Effects Of Polyhalite As A Potassium Fertilizer Source On Nutrient Utilization,Yield And Soil Fertility Of Maize

Fertilizers play a vital role in increasing grain yields,and fertilization is one of the most effective ways to increase crop yields.However,the soluble potash resources of China are very scarce,and the distribution of potash resources show highly uneven to potash fertilizer consumption.In order to alleviate the contradiction between the supply and demand of soluble potash in my country and increase the self-sufficiency rate of potash fertilizer in my country,the development and utilization of low-grade potash-containing ore will be a sustainable agricultural One of the important ways of sustainable development.Polyhalite is a mineral rich in multiple elements such as potassium,calcium,magnesium,and sulfur.The theoretical potassium content（K2SO4）can be as high as 28%,which has the potential to be used as a commercial fertilizer.Taking polyhalite rich in potassium,calcium,magnesium and sulfate as the research object,this study investigated the effects of polyhalite as a source of potassium fertilizer partially or completely replacing potassium chloride on maize growth and soil fertility under the same potassium fertilizer application rate（120 kg·hm-2,calculated as K2O）.There are 6 treatments in the experiment:blank control（CK）;potassium chloride only（T1）;polyhalite 30%and potassium chloride 70%combined（T2）;polyhalite 50%and potassium chloride 50%Combined application（T3）;combined application of polyhalite 70%and potassium chloride 30%（T4）;single application of polyhalite（T5）.The main findings are as follows:1.Potassium fertilizer has little effect on the plant height and ear height at the mature stage of maize,but it can promote the growth of the corn stalk,and the increase rate is 6.91%～7.42%.Under the condition of the same plant height and ear height,the corn stalk is thick the increase of is beneficial to reduce the lodging rate of corn.2.After each potassium fertilizer treatment（T1-T5）,the dry matter accumulation of different corn organs（leaf,leaf sheath,stalk,grain,cob）is higher than the CK,and T3 treatment（polyhalite 50%and potassium chloride 50%combined application）corn grain and aboveground part dry matter accumulation are the highest,which are significantly increased by 20.76%and 16.76%compared with the control CK,and significantly increased by 6.59%and 5.30%compared with potassium chloride alone in T1.Meanwhile,the corn grain harvest index is also reaching 56.99%,much higher than other treatments,3.Compared with CK,the accumulation of potassium,nitrogen,phosphorus,calcium,magnesium and sulphur in T1 maize plants with potassium chloride alone increased by 15.98%,21.34%,21.68%,11.30%,13.22%and respectively.17.72%,the combined application of polyhalite and potassium chloride（T2-T5）showed no significant difference in the accumulation of nitrogen,phosphorus,calcium and magnesium in corn,but the combined application of polyhalite and potassium chloride（T3,T4）The accumulation of potassium and sulfur in treatments was significantly higher than that of potassium chloride single application T1,increasing by 6.29%～8.87%and 11.70%～16.54%respectively.4.The application of potassium fertilizer is conducive to the increase of corn grain yield,with an increase rate of 4.75%～28.08%.The corn yield increase rate of different polyhalite and potassium chloride treatments（T2-T4）is not significant compared with that of potassium chloride T1 alone.The potassium utilization rate of different polyhalite and potassium chloride treatments（T3,T4）was significantly higher than that of potassium chloride T1,which was 22.85%and 25.78%,respectively.5.Polyhalite partially replaces or completely replaces potassium chloride treatment（T2-T5）.Soil conductivity（EC）does not show significant difference,but compared with potassium chloride T1 alone,polyhalite is used as a source of potassium fertilizer（T2-T5）.)The soil pH increased by 5.37%,6.29%,6.15%and 5.92%respectively,which has certain practical significance for alleviating the status quo of soil acidification.6.Soil pH,available potassium,exchangeable calcium,exchangeable magnesium and available sulphur showed an increasing trend with the increase of the proportion of polyhalite mixed application.Single application of polyhalite T5 soil pH,available potassium,exchangeable calcium,exchangeable magnesium and effective Compared with the control CK,sulfur increased significantly by 4.46%,30.38%,5.65%,20.35%,and 4.32%,and significantly increased by 5.92%,12.47%,15.16%,18.16%,and 7.92%compared with the single application of potassium chloride T1.Halite is more conducive to improving soil fertility than potassium chloride.In summary,when polyhalite replaces part of potassium chloride as a source of potassium fertilizer（50%polyhalite and 50%potassium chloride）,it has a good effect on corn growth indicators and soil fertility.This study is based on polyhalite as a potassium source to explore its potential to replace commercial fertilizers.The results of the study show that the combined application of polyhalite can have a better effect on soil fertility and corn growth indicators.This is an important factor for the mining and utilization of polyhalite in my country.The popularization and application of stone in agriculture provides more theoretical basis.