Effects of Planting Sugarcane and Napier Grass on N Leaching from Lysimeters under High Application of Cattle Manure

Abstract

Aims: Excess manure accumulated in livestock areas has been a concern in Japan where a great amount of nutrients such as nitrogen (N) has been imported from abroad contained in various agricultural commodities especially feeds for livestock animals. Aims of the present study is to look into the effects of planting sugarcane and napier grass on nitrate leaching from fields overdosed with excessive amount of manure application. Study Design: A lysimeter experiment of 3 treatments with 2 replicates. Place and Duration of Study: NARO-Shikoku Research Center (Kagawa, Japan), three years. Methodology: (1) Monitoring of water samples drained from lysimeters during study period, (2) Sampling of planted crops and soils. Results: The plots planted with either sugarcane or napier grass showed less drainage of water as well as less leaching of mineral N compared to control plots after summer when canopy was fully established. However, leaching of mineral N could not be completely prevented at the events of severe rainfalls except for the plots planted with napier grass.  The reduced amount of drainage water for the plots planted with either sugarcane/napier grass was considered to be attributable to evapotranspiration of these crops. Both sugarcane and napier grass recovered a great amount of N in the above-ground part by the time of harvest. Yet, total N concentration of soil layers did not appear to have been affected by the presence of these crops compared to control plots.  Conclusion: It was concluded that planting sugarcane/napier grass was effective in the studied area in reducing leaching of mineral N especially by reducing drainage water