Conversion from flood to sprinkler irrigation has varying effects on soil health

Abstract

Despite increased funding for conversion from furrow to sprinkler irrigation to conserve water in semiarid agricultural watersheds, little is known about the effects of this conversion on soil health. To address this gap, soil health changes were monitored under two fields that underwent a furrow-to-sprinkler transition: one field at a university research station and the other a producer-managed field. Soil samples were collected at the top and bottom of each field in the first year and 1–4 years after the conversion. Soil health was assessed using the Soil Management Assessment Framework, a scoring tool for 10 soil health characteristics that indicate physical, biological, chemical, and nutrient soil health. Results showed that conversion to sprinkler irrigation marginally improved soil health, though salinity concerns emerged at the research field (an increase from ∼0.48 ds/m to ∼1.7 ds/m over 4 years). There was some limited evidence of homogenization of soil health during the transition to sprinkler irrigation. At the research field, soil organic carbon began as highly uneven from the top to the bottom of the field (1.54% and 1.08%, respectively), but became more evenly distributed (1.39% and 1.68%, respectively) after 5 years of sprinkler irrigation. Spatial homogenization should be viewed as a soil health improvement as it simplifies decisions relating to nutrient and irrigation management and helps farmers to predict yields across the field. Consequently, converting from furrow to sprinkler irrigation may help producers more easily manage homogenized fields due to on-site soil health improvements.