Arable land 

Arable land can be said to those lands that are capable of being ploughed and used to grow crops. Arable land is the land under temporary agricultural crops , temporary meadows for mowing or pasture, land under market and kitchen gardens and land temporary fallow ( less than five years ) .The abandoned land resulting from shifting cultivation is not included in this category. In this 21st century of rapid  growing of urbanization and industrialization , arable land plays an important role in maintaining food security.  Some of the conservation technologies for the conservation of arable lands are described below:

A. Agronomic measures

Agronomic measures on the cultivated lands are generally recommended on the mild sloppy areas (1-6%) with the objective of maximizing conservation of in – situ rainfall for sustained and higher production . Those measures are contour farming , inter- cropping , strip –cropping , mixed cropping , tillage practices , mulching , cover management and manipulation of crop canopy.

1. contour farming :- up and down cultivation is generally practiced by farmers for the sake of convenience, which facilitates run- off water to attain higher velocity in more of run- off and soil erosion. It was recorded that , in shiwalik foot hills , contour cultivation instead of up and down cultivation reduced run-off by approximately 20% and soil by 43.5% and increase maize yield by 23%.

2. Inter- cropping:- The practice of line sowing of mixed crops is inter- cropping . Inter-cropping of low canopy legumes such as ground nut , green gram , black gram , soyabean and cow pea in wider inter-row spaced of crops like , maize sorghum and castor provides sufficient cover on the ground and there by reduces soil erosion Hazards. It was recorded that maize + cowpea and maize + black gram intercropping system reduces run- off by 14.9 and 15.8 % and soil loss by 29.7% and 30.9% respectively over sole maize.

3. strip cropping:- strip cropping is well accepted conservation measure all- over the world in controlling run-off and soil erosion and there by maintaining fertility of soil.  It helps in shortening the length of slope , reducing run- off  , arresting soil by providing a biological filter/ barrier and increasing absorption of rain water into the soil- profile. It is reported that maize and cowpea in 2: 1 ratio to reduce run – off from 43 -37 % and soil loss from 21 to 11 tons per hectare , and was effective as graded contour bounding.

4.  Mixed cropping :- Small sized land holding restricts farmer from adopting strip  cropping . In such condition , mixed cropping of low canopy legumes with widely spaced crops is most suitable which provides better and continuous cover to ground , protection against beating action of rain drops . It is reported that wheat + chick pea gave a higher yield than pure crops and maize + rice reduced run – off by 29.8% and soil loss by 33.4% over pure crop of maize.

5. Tillage practices: Tillage is a well known soil and water conservation practice which makes soil surface more permeable to increase infiltration of rain water into soil which in turn , reduces run- off , soil and nutrient losses and enhance crop yields. Conservation tillage with maintenance of crop residues cover on 30 % of the soil surface is soundly based within the framework of conservation of natural resources and sustained production.

6. Mulching :- Mulching is an important agronomic practice that not only prevents soil erosion by dissipating kinetic energy of rain drops  but also facilitates infiltration eventually enhance crop yield . In low rainfall areas, mulching helps in conserving moisture in the soil profile while in rainfall areas , it reduces run- off and soil lose which , in turn are reflected in higher crop yield .

7. Timely sowing and crop canopy manipulation:- A large fraction of erosion occurs during few initial storms after the onset of monsoon when land surface is bare without any crop cover. Hence sowing of the crop as early as possible with the onset of monsoon helps in early establishment of crop , better root and shoot growth and development of canopy cover which minimizes soil erosion.

B. Mechanical measures

Mechanical measures or engineering measures are often needed on agriculture lands to supplement agronomic measures when slope becomes steeper or velocity of run-off and discharge becomes high.

1. Contour bonding :-  it consists of constructing narrow trapezoidal or parabolic shaped bunds on gentle slope ( 0.5-6.0% ) is generally recommended for low rainfall areas and relatively permeable soils.

2. Bench terracing : This is the most commonly used conservation measure in hill and mountainous areas for the reduction of  degree and length of slope , to reduce intensity of scouring action of run- off flowing down hill slopes.

3. Graded trenches : this is generally recommended in the agricultural lands having slope between 10 – 16% for diverting excess run-off safely into grassed water ways.

4. Grassed waterways : these are essentially required on agricultural land where a suitable natural drainage way is not available to drain off excess run-off safely.