Deep Banding Increases Phosphorus Removal by Soybean Grown under No‐Tillage Production Systems

Abstract

Core Ideas Deep band P is a potential strategy to reduce P losses by runoff. Deep band P improve soil fertility in subsurface in no‐till system. Greater amount of P removed with grain compared to the total P input. Phosphorus fertilizer placement can have significant agronomic and environmental implications in long‐term no‐till (NT) systems. The objective of this study was to evaluate soybean [Glycine max (L.) Merr.] response to P fertilizer placement strategies under long‐term NT management. A field study was performed near Nao‐Me‐Toque‐RS (Location 1) and Sao Sepe‐RS (Location 2), southern Brazil, during the 2014/2015 growing season. The experimental design was a randomized complete block with three replications. Triple superphosphate was applied using five strategies: (i) strip tillage with deep band (ST‐DB); (ii) strip tillage with band‐applied 5 by 5 cm (ST‐B); (iii) no‐till with broadcast (NT‐BR); (iv) no‐till with band‐applied 5 by 5 cm (NT‐B); (v) and no‐till with surface band (NT‐SB). Plant height, dry weight, and P uptake were evaluated at 20, 40, 60, and 80 d after emergence (DAE) as well as P removed and grain yield at harvest. The ST‐B application promoted greater plant height, dry weight, and P uptake at 80 DAE. However, ST‐DB showed the greatest P removal compared to other treatments. Also, greater yields were obtained for ST‐DB and NT‐BR. Soil sampling after harvest showed that ST‐DB increased soil test P levels by 19 and 11% at the 15‐ to 25‐cm layer for Locations 1 and 2, respectively. While NT‐BR increased soil test P by 43 and 36% at the 0‐ to 5‐cm layer for Locations 1 and 2, respectively. Deep band P fertilizer placement maintained or increased soybean yield and P use under long‐term NT in tropical soils.