RESIDUAL EFFECTS FROM FERTILIZER ON NATIVE RANGE IN SOUTHWESTERN SASKATCHEWAN
Residual effects of fertilizer on native grassland throughout southwestern Saskatchewan persisted for six years or more, and were more important than the initial response. These residual effects resulted in yield increases and in increased phosphorus content of the forage. The sodium bicarbonate-extractable (available) phosphorus in the soil was increased by the use of phosphatic fertilizer; this increase persisted for six years after fertilizer application. The correlation coefficients between yield response and measured soil properties were not high for any of the measurements. The yield response was more closely related to the amounts of available N in the soil, the pH, and the texture than to the other soil and plant measurements. Responses were greatest on medium-textured soils, low in fertility and with a pH above 7.