The Effects Of Four Kinds Of Forage Grass On The Biochemical Properties Of Soil

Perennial ryegrass, tall fescue, smooth bromegrass and slender wheatgrass were used as materials in this pot experiment to investigate the effects of different forage grass species and clipping treatment on the biochemical properties of soil. The measurements of soil included the total carbon and total nitrogen soil pH(1:2.5),Soil microbial biomass C and N (extracted by chloroform fumigation-extraction method (Vance et al.1987); analyzed with a Multi C/N3100analyser (Analytik Jena, Jena, Germany) by hight-temperature combustion),Inorganic N (extracted in1M KC1, the extracts were centrifuged and the supernatant was analyzed by standard colorimetric methods), the content of Olsen-P(rapidly available phosphorus), the content of soil TOC,B-Glucosidase activity, alkaline phosphatase activity and urease activity. The main findings were as follows:1. The order of the change Of the four kinds of forage grass above-ground biomass was ryegrass> tall fescue> smooth bromegrass and slender wheatgrass, and the order of the change Of the four kinds of forage grass underground biomass was smooth bromegrass> slender wheatgrass> ryegrass> tall fescue. Comparing with no clipping treatment, clipping treatment increased the above-ground biomass of ryegrass, tall fescue, smooth bromegrass and slender wheatgrass by65,103,21and17%, while decreased the underground biomass by44,10,34and43%. These results suggested that the above-ground production increase of the four kinds of forage grass significantly inhibited the growth of underground parts.2. Comparing with ryegrass, tall fescue and slender wheatgrass, smooth bromegrass significantly lowered soil pH. And comparing with smooth bromegrass and slender wheatgrass, ryegrass and tall fescue significantly increased soil P availability. Smooth bromegrass significantly increased soil urease activity comparing with the other three kinds of forage grass. These results indicated that the effects of the four kinds of forage grass for research on the soil properties were different.3. Comparing with no clipping treatment,clipping treatment reduced the soil (3-glucosidase activity under the ryegrass, smooth bromegrass and slender wheatgrass by16.7,33.3and75.0%, and decreased the alkaline phosphatase activity under smooth bromegrass significantly by15.4%, indicating that the impact of forage grass on soil properties was related to the aboveground productivity or the presence or absence of grazing feeding.4.Soil available phosphorus, soil organic carbon content, soil total nitrogen, soil carbon and nitrogen ratio, beta-glucosidase activity and microbial biomass carbon content were also affected by the interaction of forage species and clipping.The aboved results have a reference value of the further research on the effects of the four kinds of forage grass on the properties of soil and the differences in response to grazing.