Estimation of the amount of nutrients in livestock manure

Abstract

Nutrient amounts in livestock manure management, including manure treatment and use, were estimated using published statistical data and other information. The eight categories for manure treatment were defined in this study as composting at facility, composting at stockyard, raw faeces, dried faeces, urine, slurry, purification, and other. The three categories for use of manure include application to farmland, for sales and exchange and other. The regional daily excretion units per head of dairy and beef cattle, including the amount of excreta, nitrogen (N), phosphorus (P) and potassium (K), were calculated based on the quantities and qualities of feed in each region. There was a difference found in the values for Hokkaido and other regions. Concerning manure treatment methods in the dairy sector, the sum of the proportion of raw faeces and compost at stockyard was high in Hokkaido. On the other hand, the sum of the proportion of composting at facility and dried faeces was high in Hokuriku, Tokai, Kinki and Shikoku. In Kyushu, the proportion of slurry production was higher than in any other region. The amounts of N, P, and K in compost estimated in this study were compared with those calculated from published statistics. The results showed that the amounts of N, P, and K in dairy cattle compost, N and K in beef cattle compost, and N in poultry compost were similar to the amounts cited in reported statistics. The amounts of P in beef cattle, swine, and poultry compost were lower than those cited in reported statistics. As for the use of manure, application to farmland is the most common use of manure in the dairy and beef cattle sector. The proportions of purification, and sales and exchange were high for the swine and poultry sectors, respectively. Large amounts of liquid manure, such as urine and slurry, are applied to farmland. To clarify the nutrient load resulting from liquid manure, the usable amount of dairy slurry was calculated based on both the standard application rate of fertilizer and the area of grassland and forage crops. As a result, the amount of usable N was lower than the amount of liquid manure N in the Kanto-Tosan, Tokai and Kinki regions.