Allelopathy Of Cover Planting On Decline Of Phyllostachys Praecox Stand

As an eximious monopodial bamboo species, phyllostachys praecox has the virtues of sprouting earlier, longer producing time, delicious taste and high yield with its shoots. Since the technique of covering has been used on bamboo planting in Lin'an, Zhejiang from 1990s, as a kind of anti-season vegetables, bamboo shoots made farmer rich, and this has been a special and important industry of Zhejiang province. In recent years, however, there is a decline phenomenon around phyllostachys praecox stand that yield of bamboo shoots decrease obviously, some bamboo begin to flowering, or wholly decay to death. The farmer lost seriously. It has been the most exigent problem what the farmer wish to solve. The purpose of this study is to fmd an ultimate method to keep phyllostachys praecox industry continuable developing.This project launched on the allelochemicals in soil of phyllostachys praecox stand brought by covering materials, analyzed content of main phenolic acids (ρ-Coumaric, Vanillic, Ferulic, ρ-hydroxybenzoic) in rice straws and bamboo leaves that the total content of four phenolic acids are 158.06μg·g^-1 and 371.24μg·g^-1 respectively, approved that the content of phenolic acids of soil increased sharply, pH and polyphenoloxidase activity of soil decreased seriously in covered sample-stand. In thus environment, the phenolic acids which from decomposed organic materials is difficult to be transformed into quinine, so that the content of phenolic acids would be higher in case of the covering years longer. For example, the content of phenolic acids of soil which covered for 7 years are 4263.14μg·g^-1 and 6798.7μg·g^-1 higher than which never covered 19.80% and 39.00% , respectively.At lower concentration, the allelopathy of phenolic acids will promote the plant growth, for example, inhibiting disease or pest in soil and promoting seed germination, etc. On the other side, phenolic acids will destroy the absorbing function of root system at higher concentration, inhibit the plant growth. Through this research, the root activity of phyllostachys heterocycla stand fall down along with content of phenolic acids of soil increasing and years of covering elongation.For example, compared with never covered stand, the root activity of phyllostachys heterocycla stand which covered for 4 and 5 years was cut down 25.60% and 33.47%, respectively. This showed that root system of covered stand would...