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为了阐明膜下滴灌棉花吸水根系空间分布特征,给膜下滴灌棉花二维根系吸水模型的建立提供依据,通过田间灌溉试验,采用根钻双向采样法,研究了最佳灌水处理下膜下滴灌棉花吸水根系二维分布特征,拟合了根长密度二维分布函数模型。结果表明:在水平方向,吸水根系主要分布在膜下,占总根长密度的78.7%,从棉株向行外空地,根长密度减少,仅占总根长密度的21.3%,从棉株向行内,根长密度增大,距离棉株15cm处根长密度最大;在垂直方向,吸水根系呈先增后减的“单峰型”变化规律,根长密度在0-10cm深度较小,10-20 cm深度最大,20 cm以下随着土壤深度的增加递减。膜下滴灌棉花根长密度二维分布可以用复合指数模型表达,预测在水平方向行内距离棉株24.1 cm,垂直方向12.9 cm处棉花根长密度最大为26.48mm·cm-3,与实测最大根长密度28.04 mm·cm-3相差1.56 mm·cm-3。
In order to elucidate the spatial distribution characteristics of water-absorbing roots in cotton under drip irrigation, the basis for establishing two-dimensional root water absorption model of cotton under drip irrigation was provided. Through field irrigation experiment and bidirectional sampling with rhizome, Water absorption root two-dimensional distribution characteristics, fitting root length density two-dimensional distribution function model. The results showed that in the horizontal direction, the water-absorbing roots were mainly distributed under the membrane, accounting for 78.7% of the total root length density. From the cotton plant to the outer space, the root length density decreased only 21.3% of the total root length density. The density of roots and roots increased to the maximum at 15 cm from cotton plant. In vertical direction, the root of water absorption increased first and then decreased, and the root length was smaller at depth of 0-10 cm. The depth of 10-20 cm was the largest, and the depth of 20 cm decreased with the depth of soil. The two-dimensional distribution of cotton root length under two-dimensional distribution of cotton under drip irrigation can be expressed by composite index model. The maximum cotton root length density at the horizontal direction is 24.1 cm and the maximum at 12.9 cm in vertical direction is 26.48 mm · cm-3, The difference of the length of 28.04 mm · cm-3 is 1.56 mm · cm-3.