Know Your Soil

To reach to the soul of soil, a famer needs to test and check what nutrients it has, and what it needs to make crops flourish and grow. Soil testing can help reduce unnecesary use of fertilisers, check the fertlility, and reduce cost. Most of all, soil testing helps in producing a bountiful crop.

In soil testing, the soil of a farm land is tested to check for its chemical properties, its nutrients, salt content and acidity or alkalinity.  These properties are estimated by chemical analysis. Soil testing is done across countries, state and even at the district level. Periodical soil testing can help maintain the health of soil and know the right state of fertility.

Soil across different areas can have extremely different properties across areas. The type of soil determines the kind of seeds than can be sowed in a land. Though a farmer knows his soil well, it is important to test it regularly as soil can change over time and lose nutrients. Environmental factors along with man-made factors like industries close by can change it over time.

Benefits

1. The right state of fertlility of a soil can be determined
2. Balanced dose of fertilisers can be used  for the right kind of crop production. Financial losses due to over-use of fertlilisers can be avoided
3. High dose of chemical fertilizers are used by the farmers to increase production of various hybrid crops. This can be avoided if a farmer can know the right state of soil
4. Soil testing can held find out the type of soil whether it is acidic or basic by assessing its Ph status. Appropriate fertilizers are necessary based on this property of the soil
5. The type of soil can be found out and classified into categories. There are different types of soil whether it is saline, alkaline or a mineral soil. Such soils can be converted into normal soil, if the right type is assessed

 

Fertility Map

If a farmer knows his soil quality, he can supplement it in organic and natural methods intstead of chemical fertilizers and insecticides. Tough conditions of fields can be changed and right ingredients can be used to reclaim acidic soil or saline soils.

If fertlizers have to be used, right amounts can be specified and recommended. For example if a field has normal soil which has Ph of around 6 to 6.5, one can use all the nitrogenous fertilizers like are  Super phosphate and Ammonium phosphate et cetera.

Soil which has less than 6.00 Ph value, one can use fertlisers like Calcium ammonium nitrate, Sodium nitrate and Phosphoric fertilizers. Super phosphate, murate of potash also can be used. Soil which have more than 8.5 Ph value, Urea, Ammonium sulphate, Ammonium chloride, Super phosphate, Ammonium phosphate, Murate of potash can be used. Urea, Amoninium sulphate, Super phosphate, Ammonium phosphate and Ammonium chloride can be used in water logged soils.

The right kind of crop can be recommended for an entire area by making a fertlity map. Specific areas can be named a block or micro watershed based on soil testing report. This will help advocate the right manner of cropping of the area. The testing report can also help a farmer choose the most economical way of cropping.

What is in your soil?
One of the major objectives of soil testing is identifying the amount of organic carbon in the soil. This determines the growth of a crop in the field and how the nutrients in the soil are available to plants. In an optimum soil, the ratio of organic carbon and nitrogen is around 10-12:1. This ratio also helps the propagation of useful bacteria.

Soils which are deficient in important micro element like Zinc, Copper, Boron, Molybdenum, Iron, Cobalt, Silicon, Manganese and Chlorine, can be supplanted. If soils remain deficient, crop conditions and ultimately the production is affected.

Soil Sample

Testing soil in the laboratory requires only a few grams of the soil. However, this little amounts of sample, it must be a true representative of the field. The layer of a soil sample is taken in a homogenous field, samples should be taken from the plough layer (0-15cm). It should be selected randomly in a zigzag manner. These samples should not be collected from bunds, water channels, field paths heaps of crop straw, stubbles and manure.

Sampling:

1. The sample collected from selected sites should be composite, and mixed thoroughly in a container. A lot should be made from all the soils taken across the field
2. From this lot, a representative sample which has about 500 gms should be taken out and air-dried under the shade
3. The air-dried sample should be transferred into a clean cloth bag with a slip. It should be labelled with the following details and give all the information.
   1. Name and address of the farmer (or farm owner).
   2. Name of the block
   3. Plot number or any other number that identifies the plot (or soil unit)
   4. Soil texture (sandy/clay/loam).
   5. Availability of irrigation facilities
   6. Availability of drainage system
   7. Upland/Mediumland/Lowland
   8. Depth of the soil sample
   9. Information of the previous crop
      1. Name and variety of the crop
      2. Dose of organic manure, if applied
      3. Dose of fertilizers, if applied
      4. Yield
   10. Informations of the crop that will be grown
       1. Name and variety of the crop
       2. Season (pre-Kharif/Kharif/rabi)
       3. Problem, if any
       4. Date of sample collection
       5. Signature of the farmer (or farm owner)

Such labelled samples should betaken  to the laboratory where facilities for testing soils for micronutrients are available.

Picking up the sample:
Follow the directions and as indicated in the pictures.
Pictures-----followed by the picture of mixing of soil

Collecting of a sample from the plantation crop
Farmers should dig wells or pits of 1.8 meter depth. Depth may vary depending on depth of the roots of a crop. Collect the soil-slice of ½ inch thick from the exposed surface of pit at different depths as follows: 0-15, 15-30, 30-60, 60-90, 90-120, 120-150 and 150-180 cm.

Collection for local problem soils: Local problem soils are treated as separate soil units or plots. Separate composite samples are collected from problem soils. The problem soil samples should not be mixed with normal soils or non-problem soils. Both surface soil and sub-soil samples are collected.

Collection of surface soil sample-Take 10-30 furrow-slices or cores that extend through A1 horizon.

Collection of sub-soil sample Dig a well or a pit of one meter depth. Take soil-slices of ½ inch depth below A1 horizon from different depths as follows: 0-15, 15-30, 30-60, 60-100 cm.

When to take a sample?
Samples should be taken a month before planting time. As a rule 'if soil is too wet to plow, it is too wet to sample’. Samples should be collected at the same time every year.

Frequency of Soil Sampling
Soils from coastal plains, sandy, light textured soils should be sampled once in every 2-3 crops.  Silty, clay loams and mountain soils should be sampled once in every four cropping years.