钾硅肥替代化学钾肥施用效果及钝化土壤重金属效果研究

发布时间：2018-09-18 09:11

【摘要】：钾是植物生长过程中所必需的大量营养元素之一,合理施用钾肥是保证作物产量和品质的重要途径。但我国可溶性钾矿资源短缺,寻找合适钾肥替代措施关系国民粮食安全。由难溶性含钾矿物制成的钾硅肥对作物生长起到一定促进作用。为探究钾硅肥替代化学钾肥的施用技术,本研究采用盆栽试验,研究了水旱轮作模式下不同钾肥种类,钾硅肥不同用量,不同形态钾肥配比对油菜-水稻生长,钾素吸收及钾肥利用率的影响,明确了钾硅肥替代钾肥施用技术。在此基础上,为探究钾硅肥中含有的硅、钙等元素对土壤铅、镉的钝化效果,进一步研究了钾硅肥及其副产品(硅钙肥)施用对重金属污染土壤上水稻生长及重金属吸收的影响,结合土壤有效态重金属含量变化,分析了钾硅肥及硅钙肥降低水稻地上部各部位重金属含量的机制。为钾硅肥合理施用及改良重金属污染土壤提供理论依据。主要研究结果如下:1.在等量钾肥(K2O)投入的情况下,钾硅肥施用效果和硫酸钾施用效果等同,都显著增加了两季作物的生物量。与不施钾处理相比,钾硅肥处理前、后两季的作物增产率分别为61.2%和37.8%,粉碎性钾矿粉对两季作物增产效果均不显著。钾硅肥施用显著增加了前季油菜和后季水稻茎秆的钾素含量,钾硅肥处理前、后两季的钾肥吸收利用率分别为50.7%和26.0%。钾硅肥施用显著增加了前季作物种植后土壤钾素含量。从钾的养分供应角度考虑,钾硅肥可以替代水溶性钾肥。2.盆栽试验条件下,钾硅肥的适宜用量为0.15-0.225 g K2O/kg。前季油菜生物量随着钾硅肥用量的增加而增加,当施肥量达到2.25 g K2O/盆时,油菜生物量达到最大值,最大增产率为70.6%,显著高于其他处理。后季水稻生物量随着施肥量增加而增加,当施肥量为3.00 g K2O/盆时,生物量最大,最大增产率为57.0%。两季作物种植后,只有当施肥量为3.00 g K2O/盆时,偏养分平衡值小于1,此时土壤钾素处于盈余状态。3.综合结果表明,含25%~50%水溶性钾的钾硅肥效果较好。不同形态的钾肥配比均能显著提高两季作物生物量和钾素积累量。与不施用钾肥处理相比,25%水溶性钾的钾硅肥处理春油菜和水稻的增产率分别为61.5%和50.7%,显著高于其他处理。含50%水溶性钾的钾硅肥处理两季作物总吸钾量最高,春油菜和水稻钾肥吸收利用率分别为58.0%和52.0%,钾肥真实利用率分别为98.3%和58.4%。钾肥施用显著增加第一季作物种植后土壤速效钾和缓效钾含量。4.钾硅肥的施用显著降低了水稻地上部各部位铅、镉的积累量,且水稻地上部铅、镉的积累量随着钾硅肥用量的增加而降低。钾硅肥的施用显著降低了水稻茎、叶和籽粒中铅和镉的积累量,与施用硫酸钾处理相比,水稻茎、叶和籽粒中铅和镉的积累量分别降低了34.2%、49.0%、18.6%和28.2%、42.4%、24.4%,且随着钾硅肥用量的增加,水稻地上部各部位铅镉的积累量显著降低,但水稻根部重金属积累量并无显著差异。土壤中有效态铅、镉经过一季水稻种植后均有不同程度降低,钾硅肥处理和硫酸钾处理土壤有效铅、镉含量并无明显差异。钾硅肥的施用即满足了水稻对钾素的需求,又降低了水稻地上部各部位对土壤重金属的吸收。5硅钙肥施用显著提高了水稻产量,显著抑制水稻对重金属的吸收与积累。与对照处理相比,水稻产量增加51.9%;与重金属处理(M)相比,重金属+硅钙肥处理(MF)的水稻茎秆、叶片和籽粒中Pb浓度分别降低了50.9%,56.3%和24.3%,水稻茎秆和籽粒中Cd浓度则分别下降36.1%和60.4%;硅钙肥施用增加了水稻各部位硅浓度,水稻地上部重金属浓度减少的原因可能是硅的沉积,各部位硅的浓度和重金属浓度呈现明显的负相关。水稻种植后,土壤Pb、Cd浓度都有一定程度的降低,硅钙肥施用未能明显促进土壤重金属从酸可溶态和可还原态向可氧化态和残渣态的转化。
[Abstract]:Potassium is one of the essential nutrient elements in plant growth process. Rational application of potassium fertilizer is an important way to ensure crop yield and quality. However, China is short of soluble potassium mineral resources and seeking suitable potassium fertilizer substitution measures is related to national food security. In order to explore the application technology of potassium-silicon fertilizer instead of chemical potassium fertilizer, pot experiment was carried out to study the effects of different potassium fertilizer types, different amounts of potassium-silicon fertilizer and different forms of Potassium Fertilizer on rape-rice growth, potassium uptake and potassium utilization efficiency under paddy-dry rotation. In order to study the passivation effect of silicon and calcium in potassium-silicon fertilizer on lead and cadmium in soil, the effects of potassium-silicon fertilizer and its by-products (silicon-calcium fertilizer) on the growth and heavy metal uptake of rice in heavy metal contaminated soil were further studied. The main results are as follows: 1. Under the same amount of potassium fertilizer (K2O), the application effect of potassium silicate fertilizer and potassium sulfate fertilizer were the same, and the biomass of two crops increased significantly. Compared with the treatment without potassium fertilizer, potassium silicate fertilizer increased significantly. Before and after silicon fertilizer treatment, crop yield increased by 61.2% and 37.8% respectively, and the effect of comminuted potassium mineral powder on crop yield was not significant. Potassium and silicon fertilizers can replace water-soluble potassium fertilizers from the point of view of potassium nutrient supply. 2. Under pot experiment conditions, the suitable amount of potassium and silicon fertilizers is 0.15-0.225 g K2O/kg. The biomass of rape in the first season increases with the increase of potassium and silicon fertilizers. When the amount of potassium and silicon fertilizers reaches 2.25 g K2O/pot, the rape is raw. The biomass of rice in the later season increased with the increase of fertilizer application. When the fertilizer application rate was 3.00 g K2O/pot, the biomass was the largest, and the maximum yield was 57.0%. After two cropping seasons, the partial nutrient balance was less than 1 only when the fertilizer application rate was 3.00 g K2O/pot. The results showed that potassium and silicon fertilizers containing 25% ~ 50% water-soluble potassium had a better effect. The biomass and potassium accumulation of two crops could be significantly increased by different forms of potassium fertilizer. Potassium and silicon fertilizers containing 50% water-soluble potassium had the highest total potassium uptake by crops in the two seasons. The potassium uptake and utilization rates of spring rape and rice were 58.0% and 52.0% respectively. The true utilization rates of potassium fertilizer were 98.3% and 58.4% respectively. The accumulation of lead and cadmium in the shoots of rice decreased with the increase of potassium and silicon fertilizer. The accumulation of lead and cadmium in the stems, leaves and grains of rice decreased significantly with the application of potassium and silicon fertilizer. With the increase of potassium and silicon fertilizer, the accumulation of lead and cadmium in the above-ground parts of rice decreased significantly, but the accumulation of heavy metals in the roots of rice had no significant difference. There was no significant difference in available lead and cadmium contents in the soil. Compared with the treatment of heavy metal (M), the Pb concentration in rice stems, leaves and grains decreased by 50.9%, 56.3% and 24.3% respectively, while the Cd concentration in rice stems and grains decreased by 36.1% and 60.4% respectively. After rice planting, the concentrations of Pb and Cd in soil decreased to a certain extent, and the application of Si-Ca fertilizer could not significantly promote the transformation of heavy metals from acid-soluble and reducible to oxidizable and residual state.
【学位授予单位】：华中农业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S143;S511

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