Fertilizer recommendations for day and night grazing of milking cattle on land in Hokkaido are based on previous studies of nutrient dynamics. This study confirmed the applicability of recommendations to different grazing conditions and conducted observations to extend the versatility of the fertilizer recommendation. We estimated the dynamics of fertilizer nutrients under various grazing regimes, namely with different cattle types (dairy heifers, beef breeding cows or beef heifers), stocking methods (rotational stocking or continuous stocking), seasons (throughout grass growing season or after harvest of the first crop) and times (24‐hr grazing or time restricted to 5–9 hr/day). Body weight, herbage intake and excretion were measured, and the total intake and return of nutrients to the pasture were calculated. Nutrient removal by grazing, calculated as intake minus return through excretion, increased with herbage intake. Almost all the nutrients removed under grazing throughout the growing season approached the upper or lower limits of our previously reported levels. In many cases, changes in the amounts of soil nutrients with grazing were close to the estimated amounts removed from the soil in the grass growth periods. These results show that the pasture nutrient dynamics quantified in our previous study for lactating cattle are also applicable to dairy heifers and beef cattle and to time‐restricted grazing as well as grazing after 1st cut. Regression equations were obtained to predict the fertilizer recommendations from herbage intakes for these various grazing conditions.

中文翻译：

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日本北海道不同饲养方式和牛型温带牧场的养分动态

在北海道陆地上白天和晚上放牧奶牛的化肥建议是基于先前对养分动态的研究。这项研究证实了建议对不同放牧条件的适用性，并进行了观察以扩大肥料建议的通用性。我们估算了不同放牧制度下肥料养分的动态，即不同类型的牛（奶牛，奶牛或小母牛），放养方式（旋转放养或连续放养），季节（在整个草生长季节或收获后）。初次播种）和时间（24小时放牧或时间限制为5 –9小时/天）。测量体重，牧草的摄入量和排泄量，并计算养分的总摄入量和返回牧场的养分。放牧对营养物的去除量（计算为摄入量减去通过排泄物返回的量）随草料的摄入量而增加。在整个生长季节中，几乎所有在放牧过程中清除的养分都达到了我们先前报道的水平的上限或下限。在许多情况下，放牧引起的土壤养分含量的变化接近草生长时期从土壤中去除的估计数量。这些结果表明，在我们先前的研究中对泌乳牛进行定量研究的牧场养分动态也适用于奶牛和奶牛以及有时间限制的放牧以及第一次割后的放牧。