The impact of phosphorus fertilizer placement on crop production
Improved phosphorus (P) fertilizer management is viewed as a way to improve yields in highly productive cropping system. A study was conducted at numerous sites during the 1990’s to assess plant density and yield of canola (Brassica napus L.), barley (Hordeum vulgare L.), spring wheat (Triticum aestivum L.), and winter wheat respond to greater P fertilizer rates (0, 15, 30, 45, and 60 kg P ha-1) when seed placed and side banded. We did find that canola stand was insensitive to rates of P tested when banded, but greater rates of seed-placed P caused stand thinning. It is thought the compensatory growth of canola was the reason why canola yield did not respond to P treatment. Both barley and winter wheat yielded most when the greatest rates of P were applied. Spring wheat showed a similar response when P was side banded, thus indicating improved tolerance with P placed away from seed. Therefore, spring wheat was the only crop that fit with our hypotheses; side banding P will allow crops to respond positively to greater rates of P fertilizer. The fact the cereal crop density was unresponsive to P management indicates that seedlings show early-season better tolerance than canola. Unlike canola, yield-forming factors for cereal crops responded to greater rates of P.
Soils and Crops Workshop