This study in Ecological Economics looked at the effects of organic vs. conventional farming and owner vs. tenant farmers on soil biochemical activity. To paraphrase and oversimplify, what they found is that owners take better care of the soil than tenants, but organic farming methods can offset this effect so that the soil remains active under either type of farmer. I also found it interesting to hear how scientists use enzymes to measure the health of soil, which is a living system after all.
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.
I think research on organic farming is crucial. (And no, “organic” is not the perfect word to describe it, but everybody knows what it means so it works.) If we are going to feed 10 billion or more people, we have to get more food from the same land because there is not going to be a whole lot more farm land opening up on this planet. In the past, we have done exactly this by dumping fossil fertilizer and irrigation water on our crops. This may continue to work for awhile, but it doesn’t seem sustainable for a number of reasons, ranging from overpumping of groundwater to loss of glaciers and snowpack we have relied on to nutrient pollution of our coastal waters to desertification to collapse of fisheries, all at the same time the population is not only growing but each individual’s impact is growing. If we can find ways to actually improve the land and soil over time, without causing pollution downstream, and without losing yield, that would be ideal.