Objective To study the relationship between site conditions and Phyllostachys heterocycla disease index.

Method A monitoring survey was conducted on 60 Ph. heterocycla sample plots with different site conditions in Jiangxi Province, and the effects of five site factors (slope, slope position, slope direction, altitude and soil thickness) on the disease index for Ph. heterocycla were analyzed.

ResultsThe results showed that there was a certain correlation between the five factors and the disease index of Ph. heterocycla. The disease index was significantly different under different conditions of slope, elevation and soil thickness. The disease index was positively related with the slope and altitude, and negatively related with soil thickness. There was no significant difference on the disease index under different slop conditions, but a weak negative relation was observed. The slope position also had no significant impact on the disease index of Ph. heterocycla. In the meantime, in order to explore the comprehensive effects of the five site condition factors on the disease index of Ph. heterocycla, a multivariate linear regression prediction equation was established by using the quantitative theory, with the five site condition factors were taken as independent variables, and the disease index was taken as dependent variables. The prediction equation's R=0.854, F=10.432 > F_0.01(11.48)=2.64. Also, it was found by T test that altitude and soil thickness were the most two significant factors affecting the disease index.

Conclusion It is concluded that the value of disease index of Ph. heterocycla is the highest under the site conditions of steep slope, upper slope, sunny slope, high altitude and thin soil layer, and the value is the lowest under the conditions of flat and gentle slope, downhill position, shady slope, hilly land and fertilizer soil.