杨粮间作系统农作物产量研究

为寻找协调农作物与林木间作模式 ,通过 6a研究说明 ,在杨粮间作系统中 ,农作物产量与间作年限的关系呈抛物线形状 ,达到最高产量的年限与林木的行距有关。在一定范围内 ,行距越大 ,产量达到最高的年限就越推后。研究还说明 ,合理的间作年限和合理的间作行距 ,可以有效地提高作物的产量 ,如行距 18m时 ,作物总产量在间作的第 3～ 6年间 ,比对照提高8 0 % ;而行距 30m时 ,间作的第 3～ 9年间 ,小麦产量平均每年比对照提高 2 2 6 %。作物产量在间作行间分布的共同特征是中间高、两端低 ,这反映了林木除对农作物有保护作用外 ,“胁地”现象是普遍存在的。所以 ,当“胁地”作用明显时 ,对林木进行间伐 ,可以提高作物产量。建议杨粮间作在杨树成林时 (10～ 15a) ,树木行距保持在 4 0～ 6 0m

THE STUDY ON CROP YIELD UNDER POPLAR-CROP INTERCROPPING SYSTEM

The results of 6 years of studies showed that the relationshipbetween the crop yield and the intercropping years was of the parabola form under the poplar-crop intercrpping system,and the year when the highest yield achieved was relative to tree spacing.In the reasonable bound, the more tree spacing between-rows was wider,the more the year to get the highest yield was later.It also demonstrated that proper intercropping years and tree spacing between-rows would effectively increase crop yield.For example,the total crop yield was 8.0% higher than that of control land from the second year to the sixth year when the tree spacing between-rows was 18m but the per year wheat yield was 22.6% higher over the third year to the ninth year when it was 30 m. The crop yield distributed between-rows had the same pattern when the tree rows were different, i.e. higher in middle and lower near the tree rows. That means the poplar, besides its protection effect to crop, strive for resources from crop as well. When it makes crop yield to decrease seriously, poplar thinning will obviously increase crop yield. It is proposal that the spacing between-rows should maintain 40～60 m when poplars get to mature stage(10～15 years).