A soil research finding shows that over two-thirds of the country's agricultural lands lack essential organic elements because of the indiscriminate use of chemical overdoses and over-exploitation of lands for year-round farming. As per the findings of a just published government's Soil Resource Development Institute (SRDI) report, almost 62 per cent of the country's arable lands are in critical state having organic matters as low as 1.74 per cent. Whereas there should be ideally 5.0 per cent of organic matters in soil but over 21 per cent of lands possess organic elements in between 1.74 to 3.5 per cent.
The SRDI reports that fertile lands of the country contain up to 45 per cent minerals, 25 per cent each of water and air, and the remaining 5.0 per cent organic elements. But 61.6 per cent of the 8.75 million hectares of farm lands in the country is currently witnessing a lack of organic substance due to the effects of excessive applications of chemical fertilisers and pesticides. The amount of chemical fertiliser use in arable land is gradually increasing. While in 2005-2006 financial year the use of chemical fertiliser in arable land was 3.68 million tonnes, within ten years the amount stood at 4.8 million tonnes. The additional reason is for not giving the land enough time to rest and factors relating to global warming and climatic changes. Md. Delwar Hossain Mollah, immediate-past SRDI Director who oversaw the report entitled "Bangladesh's Soil and Organic Agriculture", noted that over-exploitation of soil for augmenting per unit crop production is causing the soil to lose its fertility in the long run.
It is understandable that in pursuit of feeding the growing population farmers have to grow three to four crops from same land a year. But, at the same time it is also desired that they must be mindful about proper management of the soil they cultivate.
It is also to be noted that as the fertility of the soil is reliant on temperature, global warming has bearings on the soil in the form of losing capacity of natural nutrition intake. But farmers are inclined to apply excessive chemicals in the forms of fertilisers and pesticides as food production must not be stopped and should keep pace with the increasing population of the country.
Agriculture researchers point out that farmers used to apply two to three types of chemical input previously. But now with the rise of demand for agricultural products many of the farmers use even 17 types of fertilisers and pesticides in the drive of higher productivity and crop protection.
The organic substances in the soil of arable land are most fragile in the districts of Dinajpur, Sherpur, Jamalpur, Rajshahi, Pabna, Kushtia, Bogra, Nowngaon, Rangpur, Khagrachari, Bundarban and Chittagong. But these districts are contributing a lot in the field of agricultural production in the country. The condition of the soil of arable land of other districts of the country has also been shown in the research report. The research finding is that the presence of organic substances is also meagre even in the soil of those districts. Thus the overall health condition of the soil of the country's arable land is alarming.
The agriculture ministry maintains that the need to meet the country's rising food demands is fuelling the use of more chemicals in the form of fertilisers and pesticides and over mining soil's natural nutrients.
The SRDI report also found that many of the farmers tend to grow same crop over and over again on the same land. Such practices lead to losing of farmlands' essential organic elements. Professor Dr Mohammad Mosharraf Hossain, who teaches soil science at Sher-e-Bangla Agricultural University, has suggested crop-rotation - for instance, growing rice is followed by lentils, mustards, etc. Such scientific rotation of crops keeps soil rich in organic contents. He repented that "We only know how to take from the soil, but not to give back, let alone giving it rest".
The SRDI statistics show that 3.7 million hectares of land of the country lack phosphorus, 2.7 million hectares lack potassium, and 300,000 hectares lack calcium, magnesium etcetera. The Additional Director (Cash Crops) at the Department of Agricultural Extension and agriculturist Dr Md. Zahangir Alom acknowledged the dip in organic substance in the soil of arable land. He opined that the government needs to carry out the recommendations given in the research reports without taking further time in contemplating the next initiatives. According to the noted agricultural scientist Professor Zahurul Karim "if we keep relying on chemical fertilisers, then the condition of the soil will deteriorate quickly". He advised taking good care of the soil and using fertilisers with restrain to keep the health of the soil in check.
We have to protect the fertility of the soil used for agricultural purposes. It is true that food security is the prime concern as it is a difficult task to feed the booming population of the country. The main bugbear to our attaining the food autarky is the very limited acreage of arable land that we have in hand. Besides, our crop production very often suffers serious damages because of the vagaries of nature like floods, drought and climate change effect. So, it is quite natural that in pursuit of feeding the growing population farmers must grow three to four crops from the same land a year. The over-exploitation of soil for boosting per unit crop yield is gradually causing the soil to lose its fruitfulness. Apart from the operation of the law of diminishing return in agricultural production, the fallout is discernible that per acre crop output is decreasing every year. We must, therefore, be mindful about proper management of soil and its productiveness. The authorities must encourage farmers to use chemical fertilisers with restraint so that the fertility of the soil is not lost. As an alternative the use of compost may be encouraged as it helps soil retain its health and fecundity.
The writer is a retired Professor of Economics, BCS General Education Cadre.
