The Ecological Adaptability And Interspecific Competition Of Several Pastures In Loess Hilly Regions

The study of ecological adaptability and inter-specific competition in excellent pastures will promote the engineering of withdrawing tillage and returning forestry and the development of eco-environment sustainability, and increase local peasants'income on the Loess Plateau regions. In the present research, both ecological adaptability in C4 perennial weedy plants like local cultivated Bothriochloa ischaemum L. and introduced Panicum virgatum L. grown in typical semi-arid Ansai regions, and inter-specific competition in perennial leguminous weedy pastures such as semi-artificial and semi-wild Astragalus adsurgens L.and artificial domestic Medicago sativa L. was conducted in the Loess plateau area. Accordingly, the important findings were displayed as the following.1. The ecological adaptability of different pastures grown in various locationsThe comparison of growth adaptability of native Bothriochloa ischaemum and introduced Panicum virgatum was conducted in the Loess Plateau regions. A significant difference was found in soil moisture, aerial and root growth of both pastures, among which there was a decreased order of mean soil moisture as B. ischaemum in terrace> P. virgatum in terrace>B. ischaemum in sloping field>P. virgatum in sloping field. In terraces the aerial biomass of B. ischaemum was higher than that of P. virgatum significantly, which was contrast with aerial biomass in sloping field of both. However aerial biomass of both in sloping field was greater than that of terrace. Both pastures distributed their roots in soil of 0-20 cm mainly. The total roots'biomass exhibited an increasing trend from B. ischaemum in sloping field to B. ischaemum in terrace to P. virgatum in sloping field to P. virgatum in terrace. Meanwhile in the trial aerial biomass surpassed root biomass in four plant communities named as B.