Adverse Effects of Over Irrigation in Soil And Plants

People frequently believe that there is no such thing as excessive irrigation. Any excess, however, can be hazardous, and this is true for irrigation as well. Just as a lack of water hinders plant growth, too much water hinders plant growth. 

Excess water in the soil fills gaps or gathers on the soil surface. Pores lose their equilibrium of air and water, and plants can’t breathe without air. Excessive irrigation is harmful; thus, it should be used only as needed. There are several effects of over irrigation.

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Growers must maintain soil moisture for healthy plant growth and maximum output in the crop root zone. Extra water or moist soil affects crop growth, yield, soil oxygen, and carbon dioxide content. Crop type, soil features, duration of excess water or floods, initial soil water and nitrogen status before flooding, crop stage, soil and air temperature affect crop growth and yield concerning over-irrigation.

Overwatering can harm soil in various ways, but how does this happen? In this article, we are going to discuss the  effects of irrigation.

Effects of Over Irrigation on Soil

1. Reduces Oxygen Availability 

• Keeping the root zone oxygenated is crucial for optimum crop growth and output. Roots require oxygen. Too-wet soil reduces oxygen content, and plant roots absorb minimal oxygen. 
• Plant beds can act like sponges in excess water, absorbing water while rejecting oxygen. It is one of the prominent effects of over irrigation.
• Microorganisms compete with plant roots for oxygen when oxygen is scarce. Because oxygen is scarce, bacteria may use metabolic pathways that alter plant nutrient availability and uptake. 
• Yellowing and death (leaf chlorosis and necrosis) of lower leaves is a common indication of low oxygen levels in damp situations.

2. Acidity in Soil

• One of the Effects of over irrigation is H+ replaces positively charged Ca2, Mg2+, K+, and Na+, which cling to soil colloid granules. 
• These positively charged particles flow away to lower levels, decreasing basic positively charged particles and an abundance of colloidal granules. 
• As a result, there is an excess of H+ in the soil water, and the soil becomes acidic.

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3. Increase in Nitrate Formation

• The de-nitrification process begins due to the lack of oxygen in waterlogged soil. Organisms begin to take available oxygen from nitrate, converting it to nitrous oxide, nitric oxide, and nitrogen gasses. 
• These forms of nitrogen are worthless to plants since they are in gas form. Balanced irrigation eliminates such issues.
•  Removal of nitrogen from the available form is one of the crucial effects of over irrigation.

4. Salt Accumulation

• When excessive water is used for irrigation, the groundwater level rises, and the amount of solvent salts increases. Salts from saline groundwater gather on the soil’s surface due to evaporation.
• Canal water seepage increases the salt content of irrigation water. As discovered in Rajasthan, India, the concentration of soluble salts in these soils is so high that it negatively influences crop development and production.
• Plant growth is halted when the concentration of soluble salts in the soil exceeds 0.1. It is one of the life-threatening effects of over irrigation.

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Effects of Over Irrigation on Plants

1. Hindrance in Root Growth

• The roots cling to the surface because of the lack of oxygen and water. Plants can’t obtain enough nutrients, and weak, shallow roots can’t grow or withstand strong winds. As a result, the plants fall. So this is one of the deadly effects of over irrigation.
• Over-irrigation disrupts the root zone’s oxygen balance, drowns roots, lowers plant water intake, and consequently stresses plants.
• It decreases air (oxygen) exchange between the soil and the atmosphere, resulting in reduced root growth (particularly in the higher soil layers) and less delivery of water and nutrients through the roots to the plant’s upper portions.

2. Makes Crops More Prone to Diseases

• Over-irrigation can increase crop output losses due to bacterial and fungal foliar and root rot diseases. Infection requires high humidity and often surplus water on the soil surface and plant leaves.
• Also, many viruses rely on splashing water to spread to nearby leaves and plants. Excess water raises the risk of runoff, spreading soil-borne diseases over the field and to nearby areas.
• Extra water might cause bug and weed problems. It is one of the effects of over irrigation that can severely decrease yield.

3. Decreases Transpiration

• Due to moist conditions, reduced oxygen concentrations in soil trigger stomatal closure in plants, causing stress since plants cannot transpire water optimally.
• Some researchers claim that soil oxygen shortage can close stomata even with no plant water stress. It is one of the deadly effects of over irrigation.
• Stomata closure reduces transpiration rate and yield because transpiration and yield are tightly connected.

Preventing Over Irrigation 

• Smart irrigation is the most effective technique to avoid all of these issues. Acting too late and attempting to repair the damage caused by irrigation causing waterlogging to the soil is difficult and time-consuming and can cause your yard to seem untidy for several years before the plants begin to grow again. 
• Automatic sprinkler systems are ideal for your yard because they save time, water, and money by watering the plants automatically as needed. Considering the effects of irrigation and water loss is an important feature towards mitigating the climate crisis.
• Another factor to consider is drainage, as poor drainage can harm your soil and plants. Having a drainage system ensures that the soil is adequately aerated by eliminating excess water and aids in the retention of necessary nutrients in the soil.

(Also Read- Surface Irrigation)

Conclusion

Everything must be in balance for healthy plants. Water, sunlight, and nutrients in balance are the ideal mix for a beautiful yard for years to come. 

They all work together to keep the soil healthy for your plants; disrupting this balance with too much water or nutrients can cause long-term damage to the soil. To maintain optimum soil fertility, you should avoid over-irrigation at all costs and prevent the effects of over irrigation.

If your garden or field is facing issues with the effects of over-irrigation, it’s time to make some modifications. The consequences can be long-lasting, so it’s critical to act now.