Preparation Of Potassium-rich Organic Liquid Fertilizer And Its Application In Chinese Cabbage

Potassium is one of the essential mineral nutrients for crop growth and development.Rational application of potassium fertilizer plays an important role in increasing crop yield and improving product quality.China is a country with shortage of potassium mineral resources,and 50%of potash fertilizer depends on imports.With the development of eco-circular agriculture,the market demand for organic potash fertilizer is increasing,especially the demand for organic liquid potash fertilizer in organic agricultural production is more urgent.Vegetable waste contains rich mineral nutrient elements,but most of the vegetable waste is not used scientifically,which becomes the pollution source of the environment and the problem that must be solved in the development of cleaner production.Therefore,taking vegetable waste as the main raw material,the research on the preparation of potassium-rich organic liquid fertilizer technology has important ecological and economic significance for realizing the utilization of vegetable waste resources,developing vegetable clean production and promoting the development of eco-circular agriculture.In this experiment,Chinese cabbage tail as the main material,adding a certain proportion of wheat bran,soybean meal,brown sugar as carbon and nitrogen sources as well as potassium feldspar powder,solid-state aerobic fermentation was carried out to study the proportion of Chinese cabbage tail and the addition of Bacillus mucilaginosus spore rod on the content of potassium in fermented organic fertilizer,in order to obtain the best fermentation formula rich in potassium solid organic fertilizer.Solid potassium-rich organic fertilizer was used as raw material and water was used as extraction agent to prepare potassium-rich organic liquid fertilizer by immersion.The effects of three factors including ratio of material to water,soaking time and extraction times on the extraction effects of total potassium and quick potassium were studied,and the optimal extraction parameters of potassium-rich organic liquid fertilizer were obtained.Using Chinese cabbage as experimental material and vermiculite substrate cultivation,the application effect of the prepared potassium-rich organic liquid fertilizer on Chinese cabbage was tested.The research results are as follows:1.By comparing the changes of physicochemical properties and available potassium content of different fermentation ingredients in the process of fermentation,it was found that the addition of Bacillus mucilaginoss could increase the EC value,organic acid content and available potassium content,and decrease the pH value.There was a significant positive correlation between available potassium content and organic acid content.On the 20th day of fermentation,the content of available potassium in T3(70%of tail vegetables,30%of carbon sources,nitrogen sources and potassium feldspar powder,and the addition of Bacillus mucilaginosus)increased the most,reaching 11.02 g/kg,which increased 159.29%compared with the initial value.T3 treatment is the best fermentation formula for preparing solid potassium-rich organic fertilizer.2,In the experiment of preparation of solid potassium-rich organic liquid fertilizer,it was found that the extraction times had the greatest effect on total potassium and available potassium,followed by the ratio of material to water,and the soaking time had the least effect.When the ratio of solid potassium-rich organic fertilizer to extraction agent water was 1:7.5(w:w),the soaking time was 16 h,and the extraction times were 3 times,the extraction amounts of total potassium and available potassium were the highest,reaching 9.34 g/L and 6.57 g/L,respectively,which were the optimal extraction parameters for preparing potassium-rich organic liquid fertilizer.3.In terms of Chinese cabbage yield,85%potassium-rich organic liquid fertilizer can achieve the effect of 100%chemical fertilizer.Potassium-rich organic liquid fertilizer significantly improved the quality indexes of Chinese cabbage,among which the contents of total phenol,soluble sugar and vitamin C in OF 1(100%potassium-rich organic liquid fertilizer application)were increased by 59,92%,17,39%and 34.00%,respectively,compared with chemical fertilizer application,and nitrate nitrogen content was decreased by 40.00%.Further analysis showed that the application of potassiumrich organic liquid fertilizer increased the diversity and richness of soil microbial community,and the microbial community diversity and abundance of OF1 treatment were the highest,and the microbial community composition was inconsistent with the application of chemical fertilizer.Firmicutes were the dominant bacteria group under potassium-rich organic liquid fertilizer application,and showed a positive correlation with mineral element content(N,P,K,Ca and Mg).In conclusion,OF1 has the best effect and can be used for organic cultivation of Chinese cabbage.