The behavior of the fertilizer nutrients of barnyard manure covered with a sheet

The barnyard manure produced on a dairy farm (0.78-0.82 kg kg(-1) water content) was stored on a grassland for a period of 82 -127 d. In order to consider the influence of the difference in the method of manure management on the behavior of fertilizer nutrients from the barnyard manure, two methods of treatment were prepared. One of them was the CM, which involves covering the barnyard manure with a sheet, and the other was the NCM, in which the barnyard manure was not covered with a sheet. The barnyard manure was measured prior to and after storage. Concentrations of N, P, and K were also determined prior to and after storage. In 1999, the amount of the effluent and the concentrations of fertilizer nutrients in the effluent from the barnyard manure were investigated. The following results were obtained: 1) The concentrations of N. P, and K in the barnyard manure were 3.8-6.6 g kg(-1), 1.5-1.9 g kg(-1), and 4.0-10.4 g kg(-1) at the end of storage, respectively. As compared with the NCM, the concentrations of N and K in the barnyard manure were observed to be higher in the CM at the end of storage. Furthermore, the difference between the two treatments with respect to the concentration of P in the barnyard manure at the end of storage was negligible. 2) More than half of the nitrogen in the barnyard manure was lost during storage. It was considered that the main cause was not the outflows accompanied by the movement of water, but discharge to the atmosphere by ammonia volatilization and denitrification of the barnyard manure. 3) The rates of disappearance of P and K from the barnyard manure at the end of storage were 7-10%, and 23-47%, respectively. With respect to both the nutrients, the rate of disappearance in the CM was observed to be lower than that in the NCM. Covering the barnyard manure with the sheet considerably reduced the amount of effluent, and was thus very effective in reducing the loss of P and K in the effluent. 4) Based on these results, it was concluded that covering the barnyard manure with a sheet was an effective method with respect to keeping the losses of fertilizer nutrients from the barnyard manure to a minimum, maintaining the fertilizer efficiency of the barnyard manure at a high level, and preventing water pollution caused by the outflow of fertilizer nutrients.