PERENNIAL CROPS CAN IMPROVE SOIL SALINITY
Augustin, C.11Area Soil Health Specialist, North Dakota State University, North Central Research Extension Center, Minot, ND, 58701
Abstract:
Since the mid 1990’s, saline soil acres have increased in North Dakota due to an abnormally wet period that spanned for more than 20 years. Soil salinity is caused by the translocation and accumulation of water soluble salts in the soil to a level that impedes plant growth. Excess salts restrict plant water uptake by adversely affecting soil water osmotic potential. Soil salinity is determined by measuring the electrical conductance (E.C.) of a soil:water slurry and is expressed as mmhos cm-1. Soil E.C. levels greater than two mmhos cm-1 can hinder growth of many crops. Soil salinity is only managed through water management. Water management strategies include subsurface drainage and cropping systems. Cropping system strategies include perennial cropping and cover cropping. This project monitored the changes of soil salinity from the perennial forages alfalfa (Medicago sativa L.) and hybrid wheatgrass (Elymus hoffmannii L.). Salt tolerant alfalfa was planted in areas where the salinity was less than four mmhos cm-1 and hybrid wheatgrass was planted in soils with electrical conductance greater than four mmhos cm-1. Both forages where planted at 16.5 kg ha-1. Soil E.C. was measured at the 0-15 cm depth with an in situ soil E.C. probe. Measurement points were recorded by a handheld global positioning system. Soil E.C. was measured in the fall of 2013 at the Minot site and 2014 at the Bowbells site. Final E.C. measurements of both environments were recorded in the fall of 2019. Soil salinity decreased from 2.8 to 1.8 mmhos cm-1 (p < 0.001) at the Bowbells site and 3.2 to 1.0 mmhos cm-1 (p < 0.001) at the Minot site. This research suggests that saline areas can be improved over time with perennial forages.