Yields and N uptake of barley and ryegrass from soils with added animal manure differing in straw and urine content.

摘要

Cattle manure with high, medium, or low proportions or no urine + straw stored for 3-6 months were applied in amounts corresponding to 120 kg N ha-1 in spring or autumn 1993 to a sandy loam at Askov and a coarse sand at Lundgard, Denmark. Barley cv.Alexis and Lolium perenne cv. Borvi were grown in 1993-94 and 1993-95. Barley was harvested at maturity and the wintering ryegrass was cut three times in the second year. Additional mineral N in the form of 15N-labelled mineral fertilizer (50 kg N ha-1)was added to all barley plots at sowing in spring. Non-manured plots receiving only the 15N-labelled mineral fertilizer were included. Manure without urine + straw contained more NH4-N than the other manures and spring incorporation of this manure gavethe highest dry matter yield and N uptake by barley. When manure without urine + straw was applied in autumn, the yield and N uptake were increased only on the sandy loam. On the coarse sand, the NH4-N was probably leached as NO3-N during the winter. Thethree manures with urine + straw did not affect barley grain yield or total N uptake. Thus these manures did not mineralize nor immobilize measurable quantities of N in the first growth period. On the sandy loam, the patterns of N uptake in ryegrass indicated an increased availability of manure N during the second growth period. The availability of N from the 15NH415NO3 was similar in all plots when manures were applied in spring. Less 15N was taken up by the spring barley when manure was added in autumn compared with crops given 15NH415NO3 only. Thus short-term effects of N in cattle manure stored with or without urine + straw are low. For soils low in mineral N such manures may potentially reduce crop N uptake.