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Mulch, Their Types And Disadvantages
Mulch: Any material used (spread) at surface or vertically in soil to assist soil and water conservation and soil productivity is called much.
To achieve optimum advantage from the mulch the mulch should be applied immediately after germinationofcrop@5 ton/ ha (organic mulch). The practice of applying mulches to soil is possibly as old as agriculture itself. Mulches are used for various reasons but water conservation and erosion control are the most important objects in agriculture in dry regions. Mulches when property managed definitely aid wind and water erosion control. Other reason for high mulching is followed includes soil temperature modification soil conservation nutrient addition, improvement in soil structure weed control and crop quality control.
Disadvantages Or Limitations:-
1. Mulch is not been found effective other than Rabi Jawar.
2. In excess rainfall years mulch may not be effective.
3. Residue production in dry land is inadequate to result in sustainable water conservation.
Types of mulches: Materials used for mulches are crop residues levees clippings, bark manure, paper, plastic films, petroleum products, gravels etc.
1. Plastic films: Plastic fnms are more widely used as mulch. They help in maintaining higher water content in soil resulted from reduced evaporation, induced infiltration, reduced transpiration from weeds or combination of all these factors. They are relatively expensive expensive and difficult to manage under large scale field conditions for low value crops. (Polythene, polyvinyl).
2. Petrolium products: These are less expensive than plastic films and more readily applicable materials e.g. petroleum and asphalt sprays, resins etc.
3. Crop residues or stubble mulch: - Crop residues and other plant waste products (Straw, cloves, leaves, corn, and sawdust) are widely used as mulch. These materials are cheep and often readily available. The permit water to enter in the soil easily, when maintain at adequate level. These materials result in increased water content and reduced evaporation. Amongst the mulches tried light and thin stem material like dry grass was most effective as it provide good canopy, followed by gram stalks and wheat. Jawar stubbles were not as effective as other because of it is heavy weight and less canopy (cover). Use of mulch @ 5 tons / ha is found to be most effective in dry farming area. The mulch should be applied immediately after crop emergence to get optimum advantage. When these mulches are used the other crop operations like interculturing are not physible hence saving in cost of cultivation.
The effectiveness of various other materials as a mulch has been investigated. These materials have favourably influenced soil water content and evaporation but their use does not appear practically under large scale conditions e.g. gravels stones, granular materials, manure etc.
4. Vertical mulch: - Rainfall in dry farming area is with high intensity; due to moderately slow rate of infiltration the runoff is heavy. The water thus running as runoff could be stored in profile itself. In the recent past new technique has been evolved to tap such water.
Vertical mulch is a technique which consists of digging suitable trenches across the slope and thus making more surface are a available for water absorption. The open treaches are likely get silted in short period. This however can be prevented by inserting organic form waste material like straw stubbles or stalks which is called filter. The filter should be resistant to decomposition and provide service for 3 - 4 years. Such trenches at suitable intervals provide portion of low density which helps to intake water at higher rates. Water thus percolates in a trench and gets distributed in the profile. The width of trench should be adjusted in such a lastion that least area temains uncultivable. If trench could be accommodated between crop rows, there is practically no area wasted for trenches. Width of 20 cm is ideally suited for these propose. Depth of trench in black clay soil should be up to merum level and distances between two trenches may be about 4 m.
5. Soil or Dust mulch: If the surface of the soil is loosened, it acts as mulch for reducing evaporation. This loose surface of soil is called soil mulch or dust mulch. Interculturing creates soil mulch in growing crops and helps in closing deep cracks in Vertisols.
Effect of mulches on soil and plants:-
1. Soil water: - When soil surface is covered with mulch helps to prevent weed growth, reduce evaporation and increase infiltration of rain water during growing season. The water infiltrated in soil can be utilized by crops there by crop yields are increased. Mulches obstruct the solar radition reaching to soil.
2. Soil structure: - Crop residues when applied at adequate level increase infiltration rate. Decomposition of these residues results in improving soil aggregation and suability. Mulch slows (reduce) velocity of runoff.
3. Soil erosion: - Soils from dry region are nightly susceptible to water erosion and wind erosion because rainfall occurrence is frequent during intense storms and surface is adequately protected by vegetation effectively retard runoff. Therefore to reduce erosions by wind and water is an important reason for using mulches in dry regions.
4. Soil temperature: - Mulches results in greater water content and lower the evaporation. However effects on soil temperature are highly variable. White mulches decrease soil temperature while clear plastic mulches increase soil temperature.
5. Crop plants: - The effects of mulches on plants are operative through the effects of mulches on soil water, soil temperature structure and erosion. Reduced evaporation is major reason for the growth of the plants and there by high crop production due to mulch.
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