PHOSPHORUS AND POTASSIUM EFFECTS ON YIELD AND NUTRIENT UPTAKE IN ARROWLEAF CLOVER.

Arrowleaf clover (Trifolium vesiculosum Savi 'Yuchi') is a winter annual legume that can be used to extend the grazing of warm-season perennial grasses in forage production systems. Stand establishment from overseeding often fails because of unfavorable climatic coditions and nutrient deficiencies in soils. The objectives of this research were to determine the effects of P and K fertilization on yield and nutrient uptake of arrowleaf clover and accumulation of soil P and K. Arrowleaf clover was seeded in field plots in the fall of 1978. Fertilizer treatments consisted of an incomplete factorial arrangement of multiple rates of P, K, and P plus K. The soil type was a Taloka silt loam (Mollic Albaqualfs). Yield and N, P, and K uptake in forage were determined in four consecutive years starting in 1979. Soil test indices were measured prior to seeding in 1977, in the fall of 1978, and after four annual fertilizations in 1982. Regression equations with linear, quadratic, and interaction terms were calculated to describe dependent variable response surfaces for each year and the average over years. Phosphorus fertilization increased yield each year.