The Research On The Agro-ecosystem Productivity Development In The Ecotone In Dry-semidry Area Between Agriculture And Pasture In North China

The ecotone between agriculture and pasture in the dry-semidry area in North China is vulnerable in both ecology and economic. Under the traditional concept of the productivity which caused the neglecting eco-system productivity is the main reason that the environment and economic deteriorated. The development of the eco-system productivity was discussed based on the eco-system productivity conceptual in this paper. Sweet sorghum (Sorghum bicolor), millet TG118 (setaria italica beauv), maize (zea maizes), switchgrass (panicum virgatum), Russian wildrye grass (Psathyrostachys juncea), which meet the eco-system productivity need were chosen planted in Ansai county. In dry-semidry areas, water was the limited factor, so the water use efficiency (WUE) of the crops and grass was mainly recorded to be analyzed as the efficiency of utilizing nature resources, especially the superiorities of climate resources. The harvest biomass, energy and protein were also tested.The result was showed as follows:1. High biomass and low grain yield were the main character of the crops and grasses which were selected. The yield of biomass, energy and nutrient of the crops and grasses were far more than the local kinds. Compared with the traditional productivity there was a higher capacity of population both based on the energy and protein under the condition of the concept of the agro-ecosystem productivity.The WUE of the chosen crops and grasses were higher than the local kinds, in the mountain field, maize is the highest with the value 55DM ?kg ?mm"1, and millet TG118 is the highest in mountain foot field, with the value 52 DM ?kg ?ram"1. The highest value of the ratio of achieved the potential yield is the millet in the mountain foot field and Sorghum bicolor in mountain field, and the value is 56.5% and 49.1% respectively.The soil erosion of the seleted crops and grasses in mountain field is higher than the mountain foot field. The soil erosion of the crops and grasses both in the mountain filed and mountain foot feild are far more less than the local crops that the average value is 60 t/hm2.The agro-ecosystem productivity comprehensive evaluation showed that "the primary productivity is fluctuating while the primary productivity is going up. The secondary productivity is more stable while developing slowly. Both the ecological services value and the economic productivity of farm household are going up, in another word that they are both in a very poor level.In Ansai County, on the base of developing the agro-ecosystem productivity, the estimation of the agriculture value is 577000000RMB, 1.98 folders higher than that in the 2000.The agriculture productivity would increase 8.8%, andl4.4%, when the primary productivity is complimented by the secondary productivity and that the ratio is 10%, and 30%.In dry-semi-dry regions, in term of agro-ecosystem productivity, which scarify the "tasty" to the human kind, which was aimed at the high biomass, energy or protein, can harmonize the ecological environment and economy.