ABSTRACT

To determine the impact of K fertilization on crop yields and soil K supplying capacity in rice (Oryza sativa L.) and oilseed rape (Brassica napus L.) rotation, four field experiments were conducted with five K fertilizer rates: 0 (K0), 90–147 (K1), 180–210 (K2), 270–300 (K3) and 336–390 (K4) kg K₂O ha⁻¹ per rotation. Compared with K0, adding K increased the yield of rice and oilseed rape by 4.2–8.9% and 7.5–32.6%, respectively. Potassium fertilization increased K uptake at four sites, whereas yields remained stagnant in K2, K3, and K4 treatments despite increasing K uptake. Continuous K removal decreased soil K supplying capacity. For the 0 to 20 cm and 20 to 40 cm soil depths, the NH₄OAc-K and boiling HNO₃-K at the harvest were decreased in K0 and K1 treatments, whereas it maintained or increased in K2, K3, and K4 treatments, although negative K balances were recorded at all sites. It suggests that application 180–210 kg K₂O ha^–1 in rice-oilseed rape cropping systems improved crop yield and maintained soil potassium fertility.

摘要

为了确定钾肥对水稻（Oryza sativa L.）和油菜（Brassica napus L.）轮作中作物产量和土壤钾供应能力的影响，在五种钾肥施用量下进行了四次田间试验：0（K0），每转 90–147 (K1)、180–210 (K2)、270–300 (K3) 和 336–390 (K4) kg K ₂ O ha ^-1。与K0相比，添加K使水稻和油菜的产量分别提高了4.2-8.9%和7.5-32.6%。施钾增加了四个地点的钾吸收，而尽管钾吸收增加，但 K2、K3 和 K4 处理的产量仍然停滞不前。持续的钾去除降低了土壤的钾供应能力。对于 0 至 20 cm 和 20 至 40 cm 的土壤深度，NH ₄ OAc-K 和沸腾的 HNO_{收获时的3} -K 在 K0 和 K1 处理中降低，而在 K2、K3 和 K4 处理中保持或增加，尽管在所有地点都记录到负 K 平衡。这表明在水稻-油菜种植系统中施用 180–210 kg K ₂ O ha ^{–1可以提高作物产量并保持土壤钾肥力。}