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研究了3种主要磷肥品种和3种主要钾肥品种对不同生育期小麦吸收镉的影响。研究表明:不同磷、钾肥处理对小麦吸收镉存在显著差异。施用磷肥都比无肥处理增加小麦对镉的吸收,其中以磷酸二铵的促进作用最大,其次为高量普钙处理;低量普钙和磷酸一铵处理小麦吸收镉相对较少。所有钾肥都比无肥处理增加小麦对镉的吸收,其中以高量KCl处理的促进作用最大,其次为低量KCl处理;硝酸钾和硫酸钾处理小麦吸收镉最少。小麦生育前期吸收的总镉量较少,中、后期明显增大;但植株体内的镉浓度却表现为前期高,后期低,呈现随生育期递进而逐渐降低的趋势,只有磷酸一铵和无磷处理表现为拔节期体内镉含量为最高。镉在小麦体内的累积与其生物量的增加呈正相关,从秸秆向籽粒转移的总镉量随着小麦籽/秆比的增加而降低。本试验土壤镉小于土壤环境质量污染二级标准,但籽粒含镉量均超过国家食品卫生标准允许量(0.1 mg.kg-1),表明土壤Cd污染指标与品种有关,而不是一个对所有作物种类或品种一成不变的固定值。在土壤Cd含量处于污染临界值附近或已受镉污染的土壤上,应选用低富集Cd的小麦品种,控制磷酸二铵和KCl的用量,或选用磷酸一铵、普钙、硫酸钾等肥料,配施碱性物质(如石灰),以降低土壤镉的活性,保证小麦的无公害生产。
The effects of three major phosphate fertilizers and three major potash fertilizers on cadmium uptake in different growth stages of wheat were studied. The results showed that there were significant differences in Cd uptake by different P and K treatments. Compared with no fertilizer treatment, the application of phosphate fertilizer increased the Cd uptake by wheat, with the promotion effect of diammonium phosphate being the largest, followed by the high amount of calcium supplementation, while the low amount of calcium supplementation and monoammonium phosphate treatment absorbed less cadmium. All potassium fertilizers increased Cd uptake in wheat compared with no fertilizer treatment, of which KCl treatment was the most effective, followed by low KCl treatment, while potassium nitrate and potassium sulfate had the least Cd uptake. The total amount of cadmium absorbed in the early growth stage of wheat was less and the mid and late stages increased obviously. However, the concentration of cadmium in the plant was high in the early stage and low in the late stage, which showed a trend of decreasing gradually with the progress of growth period. Phosphorus-free treatment showed the highest cadmium content in the jointing stage. The accumulation of cadmium in wheat was positively correlated with the increase of biomass, and the total amount of cadmium transferred from straw to grain decreased with the increase of wheat seed / stalk ratio. The soil cadmium in this experiment was less than Grade II standard of soil environmental quality pollution, but the content of cadmium in grain exceeded the allowable level of national food hygiene standard (0.1 mg.kg-1), indicating that the indicator of soil Cd pollution was related to variety, not to all crops Variety or variety of a constant fixed value. In the soil Cd content near the critical value of pollution or have been contaminated by cadmium in the soil should be selected low Cd-enriched wheat varieties, control the amount of diammonium phosphate and KCl, or the use of monoammonium phosphate, calcium, potassium and other fertilizers , With alkaline substances (such as lime), to reduce the activity of soil cadmium, to ensure the production of wheat pollution-free.