Presentation on theme: "Morphology,Cultivation,Area of cultivation&High yielding Varieties(HYV) of Rice(Oryza sativa) Dr VISHAL SHARMA Assoc. Proff Government Post Graduate College."— Presentation transcript:
Morphology,Cultivation,Area of cultivation&High yielding Varieties(HYV) of Rice(Oryza sativa) Dr VISHAL SHARMA Assoc. Proff Government Post Graduate College For Girls-11,Chandigarh
Introduction India is one of the major rice (Oryza Sativa) producing and consuming countries in the world. Rice is also the single most important crop in Indian agriculture. It is produced in all the states of the country and is part of the staple diet of a very large section of the Indian population. Rice is a wet season crop and primarily grown under assured rainfall or irrigation. At present rice is cultivated in India with irrigation coverage of only 45 per cent. Season Rice is grown in three seasons in India, autumn and winter in kharif and summer or Rabi. Most of the rice production (around 56 per cent) is in the autumn season in which the sowing is done between March and August and harvesting is between June and December. This indicates the high dependence of the rice crop on the monsoons, which are concentrated in the months of June to September. The winter crop, whose sowing takes place between June and October and harvesting is between November and April, provides about 33 per cent of the total rice crop. The remaining 11 per cent is sown in the summer season.
Area of Cultivation India has been broadly classified into the following eight agro-climatic zones: The humid western Himalaya region, which comprises of Jammu and Kashmir, Himachal Pradesh and Kumaon and the Garhwal division of Uttar Pradesh. The major soil groups are submontane, hills and terai soils. The humid Bengal – Assam basin, which includes West Bengal and Assam. The major soil groups are Riverine alluvium, terai soils, lateritic soils, red-yellow loams and red sandy soils. The humid eastern Himalayan region and the Bay Islands, which include Arunachal Pradesh, Nagaland, Manipur, Mizoram, Tripura, Meghalaya and the Andaman and Nicobar Islands. The major soil groups are Red loamy soils, lateritic soils, red yellow soils and alluvial soil. The sub-humid Sutlej-Ganga plains which include Punjab, Uttar Pradesh, Bihar and Delhi. The major soil groups are calcareous alluvial soils, riverine alluviums, saline and alkaline soils, red-yellow loams, mixed red and black soils and red sandy soils. The sub humid to humid eastern and south eastern uplands comprising of Orissa, Andhra Pradesh and eastern Madhya Pradesh. The major soil groups are lateritic soils, red-yellow loams, mixed red and black soils, deltaic alluvium, deep and medium deep black soils, red loamy soils and coastal alluvium. The arid western plains, which include Haryana, Rajasthan and Dadra and Nagar Haveli. The major soil groups are alluvial soils, red-yellow soils and medium to deep black soils
Soil Soils having good water retention capacity with good amount of clay and organic matter are considered ideal for rice cultivation. Hence, clay and clay loams are most suited for rice cultivation. Rice being a semi aquatic plant grows best under submerged conditions. A major portion of land under rice cultivation in India is under ‘low land’ conditions. Rice plant is able to tolerate a wide range of soil reaction, but it does have a preference for acidic soils. It grows nicely in soils Having a pH range between 5.5 and 6.5. It can also be grown on alkali soil after treating them with gypsum or pvrite. Rotations Irrigated Area Paddy - wheat Paddy – potato – urad (black gram) Paddy – toria –wheat Paddy – wheat – moong (green gram) Paddy – potato – moong (green gram) Paddy – pea (for pods) - moong (green gram) Unirrigated Area Paddy – gram Paddy – lentil Paddy - pea
Cultivation The systems of rice cultivation in various rice-growing areas of the country are largely dependent upon the rice-growing conditions prevalent in the respective regions. The principal systems followed in India are ‘dry’, ‘semi-dry’ and the ‘wet’. The dry and semi-dry systems of cultivation are mainly confined to tracts which depend on rains and do not have supplementary irrigation facilities. The wet system is practiced in areas with assured and adequate supply of water, either by way of rainfall or by irrigation. Dry And Semi-Dry Systems: Basically, the steps involved are essentially the same under both these systems of rice-culture. The fields are ploughed and harrowed in summer for achieving the required-tilth. Farmyard manure is uniformly distributed 2-3 weeks before sowing. The seed is sown directly with the onset of the monsoon showers, either by broadcasting, dibbling behind the country plough or by drilling in lines. Line-sowing is preferable, as it ensures an adequate stand establishment and facilitates easy weeding and interculture. The reduced seed-rate requirement is another advantage. The row spacing may be suitably adjusted from 20 to 25 cm. Under the semi-dry system, the rain-water is impounded when the crop is about 1½-2 months old and thereafter it is converted into a wetland crop. By that time, major operations, such as weeding, interculturing and fertilizer application might have been completed.
Wet System: Under this system, the land is ploughed thoroughly and puddled with 3-5 cm of standing water in the field. The optimum depth of puddling is found to be around 10 cm in the clay and clay-loam types of soils. The primary objective is to obtain a soft seedbed for the seedlings to establish themselves faster, to minimize the leaching losses of nutrients and thereby increase the availability of plant nutrients by achieving a reduced soil conditions which facilitates a better availability of nutrient elements, to incorporate the weeds and stubble into the soil and to minimize the weed problem. Puddling can be done with ploughs, tillers or tractors, depending upon their availability and soil conditions. The land is leveled after puddling to facilitate a uniform distribution of water and fertilizers. Sowing Seeds may be sown after sprouting them or the seedlings be transplanted under this system. The weed problem is serious under direct-seeded conditions and is difficult to control completely in a broadcast crop. Water management also poses a major problem in unleveled lands and, therefore, transplanting has been generally practiced. Transplanting in a puddled field has the following advantages: A good leveling of the land is ensured. The weeds are buried at the time of puddling and the weed problem is reduced. The population of plants becomes more uniform. The availability of most of the plant nutrients, such as phosphorus, iron and potassium, is increased and nitrogen is conserved better.
The seedlings transplanted in a soft puddle are able to establish themselves faster and start early tillering and growth. Nurseries occupy only 10 per cent of the main field area and the cost of maintaining them (irrigation and plant protection) is reduced considerably as compared with a crop sown broadcast. The seed-rate for direct sowing by broadcasting is 80 to 100 kg/ha and by dibbling it in 60-70 kg/ha. Only well-filled viable seeds should be used for sowing. Lighter seeds that float on a solution of common salt (1.06 specific gravity) should be rejected. The choice of a suitable variety based on topo-sequence, soil type and duration is a prerequisite for obtaining high yield. Seed treatment with Thiram or Ziram or Vitavax at the rate of 100 g per 50 kg of seeds is generally recommended to prevent seed-borne diseases. The untreated seeds of high-yielding varieties should be soaked for 12 hours in a solution of wettable Ceresan or Carbendazim (0.1 per cent, i.e. 1 gm in one litre of water). The seeds should then be thoroughly dried in shade and used for sowing. The nursery area required to provide seedlings for transplanting one hectare is roughly 1/10 of a hectare and the seed-rate is 40-50 kg/ha. To ensure rapid and uniform germination, selected seeds should be soaked for 24 hours in clean water, which should be drained away thereafter and the seeds be incubated in a warm, moist place for 36- 48 hours to let them sprout for sowing in the nursery.
Rice Nurseries The general practice in India is to go in for wet nurseries. Another system of nursery-raising, known as the "dapog" method, had been recently suggested for areas where the seedlings are to be obtained within a fortnight for immediate transplanting. Wet nursery: The site selected should be near an assured source of irrigation. The land is ploughed twice in the dry conditions and puddled subsequently by ploughing it in standing water (2-3 cm deep) three or four times, preferably at intervals of 5-6 days. Farmyard manure, greed manure or compost can be applied uniformly @ 5-8 t/h at the time of the first puddling, 3-4 weeks before sowing the nursery. The field is levelled perfectly after the final puddling and made into raised beds, 1-1½ metres in width and of convenient length, leaving 30 cm of channel space in between the beds. Sprouted seeds are broadcast evenly on the soft mud, and only a thin film of water is maintained. The beds are maintained at the saturation level by sprinkling water periodically to maintain only a very thin film of it till such time that the germination is complete and the coleoptile turns green. The level of water is raised gradually and is maintained at a depth of 2-5 cm. Fertilizer Requirement:In soil poor in natural fertility, it is advisable to fertilize the seedbeds with 0.5 to 1 kg of N, 0.5 kg of P 2 O 5 and 0.5 kg of K 2 O for every 100 m 2 area of the nursery before the final leveling of the nursery-beds. In regions of low temperature, during rabi it is desirable to supply a slightly higher dose of phosphorus to promote root development and to establish a good stand in the nursery
When the seedlings are at the 4-5 leaf stage, the nursery is adequately irrigated and the seedlings are removed without causing, as far as possible, any damage to their roots. Young, healthy and vigorous seedlings establish themselves faster and grow better and the major objective of nursery management should be aimed at obtaining such seedlings. Dry nursery. In regions of non-assured water-supply, where wet-bed nurseries cannot be raised, dry nursery-raising is practiced. The field is brought to a very fine tilt by polishing it four or five times at 4-5 day intervals. Ten to fifteen tonnes per hectare of farmyard manure or compost is spread uniformly and incorporated into the soil 2-3 weeks before sowing. Raised beds 1-1½ metres in width, 15 cm in height and of convenient length, are prepared, keeping a 40-50-cm wide channel all around to facilitate drainage, as and when required. The seeds are sown dry, either broadcast or in lines closely, and are covered with a thin layer of soil or compost. The nursery beds are irrigated by sprinkling water on them periodically once in 2-3 days, depending upon the soil and environmental conditions. Light soils may require frequent irrigation. Timely weeding and plant- protection measures are to be adopted. In dry areas and in calcareous and saline-alkaline soils, chlorosis is he major problem is dry nurseries. Seed treatment with FeSO 4, the application of iron-chalets or spraying the nurseries with FeSO 4 and flooding them gives some relief.
However, in such areas, it is advisable to go in for wet nurseries. The seedlings obtained from the dry nurseries are generally hardy and establish themselves very fast when transplanted. ‘Dapog’ nursery. The ‘dapog’ method of nursery-raising consists in growing seedlings on a concrete floor or on a raised bed of soil covered with polythene sheets. This method is used especially in places where there is assured water-supply and when early transplanting is needed. A small area is required for raising this type of nursery, 30-40 m 2 being enough to raise seedlings for transplanting one hectare. The seedlings are ready after 14 days by using this method. The preparation of land, if needed, is done essentially in the same way as in the case of the wet-bed method. Raised seedbeds are prepared after final leveling and are packed, leveled and covered with polythene sheets. Banana leaves, with their midribs removed, can also be used instead of polythene sheets. Pre- germinated seeds should be sown on top of these sheets at the rate of 1 kg of seed per square metre of the nursery. The germinating seeds are sprinkled with water and pressed down gently with hand or with a wooden flat board twice a day for the first 3-6 days. This helps the roots of the seedlings to remain in contact with water retained on the surface and prevents drying. After six days, the seedbed could be irrigated up to a depth of 1-2 cm of water. The seedlings raised by using the ‘dapog’ method are then divided into convenient sizes and rolled like a mat with roots outwards. It is necessary to control the water level in the main field transplanted with ‘dapog’ seedlings, as they are too small and are liable to be damaged very easily by letting in too much of standing water. The leveling of the fields is very essential to avoid the stagnation of water and the mortality of the seedlings. Six to eight seedlings are placed in a hill. This method of nursery is also useful for raising a post-flood rice crop in Assam and West Bengal.
Water management The water requirement of rice is higher than that of other cereal crops of similar duration. Figures ranging from 37 to 75 acre-inches of water have been reported from various locations in India as the water requirement of rice, and this variation is primarily due to different soil and environmental conditions obtaining in different parts of the country. Losses due to percolation are more in submerged rice lands. In lighter soils, such losses amount to about 60 per cent of the total water requirement. Soil compaction and puddling help to reduce percolation losses. Losses due to transpiration account for about 40 per cent. Losses due to evaporation depend upon the climatic factors and range from 20 to 40 per cent. Considerable saving (30-40 per cent) in water is possible Rice Transplanting The seedlings are ready for transplanting in kharif within 20 to 25 days (4-5-leaf stage), where as in rabi it may take 30 to 40 days. Two to three seedlings are planted at 20 X 10 cm or 20x15 cm spacing in leveled fields. In regions of low fertility, and for late planting, closer planting is advocated. Weed Control In line-planted or drilled rice, weeding can be done with a hand-hoe or with rotary weeders. In a broadcast-sown crop, weeds pose a major problem and hand-weeding is still practiced. The best time to weed the crop is three weeks after sowing or planting. Herbicides, such as Butachlor, 2,4 D and Propanil, give a satisfactory weed control in rice and can be used as a tool for controlling weeds, when used at the recommended doses and at the right time. Irrespective of the method of weeding, it is ideal to maintain a weed-free condition up to 40-45 days