| These experiments were carried out in the farm of Anhui Agricultural University from 2003 to 2004. The experiments studied yield, physical and ecological characteristics of Zhongsi237-Tea intercropping system and Alfalfa-Tea intercropping system at different intercropping modes. The results show : 1. Compared with triticale photosynthetic characteristics of monoculture system, differences of these of tea-grass intercropping systems (TGS) are smaller. However, intercropping systems, which have bigger effects on tea photosynthetic characteristics, can significantly reduce photosynthetic midday-depress of tea leaves in spring and summer. In every stage, chlorophyll contents (CHL) and net photosynthetic rates (Pn) of triticale leaves in different treatments firstly ascend; when CHL and Pn enter the flowering stages, they go up to the peak; afterwards they begin to descend rapidly. But the differences between TGS and MTrS of CHL and Pn are not evident. So diversified intercropping densities affect hardly triticale photosynthetic characteristics. In different treatments, diurnal variations of tea leaves' Pn are twin-peaked curves with obvious falls in midday. Photosynthetic midday-depresses of tea leaves are meliorated in spring and summer, and ameliorative effects are more evident in summer. Pn of tea leaves in TGS are higher than in MTS, and Pn rise with distances between teas and grasses shortening from 90cm, 60cm to 30cm. That is to say, when intercropping densities become bigger, tea leaves' photosynthetic ability has been greatly improved. 2. TGS can meliorate micro-climate characteristics, and makes for tea growth and development. TGS can reduce illumination intensities. In the overwinter stage, illumination intensities differences between TTrS and MTS are not obvious; But in the jointing stage, grouting stage of TTrS and midsummer of TAS, illumination intensities are smaller than that of MTS. and with intercropping densities increasing, illumination intensities decrease in turn. TGS can change atmosphere temperatures conditions. With planting densities increasing, TTrS heightens air temperatures in winter and TAS drops them in summer. And compared monocultural systems' air temperatures with intercropping systems', differences are significant (P<0.05) in the overwinter stages, the grouting stages of TTrS, and July end of TAS. TGS can make air relative humidity bigger. MTS air relative humidity is lowest in different treatments, different growth stages and different observation time. Experimentations show that, air relative humidity in 90cm distance between tea and grass < that in 60cm distance < that in 30cm distance. 3. TGS can meliorate soil traits, and accelerate growth of underground roots. TGS can make soil temperatures calmer. In winter, the bigger cropped densities, the higher soil temperatures, and namely intercropping systems can increase soil temperatures significantly, which is useful to tea roots' living through the winter. On the contrary, soil temperatures in the intercropping systems reduce obviously with cropped densities rising in summer. TGS can optimize soil physical and chemical characteristics. Through intercropping, soil moisture contents and total porosities are higher, which are inverse proportional to cropping densities; soil bulk densities are lower, which are direct proportion. The contents of soil O.M., total N, available N, available P and available K show regulated variations. Most soil nutrient indexes in MTrS and TTrS are lower than those in MTS; but soil nutrient in MAS (monocultural alfalfa system) and TAS are higher. TAS is more useful to fertilize soil and keep soil fecundity. 4. TGS can increase plants' varieties and quantities, and make the systems steadier. Tritacale or alfalfa is ecological predominance population respectively in TTrS or TAS. Relations between plants' quantities (y) and SW indexes show that: when cropping densities ascend, plants' quantities are bigger, so SW indexes become smaller and plants' diversities are not in evidence. The p... |
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