紫花苜蓿品种产量及营养品质对调亏灌溉的响应

Effects of regulated deficit irrigation on biomass andnutrient quality of different alfalfa varieties

摘要:

【目的】 探索甘肃荒漠灌溉区最适宜的节水型苜蓿生产灌溉技术。【方法】 以12 份不同品种紫花苜蓿为试验材料，设置中度水分胁迫（T1：田间持水量的 45%~55%）、轻度水分胁迫（T2：田间持水量的55%~65%）和充分灌溉（T3：田间持水量的65%~75%）3 个灌溉梯度。以充分灌溉为对照，观测不同水分处理下各品种产量与营养指标的差异，筛选适宜该区域节水苜蓿生产的品种与灌溉技术。【结果】 水分生产力总体表现为：轻度水分胁迫（23. 01 kg/（hm²?mm）＞充分灌溉（20 kg/（hm²?mm））＞中度水分胁迫（18 kg/（hm²?mm）），轻度水分胁迫水分生产力提高了15%，中度水分胁迫降低了10%。品种间相比，WL319HQ 在3 个水分处理下水分生产力均达到最高。其中WL319HQ 的水分生产力在轻度水分胁迫条件下最高，较其它两种水分处理分别提升3. 8、5. 7 kg/（hm²?mm）。充分灌溉、轻度水分胁迫下WL319HQ 的产量均显著高于其它供试品种。中度水分胁迫下苜蓿总体产量显著低于其它两种水分处理（P＜0. 05），其中产量最高的为甘农3 号。所有试验组中，WL319HQ 在轻度水分胁迫时，粗蛋白含量与粗脂肪含量最高，酸性洗涤纤维、中性洗涤纤维含量最低，相对饲喂价值显著高于其他水分胁迫处理。【结论】 甘肃荒漠灌溉区在轻度水分胁迫（田间持水量的55%~65%）下种植WL319HQ 有利于提高灌区草地生态生产力。

Abstract:

【Objective】 In order to explore the most suitable water-saving irrigation technology for alfalfa productionin the desert irrigation area of Gansu province，this study examined the effects of regulated deficit irrigation onabove-ground biomass，nutrient quality，and water productivity of different varieties of alfalfa，focusing on the triplegoals of high yield，high quality and efficient water conservation.【Method】 Twelve alfalfavarieties were selected asexperimental materials and subjected to three irrigation treatments： moderate water stress （T1：45%~55% of fieldwater capacity），mild water stress （T2：55%~65% of field water capacity） and full irrigation （T3：65%~75% fieldwater capacity）. Full irrigation was used as the control. Differences in yield and nutrient indices of the different varietiesunder these water treatments were observed to identify suitable varieties and irrigation techniques for watersavingalfalfa production in this region.【Result】 The results indicated that water productivity followed this pattern：mild water stress [23. 01 kg/（hm²·mm）]＞ full irrigation [20 kg/（hm²·mm）]＞moderate water stress [18 kg/（hm²·mm）]. Water productivity under mild water stress increased by 15%，while it decreased by 10% under moderatewater stress . Among the varieties，WL319HQ achieved the highest water productivity under all three water treatments，with the highest productivity under mild water stress，outperforming the other two treatments by 3. 8 and 5. 7kg/（hm²·mm），respectively. Under full irrigation and mild water stress，WL319HQ also had significantly higheryields compared to the other tested varieties. However，under moderate water stress，the total yield of alfalfa was significantlylower than under the other two treatments （P＜0. 05），with Gannong 3 achieving the highest yield underthese conditions. Across all experimental groups，WL319HQ had the highest crude protein and crude fat contents，thelowest acid detergent fiber and neutral detergent fiber contents，and the highest relative feeding value，significantly outperformingother varieties under other water stress treatments.【Conclusion】 Planting WL319HQ under mild waterstress（55%~65% of field water capacity） in the desert irrigation areas of Gansu was beneficial for improving grasslandecological productivity.