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为了提高土壤中氮磷钾肥的利用率,通过恒温振荡试验研究了硅藻土、改性海泡石对氯化铵、磷酸二氢钙和氯化钾的吸附作用。通过盆栽试验,测定了玉米不同生长时期土壤中氮磷钾含量,研究了硅藻土、改性海泡石对氮磷钾的缓释作用。研究结果表明,在25℃条件下恒温振荡4 h,氯化铵和氯化钾的初始浓度为60 mg/L时,硅藻土对氮、钾的吸附率分别达到最大值12.80%和17.26%;改性海泡石对氮、钾的吸附率分别达到最大值19.22%和14.75%。当磷酸二氢钙的初始浓度为60 mg/L时,恒温振荡6 h,硅藻土、改性海泡石对磷的吸附率分别达到最大值35.42%和13.42%。对玉米盆栽试验土壤中氮磷钾含量的测定结果表明:硅藻土、改性海泡石对氮磷钾具有良好的缓释作用。该试验获得了硅藻土:改性海泡石:尿素:过磷酸钙:氯化钾的优化质量比为3:3:17.3:9.3:9.6,为缓释肥的研制奠定了基础。
In order to improve the utilization of nitrogen, phosphorus and potassium in soil, the adsorption of diatomite and modified sepiolite to ammonium chloride, monocalcium phosphate and potassium chloride was studied by constant temperature oscillation test. Through pot experiment, the contents of N, P and K in soils of different growth stages of maize were determined. The sustained-release effects of diatomite and modified sepiolite on N, P and K were studied. The results showed that when the initial concentration of ammonium chloride and potassium chloride was 60 mg / L at 25 ℃ for 4 h, the adsorption rates of nitrogen and potassium for diatomite reached the maximum of 12.80% and 17.26%, respectively, ; Modified sepiolite nitrogen and potassium adsorption rates reached the maximum 19.22% and 14.75%. When the initial concentration of monocalcium phosphate was 60 mg / L, the adsorption of phosphorus by diatomite and modified sepiolite reached 35.42% and 13.42%, respectively, at a constant temperature for 6 h. The results of the determination of NPK content in the soil of pot experiment showed that diatomite and modified sepiolite had a good sustained-release effect on NPK. The optimum mass ratio of diatomite to modified sepiolite to urea to superphosphate to potassium chloride was 3: 3: 17.3: 9.3: 9.6, which lays the foundation for the development of slow-release fertilizer.