棉花成苗和幼苗生长对咸水滴灌的响应特征

Responsive Growth of Seedling and Matured Cotton to Drip Irrigation with Saline Water

【目的】解决咸水灌溉植棉成苗率低的难题。【方法】采用膜下滴灌灌水方式,研究了不同灌溉水矿化度(1、3、5、7、9 g/L)和不同灌水控制下限(田间持水率的70%和60%)相组合对棉花苗期土壤水盐变化及棉花出苗过程、成苗率和幼苗生长的影响。【结果】0~30 cm土层土壤盐分随着灌溉水矿化度的增加而增大,土壤水分变化不明显;随着灌水控制下限的提高,土壤水分和盐分分别呈增加和降低的趋势,但变化幅度不大。与1 g/L灌水处理相比,3 g/L咸水滴灌加快了棉花的出苗进程,平均成苗率提高了6.06%;5 g/L咸水滴灌对棉花出苗影响不大,成苗率增加了0.45%;7 g/L和9 g/L咸水滴灌延迟了出苗过程,平均成苗率降低了3.66%和12.97%,其中仅9 g/L与1 g/L灌水处理间的差异达到显著水平。不同处理棉花幼苗的生长指标呈现出随灌水控制下限的提高而增大的趋势;2组灌水控制下限条件下,棉花苗期的单株叶面积、茎粗和地上部干质量等指标的大小顺序均是3、1、5、7、9 g/L,其中7、9 g/L与1 g/L处理间的差异达显著水平。棉花相对成苗率与灌溉水矿化度之间呈显著的二次函数关系,相对成苗率为1和0.9时,对应的灌溉水矿化度特征值分别为6.0 g/L和8.4 g/L。【结论】采用≤7 g/L的咸水滴灌不会对棉花成苗率产生显著影响,适度提高灌水控制下限、增加咸水灌溉次数,可促进棉花幼苗生长。

【Objective】Increase of salt content in soil irrigated with saline water could inhibit germination and subsequent establishment of crop seedings. This paper aimed to study how to resolve this problem via controlled drip irrigation.【Method】We used cotton as the model plant and examined two factors： one was water salinity and the other one was irrigation amount. The salt content in irrigation water was set to be 1, 3, 5, 7 and 9 g/L, and we considered two irrigation amounts to control the soil moisture content at 60% and 70% the field capacity respectively.In each treatment, we measured the germination and subsequent establishment of cotton seedlings in a mulched field under drip irrigation.【Result】The salt content in 0-30 cm soil layer increased with salinity of the irrigation water, while the soil moisture content in it remained almost unaffected. With the irrigation amount increasing, both soil moisture and soil salt content increased. Compared with the 1 g/L treatment, the 3 g/L treatment boosted the germination with the average seedling establishment rate increasing by 6.06%, while the 5 g/L treatments did not have a noticeable impact on germination with the seedling establishment increasing only by 0.45%. Increasing salt content of the irrigation water to 7 g/L and 9 g/L delayed the germination with the average seedling establishment rate reduced by 3.66% and 12.97% respectively, compared to the control. The growth traits of the seedling showed a trend of decrease as the irrigation amount increased. The average leaf area per plant, stem diameter and dry mass of the seeding changed with water salinity in the rank of 3 g/L1 g/L5 g/L7 g/L 9 g/L under the two irrigation amount treatments. Compared with the 1 g/L treatment, the leaf area, stem diameter and dry mass in the 7 g/L and9 g/L treatments were significantly reduced. There was a quadratic functional relation between water salinity and the seedling establishment rate, meaning that when salinity of the irrigation water was 6.0 g/L and 8.4 g/L, the relative seedling establishment rate would be 1 and 0.9 respectively.【Conclusion】Mulched drip irrigation with saline water of less than 7 g/L has no significant impact on seedling establishment, and the growth of the seedling can be promoted by moderately increasing the irrigation amount and irrigation frequency.