生物炭覆盖垄沟集雨种植对紫花苜蓿根芽、干草产量和水分利用效率的影响

Effects of ridge-furrow rainwater harvesting with biochar application on root buds,fodder yield and water use efficiency of alfalfa

【目的】探索半干旱区垄沟集雨种植紫花苜蓿根芽数量规律和紫花苜蓿高产栽培技术。【方法】采用随机区组设计,以平作为对照,研究了不同生物炭覆盖量[0×10^(4)(土垄)、3×10^(4)(单倍生物炭垄)和6×10^(4) kg/hm^(2)(双倍生物炭垄)]和不同垄宽(30、45和60 cm)对紫花苜蓿农田土壤水分、温度、紫花苜蓿根芽、分枝数、干草产量和水分利用效率的影响,处理为平作(FP)、垄宽30、45、60 cm的土垄(MCS_(30)、MCS_(45)、MCS_(60))、垄宽30/45/60 cm的单倍生物炭垄(SMSBA_(30)、SMSBA45、SMSBA60)、垄宽30、45、60 cm双倍生物炭垄(DMSBA_(30)、DMSBA_(45)、DMSBA_(60))。【结果】生物炭覆盖垄沟集雨种植提高垄上表层土壤温度和沟中土壤贮水量,增加紫花苜蓿根芽数(茎枝芽+根颈芽)、分枝数、干草产量和水分利用效率。随着垄宽的增加,土壤贮水量、紫花苜蓿根芽数和分枝数随之增加,紫花苜蓿实际干草产量和水分利用效率随之降低。紫花苜蓿茎枝芽数量是根颈芽数量的2.2~2.9倍。与平作相比,MCS_(30)、MCS_(45)、MCS_(60)、SMSBA_(30)、SMSBA45、SMSBA60、DMSBA_(30)、DMSBA_(45)和DMSBA_(60)的土壤贮水量分别增加20.7、30.8、41.7、8.7、23.0、35.7、6.2、12.0和11.0 mm,根芽数分别增加了-0.4、0.4、2.0、1.2、0.7、4.1、0.4、3.0和4.6个/株,分枝数分别增加8、28、50、48、84、109、45、91和71个/m^(2),总干草产量分别增加3.34%、-0.52%、-0.70%、26.81%、17.11%、3.00%、18.28%、5.79%和-11.03%,水分利用效率分别增加-1.76、-0.04、2.67、5.77、4.26、2.99、4.66、1.62、0.10 kg/(hm^(2)·mm)。【结论】垄宽30 cm的单倍生物炭垄具有较高紫花苜蓿根芽数量、紫花苜蓿产量和水分利用效率,是半干旱区种植紫花苜蓿的适宜栽培模式。

【Objective】To explore the effects of ridge furrow rainwater harvesting(RFRH)with biochar application on the number of root buds of alfalfa and cultivation techniques for high-yield of alfalfa in semi-arid region.【Method】A randomized block design was designed to investigate effects of different biochar rates 0×10^(4)(ridges compacted with soil),3×10^(4)(ridges compacted with soil mixed with single biochar application),and 6×10^(4) kg/hm^(2)(ridges compacted with soil mixed with double biochar application))and different ridge widths(30,45,and 60 cm)on soil moisture,temperature,root buds,branch number,fodder yield,and water use efficiency(WUE)of alfalfa in RFRH,and flat planting(FP)was used as a control.The treatments were flat planting(FP),30/45/60 cm wide ridges compacted with soil(MCS_(30),MCS_(45),MCS_(60)),30/45/60 cm wide ridges compacted with soil mixed with single biochar application(SMSBA_(30),SMSBA45,SMSBA60),30/45/60 cm wide ridges compacted with soil mixed with double biochar application(DMSBA3,DMSBA_(45),DMSBA_(60)).【Result】The number of stem buds of alfalfa was 2.2~2.9 times greater than that of root neck buds.The topsoil temperature at ridge top was affected by the ridges compacted with soil-biochar crust,but not at the topsoil temperature at the bottom of the furrow.With biochar application ridge-furrow rainwater harvesting increased soil water storage,the number of root buds(stem buds+root neck buds),branch number,fodder yield,and WUE of alfalfa.With the increase of ridge width,soil water storage,branch number and root buds increased,while fodder yield and WUE decreased.Compared with FP,soil water storage increased by 20.7,30.8,41.7,8.7,23.0,35.7,6.2,12.0 and 11.0 mm,for MCS_(30),MCS_(45),MCS_(60),SMSBA_(30),SMSBA45,SMSBA60,DMSBA_(30),DMSBA_(45),and DMSBA_(60) respectively.Root buds increased by-0.4,0.4,2.0,1.2,0.7,4.1,0.4,3.0 and 4.6 per plant for MCS_(30),MCS_(45),MCS_(60),SMSBA_(30),SMSBA45,SMSBA60,DMSBA_(30),DMSBA_(45),and DMSBA_(60),respectively.Branch number increased by 28,50,48,84,109,45,91 and 71 per square meter for MCS_(30),MCS_(45),MCS_(60),SMSBA_(30),SMSBA45,SMSBA60,DMSBA_(30),DMSBA_(45),and DMSBA_(60),respec-tively;while fodder yield increased by 3.34%,-0.52%,-0.70%,26.81%,17.11%,3.00%,18.28%,5.79%and-11.03%.For the same treatments,the WUE increased by-1.76,-0.04,2.67,5.77,4.26,2.99,4.66,1.62 and 0.10 kg/(hm^(2)·mm),respectively.【Conclusion】Optimum ridge width was 30 cm,and biochar application rate was 3×10^(4) kg/hm^(2) for ridge-furrow rainwater harvesting with biochar application in semiarid regions of China.