Can the new boron-fertilization method improve the system productivity of rice (Oryza sativa L.) – mustard (Brassica juncea L.) cropping system under upland calcareous soils?

Abstract

Background Calcareous soils are highly deficient in boron (B) which has become one of the most important deficient micronutrients in Indian soil after zinc (Zn). For various rice-based cropping systems, B-fertilization is essential for increasing crop productivity and the biofortification of the crop, thus suitable soil application protocol for B-fertilization are required for B-deficient soils. Results In a six years-long experiment, different rates of B application viz. 0.5, 1.0, 1.5, and 2.0 kg ha− 1 y− 1 were evaluated to determine the effects of three different modes of B fertilization viz. applied only in the first year, in alternating years, and every year in rice ( Oryza sativa L.) – Indian mustard (Brassica juncea L.) cropping system. It was observed that the application of B at 1.5 kg ha− 1 in every year or 2 kg ha− 1 in alternate years resulted in the highest yield of rice and mustard as well as the system productivity of the rice–mustard cropping system. Application of 2 kg ha− 1 B in the initial year showed the maximum B-uptake by rice, while, application of 1.5–2.0 kg ha− 1 B in every year resulted in the maximum B-uptake by the mustard crop. Conclusion Application of B at 2 kg ha− 1 in alternate years or 1.5 kg ha− 1 in every year was the best B-application protocol under rice–mustard cropping system in B-deficient calcareous soils for ensuring the best system productivity of rice–mustard cropping system and B-availability in soil.