Slow-release microcapsule type polymer acidic soil conditioner and preparation method thereof

Abstract

The invention discloses a slow-release microcapsule type polymer acidic soil conditioner and a preparation method thereof. The preparation method of the acidic soil conditioner takes chitosan oligosaccharide as a raw material, and is characterized by comprising the following steps: 1) dissolving a functional organic weak acid, inorganic nutrient salt, a nitrification inhibitor and chitosan oligosaccharide in water, then dissolving a water-soluble surfactant in the solution, and mixing and stirring to obtain a water phase; 2) dissolving an oil-soluble surfactant in an organic solvent, and mixing and stirring to obtain an oil phase I; 3) dissolving a cross-linking agent in the same organic solvent to obtain an oil phase II; and 4) mixing the water phase and the oil phase I, cutting and stirring to form an emulsion, switching to top stirring, slowly adding the oil phase II, carrying out an interfacial polymerization reaction to obtain a reversed-phase microcapsule suspension emulsion, andcarrying out post-suction filtration to obtain microcapsule particles. The acidic soil conditioner can improve the pH value and the acid-base buffer capacity of soil, and improve the cation exchangecapacity and the base saturation of the soil.

Description

technical field [0001] The invention belongs to the field of agricultural soil improvement, and in particular relates to a slow-release microcapsule polymer acidic soil conditioner and a preparation method thereof. Background technique [0002] Soil acidification in southern my country is widely distributed, including the vast tropics and subtropics, with an area of ​​up to 2.03×10 8 hm 2 , accounting for 21% of the country's arable land, and most of the soil in these areas has a pH value below 5.5, or even below 5.0. Soil acidification will be accelerated in the case of artificially excessive application of chemical fertilizers, especially ammonium nitrogen fertilizers. Soil acidification directly leads to the deterioration of the physical, chemical and biological properties of the soil, which not only destroys the normal aggregate structure of the soil, causes soil compaction and nutrient loss, but also activates aluminum, manganese and toxic heavy metals (cadmium, lead,...

AI Technical Summary

Problems solved by technology

Soil acidification directly leads to the deterioration of the physical, chemical and biological properties of the soil, which not only destroys the normal aggregate structure of the soil, causes soil compaction and nutrient loss, but also activates aluminum, manganese and toxic heavy metals (cadmium, lead, copper, etc.), inhibits microbial activity, and thus Seriously affect the growth and development of crops and pose a huge threat to human health

[0003] The currently used acidic soil improvers mainly include lime, natural clay minerals, industrial by-products, calcium magnesium phosphate fertilizer, crop straw, manure and biochar and other improvers, among which lime is the most commonly used traditional acidic soil improver, with soil acidity improvement Obvious and rapid effect (Zeng Tingting et al., 2017), but the nutrient is single, and if it is used for a long time or in large quantities, it will cause adverse effects on the soil itself, such as "soil lime board knot field", the balance of the three elements of soil calcium, magnesium, and potassium Imbalance (Hu Min et al., 2017), secondary salinization and even acid reflux (Meng Cifu et al., 1999) and other adverse phenomena

Clay minerals (Du Yufeng et al., 2016) such as dolomite, montmorillonite, attapulgite, zeolite and sepiolite, etc., although they can improve soil acidity, are difficult to develop and are not economical and convenient.

Industrial by-products such as phosphogypsum, fly ash, red mud, steel slag and alkali slag are applied to the soil. These substances have strong alkalinity and can neutralize the acidic substances in the soil (Li Jiuyu et al., 2009), and are cheap , convenient, but most of them contain a certain amount of toxic heavy metals, resulting in the threat of secondary pollution

Increasing soil organic matter is often put into organic fertilizer made from livestock and poultry manure. Although it can increase the content of base ions and organic matter in the soil, and reduce the content of exchangeable acid and exchangeable aluminum in the soil (Meng Hongqi et al., 2012), but because the feed contains Long-term application of a certain amount of heavy metal elements, such as Cu, Zn, Mn, Cr, Cd, Ni, etc., will lead to the accumulation of heavy metals in the soil and form secondary pollution

Biochar can increase soil pH, increase soil nutrient content and improve soil structure (Yuan Jinhua et al., 2019), but it may contain toxic and harmful substances such as polycyclic aromatic hydrocarbons, which may cause potential harm to crops and humans. In addition, increasing nitrogen Phosphorus leaching and methane emission bring secondary pollution risks to the soil

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