Abstract: humic acid is widely used in medicine, agriculture and so on. This paper reviews the research progress in application of humic acid fertilizer in tobacco production, and introduces the research situation of humic acid pesticides, and discusses the possibility of application of humic acid in tobacco residue control of humic acid in tobacco production application to provide a theoretical basis.
Keywords: humic acid; tobacco; humic acid fertilizer; humic acid pesticide
Humic acid (humic acid - HA) is a plant and animal remains, are the remains of plants, through the decomposition and transformation of microorganisms, a kind of high molecular organic acid mixture of [1] and physical geochemistry, a series of changes in the process accumulated. Humic acid is a natural organic macromolecular compound, its role in agriculture are: soil improvement, improve efficiency, stimulate plant growth, increase the resistance of plants, improve the quality of plants. Application of humic acid in tobacco production is mainly used as fertiliser and pesticide with two aspects of application.
Application of humic acid fertilizer in tobacco production, the
Fertilizer on tobacco growth and tobacco leaf appearance quality and inherent quality of tobacco production and has important influence on [2]. The application of humic acid in tobacco production mainly concentrated in the fertilizer utilization. Humic acid can reduce tobacco rhizosphere soil pH value, the calcareous soil, are conducive to the growth of tobacco [3]. On the other hand, the application of humic acid fertilizer can increase the tobacco storage water of tobacco soil, reduce the effects of drought on tobacco growth, promote tobacco growth and development, and can improve the appearance quality of tobacco leaves in a certain extent, tobacco yield increased, the coordination of main chemical components of tobacco leaf [4]. Li Guangcai and [5] found in the pot experiment, the effects of humic acid and cake fertilizer could increase soil pH value decreased, improve water and fertilizer conditions, optimizing the tobacco growth environment, so as to promote the early onset of tobacco plants; leaf dry matter accumulation and plant root volume increased significantly, and the chlorophyll a degradation and mature and has a good effect. Cheng Shaoxin [6] found that humic acid has inhibitory effect on the activity of nitrifying bacteria. Experimental results show that the addition of humic substances in 2%-20% urea, in the soil to keep within 35 days, the total inhibition rate reached 69.3%. 62 days later than urea containing humic acid urea preserved 42%-50% of nitrogen in the soil. Lu Xin et al [7] that humic acid has inhibitory effect on soil urease activity, can be maintained at around 100 days. Wang Yaofu, the [8] study found that tobacco humic acid can improve the content of nitrogen, phosphorus and potassium in tobacco, iron, and with the increase of the quantity of humic acid, the yield, the proportion of superior tobacco and nicotine content increased significantly, reducing sugar content decreased significantly. Liang Wenxu [9] believes that HA could increase the chlorophyll content and photosynthetic rate, thereby improving the tobacco plant photosynthetic performance, provide adequate sources of C for dry matter accumulation and quality formation of tobacco at the same time, ha can promote the improvement of early growth of nitrate reductase activity in tobacco plant, and can make it in Flue-cured tobacco nitrate reductase activity in the mature stage of failure to timely. The tobacco before the mid maintain high nitrogen metabolism level, to provide sufficient nitrogen nutrition of flue-cured tobacco growth, and can make the normal and mature leaves. The role of HA also improved the absorption of mineral elements in flue-cured tobacco and flue-cured tobacco use, the phosphorus and potassium, magnesium, zinc and boron contents of mineral elements have different degrees of improvement, coordination and balance of mineral nutrition tends to tobacco, tobacco yield, output value and proportion of superior tobacco nicotine will be improved. The aroma containing substances in the coordinate, sugar and egg ratio, the ratio of sugar to nicotine, the ratio of nitrogen to nicotine and other quality index is more reasonable. Sun Meixia [10] study found that humic acid can prevent the loss of soil moisture, the early onset of tobacco and tobacco continued steady growth. The formation of tobacco plant canopy structure reasonable, larger leaf area index, scattering radiation transmittance is high, the leaf distribution, can make full use of solar energy for photosynthesis. Jin Zhili [11] of humic acid and basal fertilizer for tobacco pot experiment. The results showed that humic acid can effectively stimulate root physiological activity. Improve the root of ascorbic acid oxidase and polyphenol oxidase and respiratory enzyme activity, enhance root activity, and can effectively promote tobacco root growth, root dry weight, volume and length were increased. In a certain dosage range, with the increase of the amount of HA, on the growth and vitality of the role of the root effect gradually increased, but beyond a certain range, reducing or even negative effect. Therefore, around to the amount of HA test before use, to find the best range of HA dosage and cultivation conditions suitable for local area.
The research results show that: Yuan Xiuyun [12] from the whole process of root development, cake fertilizer and humic acid and fertilizer application with tobacco growth rule of fertilizer than any single nitrogen fertilizer. According to the study by Liu Weiqun [13], humic acid + chemical fertilizer can improve tobacco bud carbon and nitrogen metabolism timely transformation, may be due to the adsorption of humic acid organic polymer structure can be more mineral elements and slowly release, for the absorption of tobacco use by. At the same time, the humic acid fertilizer also plays a buffer and sustained release of fertility effect. Yao Zhixin [14] believes that humic acid fertilizer is a new fertilizer in tobacco root, in the application of semi arid area, with high efficiency, strong release of nitrogen and phosphorus, potassium nutrient content is coordinated, can better meet the growing needs of the fertilizer in Flue-cured tobacco. These studies show that humic acid and other fertilizer application more balanced in the whole growth process of tobacco plant nutrition than single application of humic acid, which also shows that the humic acid fertilizer development is necessary. Yunnan Manhao fertilizer limited company based on leaf, soil survey, developed using humic acid as raw material, suitable for all stages of Yunnan tobacco growth demand and soil characteristics of humic acid organic inorganic compound fertilizer for tobacco. Found that the use of humic acid organic inorganic fertilizer than a domestic tobacco tobacco fertilizer increased by 11.6%, the proportion of superior tobacco increased by 24.26%, the proportion of secondary smoke increased 9.97%, nitrogen utilization rate increased by about 20%, while improving the soil, enhance the disease resistance of tobacco [15].
Overview of pesticide research, two humic acid
In recent years, and has become a hot research of humic acid pesticide. At present, in China's pesticide industry in high toxicity, low efficiency, long residual pesticides also occupies a large proportion of ways to solve this part of the pesticide has three, one is the development of high efficiency, low toxicity and low residue pesticides, no pollution to the environment, the need to invest a lot of money and time; two is the elimination of some do not meet the environmental requirements of the pesticide; three is the transformation of the original pesticide, pesticide research and development of polymer complex, high toxicity, low pesticide to the original, to become environmentally friendly pesticides. Combined with humic acid and pesticide, pesticide is composed of polymer complex is one of the best ways to create or modify the original pesticide environmental pesticides [16]. The relationship between humic acid and pesticide two, mainly through ionic bond, hydrogen bond, proton transfer, electron transfer, complexation interaction between a new generation of pesticide polymer complex. We can be referred to as environmentally friendly pesticides humic acid. It is different from that of humic acid, but also different from the original body of pesticide. Research shows that the effects of humic substances on the pesticide are: (1) [17-18] synergistic effect on pesticide release. Mainly because the humic acid surfactant function, can reduce the surface tension of water, emulsifying effect of pesticides on. (2) reduce the decomposition rate of pesticide, improve the stability of [19] pesticide. Because of weak acid and buffer performance of humic acid, and most of the pesticide just under this condition are consistent and stable, is a good stabilizer of pesticide. (3) to reduce the toxicity of pesticides [20]. Pesticide bioaccumulation decreased with the increase of humic acid concentration decreased, the acute toxicity of pesticides showed the same decline, high toxic pesticide toxicity, the pesticides into the plant tissue to reduce the amount of 1/2 and above. It is reported that humic acid can reduce the acute toxicity of pyrethroid pesticides have bacteria lipids (such as pesticide fenvalerate, deltamethrin and phoxim fenvalerate mixed agent), organophosphorus pesticides (diazinon, two methyl parathion etc.). (4) can be used as adsorbent of pesticide, reduce pesticide in environment quantity. Humic acid connected into fiber in general, has larger specific surface area, micropore structure, so rich, has good adsorption effect on various substances, pesticides can usually 1-2 times its own weight adsorption. These characteristics of humic acid making humic acid pesticide in controlling pests and harmful microorganisms, maintaining ecological balance, reduce pesticide use, maintain the natural purification of force and other aspects better than the original pesticide effect, is one of the direction of the future development of pesticide [21]. The study on Application of humic acid in the control of crop and soil pesticide residues provided new ideas, Jilin Tonghua Hirota Economic Technology Development Co. Ltd. developed a humic acid degradation of pesticide residues in the agent control demonstration has been made [22-24] good effect of residual ginseng, vegetables, fruit trees and other crops pesticide.
Three, the conclusion
Humic substances as fertilizer in tobacco production use and there have been many reports, it is mainly to improve planting tobacco soil aggregate structure, increase the content of organic matter in soil, improve the utilization rate of chemical fertilizer, promote tobacco enzyme activity, enhance the resistance of tobacco plant, thus showing can promote the growth of tobacco, and to improve the yield and quality of tobacco. Further to find out the mechanism of humic acid on the growth and development of tobacco, and made more in line with the needs of growth and development of tobacco humic acid organic and inorganic compound fertilizer is the future research problems. While tobacco production in the extensive, large and long-term use of chemical pesticides caused the increase of pesticide residues in tobacco leaves, tobacco pesticide residues exceed the standard part of the problem may become unsafe factors to restrict our country's future development tobacco, but the tobacco pesticide residues control is not a feasible method by humic substances on pesticide has four effects can foreknow, humic acid will play an increasingly important role on the control of tobacco soil and tobacco residue pesticide protection.
