Effect of ecologically-based weed management strategies on weed community and diversity in hilly tea plantations

Ecologically controlling weeds does not only reduce consumption of soil water and nutrient, but also avoid or reduce application of chemical herbicides. Two ecologically-based weed management strategies based on pre-evaluation and competition of niche, straw mulching and white clover intercropping, were conducted in hilly tea plantations in 2005 and 2006, with clean tillage as the CK. Characteristics of weed community, including weed abundance, dominance, evenness, biomass and mean height were investigated via multi-sampling in small plot and the effects of two ecologically-based weed management strategies were compared with the clean tillage. About 16 families and 31 species of weeds are identified in the study. In April, the dominant weed species are those growing slowing with low biomass and lower than 30 cm. In July and September, the abundance (Pi) of malignant weed in CK respectively reaches 0.788 and 0.759, while that in straw mulching treatment is respectively 0.256 and 0.420, and a lower malignant weed occurrence frequency is found in white clover intercropping treatment with Pi<0.050. Weed richness, species diversity and evenness under straw mulching treatment are all higher than those under CK, though the dominant concentration index is lower than that of CK in spring, summer and autumn. Total number, biomass in spring, summer and autumn, and mean weed height in summer and autumn under white clover intercropping treatment are lower than those under the control. The two ecologically-based treatments have a favorable effect on weed control than the clean tillage. It therefore implies that white clover intercropping and straw mulching are effective ecological weed control measures.