When determining fertilizer levels it is also important to look at previous years yields along with previous fertilizer application levels. If a 50 bushel durum crop was fertilized at a 40 bushel level, the difference needs to be made up so the soil N pool is consistent from year to year. Soil tests are important periodically to verify the previous three points. Soil tests are a guideline only because of the various errors that can occur in their procedure and need to be implemented in a broad approach to fertility. If unsure, we err to using higher rates.
Maximum yield is determined by the fertility available in the earliest stages of crop development.
Foliar applications mainly affect protein therefore proper rates have to be applied with the seed. In both cases, the fertilizer rate was varied proportionately cutting the seeding units speed. Also, a poorer stand because of poor seed vigour made it more difficult to analyze the plot. In a zero-till system, fertility is just one of the many variables which need to be considered. With that noted, we feel that in our operation liquid fertilizer at seeding is an effective option.