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| AGRICULTURE TRIBUNE | Monday, July 23, 2001, Chandigarh, India |
| Weed management in paddy crop Ram Murti and R.K. Malik The rice-wheat cropping system, which covers about 10 million hectares in India, is the backbone of India’s food security and produces as high as 12.8 to 17.0 tones per hectare per annum at different levels of cultivation. With the release of high yielding, photo-insensitive and high fertiliser responsive varieties of rice and wheat in the sixties and with the extension of irrigation facilities, there has been perceptible shift in area from other crops to rice and wheat. However, there is a dark side to this success story, monoculture of the Green Revolution was encouraged and the lack of height renders the crop far less competitive with weeds and herbicide use became obligatory.
Pulses cultivation needs to be encouraged |
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Weed management in paddy crop The rice-wheat cropping system, which covers about 10 million hectares in India, is the backbone of India’s food security and produces as high as 12.8 to 17.0 tones per hectare per annum at different levels of cultivation. With the release of high yielding, photo-insensitive and high fertiliser responsive varieties of rice and wheat in the sixties and with the extension of irrigation facilities, there has been perceptible shift in area from other crops to rice and wheat. However, there is a dark side to this success story, monoculture of the Green Revolution was encouraged and the lack of height renders the crop far less competitive with weeds and herbicide use became obligatory. Rice is grown by direct seeded and transplanted methods. Weed competition is more severe in the direct seeded crop than in the transplanted crop. In these situations, jungle rice
(Echinochloa colonna) and barnyard grass (Echinochloa crusgalli) are the main weeds growing in association with other annual grasses, sedges and annual broadleaf weeds. Much of the rain-fed rice in low-land plains is dominated by
Echinochloa crusgalli and Paspalum scrobiculatum among annual grasses, cyperus iria,
Cyperus difformis and Monophobia vaginalis among broad leaf weeds. The weed flora in irrigated rice of North-West India is simple with the dominance of
Echinochloa crusgalli along with a few sedges like Cyperus iria. In deep water rice
Eichhornia crassipes and Pistia sp. are the problem weeds due to flash floods. In direct seeded rice under upland rain-fed conditions, weeds often emerge simultaneously with the crop and competition for soil moisture may begin early, especially in low rainfall areas. Weed seedlings, due to their greater competitive ability, grow more rapidly than rice seedlings. In transplanted rice flooding and puddling destroy the existing weed growth before seedlings are planted. Furthermore, a new flush of weeds establishes only after two to three weeks of transplantation, thus enabling the rice seedlings to establish well and withstand the subsequent weed competition better. The extent of yield reduction due to weeds is around 20 to 25 per cent in transplanted rice, 30 to 35 per cent in direct seeded puddled rice and over 50 per cent in direct seeded upland rain-fed rice. The weed problem is more acute in the high-yielding dwarf varieties. Weed management: Before the introduction of high-yielding varieties, a modest amount of weeding requirement was met by family labour but in the present scenario hired labour has become far too expensive and scarce. Stalebed technique: Before going in for direct seeding or transplanting, the weeds in the upper few centimetre surface soil may be encouraged to emerge in a bid to reduce competition early in the season. Non selective pre-seeding herbicides may be introduced to control weeds before seeding or transplanting. The dry seeded rice crop under irrigated conditions may be sown with the minimum soil disturbance. Nutrient management The ideal situation should accomplish weed-free condition at the time of fertiliser applications so that the gains from fertiliser application may be shared by crop and not both weed and crop. Top dressing of nitrogen after weeding is desirable to maximise fertiliser efficiency and to minimise weed growth. Crop rotation ca be another alternative approach as part of a well-considered strategy to exhaust the seed bank of highly competitive weeds like
Echinochloa sp. in rice. Water management Keeping standing water in rice fields for some time early in the season can be effective, perhaps as effective as herbicides at reducing the population of weeds. Water management when integrated with herbicides or agronomic practices directly or indirectly attributes to improved weed management. This is because growth and population suppression by standing water increases the susceptibility of weeds against herbicides. Chemical weed control: The biggest single change in the rice production system over the past two decades is the large scale of acceptance of herbicide use. The herbicide use will continue to grow as the large proportion of both small and big farmer clamour for chemical weed control. In rice nurseries, thiobencarb and butachlor (1.0 to 2.0 kg/ha) may be applied seven to 10 days after planting the seed. As these herbicides injure rice during seed germination, application soon after seedling emergence, but just before irrigation, is recommended. Application may be made easier if the EC or granular formulation is mixed with sand (50 to 75 kg/ha) and broadcast over the soil surface prior to irrigation. Anilophos (0.4 to 0.8 kg/ha) and pendimethalin (1.0 to 1.5 kg/ha) may also be used in case of thiobencarb and butachlor are not available. In case sprouted seeds are sown, these preemergence herbicides may be applied four to six days after sowing. In irrigated transplanted crop an effective broad spectrum weed control can be obtained by applying the granular mixture of butachlor (0.5 to 1.0 kg/ha) with 2,4 -D ethyl ester (0.4 to 0.8 kg/ha) three to seven days after transplantation of rice seedlings. The granular mixture is applied as a sand mix by mixing in sand (50 to 75 kg/ha). This combination is very effective against many broad leaf weeds and sedges for 40 to 60 days. The granular mixture is better than the EC mixture in terms of efficacy and duration of activity. In this combination both herbicides prevent emergence of weeds seedlings and 2,4 -D kills the emerged weeds. Other granular herbicide mixtures that may be used include thiobencrab (0.5 to 1.0 kg/ha) with 2,4 -D ethyl ester (0.4 to 0.8 kg/ha) and anilophos (0.75 to 1.5 kg/ha) with 2,4 -D ethyl ester (0.4 to 0.8 kg/ha). If the weed spectrum is dominated by broad leaf weeds and sedges, 2,4 -D ethyl ester granules (4G) alone 0.6 to 1.2 kg/ha may be used as sand mix 10 to 15 days after rice transplantation. In case annual grasses predominate the field, butachlor (1.0 to 2.0 kg/ha) alone may be applied within five days after transplantation. The efficacy of a herbicide depends upon the type of rice culture. Some herbicides are more suitable than others under certain cropping and weed situations. Generally, the effectiveness of herbicides in rice is dependent, to a great extent, on the water management practices and timely application of fertiliser in relation to the initial weed problems. |
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Collar rot ravaging tomato in Solan Tomato is an important off-season vegetable crop of the Solan area of Himachal Pradesh. In the state, tomato is being produced on an area of 4500 ha with a production of 1,30,875 tonnes. Solan is a leading supplier of fresh tomatoes to the plains of northern India during the summer and rainy seasons and the produce is marketed from June to October, fetching remunerative prices to the farmers. Tomato cultivation lately has assumed commercial status in this part of the state due to rapid development of high-yielding varieties and F1 hybrids. The popularity of tomato hybrids among the growers of the Solan area is due to its ability to withstand transport hazards as well as high-yielding capacity. Collar rot has, however, appeared in a devastating form this year in some areas of this district — Patta Barian, Kotla Ka Nala, Sultanpur, Nauni, Salogra, Shyan, Hathon, Dhrot, Jaunajee and Narag—leading to mortality of plants. The maximum intensity of the disease is during summer when the crop is infected within 40 days of planting. The most commonly affected hybrids are Naveen-2000, Naveen, Naveen Plus, Manisha, Rakshita, Sunseed, Avinash-2, Himsona, Safal-99 etc.
Symptoms: The most conspicuous symptoms seen on the plants are yellowing and sudden drooping of leaves, rotting of the collar region of the plants. There is brown to dark brown discolouration of the vascular region. The adventitious roots are more developed. The disease is aggravated in nematode infested areas. The nematodes weaken the plants and pre-dispose to invasion by the pathogen. Causal organisms: The disease has been found to be caused by a species of pythium or fusarium and ralstonia solanacearum alone or in mixed infections. Invasion and disease development are favoured by high temperature (25 to 35° C) and high soil moisture conditions. The situation is further aggravated by water stress, particularly under scanty irrigation conditions. Pythium causes maceration of tissues while bacteria liberate polysaccharides and block the vascular system of the plants resulting in collar rot followed by wilting of the plants. The organisms have a very wide host range and solanaceous vegetables have susceptibility to the bacterium. Management — Deep ploughing and application of Thimet 10-G (10kg-1) during field preparation have been found useful in the management of the disease. — Nursery bed soil treatment with Formalin (1:7) before sowing reduces carry over of the inoculum to the field. Use of healthy seed and seed treatment with Ridomil MZ (3g/kg seed) reduces the initial inoculum. — Spray of Bordeaux mixture (5:5:50) and its drench at an interval of 10 to 15 days depending on the severity of disease during morning or evening hours reduces the disease severity or
alternatively sprays of a combination of Indofil M-45 (0.25%) and Streptocycline (0.01%) at an interval of 15 days
have similar effects. — Use of bleaching powder @ 15kg ha-1 followed by light irrigation reduces spread of the disease to disease to neighbouring fields. — Burning of affected plants avoids soil sickness to the pathogens. — Crop rotation and changing of the fields to cereal cultivation for few years have been found useful in the management of the disease. The Department of Mycology and Plant Pathology of the Dr Y.S. Parmar University of Horticulture and Forestry, Solan, has been helping the tomato growers of the Solan area in diagnosis and management of this disease as well as other vegetable diseases of economic significance. The growers have been benefited by these practices of combating the disease situation and reducing loss to an acceptable level. |
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Pulses cultivation needs to be encouraged Pulses form an integral part of the vegetarian diet in the Indian subcontinent. Besides, being a rich source of protein they maintain soil fertility through biological nitrogen fixation by bacteria prevalent in their root nodules and thus play a vital role in furthering sustainable agriculture. It is sad that during the last decade there has been a shift from pulses area to wheat or paddy or even vegetable crops. Pulses have secondary status in the farming system, perhaps because of the prevalent notions like (a) cereals are the staple food; (b) pulses are not important cash crops; (c) higher risk and hence low stability of production of pulses; (d) higher losses in storage; (e) higher fluctuating market and (f) less responsive to inputs or even irrigation. Farmers, thus, grow pulses on marginal and sub-marginal lands mainly for their own needs. More than 78 per cent of the area under pulses is still rained and therefore, production has shown very little rise. The total area under pulses in India remained virtually stagnant (22 to 24 million hectares) with almost stable production of 12 to 14 million tonnes over the past four decades. The per capital availability of pulses has declined from 64 gm per day (1951-56) to less than 40 gm now as against the World Health Organisation’s recommendation of 80 gm per day. In the eighties the production of pulses stagnated or varied from 10 to 13 metric tonnes. Our target for 1984-85 in terms of production was 14.5 metric tonnes. Against this background, it is not encouraging to note the target set for the terminal year of the Ninth Plan i.e. 2001-02 is just 16.5 metric tonnes after a gap of 17 years. Even during 1998-99, generally considered the best year in the decade , the production was 14.91 metric tonnes. The working group on demand and supply projections for the Ninth Plan constituted by the Planning Commission had estimated the production requirement of pulses at 15.3 metric tonnes in 1996-97 and 17.2 metric tonnes in 2001-02 as per the
behaviouristic approach of gross domestic production at the growth rate of 6 per cent. But we are nowhere near these targets. India has witnessed Green Revolution resulting in surplus rice and wheat production. However, it has failed to make any headway in the production of pulses, with storage looming year after year. It is estimated that the country’s population will touch nearly 1350 millions by 2020 AD. The country would then need a minimum of 30.3 metric tonnes of pulses. Let us analyse whether this target is achievable or not? The most widely known grain pulses are gram and pigeon pea. Kharif pulses (pigeon pea and others) account for 41 per cent of the area and 30 per cent production, the rest being occupied by rabi pulses. Gram accounts for the bulk area (35 per cent) and production (46 per cent) among all pulses. Our national average yield is low at the level of 550 to 650 kg per hectare against the potential yield of 1500 to 3000 kg. While talking of remedial measures we should bear in mind that at the outset there should be a direct link between our analysis of the situation and action to be taken. The present infrastructure in terms of trained manpower for biotechnological researches and other scientific manpower to carry out pulses improvement programme and achieve the target of pulses productivities, is woefully inadequate. During 1993, the Government of India upgraded the Directorate of Pulses Research to the Indian Institute of Pulses Research and established three coordinated projects, but the crop wise responsibilities to carry out research at various centres could not be assigned till more time back. After all, it is the farmers who decided what to grow and in how much area and his decision is mainly based on three parameters — cost of production, the return from his labour and investment and risk involved. In this context, assurance of remunerative marketing holds the key to the decision making of the poor farmers. But bulk of the farmers whose land holdings are less than two hectares seldom get encouragement to cultivate pulses. There is good scope for expansion of area under pulses in various cropping patterns where production can be increased both by horizontal and vertical expansions. With the new technology developed, at least 12.4 m hectares can be added which will help in increasing pulses production by 5 to 6 metric tonnes. Under the National Pulses Development Project, the necessary changes have been incorporated during the Ninth Plan so as to make the various schemes (storage, milling, processing, marketing and finance) more effective to increase the production and to meet the domestic requirement. Financial assistance under the project will be provided on various critical inputs like production and distribution of seed, distribution of mini kits, improved farm implements, sprinklers sets, rhizobium culture etc. Pulses are also covered under the minimum support price (MSP) operations. A pulse policy is in the pipeline. |
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Farm operations for July HORTICULTURAL OPERATIONS — The vacant land may be put under kharif pulses like moong, mash, moth or jantar, etc. for green manuring. — Pear fruit should be carefully picked so that the spurs are not damaged/broken. The fully developed hard ripe mangoes should be picked for artificial ripening. — The full-grown ber plants should be given 500 g of urea per tree during this month. The second coat of whitewash should be given. This will help check the adverse effect of heat on the exposed tree trunk. — To control pathological fruit drop and rot in citrus, give four sprays of Bavistin (500 g/500 litres of water) or Aurofungin (21 g/500 litres pathological fruit drop and rot in citrus, give four sprays of water) or Aurofungin (21 g/500 litres of water) at 15 days
interval starting in the month of July. — To control insect-pests of citrus like citrus psylla, white fly and leaf minor, spray 625 ml Nuvacron 36 SL or 670 ml of Rogor 30 EC in 500 litres of water. This solution will be sufficient for one acre of full-grown orchard. — In citrus to check
whethertip or dieback, scab and stem-end fruit rot, cankar diseases, bordeaux mixture 2: 2:250 or 50 per cent Copper Oxychloride (0.3 %) should be sprayed at 15 days interval. — For the control of gummosis in citrus trunk paint trees with 2 g Ridomil in 100 ml of linseed oil on the infected portion and apply 25 of Ridomil as soil drench in 100 litres of water per infected tree. — To check chaffer and defoliating beetles in almond, peach, plum, ber, grapes and pear, spray Sevin 50 WP @ one kg in 200 litres of water, in the evening hours. If need be this spray should be repeated after 7 to 10 days. — In grapes, spray the vines with Bavistin @ 400g/400 litres of water to control anthracnose. — In loquat, spray the trees with 2:2:250 Bordeaux mixture during the monsoon to control crown rot disease. — Progressive Farming, PAU |
