The importance of water conservation for agriculture has been recognized for centuries. Bennett (1939), in his book Soil Conservation, cited numerous examples from ancient times of countries where canals were developed to convey water to agricultural lands for improved crop production. In addition, reservoirs were constructed for retaining water for later use on agricultural land, terraces were constructed to reduce runoff, plowed fallowing was promoted to conserve water, deep plowing was used in some cases, and contouring was used to retain water on land. Water conservation seldom was the direct object of these practices, but water conservation was achieved by using them.

Water for agriculture is derived from precipitation or from a stream, reservoir, or aquifer where irrigation is practiced. Precipitation frequency in humid regions usually is adequate to provide for plant needs, but even in such regions, precipitation amount and distribution vary considerably from average in any given year.

Precipitation frequency and reliability decrease when going from humid to subhumid, semiarid, and arid regions, thus increasing the importance of water conservation for successful agriculture in the drier regions. Some crops in humid, subhumid, and semiarid regions and most crops in arid regions are irrigated. For successful crop production under all conditions, adequate water must be stored in soil to sustain crops until the next precipitation or irrigation event. Even when using drip or sprinkler irrigation to apply water frequently, water is temporarily held in soil until used by plants.

Primary Areas of Water Conservation

The principles of water conservation for agriculture are the same whether crop production is under rainfed or irrigated conditions. Water must be captured, retained, and used efficiently for producing a desirable yield. These principles have been recognized for many years. Numerous land, climate, social, and environmental conditions and applied practices affect water conservation.

Why is conserving water in agriculture critical for environmental conservation?

Water is one of the essential natural resources on Earth. All life form, be it human, animal, plant or aquatic, needs water to survive. If there were no water, there would be no life on the planet.

Even though around 71% of Earth’s surface is covered with water, only over 2.5% is fresh water, the rest being saline.

The bulk of earth’s freshwater is used in drinking and household needs; industry & commerce and agriculture. Right from drinking, bathing, and cleaning etc. to use in industrial and agricultural activities, water is critical in every aspect of our lives.

Being as important as it is, yet we have not used it with care. The rampant and careless use of the precious resource in the last few decades is resulting in its fast depletion from our planet.

Rapid urbanisation, rising population and a drastic change in lifestyles has led to a considerable increase in water consumption over the past few decades. As a result, we are losing freshwater at a faster rate than it can be replenished.

The agriculture sector is the prime consumer of water, consuming nearly 70% of the total freshwater reserves. It is followed by industrial consumption at 20% and domestic at 10%.

Trends show that by 2050, feeding a planet of 9 billion people will require an estimated 50 per cent increase in agricultural production and a 15 per cent increase in water usage

While many farmers across the globe rely on groundwater and other pumped resources to water their crops, the environmental effects of water wastage are big areas of concern in agriculture.

Studies show that around 40% of the freshwater used for agriculture is lost either by evaporation, spills (overwatering), or deep infiltration.

The need of the hour is to understand that optimal use of water by farmers will help in conserving one of nature’s most treasured resources. Additionally, it will also help in growing healthier crops, all with less water – ‘More Crop Per Drop’. Efficient water management and utilisation are critical for sustainable growth.

The farming sector depends majorly on the environment, and we depend on agriculture. It is especially true for an agrarian economy like India’s where more than half the population is dependent on agriculture.

Therefore, environmental conservation is most critical.

Here are ways water conservation in agriculture can help in environmental conservation

Use Efficient Irrigation Systems?

Optimal use of natural resources by moving towards modern and efficient irrigation methods like ‘Drip and Sprinkle irrigation’ will help in conserving water significantly. Through the drip method of irrigation, the plant gets the water directly at its roots, unlike the traditional overhead spray method.

Reducing the percentage of evaporation, Drip Irrigation saves up to 80% more water than the conventional method. It also improves the yield by around 20%.

Schedule the Irrigation

Efficient water management is vital for ensuring sustainable growth and sustenance of the natural resources.

Watering the plants at the right time, right place, with the right amount, and in the proper manner is critical to optimal use of the natural resource.

It increases productivity and conserves water along with reducing the energy cost on irrigation. Timers, set to schedule the watering for cooler parts of the day, can reduce the water loss even further By using technology like IoT (Internet of Things), the farmers automate the irrigation schedule. Keeping in mind the weather, moisture levels of plant and soil, humidity, temperature, etc.

Recycle Water

During the periods of rain, farmers can build rain barrels to store the water. They can then recycle it for irrigating the crops when the water reserves go low.

Creating special reservoirs or ponds to store the water will also help in creating a natural habitat for the wildlife. This practice can save millions of gallons of water. This will ease off the load on the natural resource and help in environmental conservation.

Follow Best Agricultural Practices?

Sustainability-led farmers understand the far-reaching benefits of following good agricultural practices.

These include using good quality planting material and optimal use of resources. It means focussing on improving the quality of the soil so that it can hold moisture and oxygen, and the plants can thrive.

Additionally, adopting good agricultural practices also signifies the responsible use of pesticides and fertilisers. It ensures too many chemicals do not seep into the soil, affecting the environment adversely.

Continued and sustained efforts by more and more farmers in this direction will help in reducing the negative impact on the ecosystem. It will help in conserving the natural resources for future generations.

Each one of us has a deep impact on the future of the planet. How we lead our daily lives, how mindful we are in using natural resources, every action of ours impacts the future of the Earth.

Nature, when allowed to be in its glory, does a great job of keeping our planet healthy. However, when interfered with too callously, can turn around and become the biggest taskmaster.

So, let us all contribute to make our planet a thriving place again. Let us all commit to rebuilding a green world – both for ourselves and for our future generations.

Future Challenges and Opportunities

The principles of water conservation for agriculture, namely, that water must be captured, retained, and used efficiently for producing a desirable yield, have not changed during the past 100 yr. Although much progress has been made, much water potentially available for agricultural uses is not effectively conserved in many cases. With increasing demands for water by other users and the need for increased agricultural production, it is imperative that continued efforts be made to conserve and use our water supplies effectively and more efficiently. With this in mind, we list and briefly comment on some challenges and opportunities for achieving improved water conservation for agriculture.

1. Develop techniques for reducing crop residue decomposition.

Conservation tillage and especially no-tillage result in crop residues being retained on the soil surface, thereby providing major water conservation benefits under many conditions. Unfortunately, residues decay, thus decreasing their long-term effectiveness. With less decay, greater water conservation should be possible. Possible means for reducing residue decay include using improved harvesting equipment (e.g., using the stripper header), plant breeding to develop sturdier or decay-resistant plant stems, and applying chemicals to retard decomposition.

2. Identify, select, or develop more water-efficient crops or crop cultivars.

The major differences in water use to produce a unit yield for different crop species and for different cultivars of a given crop. Crop or cultivar selection is used to achieve efficient water use, but improved efficiency should be possible through genetic engineering techniques, through careful selection of existing crops or cultivars, and through development of improved crops or cultivars for use in a given situation (e.g., region, climatic conditions). For example, genes have been identified that may make it possible to alter corn plants, thereby potentially making corn less susceptible to drought and improving water use efficiency for that crop.

3. Determine crop responses to increasing atmospheric CO₂ levels.

Atmospheric CO₂ levels continue to increase. Studies regarding CO₂ level have been conducted, but continued research and plant breeding are warranted to stay abreast of the effect of CO₂ levels on crop productivity and water use efficiency.

4. Develop more effective herbicides or other methods for controlling weeds.

Some herbicides are most effective at a given weed growth stage. With a wider range of effectiveness, generally better weed control should be possible. In addition, some weeds are resistant to herbicides, and improved herbicides or different control methods are needed to adequately control them. Some herbicide-tolerant crops have become available through biotechnology, which has been a major benefit with regard to weed control. This practice is desirable for other crops. Progress in these areas is needed to achieve increased water use efficiency and crop productivity.

5. Develop improved phreatophyte and brush control methods.

Phreatophytes often grow beside canals, streams, or other waterways from which they extract water that could potentially be used for crop production. Brushy plants grow on rangeland and compete with grasses for water. Effective control of such plants is needed to increase the water supply for cropland and rangeland plants.

6. Consider the impacts of ethanol and biofuel production.

Several issues concerning ethanol and biofuel production have implications regarding water conservation for agriculture. In the production process itself, 3.5 to 6 units of water are used for each unit of ethanol produced. Where grain is used for ethanol production, a large volume of water is used to produce the crop, about 1400 kg water to produce 1 kg corn grain. Such water requirement for corn grain production results in almost 3400 L of water needed to produce 1 L of ethanol. Where corn is produced under rainfed conditions, such water use may not be of much concern. Under irrigated conditions, especially where the water supply is limited, such water use makes the production of ethanol from corn a questionable activity.

7. Increase the application of practices known to improve water conservation.

Many studies have shown the value of conservation tillage for improving water conservation and use, but the practice is not used to the extent to which it is applicable. Also, such studies have not been conducted under some conditions where it could be applicable. Additional research and demonstrations involving conservation tillage (especially no-tillage) under a wide variety of cropping systems are needed to develop information so that it can be promoted through education and extension activities to achieve greater acceptance by producers.

8. Conduct interdisciplinary, more comprehensive research.

Much research pertaining to water conservation involves a small number of variables and often is conducted by one or a few researchers. Research and development teams comprised of personnel from several disciplines (e.g., soil, crop, and weed scientists; agronomists; engineers; hydrologists; economists; environmentalists; cropping-system modelers) are needed to simultaneously study more variables and to develop widely applicable, practical, and functional integrated cropping systems. These systems should effectively capture, retain, and efficiently use water; be economically suitable for producers; and help protect the environment.

Summary

The principles of water conservation for agriculture have remained constant during the past 100 years; that is, the water must be captured, retained, and used efficiently to produce a desirable yield. Deep plowing was promoted by Shaw (1911) as the primary method for capturing water in the early 1900s. Deep plowing improves water capture in some soils, but water capture can be achieved also by various less intensive practices, including ridge tillage, stubble mulch tillage, bench terracing, furrow diking, and conservation tillage, which also provide soil conservation benefits. Conservation tillage methods, especially no-tillage, are highly effective for capturing water under many conditions because the surface residues dissipate raindrop energy, thereby minimizing soil aggregate dispersion and surface sealing and maintaining favorable conditions for water infiltration. The residues also reduce the runoff rate, thus providing more time for infiltration.