Silicon-rich manure for sustainable rice production

Rice is a plant that needs silicon (Si) as a nutrient to grow well. Silicon is an element of silica (SiO2) found commonly in sand. Rice yields decrease when soils are depleted in available silicon. A possible solution is to add silicon-rich manure to soils. Song et al performed a 10-year field experiment and found that adding silicon-rich manure doubled the amount of available silicon in soils. Using manure brings the additional benefit of recycling organic waste and providing other plant nutrients such as nitrogen and phosphorus

 

Benefits and risks of anaerobic digestate fertilisers

Intensive soil fertilization with mineral fertilizers has led to several issues such as high cost, nitrate pollution, and loss of soil carbon. Fertilization with organic wastes such as anaerobic digestates is an alternative for sustainable agriculture. Conflicting results in the literature have questioned the effectiveness of anaerobic digestates as organic fertilizers. The review by Roger Nkoa demonstrates the fertilizer values of anaerobic digestates. However, anaerobic digestates emit amonia (NH3) and contain copper (Cu), Zinc (Zn) and manganese (Mn) that could pollute the soil and the atmosphere upon repeated soil applications.

 

Cropping and soil bacterial diversity

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.

 

Irrigation increases soil carbon and greenhouse gas N2O emissions

Irrigation controls food production as plant do not grow without water. The article by Trost et al. review the effects of irrigation on soil carbon and greenhouse gas N2O emissions. Findings include that irrigation increases soil carbon up to 500 % in  cultivated deserts and up to 35% in semiarid regions. In humid regions N2O emissions often increase after precipitation or irrigation.

 

Positive effects of sustainable land management

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.

 

 

Genetically modified crops or agriculture biodiversity?

The growing world demand for food is a major challenge for humankind. Increasing food production will be more and more difficult due to fewer arable land, less water availability, pollution, warmer climate, and land competition of food production with biofuel production and cities. As a result there is a strong on-going debate on the best strategy to keep pace with global population growth and increasing food demand. One strategy favors the use of genetically modified crops, while another focuses on agricultural diversity. The review by Jacobsen et al. places genetically modified crops far down the list of potential solutions and recommend funding in other research areas of plant science.

 

 

Unexpected withdrawal from organic farming

Europe envision organic farming as a solution for sustainable agriculture. However the organic farming area has increased only from 1.8% in 1998 to 4.7 % in 2009 in European Union, still far from initial objectives. Worse, recent observations show cases of farmer withdrawal from organic farming. Madelrieux and Alavoine-Mornas studied organic farming withdrawal of 18 former organic farmers. Results show that withdrawal depends on the circumstances causing farmers to leave organic farming and what farmers learned by experience.

 

Ethylene-free biochar for plant nurseries

Greenhouse plant nurseries commonly use vermiculite and peat moss for potting plants, thus threatening natural resources of vermiculite and peat moss. They can be replaced by biochar, which is a cheap product of organic wastes. However fresh biochar emits ethylene, a gas that has adverse effects on plant at high levels because ethylene is a plant hormone. Fulton et al. found a simple solution to get rid of ethylene emission.