Organic agriculture seeks to reduce our reliance on non-renewable resources and to affect positively human health. However, its capacity to feed the growing world population is questioned. Scientists Lesur-Dumoulin et al. analysed an extensive dataset of yields from organic vs conventional horticulture and showed that in organic agriculture, yields are on average 10 to 32% lower than in conventional agriculture. Extreme yield reductions (>50%) are very unlikely and there is no evidence that organic agriculture gives more variable yields than conventional one.
Conversion to organic farming is a great challenge in vineyard systems, causing major changes in system structure and management. Agronomists Merot and Wery proposed six complexity indicators to assess modifications to cropping system structure and management during conversion. They demonstrate that conversion to organic viticulture increase the complexity of vineyard structure and management. These indicators can be extended to all agricultural systems to diagnose the impact of organic farming conversion.
The industrialization of agriculture has often led to lower efficiency, pollution and greater dependence on non-renewable energy. Organic agriculture and traditional agriculture are thus potential alternatives. Agronomist Pérez Neira studied the energetic and economic behavior of cacao in traditional, semi-intensive traditional, technified and organic farms in Ecuador. Results show that well-managed organic farms improve energy efficiency by comparison with technified or semi-intensive management strategies, and also improves the economic performance.
Conservation agriculture embraces the three principles of minimal soil disturbance, maximum residue cover and diverse crop rotations. However, organic farmers are reluctant to give up their ploughs due to concerns about weeds, crop disease and nutrient supply. Agronomists Cooper et al. review data from organic experiments and found that yields were not as negatively affected by reduced tillage intensity as expected.
Organic farming aims at reducing the use of mineral fertilisers and pesticides, and producing safe and tasty food. Agronomists Pirdashti et al. explain that growing ducks in rice field has many benefits such as weed control and fertilisation by ducks and high quality rice and duck meat.
Certifying organic crops is not an easy task due to the huge agricultural areas that have to be checked. Agronomists Denis et al. have designed a new, effective method that distinguishes organic and non-organic cotton fields with up to 86% performance in south-western Burkina Faso, West Africa. The method uses remote sensing from space.
Agriculture faces two major issues worldwide, producing safe food without the use of toxic pesticides, and producing more food to meet the projected population increase of 9 billion by 2050. Ecological intensification is a promising solution because ecosystem services such as the use of natural enemies to kill undesired pests is a safe alternative to pesticides. Agonomists Bedoussac et al. reviewed the results of 58 organic farming experiments of cereal-grain legume intercropping in Europe. They found that intercropping gives higher yields, protein and money that sole crops.
Organic farming should provide safe food without using harmful pesticides. As a consequence farmers need alternative techniques to control pests. A survey of 24 organic apple farms in France by agronomists Marliac et al. reveals four control techniques: 1) the ecologically intensive technique that favours natural enemies of pests, 2) the substitution technique using pesticides, 3) the technological technique using for instance exclusion nets, and 4) the integrated techniques using a variety of previous techniques.
Fruit tree orchards should be climate friendly because atmospheric carbon is stored during long periods of time in trees. Orchards also produce woody renewable energy. However orchard soils, which store carbon, are often eroded under the Mediterranean climate. Agronomists Aguilera et al. show that organig farming techniques such as cover cropping and pruning mulching should offset greenhouse gas emissions, thus leading to carbon neutral crop products.
Organic farming recycles local plant residues and compost to fertilize soils, whereas conventional agriculture uses mineral fertilizers that are mined then transported over long-distances. Therefore organic farming should emit less greenhouse gases. However the lower yields of organic farming may compromise the emission balance on a product basis. Agronomists Aguilera et al. observed that emissions from herbaceous crops in Spain were lower under organic farming both on an area basis and on a product basis, with the exception of rice due to higher methane emissions.