玉米大豆对农林复合系统小气候的光合响应

对黄土区核桃(Juglans regia L.)-(玉米+大豆)、李子(Prunus salicina)-(玉米+大豆)农林复合系统小气候效应的研究表明,在玉米和大豆的花期,农林间作系统与对照地相比可以降低农田地面温度1.7-1.9℃,减低风速55%-67%,提高相对湿度6.9%-8.4%,降低光合有效辐射强度13.9%-24.5%和大气CO2浓度5.3-10.9μmol.mol-1。本研究中,单作大豆叶片光合速率午间变化主要受到非气孔的限制作用。逐步回归分析结果表明,光合有效辐射强度和大气CO2浓度是影响林下作物光合速率的主要环境因子。林下小气候可能是作物避免"午休"现象的主要原因。

Photosynthetic response of maize and soybean to the microclimatic in an agroforestry system

The microclimatic effect of intercropping walnut (Juglans regia L.) and plum (Prunus salicina) with corn (Zea mays) and soybean (Glycine max) was studied in an agroforestry system in central China. The results indicated that the intercropping system, compared to a monocrop system containing only non-tree, crop species, increased the relative humidity by 6.9% to 8.4%, decreased surface soil temperatures by 1.7 to 1.9℃, reduced wind speed by 55% to 67%, reduced photosynthetic active radiation (PAR) by 13.9% to 24.5% and air CO_2 concentration by 5.3 - 10.9 μmol·~(-1).Changes in the net photosynthetic rate of soybean leaves at noon were primarily attributed to limitation of non stomatal factor. PAR and ambient air CO_2 concentration were the dominant factors influencing net photosynthesis rate as shown by multiple stepwise regression analysis. The microclimatic of the intercropping system was the key factor preventing midday depression of photosynthesis that appeared in the monocropping system.