| Ridge and furrow rainwater harvesting can convert ineffective rainfall into effective rainfall,improve crop water supply,thereby increasing crop yields and water use efficiency.This technology and some of its derivative models are widely used in arid and semi-arid areas.Although this planting mode is rarely used in semi-humid and drought-prone areas,there have been many studies and related results and opinions on using this technology and its optimized mode in irrigation areas to save irrigation water resources on the basis of effective rainwater collection,thereby saving costs and increasing effiency in production.So,in the semi-humid and drought-prone areas of Guanzhong,can the rain-harvesting planting model provide effective support for solving the seasonal water shortage problem of the wheat and maize multiple cropping system? There is no conclusion yet.Under this planting mode,the influence mechanism of changing the structure of ridges and furrows on soil water and heat,crop growth and yield is also unclear.In response to the above problems,this study was conducted at the Experimental Station of Northwest Agriculture and Forestry University in Yangling,Shaanxi Province from 2018 to 2020.Taking the winter wheat in the wheat-maize multiple cropping system as the research object,with the traditional flat cropping planting as the control(CK),three different ridge and furrow structures were set up in the rain-harvesting planting mode,namely ridge: furrow = 40 cm: 40 cm(G40),ridge:furrow=40 cm: 60 cm(G60)and ridge: furrow=40 cm: 80 cm(G80),a total of four treatments.The focus was on the study of the soil water and temperature effect and crop yield formation characteristics of winter wheat farmland under different ridge and furrow structure rain-harvesting planting modes.The main results of the experiment are as follows:(1)Rain-harvesting planting could effectively improve the surface moisture of the soil.In the two-year test,both G40 and G60 rain-harvesting planting treatments increased the soil water content of the 0-80 cm soil layer during the whole growth period of winter wheat,and the rain-harvesting planting treatment G80 increased the soil water content of the 0-20 cm soil layer during the whole growth period of winter wheat.Rain-harvesting planting strengthened the use of deep soil moisture in the later stage of wheat growth.The water content of the 140-200 cm soil layer in the winter wheat maturity stage of the three rain-harvesting treatments was lower than that of the flat planting treatment.As the width of the planting furrow increased,the rain-harvesting capacity of rain-harvesting planting decreased and the water-consumption capacity increased.After the two-year test,compared with flat planting,G40 and G60 increased the soil water storage of 0-200 cm soil layer,which had a certain effect of increasing moisture,and G80 reduced the soil water storage of0-200 cm soil layer.(2)Rain-harvesting planting had a warming effect in the early growth period of winter wheat.As the wheat growth progressed,the warming effect gradually weakened.From sowing to the greening period,rain-harvesting treatments G40,G60 and G80 had an average temperature increase of 0.88 ℃,1.20 ℃ and 1.42 ℃ in a 10 cm soil layer respectively in two years,and an average temperature increase of 0.71℃,0.88℃and 1.02 respectively in a 20 cm soil layer in two years.The temperature increasing effect was strengthened with the increase of the width of the planting furrow.Compared with flat planting,rain-harvesting planting could also effectively slow down the daily variation of soil temperature in the early stage of wheat growth,and had a good thermal insulation effect while increasing the temperature.(3)In normal water years(2018-2019),rain-harvesting planting could effectively promote the growth of wheat populations.The population dry matter accumulation of G40,G60,and G80 at maturity stage increased by 95.27%,78.91%,and 93.91%,respectively,and the maximum leaf area index increased by 97.86%,72.95% and 88.61%,respectively.In wet years(2019-2020),due to the reduction of planting area,the population was smaller,and the population dry matter accumulation and maximum leaf area index of each rain-harvesting treatment were lower than that of the flat planting treatment.However,rain-harvesting planting could significantly increase wheat plant height in both years,and the increase in normal water years wass greater than that in wet years,with G40 being the highest in both years.(4)In normal water years,rain-harvesting planting significantly promoted crop growth and strengthened the absorption and utilization of nutrients.The absorption of nitrogen,phosphorus and potassium in the stems,leaves,grains and whole plants of each rain-harvesting treatment was significantly higher than that of the flat planting treatment,of which G40 was the highest.After the winter wheat was harvested,the soil organic matter,total nitrogen,total phosphorus,total potassium,available phosphorus and available potassium content in the 0-40 cm soil layer of each rainwater harvesting treatment were reduced to varying degrees compared with flat planting.In wet years,compared with flat planting,the population of rain-harvesting planting was smaller,and the total amount of nitrogen,phosphorus and potassium uptake by each rain-harvesting treatment was slightly lower than that of flat planting;after winter wheat was harvested,each rain-harvesting treatment increased the content of soil organic matter,total potassium,available phosphorus and available potassium in the 0-60 cm soil layer.(5)In normal water years,rain-harvesting planting significantly increased the number of ears,grains per ear,and 1000-grain weight of winter wheat,and the water-saving and yield-increasing effects were significant.The yields of rain-harvesting treatments G40,G60,and G80 were significantly increased by 112.10%,83.67%,and 103.86% compared with CK,and water use efficiency were significantly increased by 118.43%,74.32% and 94.51%respectively.In wet years,rain-harvesting planting had a certain yield reduction effect than flat planting.Because the number of ears per unit area was significantly reduced,the yields of G40,G60 and G80 in rain-harvesting treatments were reduced by 8.23%,5.88% and 6.40%respectively compared with CK,but the water use efficiency was still higher than that of CK,increasing by 3.18%,3.48% and 1.84% respectively.A comprehensive analysis of the results of the two-year experiment showed that in the semi-humid and drought-prone areas,rain-harvesting planting could effectively improve soil water temperature,activate soil nutrients,promote crop growth and development,and strengthen the absorption and utilization of nutrients by crops,thereby increasing wheat yield and water use efficiency,among them,the rain-harvesting planting pattern with ridge and furrow structure as ridge width 40 cm and furrow width 40 cm had the best water-saving and yield-increasing effect. |
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