Improving Soil Water Retention and Nutrient Availability Using Carbon Inputs in Desert Croplands

Abstract

Considering that the southwestern United States provides many of the specialty crops to feed the entire nation, it is vital to maximize use of water and fertilizer in croplands in this region. Meanwhile, intensifying droughts exacerbate cropland dependence on irrigation water. Therefore, solutions are needed to maintain cropland productivity. Adding carbon-rich organic amendments temporarily improves soil properties by increasing water and nutrient retention, but benefits are short-lived as organic amendments degrade quickly in hot, arid climates. Biochar is an organic amendment that can potentially improve long-term cropland soil health, which is the ability of soil to store and provide water and nutrients for plant growth. Biochar provides a relatively stable carbon source and can increase water and nutrient retention. Most studies on the effectiveness of biochar for these purposes have been conducted in temperate agroecosystems, but few studies examine effects of biochar on soil properties in croplands of the desert southwest U.S. Therefore, the purpose of this research is to deepen understanding of effects of carbon inputs (i.e. biochar and compost) to retain more water and provide plant-available nutrients in an irrigated desert cropland.