| The Loess Plateau is a typical arid and semi-arid area,and water is the main factor that limits the agricultural development in arid and semi-arid areas.Therefore,one of the important ways to release the agricultural production potential in arid and semi-arid areas is to increase the water use efficiency of crops.In view of the lack of precipitation and extensive fertilization management in arid and semi-arid areas,this study took Yemi 2 as the research object,set up two planting modes:ridge and furrow planting（ridge and furrow 40cm as RF40,ridge width40cm and furrow width 80cm as RF80）and traditional flat cropping（TP）,with no nitrogen application（N0）as the control.Five fertilization treatments were set up:100%urea（U）,70%urea+30%slow release fertilizer（U7C3）,30%urea+70%slow release fertilizer（U3C7）,and100%slow release fertilizer（C）.The nitrogen application rate of all treatments was 150kg hm-2,and the phosphorus application rate was 90kg hm-2.To study the effects of rain harvesting and urea combined with slow release fertilizer on the growth,soil water content,soil water use efficiency,photosynthesis,chlorophyll fluorescence,nitrogen accumulation in various organs at maturity,nitrogen use efficiency,yield and yield components of broach millet,and reveal the effects of rain harvesting and urea combined with slow release fertilizer on the growth and development of broach millet.It provides a theoretical basis for the optimization of rain-collecting planting on furrow and the research progress of agriculture in dry area.The main conclusions are as follows:In 2021,with the advancement of the growth period,soil water content of glutinous millet fields under each treatment showed a downward trend on the whole.Under the same fertilization treatment,the average soil moisture content of ridge and furrow rainwater harvesting mode（RF40 and RF80）was higher than that of traditional flat cropping（TP）.The average soil water content of RF40 and RF80 was 31.0%and 23.4%higher than that of TP during the filling stage.The application of nitrogen significantly increased the soil water content,soil water storage,and reduced the water consumption.Soil water use efficiency and precipitation use efficiency were increased by ridge and furrow planting.Compared with TP soil water use efficiency and precipitation use efficiency,RF40 soil water use efficiency and precipitation use efficiency increased by 40.4%and 14.3%,respectively,and RF80 soil water use efficiency increased by 46.0%and 10.3%,respectively.In the same cropping mode,the water use efficiency and precipitation use efficiency of U7C3 were significantly higher than those of other fertilization treatments.The furrow and furrow rainfall-harvesting mode increased dry matter accumulation in the overground part of glutinous millet at heading stage and grouting stage.Urea combined with slow-release fertilizer increased nitrogen and substance accumulation in the above-ground organs of glutinous millet.In 2021,under TP,RF40 and RF80 treatments,nitrogen use efficiency of U7C3 and U3C7 treatments was reduced by 25.17%and 43.14%,17.75%and39.18%,32.06%and 34.92%,respectively,compared with N0.Compared with N0,the nitrogen harvest index of U7C3 and U3C7 treatments decreased by 2.64%and 10.76%,3.55%and 24.18%,15.47%and 11.91%,respectively.Furrow rain-harvesting planting and urea combined with slow-release fertilizer could improve the SPAD value,net photosynthetic rate（Pn）,actual photochemical efficiency（ΦPSⅡ）and photochemical quenching coefficient（q P）of mylonias leaves,thus affecting the photosynthetic system of mylonias leaves,and increasing the proportion of light energy in the reaction center of photosystemⅡfor photochemical reaction and electron transport.The ratio of light energy dissipation to heat energy is reduced,and the potential activity of photosystem II is increased.Under furrow and rain-harvesting planting mode,urea combined with slow-release fertilizer promoted the growth and development of glutinous millet,increased plant height,stem diameter,expanded leaf area at various growth stages,increased ear weight,main ear length and effective ear number,and increased yield.In 2021,when the rainfall is low,the furrow planting has an obvious effect on the yield increase.In 2021,the 1000-grain weight of furrow rain-collecting planting increased significantly by 4.94-8.95%compared with TP,and decreased by 1.65-1.75%in 2022.The treatment U7C3 and TP of RF40 planted in ridge and furrows were the most productive in 2021 and 2022,with 2781kg hm-2and 4297kg hm-2being18.49%and 10.41%higher than U of TP,respectively.Under the treatment of RF40 ridge and furrow rainwater harvesting,70%urea combined with 30%slow-release fertilizer had obvious yield increase under the condition of low rainfall.In conclusion:Under ridge and furrow rain-harvesting planting mode,the ridge width and furrow width were 40cm,the planting density was 400,000 plants/hm,and 70%urea combined with 30%slow-release fertilizer(150kg hm-2 nitrogen application)could promote the growth of broomcorn millet,improve the photosynthetic capacity of their leaves,and thus improve their yield and water and nitrogen use efficiency.This planting pattern can be the most suitable planting pattern for millet production in semi-arid area. |
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