在广泛的土壤不同类型和不同气候条件下所进行的无数次试验表明,在肥料需要方面地区性的变化很少一致。由于没有两块田或两个生长季是相同的,因此想要推荐精确的需用肥量是行不通的。在建议范围内的不同施肥率的效果,通常小于其它栽培措施或气候变化的作用。所 Numerous tests conducted under a wide range of different soil types and climates have shown that there is little agreement on regional changes in fertilizer requirements. Since no two fields or two growing seasons are the same, it is not feasible to recommend the exact amount of fertilizer needed. The effect of different fertilization rates within the recommended range is usually less than for other cultivation measures or for climate change. The