Do organic farming practices improve soil physical properties?

Organic farming (OF) is a reemerging system that could address food security and adverse environmental footprints of conventional farming (CF). However, how OF affects the soil physical environment, an essential pillar for soil ecosystem service delivery, is not well understood. This paper (1) reviews published global literature up to 13 July 2023 regarding the impacts of OF on soil physical properties compared with CF and (2) underlines research needs. Literature indicates OF improves some soil physical properties relative to CF although studies on some properties were few. Specifically, OF increased wet aggregate stability, saturated hydraulic conductivity, and plant available water in 55% of studies. OF also increased mesoporosity (5-500 mu m) and cumulative water infiltration. However, OF had mixed or no effects on soil compaction indicators (i.e. bulk density, penetration resistance). Not all studies reported both soil physical properties and soil organic C to assess how amendment-induced increase in soil organic C affected physical properties. Based on studies reporting both properties, physical properties such as wet aggregate stability were not significantly correlated (r = 0.12; p > .10) with soil organic C. Variability in data and frequent tillage under OF likely obscured this relationship. Factors tended to affect OF impacts on physical properties in this order: amendment type > duration > others. Most OF studies (1) used animal manure amendments, (2) were long-term (>10 years), and (3) were conducted in medium textured soils, highlighting the need for more comprehensive assessments of OF and soil physical properties under different management conditions. In general, OF improves some soil physical properties, which can contribute to OF sustainability.