The relationship between nutrient cycling and farm level nutrient balances in the mixed farming systems for beef fattening and rice production
2008
Tabata, Y.(Kyoto Univ. (Japan)) | Oishi, K. | Kumagai, H. | Hirooka, H.
The objectives of present study were to investigate the effects of nutrient cycling and relationship between nutrient cycling and nutrient balances in the mixed farming systems for beef fattening and rice production. Nutrient flow models for nitrogen and phosphorus in a farming system were developed from data of a surveyed farm. The models simulated nutrient balances and nutrient cycling with change of animal intensification represented as the number of steers per area. The results indicated that nutrient use efficiencies (exports/imports) were more affected by animal intensification, the ratio of products to import for beef fattening and rice production, and exports of manure than by nutrient cycling in the systems. The nutrient cycling decreased nutrient losses (imports minus exports). However, the nutrient cycling increased nitrogen use efficiency but decreased phosphorus use efficiency. The relationship between nutrient balances and nutrient cycling (cycling index) was not found clearly. It was concluded that the simulation approach was a useful tool to analyze nutrient balances and cycling in mixed crop-livestock farming systems.
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