Root Development in Dairy Manure‐Treated Soil

Abstract

AbstractEffects of dairy cattle manure on root growth of two forage crops were evaluated in a rhizotron study. The four treatments consisted of mineral fertilizer mixed into or applied to surface soils; manure incorporated into surface soils at two rates: 70 and 140 metric tons/ha; and manure layered at 25‐cm depth between the surface and subsoil at 140 metric tons/ha.Incorporation of manure promoted early root and top growth of pearl millet (Pennisetum americanum [L.] Leeke vat. ‘Gahi‐1’). The increase in growth was attributed to increased soil temperature. The layered treatment acted as a barrier to gas movement and inhibited early root growth into the subsoil. Although lack of deep rooting reduced early top growth, millet eventually grew most rapidly on the layered treatment. Total dry matter yield on the layered treatment was equal to that from the 140 metric ton/ha incorporated treatment; lowest yield was on the mineral fertilizer treatment.Yield of fall‐planted rye (Secale cereale L.) was. nearly three times that of the mineral‐fertilized plots. Root growth of rye was reduced with the high rate of incorporated manure.