6. Tillage and mulching requirements for dryland soils

Transcript

Hi Friends, after studying the Integrated Nutrient Managements for the cropping systems. In this lecture let us study tillage and mulching requirements for the dryland systems. The clean tillage methods, they are mainly four types

• Primary tillage
• Secondary tillage
• Deep tillage, and
• Shallow tillage

Coming to the conservation tillage. The conservation tillage is a tillage system, wherein at least 30% of the soil surface covered with the crop residues after the crop is planted. Conservation tillage in which the tillage is carried out, and after the tillage is carried out, nearly 30% of the land will be covered with tillage as you can see in the figure. These stubbles have been spread in between the hosts so as to conserve the moisture. Coming to the stubble mulch tillage. Mainly the stubble mulch tillage is concentrated with cutting of the stubbles and incorporating. Here the tillage system that accomplished with implements, that undercut the soil surface, thereby retaining most of the crop residues on the surface. Here whatever the stubbles are there, they will be worked out with the implements and they will be undercut, and most of the stubbles, all will be maintained on the surface. It is called as stubble mulch tillage.

The primary tillage is mainly to prepare smooth seed beds. Then secondary tillage is mainly to prepare or to control weeds and also to increase the intake of water. With this objectives the primary and secondary tillage will be there. Then coming to the primary tillage, deep tillage and shallow tillage. A shallow tillage up to a 10 centimeter depth will be carried out in case of red soils. And in deep tillage up to a depth of 30 centimeter in black soils.

Then coming to the disk tillage. This is a tillage system that is carried out with the help of a disk to bury 30 to 70% of the surface residues. It provides good weed control. Here the disk system is used as a machinery. And with this disk system about 30 to 70% of the stubbles are being incorporated. And when this quantity of stubbles are incorporated, the growth of the weeds will be checked. Then coming to what are the requirements of tillage for dryland soils. The dryland soils are of two types; black soils and red soils. But tillage requirements vary according to the character of the soils. The properties of black soils which is called as vertisols. They have a high clay content, low infiltration rate, and deeper soil depth. They are hard, dry and sticky and not trafficable with optimum soil moisture range for tillage, very narrow high draft requirement when dry. So vertisols are the black soils or the type of soils in which stickiness will be there during the moisture, during immediately after the rainfall we cannot workout with the soil. Means the tillage will not be possible immediately after the rain. That means tillage trafficability is difficult, and also the soil will be immediately dry. But these soils have a characteristic which holds moisture in a high quantity,

Then what are the management practices for this black soils.

• Deep tillage up to 30 centimeter depth
• Then fall ploughing immediately after the harvest of the crop
• Then shallow tillage up to 10 centimeter depth with blade harrow
• Then shallow tillage with inter-cultivators.

So these are the management practices. One is deep tillage up to a 30 centimeter depth, followed by fall ploughing immediate after the first receipt of the rain. Then shallow tillage, this is to with blade harrow, just to close the cracks, to check the evaporation losses. Then again shallow tillage with the intercultivators during the cropping. So these are the breaks can be filled up by the inter-cultivator operations.

Then coming to the red soils. The red soils have low clay content, but they have high infiltration rate, shallow to medium soil depth and a neutral pH. In this the surface crust formation within 2 to 3 days after sowing is a problematic. So in red soils, management of the crust is very important. You can see here after the sowing; the sowing, the crust formation will be there. These crusts, they come in the way of germination of the crop seeds. So a poor seedling emergence, more so in case of small seeded cereals. So the crust formation in the case of red soils affect the germination and establishment of the crop, which are having small seeded, especially in case of millets and cereals. So what are the management practices. So here also

• deep tillage every year to break the crust,
• inter-culturing operation 2 to 3 times during the cropping period
• then dead furrow opening at 3 meters during sowing and repeated every 30 to 40 days after sowing
• use of rotary type spiked roller on crusted soils.

So crustation or crust formation is a problem here. We have two management strategies for this crust formation to avoid. One is deep tillage every year to break the crust, and also use of rotary type of spiked roller on the crusted side. When this implement is passed on to the soil, the crust will be broken. And one more practice with respect to red soils is, opening of dead furrows. As you can see that this is a dead furrow. After about 8 rows a dead furrow is opened, and it is also called as moisture conservation furrow. Which holds the moisture heavily and this stored moisture can be available to the crops.

So then coming to the mulching. Mulching is also a multi-pronged approach. And it will be used for both dryland soils; black soils as well as red soils. It’s a multi-pronged approach to conserve the soil and water, and manage the weeds. There are three types of, three categories of mulches.

• Surface mulching
• Vertical mulching
• And live vegetative barrier

The main important advantage in case of mulching is.

• Intercept the raindrops and reduce run off
• Suppresses the weeds
• Increases the soil organic matter
• Physical-chemical properties are also improved
• Then soil water holding capacity is also improved

What are the surface mulching? The surface mulching can be carried out with the use of organic materials or the residues. These organic materials and residues are spread across in between the crop rows, and on the surface to reduce the evaporation and increase the soil moisture. Stubbles are spread in between the crop rows to check the evaporation and also to increase the soil moisture. Then surface mulching is also followed in case of soil mulch or dust mulch. It includes opening of ridges and furrows, and these ridges are make as soil mulches. So these soil mulches acts as a conservation furrow. It helps in the conservation of moisture.

Then vertical mulching. It involves opening of thetrenches of 30 centimeter depth. And at the suitable depths crop stubbles have been incorporated, and these stubbles guides the moisture to enter into the subsoil layers.

Then coming to the live vegetative barriers. These are the live vegetative barriers which have been planted across the contour line. Under this method suitable plant species are planted on the contour key length, and they act as vegetative barrier and as effective mulch. They also control soil erosion and the soil will be protected.

So in this way different types of tillage operations may be adopted in dryland areas, depending upon the situation and the farm to get more benefit. General theory of tillage in dryland areas is to reduce the tilling operations are far as practicable. Then pre-monsoon tillage and maintaining the crop residue. The time of tillage is another factor to be considered in dryland areas. So different types of tillage operations may be followed in drylands, depending upon the requirement. But general theory of tillage in dryland is to reduce the tilling operation to the extent possible or to the practicability. Then pre-monsoon tillage and maintaining crop residue at the time of tillage is another factor to be considered in dryland areas. So these are the tillage and mulching requirements in case of dryland soils, so as to maintain the soil moisture in the soil.

Thank You.