Effect Of Ridge And Furrow Cultivation On Rhizosphere Characteristics,growth And Yield Of Double-cropping Rice

Hunan is the main producing area of double-cropping rice and the rapid development area of comprehensive rice cultivation.It plays a pivotal role in ensuring my country’s food security.In recent years,with the rise of the comprehensive rice cultivation model and the improvement of the cultivation measures in the southern cold waterlogged fields,ridge cultivation and furrow cultivation have become more and more widely used in rice production.Exploring the effects of ridge cultivation and furrow cultivation on rice rhizosphere characteristics,growth,and development,and yield provides a research foundation for double-cropping rice high-yield cultivation and integrated rice cultivation.The experiment was carried out in Liuyang City,Hunan Province from March 2019 to October 2020.The main conclusions are as follows:1.Compared with flat cultivation,ridge cultivation promotes the growth of the root system at the booting stage and the full heading stage of double-cropping rice,and the increase in root bleeding intensity at each growth stage.In ridge cultivation,the total root length,root surface area,and root volume of early rice from booting stage to full heading stage average increased by 0.45%～43.39%,7.34%～9.59%,15.86%～39.86%,respectively.In ridge cultivation,the total root length,root surface area,and root volume of late rice from booting stage to full heading stage average increased by 32.49%～41.51%,35.98%～39.01%,37.12%～39.36%,respectively.In ridge cultivation,the root bleeding intensity of early rice was increased by67.07%-91.06%on average from the full tillering stage to the full heading stage,and the root bleeding intensity of the late rice was increased by 37.13%～44.21%on average from the full tillering stage to the full heading stage.Furrow cultivation hindered the growth of early rice roots,and the total root length and root surface area of early rice from the peak tillering stage to the full heading stage was reduced by an average of 4.46%～41.98%,21.05%～25.50%,but the total root length,root volume,and root bleeding intensity increased by 6.89～18.19%,2.46%～12.80%,and22.72%～47.41%in late rice from the booting stage to the full heading stage,respectively.2.Compared with flat cultivation,ridge cultivation and furrow cultivation both reduce the soil bulk density and soil water-stable clay content（<0.053mm）of double-cropping rice and increase the total soil porosity,capillary porosity,and soil water-stable large aggregate content（>0.25mm）,the average mass diameter and average geometric diameter of the aggregates.In terms of soil organic carbon,total nitrogen,and carbon-nitrogen ratio,the overall trend is ridge cultivation and furrow cultivation higher than flat cultivation.The activities of soil urease and invertase of double-cropping rice in ridge cultivation average increased by 3.75%～14.93%and7.86%～30.21%,respectively,and the activity of catalase in soil average decreased by18.82%～21.75.Furrow cultivation increased the activities of catalase and urease in late rice soil but decreased the activities of catalase and urease in early rice soil.3.Compared with flat cultivation,ridge cultivation increased the SPAD value,photosynthetic rate,stomatal conductance,and transpiration rate of early rice at the full heading stage by an average of 1.77%,15.84%,33.17%,and 1.54%,respectively.In ridge cultivation,the SPAD value,photosynthetic rate,stomatal conductance,intercellular CO₂ concentration,and transpiration rate of leaves in late rice from booting stage to full heading stage average increased by 3.18%～3.51%,10.01%～10.44%,21.56%～27.58%,3.11%～5.25%,and 11.65%～15.76%,respectively.At the same time,ridge cultivation promoted the dry matter accumulation of late rice at the booting stage and the full heading stage.The stomatal conductance and transpiration rate of early rice from the booting stage to the full heading stage average increased by 1.44%～2.95%and 0.86%～5.83%in furrow cultivation,respectively.The leaf SPAD value,photosynthetic rate,stomatal conductance,intercellular CO₂concentration,and transpiration rate of ridge cultivation from booting stage to full heading stage of late rice average increased by 0.49%～1.35%,3.95%～13.57%,26.98%～31.27%,3.05%～5.89%,and 9.55%～22.13%,respectively;but the interception rate of light energy,leaf area index and dry matter accumulation of double-cropping rice at each growth stage showed an overall decreasing trend.4.Compared with flat cultivation,ridge cultivation and furrow cultivation showed an increasing trend in early rice production in 2019,and a decreasing trend in early rice production in 2020,but the difference was not significant.Ridge cultivation is beneficial to increase the yield of late rice,with an average increase of 9.32%（7.89%～10.75%）compared with flat cultivation.The main reason for the increase in yield is the increase in the number of effective panicles per unit area.furrow cultivation is beneficial to increase the yield of late rice,with an average increase of7.96%（7.31%～8.60%）compared with flat cultivation.the main reason for the increase in yield is the increase in the total number of grains per panicle and the increase in seed setting rate.