Effects of Fertilizer, Inoculation and Sowing Time on Growth, Yield and Yield Attributes of Soybean under Field Conditions

Abstract

Two year field experiments on two different sowing dates in response to various level of added fertilizer on various growth, yield and yield attributes of soybean CV. Williams-82 was conducted in medium textured salt free soil of Quetta. Fertilizer treatments were comprised of one level (T2) of P2O5 + K2O fertilizer @ 60 + 30 kg ha -1 and five level (T3 - T7) of N fertilizer @ 25, 50, 75, 100 and 120 kg ha -1 plus the same constant dose of P and K respectively. These six fertilizer levels were applied to both non-inoculated (non-inoc) and inoculated (inoc) crop. Results showed that nodules were found absent in any set of experiment, which could be attributed to either sufficient level of soil NO3 or deficient level of total Fe and Cu or might be due to any other edaphic/climatic factor(s). Results also showed that fertilizer level generally exhibited significant positive influence on growth parameters (except middle leaflet area) of early plantings (EP), but reverse was true for late plantings (LP). While inoculation effects were noted as significant for both plantings (BP). Results further indicated that fertilizer level had slightly (P<0.05) to highly significantly (P<0.01) increased the grain yield of BP respectively, but this increase was much more prominent in EP than LP. A maximum yield (i.e., 3509 kg ha -1 and 2604 kg ha -1) was obtained in T6 non-inoc and T6 inoc of EP and LP respectively. Results also revealed that the response of yield attributes in relation to added fertilizer were found highly significant in EP and non-significant in LP (except 100 seed weight). The same was true for inoculation studies (except sterile pods and pods contained 4 beans). It was also concluded that most of the yield attributes of BP exhibited highly significant positive correlation with their yield, which could be used a suitable selection criteria for predicting the grain yield in soybean cv.Williams-82. However, growth parameters exhibited non-significant association with the yield of both sowing dates.