Build-up in soil available P and yield response of spring wheat to seed-placed P in a 24-year study in the Brown Soil zone

abonado localizado ammonium nitrate ammonium phosphate cambisol cambisoles cambisols chernozem chernozems crop yield disponibilidad de nutrientes environmental temperature fertilidad del suelo fosfato de amonio fosforo graine hiver invierno lluvia nitrate d'ammonium nitrato de amonio nutrient availability phosphate d'ammonium phosphore phosphorus placement plant habit pluie port de la plante primavera printemps rain rendement rendement des cultures rendimiento rendimiento de cultivos rotation culturale rotational cropping saskatchewan seeds semilla soil fertility spring temperatura ambiental triticum aestivum winter yields