Save the Rice Landraces and Ecotypes and Save the Ecosystems
Professor Dr Mohammed Ataur Rahman
Crop Climatologist, International University of Business Agriculture and Technology (IUBAT),
Uttara, Dhaka-1230. Email- email@example.com
Published in the New Age, Bangladesh on May 19, 2019 http://www.newagebd.net/article/72833/saving-rice-landraces-ecotypes-ecosystems
Rice is the most important grain crop of Bangladesh. There are thousands of varieties of rice were in Bangladesh. Over 5000 local rice varieties have become extinct in the country in the last few decades. Nearly I0,000 landraces are considered to exist in Bangladesh and it is estimated that about 120 000 varieties of rice exist in the world. To date, approximately 8,200 germplasm have been preserved by the BRRI genebank. From the available data of Digital Herbarium of Crop Plants only 135 varieties are in cultivation now; this situation is very alarming both for food security and biodiversity. The ongoing rapid changes in agricultural practices that favor agronomically improved varieties have become a serious threat for the persistence of indigenous rice varieties. Thus, conservation and management strategies are urgently needed to prevent further loss of genetic diversity inherent to indigenous rice varieties in the region. A detailed understanding of the genetic structure and diversity is needed for the planning and implementation of effective conservation, management and utilization of rice germplasm in the whole region.
Therefore, along with the genetic forced crop improvement, climatic adaptation and improvement of environmental factors through climatic manipulation and aggregate farming using multiple varieties of crops, pets and aquatics etc. are utmost essential for food and nutrient security in this climate change situation.
To ensure the conservation of biodiversity, protection of soil health and water quality and ultimately for the betterment of human health the government, the researchers, the think tanks and the policy makers should consider the direct and indirect benefits of our rice landraces without any delay.
Rice has the wide adaptation ability under different agroecological niches of Bangladesh. It can be cultivated on the slope of the hill, plain lands, floodplains, semi-dry to very deep flooded areas. Widely adapted with different climatic seasons; can be cultivated throughout the year. Rice is the best-adapted cereal crop in the lowland soil in the wet season. No other crops have this ability to cope with the situation. When the vast areas of our country go under flood water for considerable time in the wet season, or when intermittent flash flood affects majority of the lowlands, or when tide water rises up and falls down twice a day, rice is the only crop option to be suited in those conditions. Thus rice enables to bring these vast areas under cultivation in unfavourable conditions.
Traditionally in Bangladesh, Jhum or shifting cultivators had been paying careful attention to soil resilience by practicing short cultivation following long fallow system with minimum of disturbance to the surface soil to avoid soil erosion and to help facilitate forest regeneration thus Jhum cultivation as a means of slopeland utilization has traditionally been quite sustainable.
According to variation of climatic seasons and topography there evolved different kinds of rice with many characters and specialties. Aromatic, non-aromatic, glutinous and non-glutinous, coarse and fine grain, long medium and short grain rice with varied colors: brown, white, red and black etc.
Perhaps rice is the most sustainable food crop in the world in providing energy and nutrition, has versatile food preparations, preservation and regeneration opportunities. Comparing to vegetable crops, other grain crops, tuber and root crops and even fruit crops rice is cheaper and handy.
Rice is considered to be an auspicious symbol of life and fertility. Starch is the most important source of carbohydrates in the human diet and accounts for more than 50% of our carbohydrate intake. It occurs in plants in the form of granules, and these are particularly abundant in cereal grains and tubers, where they serve as a storage form of carbohydrates. We often think of potatoes as a “starchy” food, yet other plants contain a much greater percentage of starch (potatoes 15%, wheat 55%, corn 65%, and rice 75%). Commercial starch is a white powder. Although potatoes are cheaper than rice but it is one-fifth efficient to rice therefore costlier than rice.
Residue management practices affect soil physical properties such as soil moisture content, temperature, aggregate formation, bulk density, soil porosity and hydraulic conductivity. Increasing amounts of rice residues on the soil surface reduce evaporation rates and increased duration of first-stage drying. Thus, residue-covered soils tend to have greater soil moisture content than bare soil except after extended drought. The straws are very good fodder for cattle used both green and dry conditions. Straws contain cellulose lignin and many minerals which decompose in the field or recycled via cattle through enzymatic and microbial process enriching food chain adding value with protein, fat and minerals. The cellulose is the carbohydrate like starch with similar basic unit glucose. Therefore both rice and straw are contributing in energy conversion and nutrient supply chain and in biogeochemical cycle more efficiently than any other crop.
Usually the yield of the vegetable crops is high and consumed whole plant parts; thus all nutrients are ingested by human, very little portions are recycled through involvement of other animals. As a result, short-cycled recycling of the human faeces or excreta is not easy especially from the quickly growing urban areas. Therefore, the nutrients are not getting back to their sources of origin and the soil nutrition status is declining sharply mainly from the vegetable fields. Practically in the urban and peri-urban areas, the huge faeces are remained unutilized years together in the septic tanks; the black water overflows to the rivers or wet-bodies through sewerage system. Unfortunately, most of the wet bodies are deadly polluted with the chemicals, oils and other pollutants discharged from the industries, transports, hospitals and tanneries etc. As a result, the productivity of fishes and other aquatics is also very poor from those wet bodies. On the other hand, urban green garbage is rarely recycled rather dumps for landfill. Other than the faeces, average per capita urban waste generation rate is estimated as 0.41 kg/capita/day of which food and vegetable comprises 67.65% i.e. about 0.28 kg/capita/day and for present urban 40% of the total population of the country producing 20,160 tons green waste everyday by the urban people of which a very negligible quantity is recycled. Thus the soil fertility status of the country has been declining very sharply and the farmers are becoming increasingly dependent on chemical fertilizers. Therefore, rice-based home centered farming system for short cycled biomass recycling is utmost essential. The diversified landraces of rice have the ability to supply the necessary energy and nutrients to human and other animals associated in the cropping circle in this region.
According to recent IPBES Global Assessment Report: Since 1970, trends in agricultural production, fish harvest, bioenergy production and harvest of materials have increased, in response to population growth, rising demand and technological development, this has come at a steep price, which has been unequally distributed within and across countries. Many other key indicators of nature’s contributions to people however, such as soil organic carbon and pollinator diversity, have declined, indicating that gains in material contributions are often not sustainable.
The pace of agricultural expansion into intact ecosystems has varied from country to country. Losses of intact ecosystems have occurred primarily in the tropics, home to the highest levels of biodiversity on the planet. Bangladesh needs to revise its agriculture policy to save the ecosystem, biodiversity and to protect human health.