Effects Of Ridge And Furrow Rainwater Harvesting Cultivation With Different Supplemental Irrigation Methods On Soil Moisture And Soil Nutrients And Yield Of Winter Wheat

The objective of this study was to explore the effects of ridge and furrow rainwater harvesting(RFRH)cultivation with different supplemental irrigation methods of winter wheat at different stages on soil moisture,soil nutrients,growth and grain yield.A two-year field experiment was conducted in semi-arid area of southern Ningxia from Sept.2014 to June 2016.Four irrigation modes: zero-irrigation in growth stages,supplemental irrigation at earlier stage,supplemental irrigation at later stage,supplemental irrigation at earlier and later stages and each irrigation mode has two cultivation patterns: ridge and furrow rainwater harvesting(R),conventional flat-tillage(B),a total of 8 treatments(supplemental irrigation at earlier and later stages treatments:R1/B1;supplemental irrigation at earlier stage treatments: R2/B2;supplemental irrigation at later stage treatments: R3/B3;zero-irrigation in growth stages treatments: R0/B0)were set in this study,the main obtained results are as follows:1.In the early growth stage(seedling stage-tilling stage)of winter wheat,the soil water content of 0-200 cm soil layer of each R treatment was higher than corresponding B treatment,especially in topsoil(0-80 cm).After the first supplemental irrigation in tilling stage,due to the precipitation supplement at heading stage in two-year test period,therefore,the soil water content of 0-200 cm soil layer of each R treatment was higher than corresponding B treatment at the heading stage,average increased by 4.79% and 3.10%.After the second supplemental irrigation in heading stage,except for R1 treatment in wet year,each R treatment was lower than corresponding B treatment at the filling stage,the average of the two periods were reduced by 2.71% and 5.78%,respectively.Each R treatment was lower than corresponding B treatment at the maturing stage in wet year,average decreased by 3.56%;due to the precipitation supplement in dry year,therefore,each R treatment was higher than corresponding B treatment at the maturing stage,average increased by 8.94%.2.During the two-year trial period,the water consumption of winter wheat increase with rainfall increasing,compared with corresponding B treatment,there was positive correlation between the amount of water consumption and yield of each R treatment in wet year,among them,the yield of R1 treatment was lower than that of B1 treatment,and the water consumption was also lower than B1 treatment.The yield of R2,R3 and R0 treatments were higher than corresponding B treatment,the water consumption was also higher,average increased by 2.89%;the water consumption of each R treatment was significantly lower than corresponding B treatment in dry year,average decreased by 18.89%.Under different planting patterns,ratio of irrigation amounts to total water consumption of each R treatment was significantly lower than corresponding B treatment,the average of the two periods were decreased by 50.68% and 35.36%,respectively.Compared with the wet year,the ratio of irrigation amounts to total water consumption was higher in dry year,average increased by 125.99%(P <0.05).3.The results of two years experiment showed that the effect of ridge and furrow rainwater harvesting cultivation pattern can significantly increase the content of soil available nutrients(N,P,K)in the 0-60 cm soil layer in the catchment area.All treatments showed that the highest content of available nutrients were in the surface soil of 0-20 cm,the content of soil available N,P and K decreased with the increase of soil depth.4.The plant height and dry matter accumulation of winter wheat were showed "S" curve,in each growth period,the plant height and dry matter accumulation of each R were higher than corresponding B treatments,the average of plant height in two periods were increased by 19.90% and 25.45%,respectively,the average of dry matter accumulation in two periods were increased by 18.78% and 21.54%,respectively.Compared with supplemental irrigation at later stage,supplemental irrigation at earlier stage were more obviously improved winter wheat plant height and dry matter accumulation.5.In addition to R1 treatment and dry year of R2 treatment were no significant difference between corresponding B treatment,the grain yield of other R treatments was higher than corresponding B treatment,the average of the two periods were increased by 5.63% and 37.40%(P<0.05),respectively;the water use efficiency of winter wheat in each R treatment was higher than corresponding B treatment,average increased by 2.12% and 35.50%(P<0.05),respectively;the irrigation water use efficiency of winter wheat in each R treatment was significantly higher(P<0.05)than corresponding B treatment,average increased by 105.13% and 86.09%,respectively;the grain yield of supplemental irrigation at earlier stage was higher than supplemental irrigation at later stage,the water use efficiency and irrigation water use efficiency were higher than other supplemental irrigation treatments.