Growth, Yield and Seed Nutrient Quality of Soybean (Glycine max L.) as Affected by Organic, Biofertilizer and Synthetic Fertilizer Application

Abstract

Pot experiment was carried out in dry zone of Sri Lanka in the year 2015 with the aim of investigating the effects of organic manure, biofertilizers and synthetic fertilizer application on growth, yield and seed nutrient quality of soybean (Glycine max L.). Treatments were  field soil only (T0), field soil and 5% biochar (T1), field soil and 5% cow dung (T2), field soil, 2.5% biochar and 2.5% cow dung (T3), field soil, 5% biochar and Bradyrhizobium (T4), field soil, 5% biochar and mycorrhizae (T5), field soil, 5% cow dung and Bradyrhizobium (T6) field soil, 5% cow dung and mycorrhizae (T7), field soil and synthetic fertilizer (T8), field soil, 2.5% cow dung 2.5% biochar and synthetic fertilizer (T9), field soil, 5% cow dung, mycorrhizae and Bradyrhizobium (T10), field soil, 5% biochar, mycorrhizae and Bradyrhizobium (T11). The treatments were tested in a randomized complete block design (RCBD) with six replicates. The results indicated that application of organic and biofertilizers with synthetic fertilizers (T9) significantly (p<0.05) improved the relative growth rate, number of leaflets, root dry weight, shoot dry weight of soybean. However, soybean yield such as the number of pods and the dry weight of 100 seeds, was significantly high (p<0.05) with field soil, 5% cow dung, mycorrhizae and Bradyrhizobium (T10).  Higher seed protein percentage was observed in T10, fat percentage in T4 and crude fibre percentage in T8 treatments. In conclusion, the application of organic and biofertilizers together resulted in an improvement of the yield components and nutrient quality of soybean seeds, except for the case of crude fiber content which increased by the application of synthetic fertilizer. Overall, organic and biofertilizers could be used as efficient substitutes for synthetic fertilizers, without compromising the yield and nutrient quality of soybean.