Introduction of annual forage species (Secale cereale L. and Lolium multiflorum Lam.) into permanent swards: a technique to improve early season herbage production and nitrogen uptake

abonos abonos nitrogenados absorption de substances nutritives aliment pour animaux azote cambisol cambisoles cambisols cultivos de pasto engrais feeds fertilizers forage gramineas graminee grasses grasslands herbage herbage crops loam soils lolium multiflorum mejora de pastizales mineral nutrients nitrogen nitrogen fertilizers nutrient uptake nutrientes minerales oversowing pastizal permanente pasture improvement permanent grasslands permanent pastures piensos plante pour herbage praderas prairie permanente sandy soils secale cereale silty soils sobresiembra sol limoneux sol sableux sol sablolimoneux suelo arenoso suelo franco suelo limoso sursemis textural soil types tipos texturales de suelos type de sol textural