AGRICULTURE TRIBUNE Monday, March 11, 2002, Chandigarh, India

Managing soil activity for sustained production
V. P. Mahajan
arm soil may be visualised as a porous mixture of four constituents — mineral material, organic matter, air and water. In addition, the soil harbours a varied population of living organisms.

Boosting organic farming
Radhakrishna Rao
ccording to Mr K.C. Pant, Deputy Chairman of the Planning Commission, the government has decided to encourage the organic farming in the country in a big way. Indeed, as pointed out by Mr Pant, in the wake of the negative fallouts of the high-tech farming based on costly and ecologically disruptive chemical fertilisers and pesticides, the concept of organic or sustainable farming is picking up in the country.

Farm operations for March




Managing soil activity for sustained production
V. P. Mahajan

Farm soil may be visualised as a porous mixture of four constituents — mineral material, organic matter, air and water. In addition, the soil harbours a varied population of living organisms. Well-managed productive soil in optimum condition for plant growth contains nearly 45 per cent mineral material, 5 per cent organic matter and 25 per cent each of air and water by volume. The mineral component is made up of sand, silt and clay fractions. Of these, only clay is very active chemically, whereas the others are inert.

Organic matter also called "humus" in its relatively stable state, though present, in soil in very small amount, is extremely active chemically. Air and water occupy the pore spaces in soil. The contents of these two components in a given soil are inter-related and undergo great fluctuations under field conditions. The ideal farm soil contains optimum quantities of all the four constituents.

Sources of Activity: Above soil vision point out that clay and humus are two major centres of soil activities. These activities of clay and humus are on account of their colloidal nature, characterised by a large surface area per unit weight and presence of surface changes. As a result, these colloidal constituents, support number of soil phenomena, including chemical reactions, nutrient exchanges and water absorption.

Moreover, both the colloids by attracting nutrient cations from the soil solution to their surfaces, temporarily protect them from leaching and then release slowly for use of growing plants. Furthermore, clay and humus on account of surface charges, bind coarser particles together and, thus, improve physical condition of soil as in case of very sandy soil.

Potential source of activity: Out of the two sources of soil activity, clay content of field soil is not subject to any major alterations. The clay content of any field soil is its basic property. Even very harsh and active weathering processes fail to alter appreciably the size of the individual soil particles. Thus, the sandy soil remains sandy and clayey remains clayey. Organic matter, the other source of activity, is not as stable as clay. It is a transitory soil constituent.

In cultivated farmlands, its content undergoes wide changes due to climatic conditions and crop management practices. Harsh climatic conditions prevailing in arid and semi-arid regions cause severe losses of organic matter. Poor crop management practices, accelerate depletion of this vital soil component. Such natural and accelerated losses of organic matter can be corrected by treating the soil with organic manures. These manures are very rich, potential and renewable sources of organic matter. They also serve as major sources of phosphorus and sulphur and a sole sources of nitrogen.

Besides, these help to maintain an adequate supply of iron and other trace elements in a farm available to plants. Furthermore, these manures serve as a source of energy for micro-organisms whose activities are vital for good soil health. Organic matter, thus, being the backbone of the soil must be renewed constantly for sustained production.

Sources of organic matter: Bulky organic manures are rich sources of organic matter. These manures include green manures, farmyard manure, farm compost, urban compost, night-soil, sludge and other bulky sources of organic matter. Out of these, green manure, farmyard manure and composts are by far the most important and most widely used. Crop residues also make significant contribution to organic matter content of soil.

The practice of burning crop residues causes great loss of organic matter resulting in decline of soil activity. Ploughing under of suitable green manure crops when in succulent stage not only supplement large bulk of organic matter but also add adequate quantities of nitrogen. Farmyard manure application done at the usual 10 to 15 cartloads per acre maintain on an average 400 to 500 kg dry matter on a yearly basis.

Treatment of the soil with 10 to 15 tones of well-rotten compost keep the soil in active state for two to three crop seasons, depending upon climatic conditions and crop management practices.

Rotational manuring for managing activity: In view of great importance of bulky organic measures in ameliorating soil activity, their periodic use in culturable lands should form a regular practice.

However, on account of poor adoption of green manures and limited availability of farmyard manure and composts, most of the farmers either miss or very much delay their application. To overcome such a problem, rotational or phased-out system of manuring can be successfully practised to replenish organic matter.

The rotational system consists in planned treatment of one-half or one-third of farmland with the available manures every year in a regular sequence. By extending this practice to the remaining land during the subsequent two or three years, each field at the farm will receive organic manure treatment regularly at an interval of two to three years.

This rotational system of manuring needs to be included in the integrated nutrient schedule of the farm for the long-term management of soil activity ensure sustained production.



Boosting organic farming
Radhakrishna Rao

According to Mr K.C. Pant, Deputy Chairman of the Planning Commission, the government has decided to encourage the organic farming in the country in a big way. Indeed, as pointed out by Mr Pant, in the wake of the negative fallouts of the high-tech farming based on costly and ecologically disruptive chemical fertilisers and pesticides, the concept of organic or sustainable farming is picking up in the country. As in the West and India, the buyers are prepared to pay a premium on organic food.

Significantly, popularisation of organic farming by the Deccan Development Society (DDS) in about 40 villages of Medak district in Andhra Pradesh has resulted in putting an end to the spell of drought by making these villages self-sufficient in food, fruits and vegetables. The novel concept of circle planting pioneered by the DDS has brought immense benefits to the villagers in this part of Andhra Pradesh. Circle planting makes it easier to water the trees. Normally, when trees are planted in a line, they have to be watered separately, but in a circle they can be watered once from the centres. There is also less shading of the adjacent crops. Says Dr S. Venkat of the DDS, "All its nutrition, all its water is found within the system itself. For any system of production to be sustainable, the needs of the system must be found within the system. Unless all the needs are found within the system, the system will become unsustainable."

The use of biofertilisers and oil cakes and oil meals play a key role in the practice of organic farming. The New Delhi-based National Academy of Agricultural Sciences (NAAS)has stressed need to evolve new strategies to achieve a balanced and integrated management of a organic and inorganic nutrients to support organic farming.

In fact, the much-touted Green Revolution relying on the high yielding, vulnerable varieties and an abundant supply of water has failed to be an economically viable or ecologically sustainable farming strategy. In fact, the crisis facing the farmers in Punjab is traceable to the pitfalls of the Green Revolution strategy.

A recent scientific study by the American National Science Academy comes to the conclusion that the application of pesticides and fertilisers does not necessarily lead to better farming than the natural farming. Perhaps the credit for putting natural farming on practical footing on a global scale goes to Japanese plant pathologist Fukukoa who secured an Forward for the signal service rendered to the cause of natural farming. A staunch believer in the principles of Zen Buddhism, Fukukoa says that the soil’s nourishing qualities stem from organic matter that return to soil periodically.

On the other hand, Dr Teuro Higs, agricultural scientist and an advocate of nature farming points out that the concent of nature farming seeks to re-establish the balance of energy in nature without using pesticides and chemicals. "This ancient technique of nature farming is based on sound ecological principles", says Dr Higs. No wonder, organic farming is becoming popular in both the developed North and the developing South.



Farm operations for March


Chilli and capsicum: Sow CH-3/CH-1/Punjab Guchhedar/Punjab Surakh/Punjab Lal varieties of capsicum. Mark east-to-west lines 45 cm apart with a rake or rope. Apply 40 kg of CAN, 155 kg of superphosphate and 50 kg of muriate of potash in bands over these lines and prepare rides. Dibble (chutki) 3 to 4 seeds per hill on the southern slope of each ridge, keeping hills 30 cm apart. Use 1.5 kg seed per acre of both chilli and capsicum for dibbling. In case nurseries have been sown in November-December and kept under protection against frost during winter, transplant them also on the rides and continue irrigation after 10 to 12 days. Sow 0.5 kg seed of chilli on raised beds.One-marla bed area is enough to raise seedlings for an acre. Treat the seed before sowing with Captan/Thiram.

Onion: — From March 15, sow nursery of onion variety N-53 or Agri Fond Dark Red to produce bulb sets for planting Kharif season crop. Sow 5 kg seed to produce enough bulbs sets for planting in an acre. Sow this seed on beds having an area of 8 marlas.

— Onion thrips feed on foliage and produce white spots followed by curling — a condition known as "silver top". Spray 250 ml of Malathion 50 EC in 80 litres of water per acre as soon as the pest appears.

Okra: — Sow either variety Pusa Sawani or Punjab Padmini or Punjab-7 or Punjab-8 for better yields in this season. Apply 60 kg of CAN and 155 kg of superphosphate and 40 kg of muriate of potash per acre in bands and prepare rides from east to west. Soak 8 to 10 kg seed in lukewarm water over night. Dibble 4 to 5 seeds per hill on the southern slope of ridges, keeping hill at 30 cm. Apply light irrigation after 10 to 12 days.

— Spray one litre Stomp 30 EC/acre as pre-emergence to control weeds.

Cucurbits: — Apply 155 kg/acre superphosphate and 40 kg/acre muriate of potash. Prepare channels as per recommendation of each cucurbitaceous vegetable. Soak the seeds in water, wrap in a woollen rag of 48 hours of pre-sprouting. Use 2 kg of seed for covering an acre. Dibble at least two viable seeds per hill.

— After germination of the crop, apply 2.75 kg/acre Furadan 3 G 3-4 cm deep in soil just near the base of plants or apply 75-100 g/acre of Sevin/Hexavin 50 WP in 50-100 litres of water to check attack of red pumpkin beetle.

Pea and early season

Varieties of cauliflower: — Peas leaf miner larvae feed by making tunnels in the leaves and cause serious damage. Spray 125 ml of Dimecron 85 SL or 400 ml of Rogor 30 EC in 100 litres of water per acre.

— Harvest the seed crop of pea when few top most pods are yet slightly green. This will check shattering of seeds in the fields.

— Harvest the seed crop of cauliflower when the top most pods in bunches of early season varieties are yellowish green.

Tomato: — Apply second dose of nitrogen in the first fortnight of this month. Train plants on beds. Irrigate regularly after 10 to 12 days to encourage the maximum fruit setting.

— Late blight disease may appear on tomato early in this month. The crop may be sprayed with Indofil M 45 @ 600 g/acre to control this disease. In case of severe infestation, spray Ridomil MZ @ 500 g/acre followed by Indofil M-45 at 7 days interval.

— Spray tomato crop with 800 ml of Thiodan 35 EC or 800 g Sevin/Hexavin 50 WP or 100 ml of Sumicidin 20 EC or 40 ml of Ambush 50 EC or 200 ml of Ripcord 10 EC or 160 ml of Decis 2.8 EC per acre in 100 litres of water to check attack of the fruit bore.

Cowpea: Sow Selection 263 or Pusa Dophasli keeping lines 45 cm and plants 5 to 7 cm apart to obtain green pods for table purpose. Apply 155 kg superphosphate per acre. Sow 8 to 10 kg seed of cowpea varieties.