Cashew farmers need help

Cashew is a South American tropical tree native that has been introduced in Asia and Africa by European explorers during the 16th century. Now cashew grows worldwide, particularly in emerging countries. Cashew production a major resource for smallholder farmers. However cashew farmers face several issues such as lack of agricultural education and access to cultivation hardware, and few investment in cashew production. Those issues are particularly impacting women. Agronomists Dendena and Corsi review the cashew production chain including management practices, processing methods and uses of products and by-products. They found a lack of integrated and systematic research on cashew production and on potential solution to help smallholder farmers.

 

Rice cultivation with less water

Rice is traditionally cultivated by transplantation by farmers in water. However there is an increasing scarcity of water in a time of climate change. Moreover, transplanting in water is costly because many workers are needed. Therefore dry direct-seeded rice cultivation appears as a promising alternative. Liu et al. have compared dry direct-seeded rice and transplanted-flooded rice. They propose that dry direct-seeded rice should successfully replace transplanted rice in Central China due to less water requirement, identical grain yield and higher resource use efficiency.

 

Insects for food, fertilisers and waste management

Agriculture is actually facing three major issues. The first issue is to produce enough food for the ever growing world population. The second issue is the increasing cost and use of mineral fertilisers. The third issue is the huge amounts of organic waste produced by human activities. Insects could solve those issues. Indeed insects can be used as food and feed. Also insect larvae often feed on decaying organic matter in nature. A such process can thus be used to transform organic waste, such as compost, into food and feed. Moreover, the compost residue can be used as plant fertiliser. Lalander et al. used black soldier fly to transform compost into biomass. They observed a high waste conversion and a reduction of microbial diseases.

 

Microbes help plants to grow in saline soils

Plant growth is decreased by the presence of salt in soils. In the world 20% of agricultural land and 50% of cropland is stressed by salt. This issue will increase with global warming and soil salinization is decreasing cropping land by 1–2% yearly. A potential solution is to favour  the development of some rhizobacteria, that are bacteria living in the root zone, named the rhizosphere. Paul and Lade review the beneficial effects of plant growth-promoting rhizobacteria for plants growing in saline soils. The photo clearly shows the poor growth of wheat in the saline zone at the bottom. Salt causes yellowing and death of wheat leaves.

 

Wild coffee plants favour soil fungi that help cultivated coffee plants

Industrial agriculture has decreased the amount and diversity of soil life. However, soil life is essential for food production because some soil organisms help plants to grow by providing plant nutrients. For instance mycorrhizae are beneficial fungi that live in association with plant roots. De Beenhouwer et al. compared the diversity of mycorrhizae in wild and cultivated coffee plants. They observed that wild coffee plants had a much higher mycorrhizal diversity. Their findings reveal the conservation value of wild coffee and the possible application of mycorrhizae inoculation for producing coffee with few or without external fertilisers.

 

Nitrate leaching and slurry application in dairy grasslands

Broadcast application of cattle slurry to grassland soils is a natural means of fertilisation. However this practice is actually not optimised and leads to nitrogen loss to the atmosphere and groundwater. Novel application techniques such as injection into the soil are therefore tested. Kayser et al. found that the type of application technique has no effect on nitrate leaching. Whereas the amount of applied slurry has an effect on nitrate leaching.

 

Maize will not suffer from climate change if well watered

Global warming is partly due to increasing atmospheric CO2 concentrations. Global warming will probably increase drought periods.  Plants assimilate CO2 by photosynthesis to build plant roots, leaves and shoots. There is actually little knowledge on how plants will respond to increasing CO2  and drought stress. Erbs et al grew maize under ambient CO2 concentration, of 380 ppm, and elevated  CO2 concentration, of 550 ppm. Some maize plants were grown well-watered, others were under drought stress. Results show that maize is not altered under elevated  CO2 if maize is well-watered, contrary to some other plant species. Maize is thus a promising crop for future climate, provided that maize is well watered.

 

Earthworms like organic farming

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.