负压灌溉下不同钾水平对小油菜生长的影响

【目的】负压灌溉是一种新型供水技术,能显著节水节肥,本文拟研究5个不同钾水平对小油菜生长的影响,并比较负压灌溉下不同压力对黏壤土含水量的影响,为小油菜钾肥的合理施用提供科学指导。【方法】以小油菜为研究对象,设置4个供水处理(0,-5,-10和-15 k Pa)和无钾(K0)、1倍钾(K1,150 kg·hm~(-2))、1.5倍钾(K1.5,225 kg·hm~(-2))、2倍钾(K2,300 kg·hm~(-2))、3倍钾(K3,450 kg·hm~(-2))5个钾肥处理,确定小油菜在负压灌溉下最佳施钾量和供水压力。【结果】(1)负压灌溉不同压力下黏壤土含水量分别为28.52%、22.45%、18.13%、15.4%,其中-5—-10k Pa供水压力范围内土壤含水量为18.13%—22.45%,较为适宜作物生长,为最佳供水压力。(2)不同钾水平对小油菜产量影响显著,1.5倍钾处理产量最高,比1倍钾处理产量提高16.9%,但过量施钾产量反而显著下降。(3)不同钾水平对油菜硝酸盐含量影响显著,施钾显著降低硝酸盐含量,1.5倍钾处理硝酸盐含量比1倍钾低26.3%。(4)不同钾水平显著影响作物吸收氮磷钾的量,1.5倍钾吸收氮钾量比1倍钾处理分别高15.8%、76.3%,但吸收磷的量低于1倍钾。(5)施钾能显著提高作物钾肥利用率和钾肥农学效率,1.5倍钾钾肥利用率和农学效率比1倍钾提高173.32%和83.9%。(6)施钾比不施钾POD,SOD酶活提高69.8%和93%。不同钾水平显著影响抗氧化酶表达,相比1倍钾,1.5倍钾显著提高了POD、SOD、PPO、PAL表达量,但类黄酮和总酚表达与1倍钾处理无差异。【结论】负压灌溉下黏壤土最佳供水压力为-10—-5 k Pa。在此负压灌溉条件下,从不同钾水平对小油菜生长、品质及养分吸收等指标来看,1.5倍钾处理为最佳钾肥施用水平。

Effect of Different Potassium Levels on the Growth of Bok Choy Under Negative Pressure

【Objective】Negative pressure irrigation is a new type of water supply technology. In this paper, the effects of five different potassium levels on growth, quality, nutrient uptake, utilization ratio and antioxidant enzyme activity of bok choy were compared. 【Method】In this experiment, five K fertilizer treatments including K0, K1, K1.5, K2 and K3, and 4 water supply treatments including 0, -5, -10, and -15 kPa were designed to study the effects of different potassium levels on bok choy growth. 【Result】(1) The soil moisture in clay loam under different pressures of water, respectively, was 28.52%, 22.45% and 18.13%, 15.4%, and when water pressures were between -5 and -10 kPa, the soil moisture was 18.13%-22.45%, which was suitable for crop growth. (2) The effect of different potassium levels on bok choy yield was significant, and that in K1.5 treatment was the highest, and increased by 16.9% compared with K1. The yield in K3 treatment was significantly decreased. (3) The effect of different potassium levels on the nitrate content of bok choy was significant, and potassium could significantly reduce nitrate content, nitrate content in K1.5 treatment decreased by 26.3% compared with that in K1. (4) Different potassium levels significantly affected the amount of nutrients uptake, nitrogen and potassium absorption of K1.5 were increased by 15.8% and 76.3% compared with that in K1. Phosphorus uptake in K1.5 treatment was less than that in K1. (5) K1.5 improved K utilization of crop by 173.32% compared with K1, and K1.5 significantly improved the agronomic efficiency of fertilizer, and increased by 83.9% compared with K1. (6) Compared to K1, K1.5 significantly increased the expression of the activities of POD, SOD, PPO, and PAL, but the flavonoid and total phenolic was not different with K1. 【Conclusion】 It was concluded that K1.5 was the best potassium application level. The optimum water supply pressure was -10--5 kpa kPa for clay loam.