Although some chemical herbicides used by farmers in Martinique contaminate rivers, existing agroecological innovation is not always implemented to restore water quality. Scientists Della Rossa et al. show that each supply chain innovates independently of others with little exchange at a territorial scale. This situation adds to herbicide occurrence in watersheds. They believe territorial development should coordinate innovation for a sustainable transition of territories.
Cover crops provide many different ecosystem services, increasing soil carbon storage and mineral nutrient recycling while reducing runoff and water pollution by nitrate. Scientists Meyer et al. recently showed that cover crops also reduce water drainage. Drainage reduction may represent a disservice due to its impact on the groundwater recharge. This is an important issue, particularly in a dry climate with shallow groundwater.
Scientists Allain et al., using a modeling platform, revealed that reducing water use does not necessarily improve downstream river flows nor decrease crop yields. Symmetrically, they showed that a new distribution of reservoirs can highly impact the water consumption and the agricultural economy without changing the water storage capacity. These are new reasons to argue that solving water imbalances is not only a matter of storing versus economizing water!
Plant available water is held in soil pores, which size is affected by soil organic matter content. Organic waste recycling in agriculture can increase soil organic matter contents and improve related soil properties. Agronomists Eden et al. analyzed data from long-term field experiments and found that in almost all cases, plant available water is increased in soils amended with organic wastes.
Domestic wastewaters are used to irrigate soils, thus saving pristine waters. However wastewater contains human enteric viruses that may contaminate the atmosphere after wastewater spraying. Scientists Girardin et al. found that 11-89% of murine mengoviruses applied to the soil were aerosolized during the first half hour. They have developed a model to help policymakers refine standards governing wastewater reuse in irrigation.
Rainfed agriculture refers to farming that relies solely on rainfall for crop growth, versus irrigated agriculture that use extra water. Rainfed agriculture accounts for 60-95% of farmlands in developed countries in Africa, Asia and Latin America. Agronomists Anderson et al. review recent research on rainfed agriculture and suggest that conservation agriculture should improve soil water content and, in turn, crop yields.
Agriculture consumes more than two-thirds of the planet freshwater. As a consequence there are conflicts of freshwater allocation between agriculture and other water users. There is therefore a need for advanced methods to save water in agriculture. Scientists Gan et al. found that regulated deficit irrigation is an alternative method that saves large amounts of water without yield decrease. Moreover, deficit irrigation enhances plant adaptation to drought stress.
In arid regions drought is becoming a serious threat for vineyards and wine production.
The article by Medrano et al. reviews methods to improve water availability in vineyards by modifying pratices and selecting cultivars.
Climate change is decreasing water content in many parts of the world. There is therefore a need to adapt by designed practices that save water and use less water. This can be done for instance by reduced tillage, mulching, selecting drought-tolerant cultivars and synchronizing plant demand with rainfall. Bodner et al. describe the most efficient strategies for better water management under dry climate. They found that selecting plant roots is a promising solution, yet still overlooked.
Relay planting is planting seeds of a new crop among the plants of a mature crop so they will have a head start when the mature crop is done. As a consequence more crops per year can be brought to maturity in the same planting space. In northwestern China maize is planted about 40 days after wheat seeding, and this relay planting is popular for high yields. Yin et al. show that relay planting with reduced tillage and stubble mulching increases water use efficiency up to 46%.