The Study On Simple Estimation Method Of Aboveground Biomass Of Grassland

Grassland biomass is not only the primary indicator of ecosystem and the grassland comunity but also an important mean of the study on the variation of the grassland ecosystem. The main method of research on the grassland biomass is directly harvested and remote sensing estimation. There is few study on the grass meter. In this study we make different types of measure board by self-made and investigated the correlation between the height of grassland community and biomass in the predominate sward of white clover, then build up a regression equation. Sececting the best type of the measure board and the estimation model of biomass through the comprehensive analysis and comparison of determination coefficient(R2), f significant test, total relative error(RS) and the average absolute value of relative error(RMS) and other indicators.The field investigation is on the grassland dominated by white clover around Duzhai, Dazhai, Yangling, Shaanxi. The research tools in this study have two materials, circle and square. The square tools have four sizes, 10 cm, 20 cm, 30 cm, 40 cm while the circles five, 10 cm, 20 cm, 30 cm, 35 cm, 40 cm. Random sampling method at flat terrain. Laying the measure board flat above the vegetation when it get close to the top of the grass layer. Repeated measurement need 20 times every measure board type, then cutting the whole the aerial part of all plants at 0 cm, putting them into the sample bags, marking, weighing in the laboratory. The plants were dried to constant weight at 65 ℃in the thermostatic oven then weighing the dry weight of every quadrat. Astablishing mathematical model and carrying on the correlation analysis. The main results are as follows:1. Establishing the regression equation with the height of measure board as the independent variable and the dry weight of the quadrat. The results showed that the height of grassland community and the biomass present positive correlation, R2 is the medium of 0.3700-0.7630.2. Whether the area and weight is oversize or undersize, it will effect the the stability and the fitness to the regression model. Aluminium plastic plates are heavier than polymer plates, performing better on coefficient of variation and determination.3. The best type is the aluminium plastic plate in diameter 30 cm by the comprehensive various factors. And the best estimation model is y=1.6460x-3.3462, R2=0.7630, and its prediction accuracy can reach 82.35%.