Evaluation of Land Improvement and Heavy Rate Incorporation of Farmyard Manure into Heavy Clay Soil at Grassland Renovation on Grass Production

Abstract

A field scale trial was conducted over a period of 8 years on heavy clay soil in poor physical condition in order to assess land improvement with heavy rate incorporation of farmyard manure (FYM) at grassland renovation on grass production. The land improvement included pipe drainage, subsoiling, deep tillage to 0.6m and incorporation of FYM at heavy rate, up to 800t/ha. The land improvement without the FYM incorporation did not increase nitorogen (N) uptake by grass and grass dry matter (DM) production of the renovated sward. The land improvement with heavy rate FYM incorporation significantly increased N uptake by grass and grass DM production, with incorporation rate. The N uptake and grass DM production, however, could be explained by only mineral fertilizer, i.e. in terms of response to nutrients applied. From the results, it was suggested that the observed benefits of land improvement with heavy rate FYM incorporation were not as a result of an improvement in soil physical properties. We concluded, therefore, that the land improvement and heavy rate FYM incorporation could be explained in terms of the impact of nutrient supply, similar to the effects of mineral fertilizer application to renovated grassland, even though the land improvement were undertaken at grassland renovation on the heavy clay soil in poor physical condition.