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通过频次分布和聚集度指数的测定,以及m*-m回归和Taylor幂法则分析,研究西兰花菌核病病株田间空间分格局及其抽样技术。结果表明,西兰花菌核病病株田间分布趋向于聚集分布。被测田块都不符合二项分布,而同时符合核心分布;各田块的西兰花菌核病I指数>0,M*/M指标>1,Ca指数>0,扩散系数C>1,K指数>0,m*-m回归分析表明病株空间分布的基本成分是个体群,病株个体间相互吸引,病株在大田中存在明显的发病中心,个体群在田间呈随机分布格局,即分布的基本成分发病中心之间趋于随机分布,而个体群内的个体与核心分布相吻合。Taylor幂法则分析表明,西兰花菌核病病株个体的空间格局随着病株密度的提高越趋聚集分布。随着病情指数的增加,所需抽样数递减。序贯抽样模型为T0(N)=1.5N±2.8615N,调查株数N株时,若累计病情指数超过上界可定为防治对象田,若累计病情指数未达到下界时,可定为不防治田。病情指数15%,所需抽样数为90。
Through the analysis of frequency distribution and aggregation index, m * -m regression and Taylor power law analysis, the spatial pattern and sampling technique of field isolates of Broccoli nuclear disease were studied. The results showed that the distribution of Broccoli strains tends to aggregate. The measured plots did not fit the binomial distribution, but coincided with the core distribution. The I> 0, M * / M index> 1, the Ca index> 0, the diffusion coefficient C> K-index> 0, m * -m regression analysis showed that the basic components of the spatial distribution of diseased plants were individual groups. Mutual attraction was found among individual diseased plants. The diseased plants had a significant morbidity center in the field. Individual groups were randomly distributed in the field, That is to say, the distribution of the basic components of the incidence centers tend to be randomly distributed, while individuals within the individual population and core distribution coincide. Taylor power law analysis showed that the spatial pattern of individual strains of Broccoli scrambled with the increase of the density of the more aggregated. As the disease index increases, the number of samples required decreases. Sequential sampling model is T0 (N) = 1.5N ± 2.8615N. When the number of plants under investigation is N, the disease index can be regarded as the control target field if the cumulative disease index exceeds the upper limit. If the cumulative disease index does not reach the lower limit, field. The condition index is 15% and the number of samples required is 90.