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珠江三角洲土壤钾素含量全钾平均1.68%,缓效性钾225ppm,速效性钾118ppm,在全省居中等水平。土壤有效钾含量不高。水平分布由三角洲前缘向顶部递减。水稻吸收缓效性钾越早,土壤供钾性能越差。水稻各生育期累积吸钾量变化呈开口向下的二次曲线,出现前轻、中重、后减弱规律。水稻中期吸钾越高,土壤供钾越好。土壤速效性钾变化呈开口向下的二次曲线,曲线变化越平缓,土壤供钾量越少。连续种植水稻吸钾总量占土壤有效钾贮量越多,供钾性能越差。粘质三角洲冲积潜育性水稻土,钾素的含量中上,土壤供钾性能好,早稻钾肥肥效不显著,晚稻极显著。粘质三角洲冲积沼泽性水稻土、粘质三角洲冲积盐溃强酸性水稻士钾素含量最高,但前者地下水位高,后者有酸害,影响水稻吸钾,钾肥肥效不显著。高度熟化粘质三角洲冲积潴育性水稻土等,土壤钾素含量,供钾性能较好,但生产性能高,需钾量大,钾肥肥效早晚稻极显著。沙质砖红壤性红壤潴育性水稻土,钾素含量和水稻吸钾量最少,供钾性能最差,钾肥肥效早晚稻十分显著。
In the Pearl River Delta, the potassium content in soil was 1.68% on average, 225 ppm for slow-acting potassium and 118 ppm for quick-acting potassium, which was the middle level in the whole province. Soil available potassium content is not high. The horizontal distribution decreases from the leading edge of the delta to the top. The earlier the slow-acting potassium absorbed by rice, the poorer the potassium supply to the soil. The cumulative potassium uptake in different growth stages of rice showed a quadratic curve with downward opening, with light, medium and heavy weight decreasing. The higher the mid-term potassium uptake, the better the potassium supply to the soil. Soil available K showed an open downward quadratic curve, the more gentle curve changes, the smaller the amount of potassium in the soil. The total potassium uptake by continuous cropping rice accounted for more available soil potassium reserves, the poorer the potassium supply. In the viscous delta of alluvial soil, the content of potassium in middle and upper paddy soils was good, but the efficiency of potassium fertilizer in early rice was not significant, and the late rice was extremely significant. Clay delta alluvial marsh paddy soil, viscous delta alluvium salt collapse strong acidity rice rice potassium content is highest, but the former groundwater level is high, the latter has acid damage, affecting rice potassium, potassium fertilizer efficiency is not significant. Highly mature clay delta alluvial paddy soil, soil potassium content, potassium for better performance, but high productivity, large amount of potassium, potassium fertilizer is very significant early or late rice. Sedimentary paddy soil with sandy soil red soil had the least potassium content and potassium absorption capacity, the poorest potassium performance, and the early-late rice with high potassium fertilizer efficiency was very significant.