膜下滴灌条件下根区水分对棉花根系生长及产量的调节

在新疆气候生态条件下,选用对土壤水分敏感性不同的棉花品种为试材,采用土柱栽培法,探讨膜下滴灌条件下根区水分对棉花根系生长与活性及产量的调节作用。结果表明:滴水前耕层土壤相对含水量在50%～55%、滴水后可保持在70%～75%的根区水分环境下,棉花根系的生长发育进程受到了一定程度的抑制,根系生物量降低,但提高了40～100cm土层根系分布的比例和根系活力,降低了根冠比,提高了经济系数,最终产量增加。不同品种对滴水量的反应差异较大,新陆早8号在常规滴灌和充分滴灌量下,子棉产量高于新陆早6号;在限量滴灌量下则显著低于新陆早6号。因此,依据不同品种对水分反应的差异,在滴水周期为7～8d、滴水定额为375～450m3.hm-2的条件下,结合滴灌棉田土壤水分可控性强的特点,制定相应的灌溉制度,可实现膜下滴灌棉田节水高产高效。

Effect of Water Content in Root Zone on Root Growth and Yield of Cotton under Drip Irrigation with Film Mulching

A soil column culture experiment was conducted under the ecological and climatic conditions of Xinjiang to study the effect of water content in root zone on root growth, vigour and yield of cotton with the cultivars of different water-sensitivity Xinluzao 6 and Xinluzao 8 under drip irrigation with film mulching. The results indicated that the water content in root zone of 50%～55%, respectively, of field water-holding capacity before drip and 70%～75% after drip inhibited root growth and reduced root biomass. However, the root vigour and biomass in layer of 40～100 cm were enhanced under the water content condition. Furthermore, it reduced the root/shoot ratio and increased economic index that led to high yiled of cotton. The differences of response to drip irrigation among varieties were great, seed yield of Xinluzao 8 was higher in convention and sufficiency drip irrigation than that of Xinluzao 6.however,under limited drip irrigation Xinluzao 8 was significantly lower than Xinluzao 6. It will be of great importance to institute the optimum irrigation schedule under the condition that the dripping cycle is 7～8 d and the dripping quantity is 375 ～450 m~3·hm~(-2), according to the differences of response to soil moisture content among varieties for abstaining high yield and high water use efficiency.