Yield Gap Assessment of Cotton Crop in Tamil Nadu
Author : RAJASHREE KHATUA
AGRO CLIMATE RESEARCH CENTRE DIRECTORATE OF CROP MANAGEMENT TAMIL NADU AGRICULTURAL UNIVERSITY
COIMBATORE – 641 003
Cotton is one of the most important cash crops and accounts for around 25% of the total global fiber production. It is also called as a white gold. The primary product of the cotton plant has been the lint that covers the seeds within the boll. Lint is the most important economical product of cotton plant, provides a source of high quality fiber for the textile industry.
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The cotton seeds, the primary by product of lint production, are an important source of oil for human consumption, and a high protein meal used as a livestock feed. The cotton waste after ginning is used for fertilizer and the cellulose from the stalk may be used for products such as paper and cardboard.
Cotton is also one of the most important commercial crops cultivated in India. It plays a major role in sustaining the livelihood of an estimated 5.8 million cotton farmers and 40- 50 million people engaged in related activities such as cotton processing and trade. India is the largest producer of cotton in the World, and also has the distinction of having the largest area under cotton cultivation in the world i.e. about 126.07 lakh hectares.
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The cotton association of India (CAI) 2020, reported India’s cotton crop for the current year (2020-2021) is expected to be lower by about 4 lakh bales (each of 170kg) at 356 lakh bales as against 360 lakh bales last year, due to excess rainfall and pink bollworm infestation.
There is a rise in cotton crop estimates for the 2019-20 season because of the higher acreage if compared to that of the last season. Important cotton producing states are Gujarat, Maharashtra, Tamil Nadu, Punjab and Haryana.
Average area under cotton during year 2019-2020 was 133.74 lakh hectares with an average production of 357 lakh bales and an average productivity of 778.63 kg/ ha in Tamil Nadu. (CAB- Cotton Advisory Board, 2019-20).
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India’s cotton cultivation area is about 124.4 lakh hectare which produces 370 lakh bales (170 kg/bale) with a productivity of 506 kg/ha. Maharashtra is the leading states in area (42.07 lakh hectares) and Gujarat is the leading state in production (104 lakh bales) and
productivity (674 kg/ha). In Tamil Nadu, area under cotton is 1.85 lakh hectares which produces 5.5 lakh bales with a productivity of 505 kg/ha (Indiastat, 2018).
Cotton, the ‘white gold’ enjoys a premier position amongst all commercial crops in India. In the raw material consumption basket of the Indian textile industry, the proportion of cotton is around 59%.
In India, cotton productivity is very low as compared to other countries. Moreover, cultivation of hybrid cotton has become a costly affair because of severe pest attack, which led to indiscriminate use of pesticides and thus polluting the entire agro-ecosystem.
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With the launch of “Technology Mission on Cotton” by Government of India in February 2000 significant achievements have been made in increasing yield and productivity through development of high yielding varieties, better farm management practices, increased area under cultivation of Bt cotton hybrids. After introduction of transgenic Bt hybrid cotton in India, the productivity of cotton has increased substantially from 303 to 561 kg/ha within a span of seven years (Tayade et al., 2011).
More than 50 per cent of the cotton area is covered by cotton hybrids and the hybrids contribute about 60 per cent to national production (Santhy et al., 2008).
Conversely, about 60 per cent of cotton in India is cultivated under rainfed conditions and this is regarded as one of the reasons for the low productivity recorded in the country.
Cotton is very important to the Indian economy because it provides gainful employment for millions of people as well as source of foreign exchange for the country. Cotton fiber is an important raw material requirement of the Indian textile industry and as such, the India textile industry plays a pivotal role through its contribution to industrial output, employment generation and export earning of the country.
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Presently, nearly 60 million people depend on cotton cultivation, marketing, processing and exports for their livelihood. India is also the only country in the world that grows not only the four cultivated species of cotton but also their intra-and-inter-specific hybrids on a commercial scale. The textile industry, which consumes the cotton, as its principal raw material, contributes about 4% to the GDP and is the major exchange earner for the country.
Hence, growth and development of cotton and cotton based textile industry has a vital bearing on the overall development of the Indian economy. Most of the plants require same mineral elements but, the quantity, rate and timing of uptake may differ with crop, variety, climate and soil features. Effective management strategies for nitrogen, phosphorous and potassium fertilizer are important to ensure optimum yield, fiber quality, reduce the production cost and increase the profitability of production system. Response of cotton to applied nutrients is controlled by environment and cultural factors. Cotton crop being a heavy feeder, needs proper fertilizer application as evident to remove 43.2-29.3-53.3 kg of N-P-K/ton of seed cotton (Wajid et al., 2014).
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Effect of nutrients may differ with varieties because of their canopy structure, phenological behaviour and fruiting pattern (Shukla et al., 2013). Cotton excesses of N delays maturity, promote vegetative tendencies, and thereby result in lower yields. Application of potassium, ‘quality element’ can facilitate improvement of seed cotton yield, fiber quality, strength, uniformity and micronaire in cotton (Ueda et al., 1995). The ways to increase the yield alone could not benefit the cotton growers, for getting higher price, the primary concern is to improve the quality of cotton fiber (Srinivasan, 2003).
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Yield gap analysis also helps to inform projections of future crop yield for different regions (Lobell et al., 2009). Yield gap is defined as the difference between potential and average yields. Potential yield is the yield of an adapted crop variety or hybrid, when grown under favorable conditions without growth limitations from water,
nutrients, pests and diseases. To ensure sustainability of the cotton industry, there should be efficient production to bridge the gap between demand and supply of cotton. Cotton yield gap in India has been found to vary from 790 -1220 kg/ha (Mondal, 2011). Yield gap arises because farmers always find it impossible to achieve potential yields under field conditions (Lobell et al., 2009). However, there is a continuous effort to enhance cotton yield by both private and public research units.
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In order to provide a preliminary knowledge on the need to improve farmers’ income and to increase cotton production to sustain the textile industry that is strongly dependent on the cotton seed industry, an attempt is made to analyze the yield gap in cotton production. The yield gap analysis was aimed to determine the extent to which input gap and other farmers economic characteristics were responsible for yield loss in cotton production.
The dynamic crop simulation models are physiologically based simulation models which take into consideration phenologic development, growth, senescence, photosynthesis, respiration, infiltration, drainage and evaporation on a daily basis and respond dynamically to weather inputs.
Further, these models show considerable potential to evaluate crops, crop varieties, cropping practices and genetic potential patterns for yield. An important aspect of most of these studies is a consideration that weather influences the performance of crops, interacting in a complex way with soil and management (Jones et al., 2003).
Increase in the population demands increase in the agricultural production with available resources. Efficient management of available resources with variable weather conditions is essential to increase productivity of agriculture. In addition to this, the focus of agricultural production is changing from quantity towards quality and sustainability.
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Solution of these new challenges requires consideration of how numerous components interact to effect plant growth. Crop modeling can play a significant part in systems approaches by providing a powerful capability for scenario analyses. The crop simulation model can be used as quantitative tools to evaluate effects of agronomic and genotypic factors on crop yield. The Decision Support System for AgroTechnology Transfer (DSSAT) has been in use for the last 15 years by researchers worldwide (Hoogenboom et al., 2012). This package incorporates models of 28 different crops with software that facilitates the evaluation and application of the crop models for different purposes. DSSAT was developed to assess yield, resource use and risk associated with different crop production practices. The system DSSAT is an example of a management tool that enables farmers to match the biological requirement of a crop to the physical characteristics of the land and ambient air to attain specified objectives (Tsuji et al., 1994). DSSAT software could help the decision makers to implement future agriculture strategies under different scenarios related to agriculture practices with the use of measured site – specific pedological, physiological, agronomical and meteorological data (Hoogenboom el al., 1994).
With all these knowledge intact, a study titled ” Yield gap assessment of cotton crop in Tamil Nadu using dynamic crop simulation model” was taken up in Agro Climate Research Centre, Tamil Nadu Agricultural University during 2018-2020
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