| In recent years,due to the increasing rigorous situation of agricultural water resources scarcity,developing water-saving agriculture is becoming an important strategy to promote sustainable utilization of water resources and development of agriculture.The furrow with plastic mulched and ridge rainfall harvesting system(R)is an effective planting patterns in improving utilization efficiency of precipitation and land productivity developed in arid and semiarid regions in China.In order to apply rainwater harvesting system to irrigation farmland,and give it full play on production increasing and water saving,and then to alleviate the situation that high cost with low efficiency in water resources utilization,we performed a 3-year field study during 2012-2015 in typical semi-arid region of south Ningxia,to evaluating the effects of soil moisture characteristics,crop growth status and yield-increasing mechanism under the deficiency irrigation combined with ridge and furrow rainwater harvesting planting pattern(RI),the main obtained results are as follows:1.The effect of deficiency irrigation combined with ridge and furrow rainwater harvesting planting on soil moisture characteristics(1)Deficiency irrigation combined with ridge and furrow rainwater harvesting planting pattern is conducive to soil moisture preservation.In the three-year experiment,compared with corresponding B treatments(irrigation combined with traditional flat planting B: B1,B2,B3,B0),the R treatments(R: R1,R2,R3,R0)could increase the 0-200 cm soil layers water contents in early stage of winter wheat(during seeding and jointing),especially for the 0-40 cm soil layers,the three-year average was increased by 6.37%..(2)Deficiency irrigation combined with ridge and furrow rainwater harvesting planting pattern is conducive to adjust the distribution of water storage content in different soil layers.In most growth periods of the three-year experiment,the RI treatments were helpful for improving the water storage capacity of topsoil,the three-year average of 0-40 cm soil layers water storage content under the RI treatments in seeding-heading was increased by 6.88% than that under the BI treatments.At the same time,the RI treatments could increase the soil water consumption amounts of both 40-120 cm and 120-200 cm soil layers than the BI treatments,the three-year average of 40-120 cm layers soil water consumption amounts during seeding and maturing stage were increased by 22.28% than the BI treatments,and the average soil water consumption amounts of 120-200 cm layers were increased by 25.52%.2.The effect of deficiency irrigation combined with ridge and furrow rainwater harvesting planting on water consumption characteristics of winter wheat(1)Deficiency irrigation combined with ridge and furrow rainwater harvesting planting can increase the percentage of soil water storage to total water consumption.In the three-year experiment,compared with the BI treatments,the percentage of irrigation amount to total water consumption under the RI treatments was reduced,but the three-year average of soil water consumption amount was increased significantly by 27.11%,and meanwhile percentage of soil water storage amount to total water consumption increased by 8.07%.In the same planting pattern,the total water consumption amount and the percent of irrigation amount under RI were both increased with the increasing irrigation amount,but the percentage of soil water consumption amount showed an adverse tendency.In the normal years(2012-2013 and 2013-2014)with the same irrigation amount,the average of soil water consumption amount and its percentage to total water consumption under the R1(irrigation during the early stage combined with R)were increased by 10.37% and 6.02% respectively than that under the R3(irrigation during the late stage combined with R).(2)Deficiency irrigation combined with ridge and furrow rainwater harvesting planting can improve water consumption characteristics conditions in the growth stage of winter wheat.In the three-year experiment,the water consumption amount(ET),water consumption intensity(CI)and consumption percentage(CP)under each R treatment during seeding and regreening stage were lower than these under the corresponding B treatment,the three-year average of ET was decreased by 12.05%,and the three-year average of CI and CP were decreased by 12.3% and 9.34%,respectively.The differences has been more significant in the normal years(2012-2013 and 2013-2014).Different irrigation patterns showed differently during regreening and maturing stage that was the critical stage of more demand for water.For R1 and R3,the three-year average of ET during regreening and maturing stage was decreased by 5.45% than the corresponding B treatment(B1 and B3),and the average of CI and CP were decreased by 5.46% and 5.69%,respectively..In the experiment period,the relationship among the R treatments of the CA,CI and CP during regreening and maturing stage was similar,and was described as: R2>R1,R3>R0,in the normal years,the CA,CI and CP under R1 were distributed more to regreening and maturing stage than R3.3.The effect of deficiency irrigation combined with ridge and furrow rainwater harvesting planting on the growth of winter wheat(1)Deficiency irrigation combined with ridge and furrow rainwater harvesting planting can promote the height of winter wheat.In the three-year experiment,compared with the corresponding B treatment,the R could promote the winter wheat height during regreening and maturing stage in varying degrees,and the three-year average at this stage was significantly increased in the range of 9.11-35.96%.At the maturing stage of all the experimental years,the relationship among the R treatments was: R2>R1>R3>R0,the three-year average of height under R1 was increased by 3.78% than that under R3,which proved that irrigated during regreenting and jointing stage combined with R was more favorable to the growth of winter wheat.(2)Different RI treatments showed different effects on dry matter accumulation in different growth stages of winter wheat.Compared with the corresponding BI treatments,the RI treatments could increase dry matter accumulation amount during regreening and heading stage,in the year of 2012-2013,the increase was in the range of 4.66-15.87%,in the year of 2013-2014 and 2014-2015,the increase was in the range of 4.24-12.09% and 11.44-29.88%,respectively.After the heading stage,the dominance of dry matter accumulation amount under the RI than that under BI was decreased gradually,in which dry matter accumulation amount of heading-maturing stage under R2 was lower than that under B2.During heading and maturing stage,dry matter accumulation amount under different R treatments increased accordantly with the increase irrigation amount,and the three-year average of dry matter accumulation amount under R1 was increased by 8.53% than that under R3.(3)Deficiency irrigation combined with ridge and furrow rainwater harvesting planting can enhance dry matter accumulation amount after anthesis and its contribution to grains of winter wheat.During the whole period,the DMAAA and CDMAAATG under RI treatments were higher than these under the corresponding BI,with the increasing of experimental years,the DMAAA under RI increased by 6.21%,6.11% and 9.52%,respectively than that under BI,and the CDMAAATG increased by 6.21%,6.11% and 9.52%,respectively.In the same planting pattern,the DMAAA under RI were higher than R0(no irrigation combined with R planting pattern),and the two-year(normal years: 2012-2013 and 2013-2014)average of the DMAAA under R1 was increased by 16.92% than that under R3,the CDMAAATG under R1 was increased by 8.02%.4.The effect of deficiency irrigation combined with ridge and furrow rainwater harvesting planting on yield and economic benefits of winter wheat(1)Deficiency irrigation combined with ridge and furrow rainwater harvesting planting contributes to increasing the yield of winter wheat.Compared with the corresponding B treatments,on average,economic yield under R0 and R1 were increased by 4.81%,5.51% and 5.60%,respectively in 2012-2015.Because the planting acreage of R treatment was smaller than B treatment,the three-year average of spike density(per hectare)under R1 and R0 was decreased by 6.07% than that under the B1 and B3,however the average grain number per spike and 1000-grain weight were significantly increased by 5.06% and 6.81%,respectively,which could effectively make up for the yield loss caused by lacking of spike per hectare.For R3 treatment,due to higher values of grain number per spike and 1000-grain weight than B3(especially 1000-grain weight under R3 was significantly increased by 9.78% than that under B3 on average in 2012-2014),in the normal years(2012-2013 and 2013-2014),the two-year average of economic yield under R3 was increased by 6.54% than that under B3.In the three-year experiment,the order of economic yield under different R treatments was described as: R2>R1>R3>R0,and because of the superiority on spike per hectare and grain number per spike,the three-year average of economic yield under R1 was increased by 7.62% than that under R3.(2)Deficiency irrigation combined with ridge and furrow rainwater harvesting planting contributes to increasing the economic benefits of winter wheat.The three-year average of output values per hectare under R1,R3 and R0 was 780.15 yuan more than the average of corresponding B treatments(B1,B3 and B0),and the net incomes per hectare was 948.76 yuan more than the corresponding B treatments,and there were no significant differences on the output values and net incomes per hectare between R2 and B2.In the same planting pattern,the RI treatments could increase both of the output values and net incomes per hectare than R0,and the three-year average of net incomes under R1 was significantly increased by 16.72% than that under R3,which indicated that irrigated during regreening and jointing stage combined with R planting pattern could be more favorable to improvement of economic benefits.5.The effect of deficiency irrigation combined with ridge and furrow rainwater harvesting planting on water use efficiency of winter wheatDeficiency irrigation combined with ridge and furrow rainwater harvesting planting could produce a positive influence on increasing use efficiency of different water sources.The irrigation water use efficiency(IWUE)under RI treatments was 90.21-114.78% significantly higher than the corresponding BI treatments in the years of 2012-2015,and meanwhile the water use efficiency(WUE)under RI treatments was 0.37-10.23% higher than BI,the difference was more significant in the year of 2013-2014 which had less precipitation.In the same planting pattern and irrigation amount,the three-year average of PUE under R1 was increased by 7.68% than that under R3,three-year average of IWUE and WUE under R1 were increased by 7.44% and 4.36% respectively than these under R3. |
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