Nitrogen Effects of Barnyard Manure Applied on Andosol Grasslands in Eastern Hokkaido

Annual changes in the nitrogen (N) effects of barnyard manure (BM) were estimated on grassland of eastern Hokkaido, Japan. In pure' timothy (Phleum pratense L.) grasslands, they were as follows: in the first year after renovation, BM, when ploughed under, supplied an estimated 1 kg Nit manure; this value decreased to 0.5 kg Nit, and 0.3 kg Nit in the second and third year, respectively. When topdressed, BM supplied an estimated 1 kg Nit in the first year, and 0.5 kg Nit in the second year. In timothy-legume mixture, the amount of N supplied by BM to pure timothy grassland was estimated' as sufficient for good yield and botanical composition in comparison with the standard fertiliser plot without BM.