土壤钾素供应状况的研究——Ⅳ.禾谷类及豆类作物对土壤层间钾的利用

RESEARCHES ON THE POTASSIUM SUPPLY OF SOILS Ⅳ. UTILIZATION OF SOIL INTERLAYER POTASSIUM BY GRAMINACEOUS AND LEGUMINOUS CROPS

研究了禾本科和豆科两类作物对土壤层间钾的利用及钾肥对土壤层间钾的恢复能力,结果表明:(1)耗竭种植时交换性钾、缓效性钾均能出现“最低值”,它们可分别反映第一部分与第二部分层间钾(非交换性钾)的释放速率;(2)禾谷类稻、麦较豆类作物大豆、箭舌豌豆吸收层间钾的能力强,随着土壤钾素耗竭程度增加,作物吸钾量明显下降;(3)无论是禾本科的稻、麦还是豆科作物,新固定的钾比原来的层间钾更有效。

Pot and field cxpcrirnents were carried out to study the utilization of soil interlayer potassium by ryegrass, rice, wheat, soybean and vatch. The results revealed that (1) successively intensive cropping in pot reduced both the soil exchangeable K and slowly available K (boiling 1 mol·L^(-1) HNO_3 method) to their minimum values, which reflected the release rate of the more rcadily available interlayer K (nonexchangcable K) and the less readily available interlayer K respectively; (2) the grain crops——rice and whcat have stronger ability to absorb soil interlayer K than the legume crops——soybcan and common veteh, as the cultivation periods incrcased without any potassium applied, the amounts of soil potassium absorbed by the crops markedly decreased; (3) the potassium fixed in interlayer of minerals by potash fertilizcr application could be used more readily by both thc graminaccous and leguminous crops than native interlayer (nonexchangcable) potassium.