Decrease of nitrate content and improvement of mineral balance in corn plants and soil of forage fileds under controlled utilization of animal composts in dairy farms
1999
Masaoka, Y. (Kyushu National Agricultural Experiment Station, Nishigoshi, Kumamoto (Japan)) | Arakawa, Y. | Masuda, T.
Nitrogen nutrient derived from animal composts had been applied continuously for many years with about two times excess for forage plant growth in dairy farms at Shisui machi, Kumamoto prefecture, Kyushu because of their own insufficient crop filed for nitrogen recycling. Field experiments with reduced application of animal composts (RAAC) which contained only half of the amount of requirements for plant growth were conducted to decrease nitrate nitrogen (NN) accumulation and improve the mineral balance of corn plants and crop field soil in six dairy farms. 1) The NN concentration in the corn stem decreased to less than 5 g/kg (dry matter basis) and no whole plant shoots showed a NN concentration higher than 2 g/kg after RAAC for one year. 2) The concentration of exchangeable potassium in the dairy farm soil decreased from 60 to 27 mg/100g after RAAC for two years. 3) Average dry yield of corn plants in the fourth year was 16% lower with RAAC than that with excess utilization of animal composts, but the difference was no significant. The concentration of potassium was lower, while that of calcium and magnesium was higher in RAAC, which resulted in the decrease of the K/(Ca+Mg) equivalent ratio from 1.78 to 1.15 in the corn plant. These results suggested that RAAC could improve the feed quality by the reduction of the NN content and improvement of the mineral balance of plant
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