Study On Light And Roots Distributing Characteristics In Walnut-wheat & Walnut-cotton Intercropping Systems In Tarim Basin

In this experiment, in order to analyze the light characteristic, the physiologic response of crop to light and the overlapping of roots between fruiter and crop and discover the mechanism of competing water, rich and light in the walnut-wheat & walnut-cotton Intercropping Systems,LAI-2000 Plant Canopy Analyzer made in LI-COR company(USA), TPS-2 Portable Photosynthesis System made in Portable Photosynthesis Systems(USA) and WinRHIZO Root Analyzing System(CANADA) were adopted to observe the distribution of light, the response of crop to the Intercropping System and the distributing characters of roots, Main conclusions were as follow:Because of the shade conduced by the ranks of walnut, in the walnut-wheat & walnut-cotton Intercropping Systems, the distributing of light changed following the time and space. On the level, the smaller the distance between the ranks was. The older the age of the walnut was, the lower the PAR was. And the PAR of the western canopy was higher than that of east. In the walnut-wheat & walnut-cotton Intercropping Systems, the area of space-time window got smaller, following the increasing of age.In the Intercropping Systems, the distributing of the light influenced the Pn and the Tr. They were both reduced, comparing with the CK. The trend that the Pn changed was consistent with the PAR, and they were both descending from the middle to the two sides. At different sites, the Pn, the Tr and the Gs all reduced following the increasing of age, while the Ci increased. It indicated that the factor that limited the Pn was not the Ci, but the photo supplying.In the walnut-wheat & walnut-cotton Intercropping Systems, the result gained by analyzing distribution of roots on the level and uprightness showed that:the mainly competing region was at 10-60cm layer, which was within 175cm away from the two sides, and the roots mostly overlapped at 10-40cm. In the walnut-cotton Intercropping Systems, the 10-60cm layer was the mainly competing region, the roots mostly overlapped at 10-30cm layer at which cotton and walnut mainly competed water and rich.