滴灌量对复播大豆生理特性及农田小气候的影响

Impacts of Drip Irrigation Amount on Physiological Characteristics of Summer Soybean and Filed Micro-climate

2013年7-10月进行复播大豆滴灌量的田间试验,以研究不同滴灌量(3000、3600、4200和4800m3?hm-2,分别用W1、W2、W3、W4表示)对复播大豆冠层透光率、温度、空气相对湿度及光合特性的影响。结果表明:(1)在开花期和结荚期,大豆群体冠层不同层次的透光率均随着滴灌量的增加而减小,并均以距地面20cm处的透光率最小,且各处理群体冠层透光率均与株高呈极显著负相关关系(R=-0.98,P<0.01)。(2)随着滴灌量的增加,大豆群体内部距地面40cm处冠层的空气温度降低而湿度增加,且温度与湿度呈相反的日变化趋势。(3)开花期和结荚期,复播大豆叶片净光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs)和气孔限制值(Ls)均随着滴灌量的增加呈"先增后降"的变化趋势,均以W3处理最高。(4)大豆产量也以W3处理最高,为3741.23kg?hm-2,分别较W1、W2和W4处理增产30.42%、13.98%和8.44%,且达显著差异水平(P<0.05);灌溉水利用效率(IWUE)随着灌水量的增加而降低。本试验条件下,滴灌量为4200m3?hm-2(W3)时复播大豆群体生态环境较好,光合效率最高,达到了高产和节水的统一。

The impacts of different drip irrigation amount on physiological characteristics of summer soybean and its filed micro-climate were studied from July to October in 2013, with radomized block design method. Four treatments were conducted in this field experiment, which were named as W1（3000m3·ha-1）, W2（3600m3·ha-1）, W3（4200m3·ha-1）, W4（4800m3·ha-1）, respectively. The results showed that the different levers of transmittance were decreased significantly with the increasing of drip irrigation amount at flowering stage and podding stage, with the minimum value at 20 cm from bottom of summer soybean in different treatments. Furthermore, there was a significant negative correlation（R=-0.98, P〈0.01）between plant height and population transmittance. The relative humidity inside canopy at 40 cm height increased while canopy temperature decreased with the irrigation amount increasing, and the tend of the daily variation of temperature and humidity was conversely. The net photosynthetic rate（Pn）, transpiration rate（Tr）, stomatal conductance（Gs） and stomatal limitation（Ls） increased shortly and then decreased with the irrigation amount increasing at flowering stage and podding stage. The treatment W3 had the highest yield of 3741.23kg·ha-1, which was higher 30.42%, 13.98% and 8.44% than treatment W1, W2 and W4 with a significant difference in level P〈0.05. The irrigation water use efficiency decreased with the irrigation amount increasing. There was no significant difference between treatment W1, W2 and W3, but W3 was the best choice for summer soybean in local natural condition, with the better population ecological environment, high photosynthetic efficiency, and high yield.