Global warming is partly due to intensive monoculture farming that burns soil carbon into carbon dioxide (CO2), a greenhouse gas, which is then transferred to the atmosphere. Alternative agriculture pratices are therefore needed to preserve soil carbon. Agronomists Hu et al. found that wheat-maize intercropping with reduced tillage and stubble mulching decreased carbon emission by 10% and increased yield by 11% compared to conventional tillage.
Soils contain huge amounts of various living organisms such as worms, fungi and microbes. Those life forms play essential ecosystem services such as filtering water, removing pollutants and providing plant nutrients. However, the effect of soil biodiversity on ecosystem services is still poorly known. Lemanceau et al. show that preservation and valorization of soil biodiversity is a major challenge for agroecology. Their review highlights recent advances in the assessment of soil biological quality. Further research is needed to design decision tools that can be used by farmers to better manage soil biodiversity.
Industrial agriculture has strongly altered soil life, and, in turn, decreased fertility. Alternative practices such as conservation agriculture and organic farming could restore better conditions for soil organisms. Henneron et al compared the effect of 14 years of conservation agriculture, organic farming and conventional agriculture on soil organisms such microbes and worms. They found that conservation agriculture and, to a lesser extent, organic farming improved all soil organisms.
Soil living organisms are essential for food production by recycling organic matter and providing sustainable plant nutrients. Agricultural practices may degrade soil life, by actually precise knowledge on the impact of cropping is poorly known at the microscale, in micro- and macro-aggregates. The article by Constancias et al. reveals that cropping highly reduced bacterial density and diversity at the microscale, compared to bulk soils. The findings show that cropping practices that preserve aggregate stability should be favoured to preserve soil microbial diversity, and in turn fertility and food production.
Agriculture production in developing countries must be increased to meet food demand for a growing population. This issue may be solved by sustainable land management such as organic fertilization, lower soil disturbance, incorporation of residues, terracing, water conservation and agroforestry. From the review of 160 studies Branca et al. deduce positive effects of sustainable management, such as higher crop yield and soil carbon sequestration.
Soil compaction is a major problem for farmers and soil scientists. Indeed soil compaction decreases the yield of most agronomic crops worldwide. The alteration of soil structure by compaction limits water filtration and air access, reduces root penetration and inhibits soil living organisms. Nawaz et al. review advances in understanding, quantification and prediction of the effects of soil compaction. Sustainable remedies are also given.
Climate change and pollution are increasing drought, salinity and heavy metal contamination in food crops, and, in turn, decrease yield and threaten food safety. Salinity is caused by an excess of NaCl in soils. Salinity is a major abiotic stress for plants over 800 million hectares of land worldwide. Lokhande et al. show that shoreline purslane (Sesuvium portulacastrum) can be used for sand-dune fixation, desalination and phytoremediation in coastal regions.