Effect of fertilizer placement on yield of established alfalfa stands

Abstract

Alfalfa yield response to P and K fertilization management has been documented elsewhere, but little work has been done in western Canada. Field studies conducted on two Manitoba soils for 4 yr evaluated the effects of four levels of monoammonium phosphate and three levels of potassium chloride fertilizers, applied as a surface broadcast or as an in-soil band application, on the yield of established alfalfa (Medicago sativa L.) stands. Applied P increased total annual forage yield on the clay loam soil by 1.53 t h−1 (47%), when averaged over the 4 yr of the study, but did not increase yields on the fine sandy loam. Yield response to P application on the clay loam soil increased over the 4 yr of the study. Potassium application resulted in minor or no increases in forage yield on both soils. On the clay loam soil, there was no yield difference between banded and broadcast fertilizer applications. On the fine sandy loam soil, band application reduced yields slightly compared with broadcast application, particularly at the first harvest following fertilizer application. Grass ingress into the plots was reduced by K application but was not affected by P fertilization, which may indicate a beneficial effect of K fertilization on alfalfa vigor and persistence. Key words: Potassium, phosphorus, banding, broadcast, persistence