Effects of Boron (B) doses and forms on boron use efficiency of wheat

Abstract

Boron is one of the most limiting micronutrients in the grain production system in Brazil, mainly due to its complex dynamics in the soil-plant system. In this way, the objective of this study was to evaluate the efficiency of application forms and doses of boron with emphasis on wheat grain yield. The experiment was conducted in no-tillage system in an Oxisol with clay texture in Selvíria, MS. The experimental design was a randomized block design with four replicates arranged in a 4 x 3 factorial scheme, using four doses of boron (0, 1, 2 and 4 kg ha-1) with boric acid source (B = 17%); and three apllication forms: (A1) in desiccation of the predecessor straw, along with herbicide; (A2) at the time of sowing, in soil along with the formulated fertilization seeding and (A3) foliar application along with the syrup of the herbicide (with the application of post emergent herbicide). The increase in boron doses reduced the recovery of apparent boron (RAB), boron uptake efficiency (BUpE) and agronomic efficiency (AE), but the application of 2 kg ha-1 provided the highest boron utilization efficiency (BUtE) and wheat grain yield. We recommend application of 2 kg ha-1 of B in the soil at sowing to obtain approximately 4311 kg ha-1 of wheat.