Research on the Farm (ROTF)

Background & Info

Research from Johnston et al. (2006) determined that 25% of fields are rated low to very low in soil P and cannot supply adequate phosphorus for a corn crop. Starter P is typically applied generously as a result of this data.

This project looks at the yield benefit vs. yield draw of starter P applied on high-P testing soils

Corn has high phosphorus requirements for plant development, beginning at germination. It is a favourable practice to seed-place a portion of the phosphorus blend, resulting in vigorous seedling growth and development. The remainder of the blend can be placed in a band near the seed row, though some grain corn farmers have adopted a split application process in-crop.

Starter phosphorus increases early-season biomass and plant height when measured at V4 and V7, respectively (Rogalsky, 2016). In the same research, silking date was 2–7 days earlier in starter-P treatments than untreated checks.

Result

Only one site showed a significant decrease in yield when no phosphorous was applied.

Starter phosphorus applications in fields with high residual-P did not provide an economical boost in grain corn yield in any sites.

The only site that did see a statistically significant decline in yield when no phosphorous was applied had the lowest soil phosphorous test overall. In this case, they saw a 7.29 bu/ac increase when applying soil phosphorous. Based on current cost of production estimates from Manitoba Agriculture this site saw an increase in net profit of $16.46/ac when phosphorous was applied

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