Symbiotic Parameters, Growth, Nutrient Uptake as Influenced by Biofertilizers under Conservation Agriculture Practices

A field experiment was conducted during rainy season 2014 and 2015 at Research Farm of the Punjab Agricultural University, Ludhiana, Punjab, India to study the effect of conservation agriculture practices (Happy Seeder sowing, Straw Chopper + Zero Tillage and Conventional tillage) and biofertilizers [Bradyrhizobium and plant growth promoting rhizobacteria (PGPR)] on growth, symbiotic parameters and productivity of soybean. The results showed that Happy Seeder sowing and Straw Chopper + Zero Tillage sowing improved the emergence count, leaf area index, photosynthetic active radiation interception, plant height of soybean and symbiotic traits (number and dry weight of nodules and leghaemoglobin content). Highest pods plant−1 and 100-seed weight were recorded in Happy Seeder sowing, followed by Straw Chopper + Zero Tillage sowing and conventional sowing. Based on the mean of two years, Happy Seeder sowing recorded 14.6 and 17.0% higher seed yield than Straw Chopper + Zero Tillage sowing and conventional sowing, respectively. Total nitrogen, phosphorus and potassium uptake were significantly higher in Happy Seeder sowing than the other planting methods. Single and dual inoculation of Bradyrhizobium and PGPR did not influence the growth parameters, symbiotic traits, yield attributes, biological, straw and seed yields, nutrient uptake and protein content of soybean significantly. Therefore, retention of crop residues with zero tillage (Happy Seeder sowing) proves to be the best planting method for sustainable productivity of soybean.