| Organic farming has become one of the most | | | | properties of soil, and its ecological processes such |
| favoured options for the production of safe, highly | | | | as nutrient cycling, in organic and conventional |
| nutritious food and long-term sustainability. The | | | | farming systems have confirmed the claims of |
| market for the produce from organic farms is | | | | organic farming advocates. |
| growing, especially as consumers have become | | | | Some of the most significant studies involved the |
| more aware of food-safety issues, environmental | | | | organic and conventional farming trials in |
| preservation and wildlife protection. | | | | Switzerland (called DOK trials), which covered a |
| Organic farming is practiced in over 100 countries | | | | 21-year period. One study by Siegrist et al. (1998) |
| worldwide, and, as of 2007, there were over 26 | | | | found that organic plots had significantly greater |
| million hectares managed under organic farming | | | | earthworm biomass, soil aggregate stability, and |
| techniques. Of this total, Australia had the biggest | | | | population diversity than conventional plots. |
| share (43.3%) with its 11.3 million hectares; | | | | Another study by Mäder et al. (2000) showed |
| Argentina was a distant second with 2.8 million | | | | colonization of beneficial fungi was 30-60% higher |
| hectares. | | | | among plants growing in organic farming systems, |
| From its inception, the position of organic farming | | | | which implied that organic systems had a greater |
| has been against large-scale, chemical-farming | | | | capacity to achieve plant-fungi symbiosis. |
| agriculture. The debate between organic farming | | | | Nutrient loss |
| and chemical farming is far from settled. Some of | | | | Many studies have shown that nitrates leach out |
| the points involved are described below. | | | | at slower rates in organic farms than conventional |
| Natural controls of insect pests and diseases | | | | farms. For example, Eltun et al. (1995) found that |
| An organic-farming system does not use | | | | nitrate runoff in conventional cash crop systems |
| synthetic chemicals, including inorganic fertilisers, | | | | in Norway was at least two times higher than in |
| insecticides, fungicides and herbicides. To keep | | | | organic cash crop systems. Among farms |
| pests at acceptable levels, natural pesticides may | | | | producing forage crops, loss of nitrates in organic |
| be used. Chemical-farming advocates say natural | | | | systems was 36% less than that in conventional |
| pesticides are crude and are actually improved | | | | systems. |
| upon by synthetic pesticides, and that the | | | | Soil productivity |
| distinction between the two is arbitrary. | | | | The basic criticism against organic farms is that |
| Organic-farming advocates point out that pest | | | | yields are lower than conventional farms. The |
| control in organic farms is achieved by | | | | Swiss DOK trials found that the organic systems |
| encouraging the presence of predators and | | | | had 20% lower yields than the conventional |
| natural enemies of pests, following crop rotation, | | | | systems, but it was also noted that fertilizer |
| using cover crops, and growing healthier plants; | | | | consumption in organic systems was 50% lower. |
| natural pesticides (such as soybean oil, rotenone | | | | Organic farming advocates point to the economic |
| and pyrethrum) are only used as the last resort. | | | | costs of conventional farming systems such as |
| Research from the early 1990s has shown that | | | | the cost of environmental clean-up and the |
| organic farms have lower populations of insect | | | | depletion of non-renewable energy resources; in |
| pests than conventional farms or that there is | | | | contrast, organic systems avoid these hidden |
| little difference between them. A comprehensive | | | | costs. |
| analysis by Letourneau and Goldstein (2001) who | | | | Another factor that contributes to lower yields in |
| studied organic and conventional tomato farms in | | | | organic farms is the presence of weeds. Several |
| California showed that there was no difference in | | | | researchers have found higher weed densities and |
| the abundance of plant-eating animals (herbivores) | | | | weed biomass in organic farms compared with |
| but the organic farms had higher abundance and a | | | | conventional farms. On the other hand, |
| wider variety of natural enemies to pests that | | | | researchers have also reported the presence of |
| affected the crops, which led to better pest | | | | rare and endangered weed species on mature, |
| control. | | | | decades-old organic farms, which may indicate a |
| Soil ecology | | | | contribution to encouraging plant biodiversity. It |
| Proponents have always asserted that the organic | | | | may not favour short-term economics but it does |
| system maintains high levels of biological activity | | | | support long-term ecological concerns. |
| and fresh organic matter in humus, thus | | | | Keywords: soil ecology, organic farming, |
| promoting soil health. Numerous studies | | | | sustainable farming, conventional farming, soil |
| investigating various aspects of soil ecology, | | | | health, most profitable form of farming. |
| including the physical, chemical and biological | | | | |