Do Biochar-Manure Soil Amendments Sustain Corn Yield Under Deficit Irrigation By Increasing Soil Moisture and Nutrient Cycling?.

Increases in frequency and intensity of drought present imminent changes in agroecosystems. As competition for groundwater from industrial and municipal users grows, water scarcity has become a crucial issue for producers. This will require adaptation of agricultural practices through innovative soil, water and crop management strategies. This study aims to find methods to adapt semi-arid irrigated systems to drought in the face of these challenges. The project examines the effect of drought mitigation strategies on water and nutrient availability for two corn varieties, specifically quantifying changes in microbial nutrient cycling. How will these soil amendments impact soil moisture and thus microbial processes, such as  enzymatic activity? Will these strategies alter soil water and nutrient availability for corn production under deficit irrigation? This study is part of a three-year project at the CSU-Agricultural Research, Demonstration, and Education Center, established in October 2013. It is designed as a full factorial field experiment with soil amendments and irrigation combinations replicated four times with a randomized block design.  The soil amendment treatments include: (1) 30t/ha pine-wood derived biochar,  (2) 30t/ha manure, (3) 10t/ha biochar with 30t/ha manure, and (4) a control with no soil amendments. The two irrigation strategies consist of full irrigation and a limited irrigation treatment, with water applied only at key reproductive and growth stages. Treatment effects on carbon (C) and nitrogen (N) cycling will be assessed by measuring soil carbon dioxide flux, microbial biomass C and N, and enzymatic activities throughout the season. This data will be paired with plant phenology and physiology measurements. These results will help to illuminate the effects of biochar-manure amendments on soil moisture and plant nutrient availability under a water-saving irrigation strategy.