Maintenance Of Soil Productivity

Soil Productivity

A. Manures

Importance of manures in obtaining high crops yields was fully appreciated in ancient India. In Krishi Parashara, it is stated that crops grown without manure will not give yield and a method of preparing manure from cow dung is described. Kautilya mentioned use of cow dung, animal bones, fishes, and milk as manure. Agni Purana recommends application of the excreta of sheep and goat and pulverized barely and sesame allowed to be soaked in meat and water for seven nights to increase flowering and fruiting of trees. In Varahamihira’s Brihat Samhita growing of sesame to flowering stage and then incorporating it as green manure is recommended. The Abhilasitarthacintamani mentions a few such fertilizers—

(1) The soil underneath a tree struck by lightning is good for warding off trouble for trees from snowfall.

(2) Fumigation of trees by burning turmeric, Vidanga, white mustard, flowers of the Arjuna tree, mixed with fish and the flesh Rohita (a kind of deer) will not only help the growth of flowers and fruits but will destroy all worms and insects as well as diseases.

Surapala (c. 1000 A.D.) describes the ‘ancient’ practice of preparing liquid manure (kunapa) prepared by boiling a mixture of animal excreta, bone marrow, flesh, and dead fish in an iron pot and then adding to it sesame oil cake, honey, soaked black gram, and a little ghee (or clarified butter).

No fixed quantities of materials were required to prepare ‘kunapa’. This liquid manure was mainly used in raising trees and shrubs. Traditional agriculture practiced in the Himalayas regions of the sub continent involves use of green leaf manure as the main fertilizer for the rice crop. Surapala and Sarangadhara recommended the use of kunapa for properly nourishing trees. The preparation of kunapa is described by Sarangadhara as follows: “One should boil the flesh, fat and marrow of deer, pig, fish, sheep, goat, and rhinoceros in water and when it is properly boiled one should put the mixture in an earthen pot and add into the compound milk, powders of sesame oil cake, masa (black gram) boiled in honey, the decoction of pulses, ghee, and hot water. There is no fixity as to the amount of any of these elements; when the said pot is put in a warm place for about a fortnight, the compound becomes what is called kunapa water which is very nutritious for plants in general”.

Prior to Sarangadhara, Surapala had referred to kunapa and ingredients included excreta, bone marrow, flesh, brain, and blood of boar mixed with water and stored underground. Surapala also referred to “available” materials and these could be animal fat, marrow, and the flesh of fish, ram, goat, and other homed animals. Other materials were more or less the same as mentioned by Sarangadhara, except that quantities of ghee and honey indicated were small. It should not be difficult to standardize and prepare kunapa water concentrates on mass scale and make these available in jars to users. Here is an opportunity for an enterprise to help farmers, especially the orchardists. Firminger (1864) who was a “Chaplain of the Bengal Establishment” mentions beneficial use of “liquid manure”, prepared the way Kunapa was prepared, for vegetable cultivation. He has given no information about who first thought of liquid manure”.

B. Green Leaf Manures

Farmers relied extensively on crop residues legumes and neem for enriching the soil fertility. Ancient Tamil texts, widely quoted the use of Calotropis gigantea, Morinda tinctoria, Thespesia populnea, Jatropha gossypifolia and Adathoda sp., to be used as green leaf manure. Crop rotation and intercropping were practiced to restore soil fertility.

Fauna such as ants, earthworms and frogs were used to improve soil physical properties. Composting practices have also been documented in ancient literature on ideal farming practices. The farmers of Tamil Nadu manure the soil with farmyard manure (FYM), oil cakes, compost and green manures or green leaf manures is an age-old practice.

C. Recycling

Recycling of nutrients through pond excavation was achieved through tank silt or pond excavation in the foothill zones. The sediments from ponds coming from open spaces, field, etc., during the monsoon. The sewage slurry and dissolved minerals and nutrients in water coming from animal sheds and household washings are also diverted to the common village pond.

All the flocculated clay and organic materials usually settle quickly to give clear water of the pond. Animals used to drink water from this pond. As soon as the ponds dry up in summer season, the farmers dig the pond base by lifting the soil and transport it to the fields. The surface layer of pond base usually removed is about 30 cm depth.

This is a rich source of plant nutrients. The application of pond sludge to each field is done once in a span of 10–15 years. Tank silt increases clay content in light textured red soils, which helps to increase soil moisture content and finally the crop yield. In Coimbatore and Trichy districts, farmers apply tank silt to crops like banana, turmeric and jasmine where as in Ramanathapuram farmers apply it to rice @ 25 t/ha. The excavation of pond basin and its application to field was abandoned with the introduction of chemical fertilizers. Farmers excavate ‘murrum’ a uppermost weathered basalt rock and apply to the fields.

D. Compost

The compost becomes ready to use in five to six months. This partially decomposed farmyard manure after spreading evenly in the field is worked into the soil by ploughing followed by planking.

Crop straw- Grain to straw ratio

Rice- 1:1:5

Pearl millet- 1:2:0

Maize- 1:1:5

Cotton- 1:6:0

Wheat- 1:1:5

Barley- 1:1:5

Mustard- 1:2:0

Pulses- 1:1:0

Sugarcane- 1:0:2

E. Penning

Penning of sheep, goat, cattle and pig in the fallow fields is common. One or two fields by rotation are kept fallow to receive the animal dung and urine during summer as well as winter months. Large herds of sheep, goat and cattle are kept in the fallow fields. The farmers used to feel obliged and usually come with a request to cattle herd owners for the night stays at their farm land. The litters of sheep get well mixed with soil during the period of penning.

Light cultivation before the onset of monsoon makes it more effective. Sheep feed on the existing farm residue and drops litter in the same field during resting period. The excreta of sheep is acidic in reaction. On each piece of land, penning is continued for 2 to 4 days depending on the size of the flocks to gather or accumulate sufficient manure to improve the fertility status of the soil.

F. Rishi–Krishi Method of Vermiculture

The Amrit pani consists of 250 g ghee from cow milk + 500 g honey + 200 litre water + 10 kg cow dung. Firstly, ghee is mixed with cow dung thoroughly followed by honey and then water is added to it. Farmers collect 25 kg soil from the base of banyan tree which is sufficient for sprinkling well-prepared Amrit pani on an acre uniformly.

Normal earthworm count in an acre gets double (87120) due to enhanced energy and congenial soil environment. If the weight of one worm is 20 g which eats about the same quantity of soil, in 100 days, one worm can excrete 1kg excreta. Then 87 thousand worms will excretes 87 t of excreta rich in mineral nutrients, organic carbon, microbial population, organic acids, growth hormones and growth promoting substances.

G. Dead Animals

Dead animals (pet or domestic) were buried under the fruit trees such as mango tree. The dead animal contains large amount of biomass, mineral matter in the form of structure and bones specifically nitrogen in protein, phosphorus in bones etc. H. Crop Rotation Crop rotation helps in efficient use of nutrients. Farmers usually change crop rotation in every three or four years to have a better growth and performance of the cropping system. Stubble mulching is common in the high rainfall areas. Mulching raised the organic matter and nutritional status of soil.

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