10 FACTORS INFLUENCING CONSUMPTIVE USE OF WATER BY A CROP

Several factors work alone or in combination to affect the amount of water consumed by plants. Their effect is not necessarily constant, but factors can vary with locality and water consumption can fluctuate from year to year. Some of the influences include human factors; Others relate to the natural effects of the environment and the growth characteristics of plants.

Of the more important natural influences are climate, water supply, soil and topography. Climatic factors that specifically affect consumable use are temperature, solar radiation, precipitation, humidity, wind speed, length of the growing season, latitude and sunlight. Data were not available for solar radiation.


1. precipitation

The amount and rate of rainfall can have some minor effect on the amount of water used in any given summer. Under certain conditions, precipitation may occur as a series of continuous, light showers during a hot summer. Such showers may add little or nothing to soil moisture for use by plants through transpiration, but reduce extraction from stored moisture. Such precipitation can be largely lost by direct evaporation from the leaf surface of the plant and the land surface.

Surface runoff can destroy some of the precipitation from heavy storms. Other storms may be of such intensity and volume that a large percentage of moisture will enter the soil and become available for plant transpiration. This available soil moisture can reduce the amount of water needed for irrigation.

2. Temperature

The rate of water consumption by crops in a particular area is probably influenced more by temperature, which is a good measure of solar irradiance over a long period of time, than any other factor. Abnormally low temperatures retard plant growth and abnormally high temperatures can cause dormancy. Consumable use can vary widely even in years of the same accumulated temperature due to deviations from the normal seasonal distribution. Transpiration is affected not only by temperature but also by leaf surface area and physiological needs of the plant, both of which are related to the stage of maturity.

3. Moisture

Evaporation and transpiration accelerate during periods of low humidity and slow down during periods of high humidity. During periods of low relative humidity, a higher rate of water use by vegetation can be expected.

4. wind speed

Water evaporates from land and plant surfaces more rapidly when there is moving air than in calm air. Hot, dry winds and other abnormal air conditions will affect the amount of water consumed during the growing period. However, there is a limit to the amount of water that can be used. As the land surface dries up, evaporation practically stops and transpiration is limited by the ability of plants to extract and transmit soil moisture through the soil.

5. growing season

The growing season, which is closely tied to temperature, has a major impact on the seasonal use of water by plants. This is often considered the period between hitting frosts, but for many annual crops, it is shorter than the frost-free period, as such crops are usually planted after frost and mature before reappearing. Huh.

For most perennial crops, growth begins as soon as the maximum temperature exceeds the freezing point, and continues throughout the season despite subsequent freezing. Sometimes growth persists even after the first so-called killing frost in the fall. In the spring, and to a lesser extent in the fall, daily minimum temperatures can fluctuate from 32 degrees Fahrenheit to several degrees above and below that for several days. Hardy crops survive these fluctuations and are unaffected during a few hours of subfreezing temperatures. In fact, many hardy crops, especially grasses, can mature even when growing season temperatures repeatedly drop below freezing. Alfalfa and Citrus Trees Grow Year-round in Southern Arizona and California,

Although the frost-free season can be used as a guide for calculating consumable use, the actual dates of planting and harvesting crops and the average annual dates of the first and last irrigation are important in determining the consumption irrigation needs of crops. Huh.


6. latitude and sunlight

Although latitude can hardly be called a climatic factor, it has a great influence on the rate of water consumption by different plants. Due to Earth’s motion and axial tilt, daylight hours during summer are much longer in northern latitudes than at the equator. Since the sun is the source of all energy used in crop growth and water evaporation, this longer day may allow plant transpiration to continue for a longer period each day and produce a similar effect of prolonging the growing season. Is.

7. Available Irrigation Water Supply

All of the above climatic factors affect the amount of water that can potentially be consumed in a given area. However, there are other factors that cause significant differences in consumable use-rates. Naturally, unless water is available from a source (rainfall, natural groundwater, or irrigation), there may be no consumable use. In areas of the arid and semi-arid West where irrigation is the major source, both the amount of available supply and the seasonal distribution will affect consumable use. Where water is plentiful and cheap, farmers tend to irrigate more. If the soil surface is frequently wet and the resulting evaporation is high, combined evaporation and transpiration or consumable use may also increase. In addition, under more optimal soil moisture conditions, crops such as alfalfa can have higher-than-average yields and consume more water. In the irrigation of some crops, such as potatoes, water is applied to the field not only for the purpose of meeting the crop’s consumption water needs, but also to help maintain a favorable microclimate condition.

8. water quality

Some investigations have shown that water supply quality can have a significant impact on consumable use. Whether or not plants actually transpire more or less when water is highly saline can be debatable. However, if additional water is required to be added to the land to carry salts down through the soil, more water will probably be lost by evaporation from the soil surface and such loss will be paid for by the need for consumption of cropped area. Will go

9. soil fertility

If the soil is made more fertile with manure or some other means, an increase in yield can be expected with a small increase in water use. However, increasing soil fertility reduces the amount of water consumed per unit of crop yield.

10. Plant pests and diseases

Where plant pests and diseases seriously affect the natural growth of plants, it is reasonable to assume that transpiration will also decrease. It is believed that every year there is some damage to crops by pests and diseases. Losses generally may not vary much from year to year, but can be reduced materially in years when they are of unusually severe consumable use.


Er. Mukesh Kumar

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Er. Mukesh Kumar is Editor in Chief and Co-Funder at ProCivilEngineer.com Civil Engineering Website. Mukesh Kumar is a Bachelor in Civil Engineering From MIT. He has work experience in Highway Construction, Bridge Construction, Railway Steel Girder work, Under box culvert construction, Retaining wall construction. He was a lecturer in a Engineering college for more than 6 years.