膜下滴灌高产棉花根、冠生物量累积特性研究

Characteristics of Root and Shoot Biomass Accumulation in High-yield Cotton Fields with Mulch-drip Irrigation

在新疆膜下滴灌大田条件下,选用新陆早43号和新陆早45号2个棉花品种,测定不同产量水平棉田棉株根系生物量及其空间分布、地上部生物量、根冠比等,分析滴灌棉花产量形成过程中根、冠生物量的累积特征。结果表明:与一般产量棉田及中低产棉田相比,高产棉田在整个生育期根系生物量较高、中下层根系分布比例较大,棉株总生物量、地上部生物量、棉铃生物量均较高,根冠比较低;产量构成因子表现为总铃数较多、铃重较高。高产棉花由于其生物量快速累积起始时间较早、累积速率快,进而棉株根系生物量、总生物量累积多。因此,根据参试棉花品种的生育特点,在适期早播促生育进程提前、前期营养器官稳健生长的前提下,采取水肥后移或适当推迟停水时间,可适度增加棉花中下层根系分布,降低根冠比,提高光合产物向棉铃的分配比例,增加铃重,进一步提高棉花产量。

Under the ecological and climatic conditions of Xinjiang, differences in the temporal and spatial distribution characteristics of the roots, aboveground biomass, and root/shoot ratio in cotton fields of different yield levels were studied using the soil profile sampling method and Xinluzao 43 and 45 as experimental materials. The results showed that the root biomass, proportion of roots in the middle and lower soil layers, total biomass, and aboveground biomass in super high-yield fields was significantly increased throughout the growth season compared with common high-yield and low-yield fields. However, the root/shoot ratio was decreased. The yield components exhibited higher total boll numbers and weight. Under super high-yield conditions, the large root biomass and total biomass were mainly attributable to earlier initial time and higher rate of the rapid biomass accumulation, than under the other yield levels. This suggested that the yield of cotton varieties could be increased according to their growth characteristics, by appropriate early sowing in advance of normal growth of vegetative organs and an appropriate delay without water or water transfer measures, to ensure water supply to reproductive organs at the late growth stage and increase the boll weight by increasing the proportion of roots in the middle and lower soil layers, decreasing the root/shoot ratio, and increasing assimilate transfer from leaves to bolls.