Recent advances in fertilizer placement. II.—Fertilizer placement in england

Phosphorus and potassium fertilizers used for cereals should be drilled with the seed; half‐dressings applied in this way have produced as much grain as full‐dressings broadcast. Where potatoes are hand‐planted in furrows, fertilizer may be concentrated near the seed satisfactorily by broadcasting it over the furrows before planting. When a mechanical potato planter was used on flat land, fertilizer dressings applied in bands beside the seed produced higher yields and more profit than broadcast dressings. Fertilizer placed near the seed produced higher yields of beans and peas and several kinds of horticultural crops than the same quantities of broadcast fertilizer. For high‐value cash crops, placement may be very profitable. Absence of crop responses in field experiments may be due to fertilizers' having been applied in the wrong place. Some crops, e.g. sugar beet, mangolds and kale, made better early growth when complete NPK fertilizer was placed beside the seed than when fertilizer was broadcast, but at harvest the two methods of application gave similar yields. PK fertilizers broadcast over established temporary and permanent herbage crops gave higher yields than dressings placed in bands below the surface. Placing PK fertilizers in bands at the side of lucerne seed was not superior to broadcasting. When light dressings of superphosphate were placed directly below the seed as a‘starter’, lucerne grew more rapidly and produced higher yields than when superphosphate was broadcast. Fertilizers broadcast and incorporated deeply with the soil have advantages over dressings worked‐in shallowly in dry seasons and for deep‐rooting crops. Root growth of most crops was stimulated by dressings of mixed fertilizers placed near the seed. Nitrogen, phosphorus and potassium fertilizers placed near the seed of peas each stimulated extra root growth. The factors that affect the value of fertilizer dressings are discussed, with particular reference to the kinds of root systems developed by crops.