Water retention in soil can be understood as the water retained by the soil after it runs through the soil pores to join water bodies such as groundwater or surface streams. Pores in the soil can be defined as the air-spaces that exist in between soil particles.
Water retention is mainly dependant on the particle size of the soil. The finer the soil particles, the higher the chance that water molecules shall hold on to soil particles, such as in clay, as opposed to sandy soil, that has large and coarse particles that are not cohesive.
The water retention by soil is critical for plants and acts as the chief source of moisture for it in almost all habitats. Other than percolation through the soil, soil moisture can also deplete due to evaporation directly from the soil and by transpiration by plants.
As based on the size of the soil particles, there are four classificatory systems for the identification of soils (J. Mariamma, 2010) –
- US Bureau of Soil Classification
- International Classification
- M.I.T Classification
- Indian Standard Classification
The Indian Standard classificatory system was formulated originally for the classification of soils primarily for engineering purposes. This is because the draft for soil classification was prepared by the Soil Engineering Sectional Committee and was approved by the Civil Engineering Division Council.
The final draft was adopted by the Bureau of Indian Standards on December 19th, 1970. This system divides soils into three broad categories based on the properties of soil particles (Bureau of Indian Standards, 2004) –
i) Clay – the particles are microscopic to sub-microscopic and exhibit plasticity, allowing it to retain the most water.
ii) Silt – the particles are fine grains, but exhibit less plasticity, making this form retain lesser water.
iii) Sand and Gravel – aggregates of comparably larger particles that are coarse and loosely bound thus lacking cohesion. The least water retention is possible in this form of soil.
Different topographic and climactic patterns result in varied behaviour of soils and thus require a variety of approaches to analyze and implement soil management techniques for water retention. Soil can sometimes pose problems for not being as desired, and these problems can broadly be grouped under chemical and physical problems (National Agricultural University, NAU, 2013).
Chemical problems include high salinity or acidity in soils, along with the presence of other toxic chemicals such as phosphorous in soil (NAU, 2013). This problem becomes especially pertinent in agriculture where crop yield or productivity could dwindle due to chemicals used in the agricultural process such as pesticides and herbicides.
Among a large gamut of solutions and applications, the most common one is the use of ecologically beneficial green manure. Agricultural soil should also be frequently and properly drained to achieve effects such as the leaching of saline moisture in soils.
The physical problems can involve soil that is not able to contain much water due to lack of cohesion or due to a rigidity that can occur owing to encrustation, or a very clayey surface. Shallow depth of soil, soil that is too clayey, or the presence of hard opaque surfaces underneath can also present problems to water retention and there can be water-logging when too much water is added to soil.
These require artificial solutions to soil management that frequently involves the mixing of soil with other different forms of soil. Incorporating organic matter and regulating drainage are also frequently applied solutions.
There are various methods to enhancing the water retention capacity of soil. Some methods are more traditional, and also conventional, while some involve the utilization of technology. While most of technological investment regarding water retention in soils involves technologies for enumeration and generation of data, technological solutions can vary from simple, affordable, everyday solutions to solutions utilizing high-end technology.
Some of the simple solutions include application of organic solutions such as drought resistant crop varieties and organisms that increase the fertility of soil, management and design of irrigation according to soil properties, application of biochar – produced from biomass for low-cost carbon sequestration in soil – making soil less porous, use of the roots of plants that grip soil, and application of natural by-products such as poultry litter that provide greater cohesiveness to soil.
The solutions can also range towards using complex technologies such as mapping the global water cycle in relation to water retention in soil, and preparation of dietary fibres that have high water-holding capacity from food sources used in soil. There is however, a leaning in technological progress in engineering water retention in soil to introduce organic elements in the soil instead of inorganic matter.
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Steve Ovett, the famous British middle-distance athlete, won the 800-metres gold medal at the Moscow Olympics of 1980. Just a few days later, he was about to win a 5,000-metres race at London’s Crystal Palace. Known for his burst of acceleration on the home stretch, he had supreme confidence in his ability to out-sprint rivals. With the final 100 metres remaining,
[wptelegram-join-channel link=”https://t.me/s/upsctree” text=”Join @upsctree on Telegram”]Ovett waved to the crowd and raised a hand in triumph. But he had celebrated a bit too early. At the finishing line, Ireland’s John Treacy edged past Ovett. For those few moments, Ovett had lost his sense of reality and ignored the possibility of a negative event.
This analogy works well for the India story and our policy failures , including during the ongoing covid pandemic. While we have never been as well prepared or had significant successes in terms of growth stability as Ovett did in his illustrious running career, we tend to celebrate too early. Indeed, we have done so many times before.
It is as if we’re convinced that India is destined for greater heights, come what may, and so we never run through the finish line. Do we and our policymakers suffer from a collective optimism bias, which, as the Nobel Prize winner Daniel Kahneman once wrote, “may well be the most significant of the cognitive biases”? The optimism bias arises from mistaken beliefs which form expectations that are better than the reality. It makes us underestimate chances of a negative outcome and ignore warnings repeatedly.
The Indian economy had a dream run for five years from 2003-04 to 2007-08, with an average annual growth rate of around 9%. Many believed that India was on its way to clocking consistent double-digit growth and comparisons with China were rife. It was conveniently overlooked that this output expansion had come mainly came from a few sectors: automobiles, telecom and business services.
Indians were made to believe that we could sprint without high-quality education, healthcare, infrastructure or banking sectors, which form the backbone of any stable economy. The plan was to build them as we went along, but then in the euphoria of short-term success, it got lost.
India’s exports of goods grew from $20 billion in 1990-91 to over $310 billion in 2019-20. Looking at these absolute figures it would seem as if India has arrived on the world stage. However, India’s share of global trade has moved up only marginally. Even now, the country accounts for less than 2% of the world’s goods exports.
More importantly, hidden behind this performance was the role played by one sector that should have never made it to India’s list of exports—refined petroleum. The share of refined petroleum exports in India’s goods exports increased from 1.4% in 1996-97 to over 18% in 2011-12.
An import-intensive sector with low labour intensity, exports of refined petroleum zoomed because of the then policy regime of a retail price ceiling on petroleum products in the domestic market. While we have done well in the export of services, our share is still less than 4% of world exports.
India seemed to emerge from the 2008 global financial crisis relatively unscathed. But, a temporary demand push had played a role in the revival—the incomes of many households, both rural and urban, had shot up. Fiscal stimulus to the rural economy and implementation of the Sixth Pay Commission scales had led to the salaries of around 20% of organized-sector employees jumping up. We celebrated, but once again, neither did we resolve the crisis brewing elsewhere in India’s banking sector, nor did we improve our capacity for healthcare or quality education.
Employment saw little economy-wide growth in our boom years. Manufacturing jobs, if anything, shrank. But we continued to celebrate. Youth flocked to low-productivity service-sector jobs, such as those in hotels and restaurants, security and other services. The dependence on such jobs on one hand and high-skilled services on the other was bound to make Indian society more unequal.
And then, there is agriculture, an elephant in the room. If and when farm-sector reforms get implemented, celebrations would once again be premature. The vast majority of India’s farmers have small plots of land, and though these farms are at least as productive as larger ones, net absolute incomes from small plots can only be meagre.
A further rise in farm productivity and consequent increase in supply, if not matched by a demand rise, especially with access to export markets, would result in downward pressure on market prices for farm produce and a further decline in the net incomes of small farmers.
We should learn from what John Treacy did right. He didn’t give up, and pushed for the finish line like it was his only chance at winning. Treacy had years of long-distance practice. The same goes for our economy. A long grind is required to build up its base before we can win and celebrate. And Ovett did not blame anyone for his loss. We play the blame game. Everyone else, right from China and the US to ‘greedy corporates’, seems to be responsible for our failures.
We have lowered absolute poverty levels and had technology-based successes like Aadhaar and digital access to public services. But there are no short cuts to good quality and adequate healthcare and education services. We must remain optimistic but stay firmly away from the optimism bias.
In the end, it is not about how we start, but how we finish. The disastrous second wave of covid and our inability to manage it is a ghastly reminder of this fact.