Soil health benefits from sequence intensification, fertilization, and no-tillage in annual cropping systems

Abstract

The expansion of annual cropping systems and associated land cover changes may induce soil degradation, compromising the soil's ability to function and provide ecosystem services, also referred to as soil health (SH). Conservation practices may reduce SH decline, yet their benefits are uncertain. The main objectives of this paper were to apply a comprehensive SH assessment framework to evaluate (i) SH differences in natural grasslands and cropping areas, and (ii) how conservation practices lessen SH deterioration. Soils under natural grasslands were compared to cropped soils from three long-term experiments with treatments evaluating the effects of cover crops and/or pastures incorporation; no-tillage; and crop fertilization for Uruguayan Mollisols. Soil chemical (pH, cation exchange capacity, macro, and micro-nutrients), physical (wet aggregate stability, available water holding capacity, penetration resistance), and biological (organic carbon, active carbon, protein, respiration) indicators were measured. SH was significantly lower across all indicators under cropped areas than under natural grasslands, especially when soil fertility is not adequately maintained in cropping systems. Conservation practices lessened SH degradation, particularly soil biological properties, but had confounding benefits. Overall, gains in SH were linked to adequate soil fertility maintenance and longer active plant growth periods associated with including pastures and cover crops in annual cropping systems.