Rice residue — resource and problem
THE rice crop in Punjab has become the most important kharif crop. It was grown on about 2.44 lakh hectares in 1966-67 that increased by nine-fold (21.79 lakh hectares) by 1996-97. The average productivity per hectare in the state has also increased from 1186 kg in 1966-67 to 3507 kg in 1997-98. With the increase in production of rice there is an increase in the production of residue (husk and straw) which is approximately 188 lakh tonnes.

Improve irrigation system for food security
LESSTER Brown, a foreign expert and noted agriculture scientist, has forewarned, “Agriculturists abroad are predicting that India may have to import substantial amounts of grain once again during the next century.” So can we rest on our oars, comfortable in the belief that there are no more problems on the food front? Will there be no possibility of a repeat of the humiliation and stress the country and our people had to undergo from 1965 to 1967?

Pest and its management in cotton
P. Jeyakumar and D. Monga

Cotton is assailed by a multitude of pests as it evolved through various production levels. Pest spectrum of cotton is most complex since as many as 1,326 species of insects have been reported on this crop in the world. In India, however, 130 insect species have been listed on cotton. Many of them being time and space bound. Of these, cotton leafhopper, whitefly and bollworms are ubiquitous and pose a serious threat in arresting cotton production in India. The main thrust of Indian cotton growers has so far been toward the application of potent insecticides to combat the pest problems in cotton. This approach has attracted cotton growers because of its effectiveness and quick action. Thus, this crop alone consumes about 50 per cent of the total pesticides in the country.

Ill effects of insecticides

The over-reliance on unilateral use of synthetic insecticides mainly synthetic pyrethroids and their indiscriminate use has created serious consequences, and utility of even most potent class of insecticides is not diminishing, but also creating problems like insecticide resistance, resurgence, adverse effect on natural enemies and other beneficial insects and the way the insecticides have an important role to play in the environmental pollution.

The insects, especially lepidopterous larvae have the capability to develop resistance to a particular type of insecticides when used repeatedly. In some instances the cross resistance is also reported. The insects having resistance to a particular group of insecticides e.g. carbamates also show resistance to another group of insecticides having the same mode of action e.g. organophosphates. Apart from the resistance problem the insects have resurged against some insecticides. Resurgence means the build up in pest population to a great extent, especially after the spray, which is mainly due to the killing of natural enemies by the insecticides. The better example for this is the resurgence of whitefly, due to the use of synthetic pyrethroids. These resistance and resurgence problems were faced by the cotton farmers of Andhra Pradesh during 1997 and 1998, due to which many farmers committed suicide. These problems arise mainly due to improper and excessive use of insecticides.

Apart from these two problems, insecticides kill all the natural enemy population in the field, which are supposed to act as friendly insects by executing a natural check over the pest population. In this way insecticides cause imbalance in the natural life cycle. The greatest hazard by the insecticides is the environmental pollution, which has not yet been fully realised by either the farmers or government organisations.

Proper usage of insecticides

Though the insecticides are creating so many problems and harmful effects on human beings, the usage of insecticides as such cannot be banned, as it is still found to be an effective arm in our war against insects. Whereas, the problems due to insecticides can be minimised if it is used properly. In the usage of insecticides the following points should be taken into consideration for attaining great success in this war.

— First of all one should know the appropriate time for the use of insecticides. This can be decided based on the population of insect pests which can cause economic damage if otherwise uncontrolled. In cotton the economic threshold level for different pests which justifies the usage of insecticides are jassids 2/leaf, thrips 50/leaf, whitefly 6-8/leaf, American bollworm 20 larvae/20 plants and spotted and pink bollworm 10 per cent damage in fruiting parts.

— The selection of correct insecticides is an important step in the proper management of insect pests. Because the insecticides which are effective against jassids/whitely e.g. metasystox may not be effective against bollworms.

— The dosage of the selected insecticide also should be at the optimal level. If the higher dosage than the recommended is used the rate of development of resistance in the insects to that particular insecticide also will be faster and then a stage will be reached quickly at which that particular insecticide become ineffective. Apart from this the high dosage will have adverse effect on natural enemies as well as pollinators such as honey bees. So for this reason more emphasis should be given on the usage of right dose of the selected insecticide.

— After successfully doing all these things also the insecticides may not be effective if applied improperly. So the right method should be adopted for achieving success in this war.

At present the North Indian cotton crop is in the reproductive stage and so the bollworms are posing a major threat. The jassid and whitefly population even though found in a field can be neglected as the bollworms cause a direct yield loss. In this year the spotted bollworms (locally called at Chitkavari sundi) are dominating than any other bollworms. Whereas the American bollworm incidence is in the beginning stage which may dominate otherwise.

In the management of bollworms the important point to be taken into consideration is the ability of bollworms, especially of American bollworm, to develop resistance against any of the insecticide used against them. The same insecticide if used again and again will become ineffective in due course of time. So the rotation or use of different insecticides in a spray schedule is imminent to overcome the problem of development of resistance. Synthetic pyrethroids occupy the first position in the array of insecticides for which insects developed resistance. The severe problem with pyrethroid resistance is its irreversible nature i.e. the resistance if once developed by insects will last for long time up to which the insecticides become ineffective or requires a higher dose for obtaining an effective control. Whereas for the other group of insecticides such as endosulfan, quinalphos, etc, the reversible resistance has been found, in which case the resistance will be lost if that particular insecticide is withdrawn from the spray schedule for a shorter period of time. The synthetic pyrethroids also cause secondary outbreak of whitefly (i.e. the increase in whitefly population) due to the kill of natural enemy population as well as changes in plant constituents. This is the reason for which the excessive use of synthetic pyrethroids in cotton is restricted to the minimum level.

There is no doubt that pyrethroids are still having lot of potential in it which can be exploited if used properly at a proper time.

At present the cotton crop is severely infested by spotted bollworms, whereas the American bollworms population is in the beginning stage. The insecticides such as quinalphos (800 ml/acre) or chlorpyriphos (800 ml/acre) can be used for this purpose. If whitefly population is also found more than the economic damage level along with these bollworms, then triazophos (600 ml/acre) may be used, otherwise chlorpyriphos may be used to ward off bollworms along with jassids population.

In some cases the spotted bollworms population has crossed well above the economic damage level, and in such cases farmers may find these organophosphate insecticides as ineffective. Here the farmers can go in for the spray of synthetic pyrethroids i.e. fenvalerate (200 ml/acre) or cypermethrin 10EC (200 ml/acre) or 25 EC (80 ml/acre). The key point to be noted during synthetic pyrethroid spray is mixing of “Til Oil” at the rate of 30 ml/100 litres of spray fluid. This “Til Oil” if added will break the resistance mechanisms in the insects so that the pyrethroids can effectively kill the insect.

In the spotted bollworms problem is not in an appreciable manner, whereas the American bollworm is in the initial stage, then farmers may use the following chemicals in rotation to avoid the problem of resistance. The first spray in this schedule should be endosulfan (600 ml/acre), which may take care of the initial population of American bollworms as well as will not affect the natural enemy population in the field. This may be followed by quinalphos/chlorpyriphos (800 ml/acre) and carbryl (800 g/acre)/thiodicarb (300 g/acre). In this schedule the synthetic pyrethroid (cypermethrin/fenvalerate) should be sprayed as the last option. If the American bollworm egg population (which can be seen on the terminal young leaves as a white coloured spot) is found and the larvae are yet to emerge, then profenofos (600 ml/acre) can be sprayed immediately, which acts as an effective ovicide. At least a minimum of 15 days’ interval should be given between two subsequent sprays. At this reproductive stage (fruit-bearing stage) of the crop there is no need to worry about the sucking pests i.e. jassids and whitefly unless otherwise they occur in a disastrous way.

So far we have gone across the process of selecting right time for the management practice to be carried out and the right insecticide at right dosage. After this the last but not the least is the right method of spraying, which otherwise will hamper all the processes and labour. The main thing to be kept in mind here is to cover throughout the crop canopy completely, without leaving even a trace for the bollworms to go and hide. The spray should be done along the windward direction and the nozzle should be kept at 30-50 cm height above the crop canopy to have an effective coverage.

If the spray is done with knapsack sprayer 150-200 litres to spray fluid/acre should be used, with fixed type hollow nozzle. The pressure in the tank should be kept uniform to obtain proper drizzle which provides an effective coverage. If the spray is done through tractor-mounted sprayer, care should be taken to maintain uniform tractor speed as it affects the delivery of spray fluid. The nozzles fitted in tractor mounted sprayer should deliver around 450-600 ml of spray fluid/minute.

Rice residue — resource and problem

THE rice crop in Punjab has become the most important kharif crop. It was grown on about 2.44 lakh hectares in 1966-67 that increased by nine-fold (21.79 lakh hectares) by 1996-97. The average productivity per hectare in the state has also increased from 1186 kg in 1966-67 to 3507 kg in 1997-98. With the increase in production of rice there is an increase in the production of residue (husk and straw) which is approximately 188 lakh tonnes.

The straw can be used as dry fodder for animals, but owing to availability of better quality fodder, it is not preferred for this purpose. The manually harvested straw can be used as cheap quality fuel. Looking on this aspect, the Punjab State Electricity Board has put up a 10- MW plant at Jalkheri (Patiala). The electricity to be produced was uneconomical. The paper industry has limited use of this material as it has high silica content. The cardboard industry is yet to pick up in Punjab.

About 70 per cent of the rice residue produced is burnt in the fields, particularly after harvesting rice by combine harvesters. It is estimated that about 142 lakh tonnes of rice straw is burned annually in the state. The nutrients that are completely burnt and lost to atmosphere while burning the residue are carbon, nitrogen, sulphur and some phosphorus. It is estimated that about 3.51 lakh tonnes of nutrients in straw and husk are completely or partially lost, which is about 60 per cent of the total nutrients consumed during kharif 1996-97 in Punjab and the cost of which comes to about Rs 233 crore. The value of nitrogen alone lost to the atmosphere by burning is about Rs 64.4 crore annually. Therefore, burning of rice residue is a net loss both nutrient wise to agriculture and economically to the nation.

Burning also causes environmental pollution. A thick and black smog greeted the resident of part of Punjab on October 15, 1998. Burning also decreases the efficiency of some herbicides used for controlling weeds during wheat growth. Therefore, burning of rice residue is not advised. Alternately, it can be composted or directly managed in the field.

The direct incorporation of rice residue was tested along with the nitrogen management in the Department of Soils, PAU, Ludhiana. It was recommended that the residue should be incorporated 20 to 25 days before the sowing of wheat. The normal fertiliser management practices for wheat may be followed as such.

The combine harvester spreads the residue in the field. The residue can be turned-in with mould board plough or offset disc harrow. The rotavator can be used to do the job very efficiently. The use of shredder to chop the combine harvested residue before incorporation helps in early decomposition of the residue. After the residues are ploughed-in, the soil should be kept moist through light-irrigation. It helps the heterotrophic micro-organisms to grow fast. The increased microbial activity digests the residue at a fast rate. The field can be left for 20 to 25 days and then the normal practices for sowing wheat can be followed.

The incorporation of rice residue in rice-wheat rotation has favourable affect on the wheat yield and the soil physical and chemical properties such as pH, organic carbon, water holding capacity and bulk density of the soil. The decrease in bulk density with straw addition definitely has a bearing on the wheat yield in the rice-wheat rotation where soil aeration becomes a limiting factor. The incorporation of residue also prevents the leaching of nitrates. It adds a plenty of organic carbon and thus increases heterotrophic bacteria and fungi in the soil. Due to an increase in microbial population, the activity of soil enzymes responsible for conversion of unavailable to available form of nutrients also increases. An increase in organic matter of the soil also improves the efficiency of applied chemical fertilisers. The incorporation of rice residue is especially useful in improving the soil productivity, particularly in soils that are reclaimed or where brackish water is being used for irrigation. The farmers are, therefore, advised not to burn the crop residue but to incorporate it into the soil to improve the soil health and its productivity for sustaining the soil productivity for higher crop yields.

The recycling of crop residues has special relevance in intensive agriculture as it will help in returning to the soil a major portion of the nutrient elements removed in crop harvests. At the present rate of fertiliser consumption, nutrient replenishment is only 40 per cent. It is, however, likely that every year soils of Punjab are getting depleted of the soil nutrients and need to be recuperated through sources other than chemical fertilisers to sustain the present level of productivity. In the long run, over a period of this practice, the organic content will increase which will have a great bearing on the productivity and fertiliser use efficiency in future. — TNS

Improve irrigation system for food security
By Suraj Bhan Dahiya

LESSTER Brown, a foreign expert and noted agriculture scientist, has forewarned, “Agriculturists abroad are predicting that India may have to import substantial amounts of grain once again during the next century.” So can we rest on our oars, comfortable in the belief that there are no more problems on the food front? Will there be no possibility of a repeat of the humiliation and stress the country and our people had to undergo from 1965 to 1967?

In this regard, we may look at the following table prepared by the Technology Information, Forecasting and Assessment Council, Food and Agriculture Technology Vision 2020.

Projected grain imports in 2000 and 2010:

Our apprehension is that the annual growth rate in the Indian agriculture, which had risen to 3.3 per cent during the 1980s, has come down to about 1.8 per cent in the current decade as against a population growth of about 2 per cent. It is therefore, essential to study the scenario for domestic demand for foodgrain and other commodities.

“India has to attain an agricultural growth rate of 4 per cent neither for its short-term gains nor for long-term losses but to meet the food demand for all its people,” suggested Lesster Brown. Our people and farmers are exceptionally entrepreneurial and have proved it again and again if they are looked after well. But we can belie the gloomy predictions only when we resolve to work hard with a long-term vision.

Let us not forget that our existing food security has been mainly brought about by the increase in irrigated agriculture and the introduction of high-yielding varieties of crops. Thus among the determinants of growth of agriculture, investment in irrigation is crucial. But the new economic environment has been confined only to secondary and tertiary sectors of economy, leaving agriculture in isolation. Without agriculture, mind it, our economy cannot grow at the desired growth. The impressive growth around 6 per cent in the country’s gross domestic product in 1998-99 has been due to mainly a high growth of over 5.8 per cent in the agricultural sector. Since we need at least a 7 per cent growth to reach developed country status, for enhancement of agricultural production investment in irrigation cannot be postponed further.

Paradoxically, plan spending on irrigation has declined from 10 per cent in the Sixth Plan to 7.6 per cent in the Seventh Plan to 6.4 per cent in the Eighth Plan. The following table further illustrates the point:-

(Investment in Irrigation at constant 1996-97 prices, Rs in crore).

The exercise on investment in irrigation is mind boggling. Even by estimating the cost of irrigation at Rs 1 lakh per hectare — the World Bank’s estimate is Rs 3 lakh per hectare —it would cost Rs 2,50,000 crore to irrigate 25 million hectares with irrigation potential, said Ashok Gulati, an agriculture economist with the Institute for Economic Growth.

“It would take 50 years to irrigate the 25 million hectares if the government continues with its annual investment of Rs 5,000 crore on irrigation”, he explains.

The grim situation is that in spite of having abundant water resources in the country we have failed to channelise them optimally. Huge investments have been made in the canal system, yet output-wise the results are in the “red”. A cultivator today is sandwiched between canal officials and the revenue authorities. Canal engineers’ commitment to update the canal irrigation system is lacking. Consequently, instead of good revenue source it has become liability. In some states when the irrigation engineers failed to deliver the goods, villagers themselves took over the water management and they proved to be good managers.

In a village near Aurangabad in Maharashtra villagers with the help of some voluntary agencies have transformed the face of the village from drought stricken to a green one. This is a very good example of economic management of scarce water.

Water is a very precious commodity. It is pity that no worthwhile research work has been carried out to harness this natural source economically. Rain water, though available in plenty, is allowed to go waste every year by the state irrigation departments having a large army of engineers.

The inter-state water disputes too continue to linger on with no signs of settlement, resulting in crisis in many status: financial, political and social. India with its vast water resources can make miracles happen if there is strong will to do so.

Ornamentals Annuals
— Transplanting of the nursery of winter flowers can be continued in this month also. To use the winter season annuals in beds and for making a herbicious border, plant dwarf seasonals in the front row, medium sized in the centre and taller ones at the back side. Similarly, for flower colour combinations grow contrast coloured annuals side by side (e.g. red and blue) of harmonious (e.g. red and pink) and so on.

— For vast open area, use one type and one colour of annual in each bed to have mass effect.

— Sweet peas, planted in October, may need support of “sarkanda” for further upward growth.

— Cannas must be in their full bloom. Old stems that have flowered should be cut back to ground level.

Lawns:
— The effects of cold nights may be visible on lawns and their green luster will start fading and require occasional mowing and watering regularly.

Chrysanthemum:
— Having considerable growth and flowering phase pots can be arranged in rows or in groups at suitable positions in and around the houses or some other buildings for decoration. The faded out flowers should be removed immediately after their flowering is over.

Rose:
— New rose plants can also be planted in this month. This is the best time for the propagation for roses i.e. of budding and for plantation of cuttings of root stock (desi rose). Water and hoeing of already planted/established roses may be carried out regularly.

Bulbous plants:
— Plantation of bulbs of gladiolus, narcissus (nargis), hyacinth can be continued in this month also. Rooted cuttings of double dahlia may be planted in pots or in the beds.

Horticultural operations
— The young trees as well as the newly planted fruit trees should be covered with thatches or kullies made of sarkanda or far-waste materials. The south-west side should be left open to allow sufficient sunlight.

— This would be the appropriate time for sowing of rabi intercrops like gram, peas and senji to utilise the vacant space in the young plantations.

— If there has not been a very dry spell, it is advisable to withhold the irrigation right now to the deciduous fruits such as pear, peach, plum and grapes so that the trees enter dormancy and become sufficiently hardened to withstand cool weather. The ber trees, which carry fruit load from October to February should be provided irrigation after every 3-4 weeks.

— It is the right time to plan planting of deciduous plants in January.

— Harvesting of early variety of sweet orange like mosambi will commence towards the end of this month. While harvesting the stalk should be cut close to the fruit with a secateur of special type of clippers.

— Powdery mildew of ber may further spread and lead to premature fruit drop. The incidence of the disease may be reduced by spraying the ber plantation with 0.25 per cent wettable sulphur of 0.05 per cent karathane 40 EC. Leaf spot of ber also appear as blackish mouldy patches on underside of the leaves. Spray ber plants thoroughly with Bordeaux mixture 2:2:250 or with 0.3 per cent copper oxychloride.

— Progressive Farming, PAUs