizer utilization,reduce nutrient content in tailwater of rice paddies. |
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