Solar sterilization of the soil

Solar sterilization is a natural, non-chemical, and environmentally friendly method of agricultural pest control that uses solar energy to increase soil temperature to levels at which many soil-borne pathogens are killed or weakened.

Solar sterilization:

Solar sterilization involves heating the soil with solar radiation by covering the moist soil tightly with plastic sheets 4-6 weeks before planting during the hot summer months. This kills or weakens the pathogens of pests in the ground.

When is the solar sterilization process?

The process of solar sterilization is carried out between the months of (June and August), and perhaps the most effective time is when it is carried out between the middle of June and the end of July, while the effectiveness increases the longer the period of solar sterilization.

Soil preparation for solar sterilization:

1.     Clean the soil well of the remains of the previous crop, especially the roots.

2.     Distribute the compost well on the surface of the soil. This is in the prescribed size or weight, according to the type of fertilizer used.

3.     I was irrigating the soil with heavy irrigation to a depth of 60–70 cm, whether by surface irrigation or sprinkler.

4.     The soil is suitable for deep plowing when it becomes plowed, i.e., when its moisture content is suitable.

5.     Chop, smooth, and level the soil by using a soil comb, and this process is essential in order not to leave dirt or stones on the surface of the soil, as well as to remove any plant residues that may raise the plastic slices, such as the stumps or plasticine slices.

6.     We are extending the irrigation lines above the soil surface along the area to be sterilized so that the distance between the lines is about 50–75 cm to ensure a good distribution of the irrigation water during the period of solar sterilization.

7.     It is also essential to check all points on the irrigation pipes and ensure their validity before covering them with plastic.

8.     Covering the soil with plastic the area to be sterilized is completely covered with plastic and fixed by covering it with soil after tightening the plastic properly so that it is completely attached to the surface of the soil.

9.     Take care to place belts of dirt on the width of the plastic in at least two places to prevent it from being pulled out by strong winds.

10.After the plastic covering process, the soil is abundantly irrigated to provide the necessary moisture for the success of the solar sterilization process.

11.After that, the soil is rinsed by opening the irrigation tubes for 3–4 hours once every week during solar sterilization.

12.At the end of the sterilization period, after 4-6 weeks, the plastic is removed, folded, and stored for use in the coming seasons.

The plastic film used in the process of soil sterilization:

It is polyethylene plastic (transparent ethylene) with a thickness of 80–60 microns for heating the soil, as it is permeable to solar radiation and prevents heat from escaping from the soil.

It considers the use of polyethylene plastic with hardeners added to it to prevent cracking in the field due to high temperatures and ultraviolet rays.

There is currently "thermal plastic" available on the market.

This is characterized by raising the soil temperature to higher degrees than other types and enabling us to reduce the duration of solar sterilization.

Black plastic was used in the Jordan Valley, and covering it for two months during the summer gave results similar to those obtained using transparent plastic.

The importance of solar sterilization of soil and plants

• Solar sterilization dramatically improves the properties of the soil on farms and increases its efficiency.                                                                                                                                                                                                                                                                                                                  
• Therefore, the authority urges farmers to take advantage of the summer period to conduct solar sterilization, which helps eliminate pests and pathogens in open fields and greenhouses.