P inflow rate

Phosphorus inflow rate Root cation exchange capacity Root length density Soybean VAM Wheat A B S T R A C T Alteration of crop root morphology is a new innovative approach to provide food security. Phosphorus is the most important nutrient to influence root properties. Efficient use of P fertilizers has become an important issue of agriculture all over the world due to limited availability of rock phosphate and its nonrenewable nature. Hence, root properties and grain yield of soybean-wheat cropping system were evaluated by inoculation of phosphate solubilizing bacteria (PSB) and vesicular arbuscular microorganism (VAM) with 50% recommended P (0.5 P + PSB + VAM) against 100% P (1.0 P), 50% P and control in a Typic Ustochrepts of the Indo-Gangetic plains. The root cation exchange capacity (CEC) of soybean and wheat treated with 0.5 P + PSB + VAM were 3.6 and 4.6% higher than 1.0 P, respectively. The same treatment produced 2.3 and 2.6% higher root length density (RLD) in soybean and wheat, respectively in comparison to 1.0 P. The P inflow rate under 0.5 P + PSB + VAM was 9.2 and 4.6% higher than 1.0 P in soybean and wheat, respectively indicating higher acquisition of P through VAM, although higher rhizospheric P availability was recorded in 1.0 P. The root CEC, RLD and P inflow rate were closely related to P concentration and content in root, shoot and nodule, specific root length, root diameter and internal P requirement. The better root property observed in 0.5 P + PSB + VAM enhanced 4.1 and 4.9% grain yield of soybean and wheat, respectively as compared to 1.0 P. Inoculation of PSB and VAM could substitute 50% P of soybean-wheat cropping system with better root property and higher grain yield in semi-arid sub tropics of the Indo-Gangetic plains.