| To synthetically improve the degraded slope farmland environment in the high precipitation area of western China, to adjust the agricultural structure and seek for the optimum trees (bamboo) + herbage vegetation model, this article discussed experiments in three aspects. They are selecting suitable herbage species based on productivity, soil and water conservation ability and growth amount under shaded condition, analyzing the suitable tree (bamboo) shade degree (or canopy closer) by comparing the growth situation and net photosynthetic rate of the selected herbage under different shade degrees, as well as regarding economical consequence, and through fixed spot observation and measurement on several types of tree (bamboo) + herbage vegetation, comparing and analyzing their ecological functions like water holding, soil improvement, soil and water conservation.Experiment 1: The study targets are four herbage H. compressa(L.f), Dactylis glomerata, Medicago satiua, Cichorium inybus L, compared with empty land and corn land. Build surface runoff observation land for each herbage, and compare their productivity and soil preservation. At the same time, study the growth rate under shaded condition of H.compressa(L.f), Lolium perence L.), Dactylis glomerata, Medicago satiua, Trifolium repens L., by recording their growth situation under different shade degree (80%, 60%, 40%, 20%, 0%).Experiment 2: The study target is the selected herbage from the above experiment (H. compressa(L.f). Through manipulating the shade, analyze the relation between shade degree and the herbage's stem diameter growth rate, height growth rate, biomass, net photosynthetic rate and photosynthetic user-efficiency. Then, analyze the value of shade degree under which herbage planting income is equal to the original investment. Together with on site investigation in Liujiang, Hongya county of H.compmssa(L.f) growth situation under Pleioblastus shade, this analysis is used to decide the suitable shade degree for the herbage.Experiment 3: The study targets were pure H. compressa(L.f) land and tree-herbage land mixed with H. compressa, Betula luminifera, Pleioblastus and Bambusa pervariabilis × Dendrocala mopsis. Study is made with traditional slope farmland as contrast, on regarding surface runoff observation land. In a two year period, collect soil sample at fixed spots, installing infiltration tube at spots, keeping track of surface runoff and soil erosion. And then, analysis was made for different tree (bamboo) + herbage vegetation about their improvements to soil structure and nutrient and their ability in preserving water, soil and fertilizer.The experiment result shows:1. H. compressa(L.f) produced herbage of 71.76t/hm~2. a, higher than Dactylis glomerata (43.0 t/hm~2.a), Medicago satiua (39.0 t/hm~2.a) and Cichorium inybus L.(31.0 t/hm~2.a). It also had outstanding water and soil preserve capability. Comparing with corn, surface runoff reduced 41.9%, soil erosion reduced 68.2%. This made it very useful to slope farmland amelioration and aquatics breeding industry development, thus allow for quick adjustment of agriculture structure. Cichorium intybus L. had similar water preserve ability as Dactylis glomerata and Medicago satiua, given its much lower productivity, it was not suggested. Medicago satiua doesn't acclimatize itself to the hot humid weather in the summer, so it was not suggested, either. Dactylis glomerata had in-between productivity and soil and water conservation.H. compressa(L.f) grown slower under shaded condition, but its biomass was obviously higher than the other herbage types. Even under 60% shade degree, its biomass was still higher than the...
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