Optimizing Water Retention in Sandy Soils to Combat Drought and Promote Sustainable Agriculture:

Grade:

10

Teacher:

Mari Echols

This experiment tested the efficacy of five different blends of coconut coir and Yuma-Mesa sandy soil at increasing field capacity in forty trials. Sandy soil alone and clay soil alone field capacities were also calculated. Field capacity is the amount of water left in the soil after it has been thoroughly saturated and allowed to drain freely. A coconut coir block was moistened, broken apart, and sun-dried. Yuma-Mesa sandy soil was collected, sifted, and sun-dried. One hundred milliliters of soil and coconut coir/soil blends were prepared and placed in a coffee filter inside bottomed-out cups and weighed. The trials were saturated with distilled water and left to drain for 24 and 48 hours respectively. The trials were weighed after 24 and 48 hours. Field capacity was calculated by dividing the weight of the water in the soil by the weight of the soil. The hypothesis stated adding coconut coir to Yuma-Mesa sandy soil will increase field capacity because its porous structure allows it to expand and absorb water. On average, after 24 and 48 hours, all of the blends had higher field capacities than sandy soil alone. However, they did not have as high of a field capacity as clay soil alone. There was a range of 5.47% - 22.66% increase in field capacity. The largest increase occurred in the thirty percent blend. In the thirty percent blend, field capacity rose an average of 22.66% after 24 hours and 19.95% after 48 hours.

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