Improved manure and fertilizer practices changes nutrient dynamics in silage meadows on a dairy farm in eastern Hokkaido, Japan

Abstract

AbstractImproved fertilizer practices were gradually introduced over 8 years to the silage meadows of Konsen Agricultural Experiment Station, a working dairy farm in eastern Hokkaido (approximately 100 ha, a size common in the area). The entire amount of farmyard manure and slurry that was applied to the fields and the entire amount of harvested herbage was measured directly by weighbridge. The nutrient content of the manure was measured every year from 2004, the nutrient content of the harvested herbage and silage was measured every year from 2006, and the amounts of soil‐available nutrients were measured every year from 2008. The two improved fertilizer practices—“more effective use of livestock manure,” which was introduced in 2005, and “nutrient application depending on soil fertility,” which was introduced in 2008—clearly decreased the input of potassium to the silage meadows. By means of improved weed control at grassland renovation from 2008 onwards and implementation of the improved fertilizer practices, herbage yields were maintained at around the target yield for this area, and botanical compositions (percentages of timothy and legumes) were improved. The potassium content of herbage and silage decreased significantly. Furthermore, the potassium content of the slurry also decreased from the year following that when the potassium content of the silage decreased. Reduction of potassium in the farmyard manure tended to be observed the year following the decrease observed in the slurry. Exchangeable potassium in the top 0–5 cm of soil decreased and neared the recommended level. The cost of chemical fertilizer was also reduced. These improved effects measured directly on a commercial‐scale dairy farm at the Konsen Agricultural Experiment Station provide important quantitative evidence for promoting improved fertilizer practices.