Authors : Yong Jiang , Qiuli Zhuang and Wenju Liang
Abstract: By the methods of geostatistics combined with traditional statistics, the spatial variability of soybean yield and its relations with soil fundamental fertility was examined within a site-specific long-term experimental field at the Shenyang Experimental Station of Ecology, Chinese Academy of Sciences (a 30 m � 42 m plot was divided into 7 m � 5 m subplots, with 49 sampling sites). The results showed that the isotropic variogram for soybean yield fitted a spherical model, with R2 being 0.838 and significant at the 0.01 level. The distribution map of soybean yield was spatially dependent and the directional variability mainly occurred in the 45° and 0° directions. Soybean yield was significantly correlated with the number of seeds per m2 (R = 0.945, p < 0.01), with the number of pods per plant (R = 0.353, p < 0.05), and with soil pH (R = 0.515, p < 0.01), exchangeable calcium concentration (R = 0.386, p < 0.01) and cation exchange capacity (R = 0.387, p < 0.01). However, the soil fundamental fertility index, i.e., soil organic carbon, nitrogen, and phosphorus, exhibited no contributions to soybean yield. Soil water content was considered as the most limit factor that affecting soybean yield within the field-scale. It is suggested that soil fundamental fertility alone or other single factors be not enough to explain the observed spatial variability of soybean yield, and hence, more factors should be taken into account to diagnose causes of poor plant growth and to improve the management of site-specific farming.
Yong Jiang , Qiuli Zhuang and Wenju Liang , 2006. Field-Scale Variability of Soybean Yield and Its Relations with Soil Fundamental Fertility. Agricultural Journal, 1: 136-140.