局部控制地下浸润灌溉对叶用莴苣生长及水分利用效率的影响

通过两年的盆栽试验,对比研究了局部控制地下浸润灌溉和地表滴灌对作物根区土壤水分动态及叶用莴苣的光合速率、蒸腾速率、水分利用效率、产量和品质的影响。结果表明,局部控制地下浸润灌溉的蒸发量明显小于地表滴灌处理,莴苣产量高于地表滴灌处理;水分利用效率是局部控制地下浸润灌溉处理最高,达到了42.42 kg/m3,地表滴灌仅为15.14 kg/m3;各处理光合速率和蒸腾速率日变化均呈"双峰"曲线,且呈处理1>处理2>处理3>处理4的趋势;局部控制地下浸润灌溉处理的根冠比较高,最大值达0.187,而地表滴灌处理的根冠比仅为0.071;局部控制地下浸润灌溉中莴苣的Vc含量达到了14.62 mg/100g,而地表滴灌处理仅为12.82mg/100g。说明局部控制地下浸润灌溉能有效改善莴苣的光合产物分配,调整根冠比关系,提高莴苣的水分利用效率,使作物产量与品质得到统一。

Effect of water-controlled partial wetting irrigation on the growth and water use efficiency of leaf lettuce

Through two-year potted experiment,study was made on the soil water status around crop rootzone,photosynthetic rate,transpiration rate,water use efficiency,yield and quality under water-controlled partial wetting irrigation and drip irrigation without covering.The results showed that the evaporation capacity under water-controlled partial wetting irrigation was obviously less than drip irrigation;moreover,the yield of leaf lettuce under it was higher than drip irrigation.The water-controlled partial wetting irrigation has the highest water use efficiency(reached 42.42 kg/m3),which was more than drip irrigation(just 15.14 kg/m3).The photosynthetic rate and transpiration rate showed a split-blip curve among all treatments,and displayed a trend of treatment 1 > treatment 2 > treatment 3 > treatment 4.The root/shoot of leaf lettuce under water-controlled partial wetting irrigation(0.187) was also higher than drip irrigation(0.071).The ascorbic acid content of water-controlled partial wetting irrigation treatment reached 14.62 mg/100g,and the drip irrigation treatment was only 12.82 mg/100g.The results all indicated that water-controlled partial wetting irrigation can improve the distribution of photosynthetic product in leaf lettuce,harmonize the relationship between roots and shoot,increase water use efficiency,and unify the yield and quality of leaf lettuce.