密度对大豆群体冠层微气象特征及产量的影响

Density effect on microclimate characteristics of soybean population canopy and yield

以垦农4号大豆为试验材料,在大田条件下,研究了密度对大豆群体光合有效辐射强度、温度、相对湿度、CO2浓度、风速及产量的影响。结果表明:不同群体冠层的微气象特征存在差异,高密度与低密度群体之间差异显著。光合有效辐射强度及风速均随着密度的增加呈递减趋势。温度、湿度及CO2浓度具有明显的日变化规律,昼夜温差在14～17.3℃,群体的相对湿度正午12∶00时最低,高低密度群体湿度差相隔3%;群体间不同层次的CO2浓度越接近地面越高,从06∶00到12∶00时,密度为36万株/hm2的群体(即P2.4)各冠层CO2浓度均为最大。随种植密度增加,群体内单株荚数、粒数和粒重逐渐减少。当密度为36万株/hm2时,群体产量最高。

The effect of plant densities on microclimate characteristics of soybean cultivar Kennong 4 were in-vestigated in field. The results showed different soybean canopy micro-meteorological characteristics. There was sig-nificant difference among different densities of soybean populations. The wind speed and photosynthetic active radi-ation lowered gradually with increased density. The temperature,relative humidity and CO2 concentration obviously changed in different population. The difference of temperature ranged from 17. 3℃ to 14℃. The relative humidity tended to be the lowest at noon,and the different relative humidity between high and low density populations went up to 3% . The CO2 concentration decreased gradually from the ground. It was the highest in the population of 3. 6 × 105-plants-per-hm2（ P 2. 4） when investigated from 06∶ 00 am to 12∶ 00 pm. The pods number,seeds number and seed weight were higher with less density,and the yield of P2. 4 reached the highest.