Various effects of land tenure on soil biochemical parameters under organic and conventional farming − Implications for soil quality restoration

- In conventional system, higher enzyme activity was found in soil farmed by owners.
- Under organic management, enzyme activity was not affected by land tenure.
- Tenure insecurity in organic system was compensated by other strong incentives.
- Tenure security may affect soil biochemical activity and soil health.

Land tenure insecurity is one of the worldwide problems that often leads to soil degradation. We tested whether owner-operators maintain a higher level of soil quality and biochemical activity than tenant-operators and how this effect is modified by the agricultural system (organic vs. conventional) in arable fields. We selected 45 plots with cambisol soil based on a factorial design of owner-operator vs. tenant-operator and organic vs. conventional management. On all tested plots, the crop was wheat in shortly after harvest. We measured total carbon in soil and a set of 8 soil enzymes: acid phosphatase, β-glucosidase, α-glucosidase, cellobiohydrolase, β-xylosidase, chitinase, glucuronidase and arylsulfatase. These enzymes participate in the main geochemical nutrient cycles in soils.Differences in the activity of 4 out of these 8 enzymes and differences in the weighted means of the total enzyme activity show a joint effect and indicated higher biochemical activity of the soil under conventional farming in plots farmed by owners. However, when organic farming was practiced, no obvious differences in enzymatic activity were found between soils farmed by owners or by tenants. The total carbon showed a similar pattern, although not significant. Generally, we conclude that farmer's motivation for making investments in soil health is driven by tenure security, especially in cases where the farm economy depends on profit from crop yields. However, the positive features of tenure security can also be ensured by effective agroecological standards, strict rules, higher levels of subsidies and other incentives that are typically provided for organic farming. We propose that changes in agricultural policies may not only stop land degradation in various parts of the world but also support ecosystem restoration process.