Case3-April-2013
Increasing the productivity of the crops using minimum natural resources, in a very effective way is the challenge ahead to ensure the food security of the growing world population. The exploitative agricultural practices has already limited the availability of water and degraded the fertility of the lands to greater extent. Climate change poses a serious threat to the productivity of crops particularly in tropical countries since it alters the frequency, quantity and duration of rains and also keep increasing the global temperature. Current UN projections indicate that world population could increase by more than two billion people from today’s levels, reaching 9.15 billion by 2050. Incomes will grow even faster. To meet the increased demand, FAO projects that global agricultural production in 2050 will be 60 percent higher than in 2005/07 (FAO, World agriculture towards 2030/2050, working paper, June 2012).
Historic and genetic evidence shows that domestication of rice originated in Chine8200-13500 year ago. From there rice spread to South east and South Asia. Rice was introduced to Europe through Western Asia, and to the Americas through European colonization. Today rice in grown in 165 million ha in 114 countries and 2012-13 estimates show’s that 460 million tonnes (on milled basis) of rice is produced in the world. In India the production is 103 million tonnes (22.25 %) of the world’s production.
Rice produces maximum calories among all cereals. Rice is being the staple food for millions of people, particularly the Asians who produce and consume 90 percent of the world’s rice. More than half of the world’s population has rice as their main diet which accounts for 20 percent of global calorie intake. China, India, Indonesia, Bangaladesh, Vietnam and Japan are the major rice growing and consuming countries. Rice consumption is on increasing trend in poor Asian countries while it is on decreasing trend in countries were the percapita income is high. Crops which are nutritionally better than rice like small millets are given more attention today by the research organization to meet the future food and nutritional needs. Yet, rice will occupy a significant position in meeting the calorific and food needs of future generation.
With respect to India, in 1990-2010 the food grain production in the country grew at an average 1.4 per cent, whereas the population growth was at 1.6 per cent. Fortunately, we have achieved a food surplus during last two years. But in the long run, concern of food security is likely to become more intense with increasing population and decreasing land availability. By 2020, to meet the food demand of 1.3 billion populations, India needs to produce 281 MT of food grains with an annual growth target of 2 per cent.
The name of the grain used globally, rice, probably has its roots in India. According to the Microsoft Encarta Dictionary (2004) and the Chambers Dictionary of Etymology (1988), the word ‘rice’ has an Indo-Iranian origin. It came to English from the Greek word óryza, via the Latin oriza, the Italian riso, and finally the Old French ris. It has been speculated that the Indo-Iranian word vrihi was itself borrowed from a Dravidian word vari or even from a Munda language term for rice; the Tamil name arisi could have given rise to the Arabic ar-ruzz, from which the Portuguese and Spanish word arroz originated (http://en.wikipedia.org/wiki/ Rice).
Rice can be classified based on the area in which it is grown as Irrigated rice (lowland rice), rainfed lowland rice and rainfed upland rice (dryland rice). Apart from this deep water rice or floating rice or coastal wetland rice do occur. Rice is cultivated in both irrigated and dryland conditions. 75 % of the rice cultivated in the world comes from 80 million ha of irrigated rice.
Irrigated rice in grown in bunded fields, which ensures stagnation of water to a height of 5 to 10 cm to facilitate rice growth. Usually the seeds are raised in nursery and get seedlings get transplanted. Irrigated rice is sown in areas where the water is assured through perennial/ seasonal rivers and bore wells. Irrigated rice is grown as mono crop even two or three crops get sown in a year, which in turn depends on the water availability.
Dryland rice (upland rice) and rainfed low land rice is grown in over 74 million ha across the world, but contribute only to 24 % of the global rice production. This dryland rice depends entirely on the rainfall in the area whereas lowland rice is supported by local irrigation systems like village tanks and ponds.Aas the rainfed rice is subjected to multiple abiotic stresses due to uncertainty of rainfall, the yield is very much lesser than irrigated rice.
Both floods and drought , especially during the critical crop stages of paddy (tilling, flowering and milky stage) will have drastic impact on yield of paddy, sometimes even resulting in complete crop failure. The dry land crops are more prone to failures than wet land rice.
In dry lands paddy seeds are either broadcasted (direct sowing) or sown behind the plough. Broadcasting of sprouted seeds of paddy is also practiced in some places. In Austraila, most of the rice gets broadcasted through aircrafts through experienced agricultural pilots , who use satellite information for uniform broadcasting of seeds.
Rice is first mentioned in the Yajur Veda (1500-800 BC) and then is frequently referred to in many Sanskrit texts, which distinguished summer varieties grown in the rainy season from winter varieties. Shali or winter varieties were the most highly regarded in times past. The name of Annapurna, the Hindu god of rice, comes from the Sanskrit word for rice, anna. Rice cultivation started in Ganga river basin by 2000-1500 B.C and later extended to other parts of the country. India has rich biological diversity with respect to rice.
According to Dr. R.H. Richharia, one of the most eminent rice scientists of the world to date, 400,000 varieties of rice probably existed in India during the Vedic period. He estimated that even now, as many as 200,000 varieties of rice exist in India. Today rice is grown in 545 out of 604 districts in the country and 70 % of its people rely on rice to meet 43 % of their calorific needs. India is the second largest producer of rice next to China and provides around 20 % of the global rice production from its 45 million ha under rice. It contributes to 44 % of the total food grain production in the country. Green revolution enhanced the productivity of rice in India through introduction of new short duration, fertilizer responsive HYV, which however is not free from its de merits like extinction of traditional varieties from cultivation, which had high potential to withstand drought and other climatic stresses. In India rice is grown under irrigated, rainfed, coastal conditions and also as deep water rice in two major seasons (Kharif- June-Oct) and Rabi ( Oct- Feb).
1906 - Introduction of Single Seedling Planting in Madras Presidency
1911 - Introduction of Gaja Planting in Madras Presidency
1912 - Beginning of systematic study on rice in Coimbatore
1946 - Establishment of the Central Rice Research Institute at Cuttack
1951 - Introduction of the Japanese method of rice cultivation
1965 -Launching of All-India Coordinated Rice Improvement Project (ICAR)
1969 - Introduction of IR8 variety, surge in expansion of rice area in Punjab
2000 - First evaluations of SRI, followed by trials in other states
2006 - First National SRI Symposium in Hyderabad, followed by annual symposia in Agartala (2007) and Coimbatore (2008).
Globally rice cultivation is under stress and India is no exception. Growing need to feed the billions, changing temperature, water issues ( availability, quality and effective usage) , fragmented and less fertile lands ( modern varieties exploiting the nutrients in the sil to greater extent than the traditional varieties), shrinking of area under cultivation, Labour issues, environmental problems and no drastic improvement in productivity in recent years are the factors which remain as a threat to enhance rice production.
Among all exploitation of water resources by agriculture and industries, is growing at an alarming rate by more bore well being dug at deeper depths, while recharge of the same is occurring at a very lesser phase due to inadequate rainfall in recent years will affect rice cultivation drastically. The Cauvery delta which is known as “grainary of Tamilnadu” which used to grow paddy for at least two subsequent seasons every year before three decades is now struggling to raise paddy for one single season due to late set of monsoon and inadequacy rainfall. The Indian states and its farmers were fighting with each other for their right for water, the situation forced by the large scale exploitation of water and inadequate planning to use the water resources in right way. On the other hand the village tanks and ponds which used to be maintained by the community itself, now has become the responsibility of the government, which has failed to maintain them properly, leaving them damaged and encroached.
With respect to productivity though we pat ourselves on our back for the results of green revolution, the bitter truth is we are far behind in rice productivity than many other countries. Though we produce 4.5 times more than what we produced 50 years ago, rice productivity in India is only 3.3 tons/ha whereas China has a productivity of 6.6 tons/ha, twice that of India. We lag behind the productivity of rice 3.70 – 8.00 t/ha achieved by some of the countries like Egypt, China, Japan, and Korea.
We have a challenge ahead. We have to increase the productivity of rice so that the total rice production stands at 140 million tons by 2025. With fixed land resource and declining water resource this is indeed a great task. Increasing the productivity without damaging the fertility, organic and microbial load in the soil and with most efficient means of using water is the need of the hour. The recent development and focus on SRI method of paddy cultivation, however shows some scope for achieving the task.
Rice is a high input crop. It needs more water than any other crop, needs a fertile land and also good temperature for adequate growth. It is extremely sensitive to water shortage. It is estimated that to produce one kilogram of rice requires 3,000-5,000 litres of water. Evidence shows that the irrigated rice receives 34-43 per cent of the world’s irrigation water (Bouman et al, 2007). Rice is wetland in grown mostly in stagnated water condition and the irrigation practices followed by farmers particularly in Asia, does not ensure water use efficiency. Improper water management practices have led to wastage of water in many of the cases etc., transportation losses, evaporation losses, seepage and percolation losses and excess irrigation are very common in irrigated rice cultivation.
Also rice is grown by small and marginal farmers in fragmented piece of lands ranging from 0.5 acre to 2 acres, which remains as a hurdle to practice improved water management techniques. Though agricultural universities and research institutes suggested many water management techniques, they failed to gain the attention of farmers because of the difficulty in implementation and also partly because of neglect ion/ hesitation of farmers to adopt new techniques.
Generally inappropriate practices farmers follow in cultivating irrigated paddy range from usage if higher seed rate and less quality seeds, no seed treatment, transplanting at a later date than at appropriate time due to labor and water shortage, planting more seedlings per hill (usually 4-6 seedlings), closer spacing than recommended and sometimes even do random planting without following line spacing, excess irrigation of the land when water is available in adequate quantity and inappropriate pest and nutrient management practices. The local fertilizer dealers also have a hand in forcing farmers to use excess and unwanted fertilizers or nutrients.
However the System of Rice intensification (SRI) introduced in India by Tamilnadu Agricultural University in 2000 through their collaborative research efforts gained the attention of farmers since it not only saved water but also ensured a higher yield of over 1.5 tons/ha. Various civil society organizations also took interest in the concept and started promoting it.
The SRI method of paddy cultivation currently practiced in more than 40 countries, originally was developed by French Priest Henri de Laulanie in Madagascar, who worked along with rice farmers of Madagascar for almost 30 years, before announcing this system to the world. It is a farmers centered invention which focuses on changing the normal agronomic practices in rice cultivation for better yield.. The main feature of the method is raising raised bed nursery, transplanting young 8-10 day old seedling with a wider spacing, maintaining water to saturation level, weeding and incorporation weeds in the soil and application of organic fertilizers. The above techniques if food to save water considerably, apart from increasing its yield considerably. The technique however was discovered accidentally when Henri de Laulanie was forced to expand the area under paddy for demonstration in a school, for which he used younger seedlings of paddy which are 15 days old along with older seedling which are 30 days old (which itself is a deviation from normal practice of transplanting 60 days old seedling).
The result was astonishing that the younger seedlings started producing more tillers and later contributed to substantial increase in yield. Laulanié and others started analyzing the reason and found solid reference that rice planted at early stage before the start of fourth Phyllochron while preserve its growth potential and triggers it to produce more tillers. As a follow up of these numerous studies and trials were taken up by research scientists, farmers and civil society organizations, which showed very clearly that by changing some of the basic agronomical practices the yield of paddy can be considerably improved even to a tune of 8 tons/ha.
The general agronomic practices like raising nursery, land preparation and puddling of land, transplanting of seedlings, irrigation, nutrient, pest and disease management are all there in SRI but with striking changes in the way in which they are carried out.
The System of Rice Intensification involves cultivating rice with as much organic manure as possible, starting with young seedlings planted singly at wider spacing in a square pattern; and with intermittent irrigation that keeps the soil moist but not inundated, and frequent inter cultivation with weeder that actively aerates the soil. As Father de Laulanié observed, SRI is an nothing but an amalgamation of multiple beneficial agronomic practices rather than a standardized technological method.
The main operational elements of SRI, each having good agronomic rationales, are:
Rice consumes three times more water than wheat and other like cereals, under current water management practices, which is justified with the belief that rice needs more water. Aerobic soil conditions and at the same time adequate amount of water to paddy can be ensured by supplying small amounts of water daily, with several periods when the field is allowed to dry for 3-6 days during the vegetative growth stage, or by alternate wetting and drying (AWD) with cycles ranging from 6 to 14 days.
The alternate wetting and drying of soil is proved to be beneficial since it is found through various experiments that
In Tamil Nadu, the water management for SRI is prescribed based on field experimentation. Up to panicle initiation stage, it is recommended to irrigate the field to 2.5 cm after the previously irrigated water disappears and hairline cracks develop. After panicle initiation, irrigation is done to 2.5 cm depth one day after the previously ponded water disappears from the surface. At the hairline cracking stage, soil will not be dry, but it will still be moist.
Irrigation intervals vary with soil texture. Fine-textured clayey soils with higher field capacity need irrigation at longer intervals, while coarse-textured light soils with lower water holding capacity require irrigation at closer intervals, consuming in the process more quantity of irrigation water. Such shallow irrigation can save water up to 40% and there will not be any yield loss due to this.
The soil environment created by SRI’s wider spacing of plants, its un flooded water regime, and the churning up of the soil by weeder use are found to encourage a different microbial and nutrient dynamics in the soil. Continuous application of organic matter in the form of compost, farmyard manure, and plant residues is needed to maintain or increase soil organic carbon. Soil organic carbon levels are a good indicator of native fertility. In general, paddy soils are fairly poor in organic carbon (~ 5 g kg-1).
Thus, it is essential to use more organic biomass with most soils to achieve and sustain good fertility status. Soil organic matter increases the microbial load in the soil, which in turn supports nutrient absorption and utilization by the crop. However use of inorganic fertilizers may be as effective as use of organic fertilizers when other SRI techniques are properly followed. But it is preferable to follow a combined nutrient management strategy, based on the fertility of the soil where the rice crop is grown.
Saline or alkali soils are not suitable for SRI cultivation. In saline soils paddy yields would be satisfactory when it is cultivated under flooded conditions. But in SRI method the field is drained intermittently. When soil is allowed to dry the salts accumulate in the surface resulting in damage to the rice plant.
Land selected for SRI method should be level. When the plot is irrigated the water should spread uniformly across the field. Similarly, whenever needed there should be facility to drain the excess water.
Soils which are less fertile or made sterile by continuous use of inorganic fertilizers in large quantities, will not yield expected yield through SRI. In such cases supplementation with organic manures will be of useful, and in long run it will start providing the desired yield.
The idea of producing more with fewer external inputs which sounds impractical, is proved to be working in the case of systematic rice intensification technique. The idea and concept of SRI has caught up the attention of research institutes and voluntary organizations worldwide, which try to replicate this with other crops like wheat, rainfed rice, sugarcane, finger millets, rape seed and solanaceous vegetables.
The news from states like Tamilnadu, Bihar, Orissa and Mizoram which achieved a tremendous success in rice production by adopting SRI is promising. In fact a farmer Sumant Kumar from Darveshpura village, Nalanda District of Bihar, now is the proud owner of world record in rice production with 22.4 tons/ha surpassing the record of earlier record of 19 tons, held by a Chinese farmer. He has adopted SRI method of paddy cultivation in rasing the hybrid variety Arize 6444 Gold by Bayer. However the technique is not free from criticism who doubt whether SRI is really a revolution or just an illusion. Also there are many factors which may hinder large scale adoption of this technique
The success stories of SRI should get reflected in the national and global productivity, which is possible only through large scale adoption of this technique with suitable precautions and changes to suit the local needs. Only then SRI can become effective in addressing the future food needs.