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Current Category » Rainfed Agriculture

Tillage Practices

Tillage is defined as mechanical manipulation of soil to provide a favorable environment for good germination of seeds and crop growth to control the wees to maintain infiltration capacity and soil aeration. A well planned tillage practice provides a favorable environment, suitable for better seed germination and effective plant growth. In addition, it also protects and maintains a strong soil structure to fight against erosion.

Tillage for Soil Conservation: Tillage is an important and primary tool for conservation of the land. As per definition, its primary purpose is to provide a favorable soil environment for the plant growth which is indirectly related to the soil conservation. The effect of tillage on soil erosion is the function of its                several effects on soil such as aggregation surface sealing infiltration and resistant to crosion destruction of soi8l structure either by excessive tillage or tillage operations at improper soil moisture condition tends to increase the soil erodibility, causing significant soil loss. To achieve a best result for soil conservation the following points should be considered for tillage operations.
1. Till no more than necessary
2. Till only when soil moisture is in the favorable limit and
3. Vary the depth of ploughing.

Types of Soil Conservation Tillage Practices: There are a number of modified tillage practices have been developed; each of them related to the specified objectives for providing a better soil and water - plant relations. Reducing the runoff as well as soil crosion by enhancing infiltration capacity of the soil. The important types of soil conservation tillage practices are described below:

Mulch Tillage: It is performed either by making the soil surface cloddy or mulched with the help of crop residues. Mulch tillage is happened to be an effective measure to minimize soil erosion and to conserve the moisture when it is combined with strip cropping system. This type of tillage is also practiced to utilize the crop residues as mulch and also performing farming operations simultaneously. It can be defined as a method which permits the crops to grow where all or most of the residues from previous crops are left on the soil surface. The use of mulch tillage is based on the following profits.
1. The mulch intercepts the falling raindrops over the land surface and thus dissipating their kinetic energy which result in reduction or climination of their dispersing action on the oil structure.
2. The match ultge increases the infilte capacity.
3. The obstacles caused by leave stems and roots over the field reduce the velocity of surface flow and thus controlling the sheet crosion.
4. It maintains the soil relatively cool and moist which are essential for good plant growth and
5. Increases the crop yield by developing several conducive effects on soil.

Mulching:
It is defined as the application of any plant residues or other materials ot cover the top soil surface for.
* conserving the soil moisture.
* reducing the runoff and thereby to control soil erosion.
* checking weed growth
* protecting from winter climate.
* improving the soil temperature.
* modifying the micro - environment of soil to meet the needs of seeds for their good germination and better growth of seedlings.

The mulching is known to attribute the suppression of the weed growth conservation of moisture by checking evaporation and runoff to protect the soil against erosion (mainly from wind) to increase infiltration of water to fluctuate the soil temperature to enhance mineral nutrient availability to enhance nitrification to add nutrients and organic matters derived from decomposing of residues or other materials used as mulch to preserve or improve the soil structure. Mulching also improves the soil aeration creates better biological activates and thus to make a consequent beneficial effect on the soil fertility.

Mulching Materials:
The followings are used as mulching materials:
* Cut grasses or foliage
* Straw materials.
* Wood chips
* Saw dusts
* Papers
* Sand stones
* Glass woods
* Metal foils
* Cetto phanes
* Stones
* Plastics

Types of Mulches:
The mulches may be following types
a) Natural and
b) Synthetic
c) Petroleum
d) Conventional
e) Inorganic and
f) Organic  
The natural mulches are borned by nature itself no man's effort is required.

Synthetic Mulches: Includes organic and inorganic liquids that are sprayed on the soil surface to form a thin film for controlling the various atmospheric happenings taking place over the top soil surface. The different synthetic mulching materials are as under.
* Rasins
* Asphalt emulsions
* Latex and out back asphalt
* Canvas
* Plastic and paper products
* Polythene and polyvinyl chloride (PVC).
* Bitumen emulsions.
The plastic mulches are very useful for nurseries in semi - arid and arid regions but their demerit is to have more cost and difficult to apply on large scales. The plastic mulching is also not suitable for the taller vegetations. In nurseries the dark colored plastic mulches make the soil surface very warm during the day hours because black body absorbs greater heat from the sunlight. This type of characteristic results in lower diurnal and higher nocturnal temperature.

Petroleum Mulch: The petroleum mulches are easier to apply and also less expensive. These mulches are available inform of emulsions of asphalt in water that can be sprayed on the soil surface at ambient temperature to form a thin film in continuous form that clings to the soil but not penetrate deeply. A thin film of petrol cum substance made so is termed as mulch film. The mulch film promotes uniform and rapid seed germination and also plays a significant role for vigorous growth of seedlings. An ideal surface film is also stable against erosion sufficiently porous to allow water in the soil yet insoluble in water and resistant enough to the forces of weather causing it to last as long is necessary for permanent vegetations to cyme established.

Conventional Mulch: The mulches such as hay or straw are more effective than the petroleum mulches. These mulches not only conserve the moisture and reduce the fluctuation of soil temperature but also protect the soil from rain drop impacts and hold the excess surface water in contact with the soil so as to increase the infiltration rate and thereby reducing the runoff and soil erosion. In skit on during day hours these mulches also absourth as resulting the surface of the mulch becomes hot and the soil on the other hand, during night hours, the mulch cools down and permitting the soil to remain warm. The papers mulches are also counted under conventional mulch are reported to give a remarkable result. Paper mulches are observed to increase the soil temperature especially of the surface soil layers. There are several evidence to show that paper mulching proves bettle performance in improvement of soil condition besides promoting the carthwarn activity. List at the same time the toxic elements of chemicals are coached out of the paper which has to be guarded against. The treated papers such as pitamanised have toxic effect on the plants.

Inorganic Mulches:
Soil mulch: It is an important mulch for the conditions of arid and semi - arid regions. Its application during summer and rainy seasons should be avoided. The soil mulch is also effective to reduce the evaporation particularly where the soil is saturated as a lower depth below the top surface or the moisture content is in excess of field capacity but hot in contact with a continuous water - table. Sometimes, the soil mulches are not effective under ordinary conditions as large amount of moisture evaporation establishes a protective dry layer of the soil which if worked will cause excessive so moisture loss.
In soil mulching a loose and dried soil layer of 5 to 8 cm thick is established on the soil surface. For this purpose the land surface is ploughed for the depth as specified above and left over for sometime to get dry of the ploughed soil; after that by planking operation the tilled soils are planed in this way a layer of dry soil in loose condition is prepared over the land surface which acts as soil mulch. The soil mulch prepared so obstructs the capillary loss of water from the lower layers due to following reasons.

* Lack of close contact with moist soil lying below.
* Increase in non - capillary pore space.
* Resistance to wetting.

These effects are said to be more apparent under isothermal conditions in regards of soil and temperature. Soil mulching has beneficial effect on soil aeration also.
The formation of crust on top soil surface is also counted as soil mulching it results in clogging of the soil pores which effectively seals the lower horizons from contact with the atmosphere and also prevents the diffusion of O2 and CO2.
The soil mulching becomes more effective when it is composed of crumbs and clods of proper size which are not liable to be broken down in form of surface crust by the impact of subsequent rains. In sundy areas the soil mulch should be prepared immediately after runs and renewed after subsequent rains when they get infiltrated downward and rap the maximum amount of moisture.

The general function of mulch is to raise the soil temperature during winter season and to lower the same during summer season by allowing low heat conduction through the same during summer season by allowing low heat conduction through the mulched layer and thus to maintain the soil temperature at a uniform level. In many cases the soil mulching also plays an important role to diminish the weeds growth from the soil.

Store Mulching:It involves the spreading of stone pieces on the ground surface to conserve the moisture and also to reduce the wind crosion. It is a very old practice followed in arid zones. Soil under the stones tends to be in moist condition but the temperature of that soil is slightly higher. The soils lying below the stones Harbour small animals and involve a high nitrification. The stone mulching is also used for tapir the dews particularly in those locations where significant dew fall takes place. Central Arid Zone Research Institute Jodhpur has reported the use of rubble much which is simply combination of mall fragments of stones and bricks provides better result on moisture conservation compared to the stone mulching synthetic mulching and mulching made by straw materials.

Organic Mulches: The tree bunches twigs leaves leaf litter grasses weeds etc. and used as organic mulch to cover the soil surface. The organic mulches are found superior than the artificial mulches in respect of conservation of moistures reduction in evaporation and runoff. By this mulch the control of evaporation is more effective particularly when rainfall takes place at frequent intervals but not found much effective when the rains are few and scattered in other words the infrequent rains and small showers may not be saved at all but for large rains which result we surface for several days with excess surface water for deep percolation these mulches may have their efficiency considerably more. Further more the light mulches are almost ineffective for controlling the evaporation because moisture conserving efficiency of mulch is inversely related to their capacity to absorb water or to extract it from the soil by capillary action. Resistant mulches do not decary sonly but last for a long time as a result they are more effective for conserving the soil moisture.

Benefits of Organic Mulches:
The various advantages are listed as under:
1. Very effective in reducing the soil erosion heatuse they promote interception loss and infiltration of rain water.
2. They obstruct the import of rain drops over the ground surface and thus dissipate the corrosive power of rainfall.
3. Very effective in preserving and impacting the soil structures by criminality the crusting of soil surface and sealing of pores by runoff.
4. Organic mulches also chance the dew fall by insulating the soil the really and electrically from the atmosphere.
5. The ascorbic molehes under the condition of bighorn temperature keep the sad temperature below the highest temperature.

Current Category » Rainfed Agriculture