Application of the TeaComposition initiative in an agricultural environment
Abstract
The long-term TeaComposition initiative is a worldwide project organized under the umbrella of ILTER to study the decomposition of specific litters (green and red teas) in a large number of sites. The project has raised the interest of the agricultural sector with several questions such as what is the effect of farming practices (tillage, use of natural or chemical fertilizers, etc.) or of the type of crops on litter decomposition. However, for a number of crops (such as cereals, oilseeds, sugar beets), harvesting is done every year and it is not possible to leave the teabags for several years in the soil. The TeaComposition protocole should therefore be adapted for this type of sites. Since 2017, a large-scale experiment has been set up in the Northeast of France. Some 450 (in 2017) to 650 (in 2018) teabags of each type have been buried in different types of soil used for different crops in about 160 parcels. The incubation duration has been limited to three months, in most cases with an implementation between March and May, depending upon the crops. Practical questions such as how to bury efficiently the teabags (i.e. to insure the best contact between teabags and soil), how to weigh them simply in absence of high-precision weighing scale, how to retrieve them easily in the parcel or how to protect them from predators, had to be answered. As litter decomposition is function of soil temperature and humidity, indices has to be defined based on easily obtainable weather data (air temperature, rainfall) at the closest possible weather stations. Finally the change in the nature of the bags (PET instead of nylon) and the possible dependence of the litter decomposition upon the tea harvest year have encourage the accompanying researchers to run specific tests in lab-scale mesocosms and in the field. The presentation will discuss the results obtained with the adapted protocole by the farmers and agricultural institutions and discuss further its advantages and disadvantages.