Agricultural Pollution and Sustainable Food Security | 2018-01-13 |

Agricultural Pollution and Sustainable Food Security

Jiban Krishna Biswas PhD     13th January, 2018 08:58:10 printer

Agricultural Pollution and Sustainable Food Security

Agriculture experienced a dramatic change since the 1970s in Bangladesh. The innovation of High Yielding Varieties (HYV) of crops, the extension of irrigation facilities, availabilities of chemical fertilizer and pesticides under subsidized rate, mechanization, government intervention and farmers’ industriousness helped to promote such a change so far.


All these factors and activities were designated as Green Revolution lead to increased productivity not only limited to rice but to the other crops also. That revolution was a milestone towards the pace of food security as our predecessors were expecting for. But many of the scientists all over the world started to realize the negative impact of the Green Revolution in the late 1980s. Bangladesh was not the exception. However, based on the spirit of this revolution the country adopted an intensive high input-based and location-specific agriculture in its own way. The native scientists were also encouraged to develop rice varieties more or less adaptable to biotic and abiotic stresses. By this time the farmers got to know that agriculture could be considered as a business commodity. So they seldom keep their land barren to harness more productivity around the year. Apparently, the unit productivity of a crop mainly rice has increased several folds more than in the early 1970s. Thus the country has attained the self-sufficiency in rice and some more agricultural commodities. In fact, that was the target of a country like us since a century ago. However, this sufficiency has achieved in exchange for paying a lot—-an irreparable loss to the country and the human being as a whole. We have lost our rich biodiversity of rice. The newly introduced rice varieties have replaced the traditional ones. This phenomenon is equally applicable to other crops also. The irrigated rice culture replaced the traditional upland crops. This extreme change of cultural practices has destroyed the soil texture and soil inherent quality. The soil degradation is a factor we could easily notice around us. Thus most of the traditional and eco-friendly cultural practices relevant to our crops have been erased away forever.


In addition, farmers were accustomed to use agro-chemicals like fertilizers and pesticides. They are still using the fertilizers quite often in excess amount and in imbalanced fashion. But the efficiency of these inputs are significantly low due to some scientific and socio-economic barrier. So farmers have to supplement their crop with excessive agrochemicals. If not, the crops growing in the field have to hunt the nutrients by themselves from the inherent reserve of the soil. If the soil is poor in nutrient reserve, the crop fails to perform its potentiality. This is a common occurrence but mostly overlooked reality by the extension agents even by the scientists. Thus the soil is getting poorer day by day. Even soil is getting deficient of some nutrients which were not seen before. For example some of the crops like wheat, mustard, onion etc. are showing their significant response to boron and in some of the cases molybdenum also.

The use of pesticide is nothing new to modern agriculture. Anyway, the abusive use of agrochemicals is a serious problem related to the modern agriculture. These agrochemicals are in a process to contaminate the environment which is a serious threat to the human being, livestock, wild and aquatic lives. Scientists and environmentalists are increasingly getting concerned with this occurrence of agricultural pollution. Logically, the agricultural pollution is classified as abiotic and biotic pollution. Excessive use of fertiliser, pesticide contaminates   soil, water and air through the accumulation of nitrate from the nitrogenous fertiliser. This is a kind of abiotic pollution. The excess accumulation of nitrate from nitrogenous fertilizer makes the water unfit for drinking as nitrogen affects the transportation of oxygen in hemoglobin. Surface runoff of excess nitrate into the water bodies enhances the excess growth of nuisance algal population to make the aquatic animals unfit to survive. The soil could be contaminated with heavy metals like Cadmium by phosphorous containing fertilizer. Rock phosphate could be the source of heavy metal Fluoride and radio-active metal Uranium 238. So the excess application of phosphorous fertilizer and rock phosphate might contaminate soil with the heavy as well radio-active materials. Pesticide has the adverse effect on soil. Some of the pesticide remain active in the soil for decades. The pesticide whenever come in contact with soil is supposed to affect the biodiversity of the soil flora and fauna, so affect the organic matter. Low organic matter content goes with the soil having low Nitrogen. The earthworm population is drastically reduced after the application pesticide. The water holding capacity is low in soils with low in organic matter. In contrast, the biotic source of environment pollution are fecal waste, invasive new plant species, genetically modified (GM) crops etc. Livestock wastage is the main agricultural source of GHG (Green House Gas mainly methane). The GHGs are also released from lowland rice field in the form of methane and in the form of Nitric or nitrous oxide from the upland culture.

The soil erosion is another concern, not much taken care of in our country. It is not a component of soil polluting factor. However, it has the ability to replace a huge amount of soil nutrients through the removal of topsoil from a cultivated field to the water bodies making them shallow. Erosion (river erosion is not considered here) due to wind or irrigation, both must be taken into consideration in modern agriculture. The sea level rise due global warming effect is a threat of engulfing more area under brackish water tidal submergence. Excessive exploitation of groundwater is not only the reason for groundwater layer depletion but also helps to contaminate the fresh groundwater at the upstream through extracting saline water from the downstream.

Growing crops is not just planting seeds in the soft soil to harvest a certain amount of yield. It is more than that. It needs an extensive planning to integrate science, resource, farmers’ consciousness with respect to the environment and socio-economic condition of a certain locality. The objective of growing crop is to harvest maximum human welfare in terms of food, health, clothing and shelter just exploiting the nature as minimum as we can. But the nature’s ability is not unlimited. So, there should have an understanding of man and nature to share the resources for the mutual interest.  Unfortunately, that understanding could not be maintained as we need more food for the teeming millions every year. The effort of growing more food started since the turn of the nineteenth century. And it was thought that the high input based crop would solve the problem. So scientists developed their HYVs of crops having the research done for more than half a century. The raw materials for high input fertilizers are collected from mineral reserves. The production of nitrogenous fertilizer urea depends on the natural gas reserve which might be exhausted within a decade or so if no new reserves are explored. The phosphate and potash fertilizers are exclusively import oriented. The world phosphate reserve is at its alarming stage, may be well enough for another 50 years. The Potash reserve is quite satisfactory, and it might go for another 500 years. We have to apply a balanced dose of nitrogen, potash, phosphorous and some more essential elements. The shortage of any of the essential elements in future might have a catastrophic impact on the food production in Bangladesh and elsewhere. Because crop cannot be synthesized in the laboratory.

But as an agricultural-based developing country, we are going to be the worst victim of the abusive use of agrichemicals in either of the ways in the near future. So what would be the alternative option to get rid of this catastrophe?

A group of scientists are asking to grow food in a sustainable way based on three pillars like healthy environment, economic profitability and socio-economic equity. Do you think this sustainable approach is enough to satisfy the increasing population of the country? Maybe not. So we need more research to develop production practices with respect to topography, soil characteristics, climate, pest and socio-economic perspectives.  The sustainable technology must be in inconvenience to the circle of food system consisting of growers, food processors, distributors, retailers, consumers and waste managers where all of them have the opportunity to share the equal opportunity. The famous Agricultural Scientist MS Swaminathan said some three decades ago that we must have to strengthen our research activities for more and more yield but that must be eco-friendly, multiple crops oriented, and all agro-commodity based. Accordingly, he was asking an integrated knowledge of the different branches of sciences like Biotechnology, NASA-developed knowhow, space science, renewable energy, information and communication technology, appropriate market management system etc. under one canopy that would generate a revolution he designated that as Ever Green Revolution.  I am sure the implication of nano-technology in agriculture was not out of his expectation. In addition, the understanding of nanotechnology, the recent innovation of biotechnology (CRISPR: Clustered Regularly Interspaced Short Palindromic Repeats) and bioinformatics could find out some solutions to the abusive use agro-chemicals towards the development of sustainable technology for agriculture. The nanotechnology is quite prospective to develop fertilizer technology where significantly less amount of fertilizer would be required at the right time and in the exact amount. Similarly, the technology could be used to reduce the use of herbicide and pesticides also.

Unfortunately, we are still centred within the circle of “growing more food” in exchange for more agrochemicals. We have yet to consider a more systematic research approach towards the sustainable agricultural development.  Right now, only a few of the agricultural scientists are familiar with the application of nanotechnology, bioinformatics and CRISPER technology in the research arena of agriculture. So how could we assure the sustainability in agriculture for the next generation?

May I request our scientists, policymakers to initiate this kind of research right now to present a sustainable food security for the nation in near future?

The writer is a former Director General of Bangladesh Rice Research Institute