固定部分根区灌溉对紫花苜蓿生物量分配以及品质的影响OA

Alternate partial root-zone irrigation(APRI)is a water saving irrigation strategy that can enhance alfalfa yield but may compromise forage quality.However,it remains unclear whether fixed partial root-zone irrigation(FPRI)can improve biomass allocation and forage quality compared with APRI.A two-year pot experiment was conducted with six treatments:full irrigation(FI),deficit irrigation(DI),FPRI,APRI,alter-nate partial root-zone irrigation with low water(APRIL),and fixed root-zone irrigation with low water(FPRIL).Biomass allocation and forage quality of alfalfa were evaluated under each irrigation regime.The results showed that compared with FI,FPRI increased crude protein(CP)content of alfafa in the year of plant-ing and two-year-old alfafa by 6.88 g/kg and 3.94 g/kg,reduced neutral detergent fiber(NDF)and acid deter-gent fiber(ADF)contents of two-year-old alfafa by 46.01 g/kg and 30.10 g/kg,respectively,and increased the root shoot ratio of two-year-old alfafa by 32.76%.Compared with APRI,FPRI increased CP yield of alfafa in the year of planting and two-year-old alfafa by 1.07 g/pot and 0.38 g/pot,reduced ADF yield by 4.70 g/pot and 0.08 g/pot,increased aboveground biomass by 4.75%and 10.96%,increased underground bio-mass by 3.21%and 18.96%,increased root shoot ratio by 9.12%and 16.89%,respectively.Under further water deficit conditions,FPRIL reduced NDF and ADF yields of alfafa in the year of planting by 0.64 g/plot and 7.07 g/pot,respectively,and increased the root shoot ratio by 62.07%,compared with DI.Overall,fixed partial root-zone irrigation improved forage quality and optimized biomass allocation more effectively than alter-nate partial root-zone irrigation.These findings provide a theoretical basis for enhancing alfalfa quality and bio-mass allocation under water limited conditions.