A highly productive grass improves chemical and biological properties but does not aggregate stability in saline-sodic lowlands in Argentina

Abstract

Remediation of saline-sodic soils used for cattle breeding is particularly challenging due to the limited alternatives. We hypothesize that introducing salt tolerant and productive forage in a lowland halophytic steppe, typical of saline-sodic soils, increases belowground biomass inputs and activity, generating a series of positive effects on soil biological and chemical properties, and aggregate stability – an accepted indicator of soil degradation resistance. Under natural environmental conditions, we found that the introduction of Panicum coloratum (panicum) increased belowground biomass almost three times, the abundance of mites tended to be greater and that of springtails was 9.4 kg−1 contrasting with none found in the halophytic steppe, after 7 years. The concentration of Ca2+ and Mg2+ increased 26% and 54%, respectively, and that of Na+ was reduced 31% compared with the halophytic steppe. Soil pH decrease 5% and electrical conductivity decreased 37% (changing from moderate to very slightly saline) in panicum compared to the halophytic steppe. However, in panicum, mineral-associated organic matter (MAOM) and aggregate stability decreased 22% and 26%, respectively. We concluded that, although biological and chemical properties improved, aggregate stability – an early indicator of soil recovery – decreased, which was likely determined by MAOM reduction in saline-sodic soils.