Every year, when the rice harvest ends, the controversy over the management of their waste returns. In spite of the idyllic marshes and the rice fields of Albufera, they are also controversial: despite the ecological and landscape value of the Natural Park, the residues that derive from these crops pose a serious environmental problem.
Currently two methods are applied to get rid of the straw of some 14,000 hectares of rice fields, about 100,000 tons of waste: burn them or the puddling. You can also leave the straw dry, and that is decomposing at the same time that water begins to enter the fields. But none of the options is free of prejudice.
The decomposition of the straw, with the corresponding emission of methane – one of the greenhouse gases (GHG) – causes the death of thousands of fish and a smell of putrefaction that spreads through the rice fields and attracts mosquitoes. In addition, all this is accentuated when the fields begin to flood, and the water acquires black color. We must add, also, the proliferation of diseases and pests that spread through water, with consequent damage to the future crop.
As far as puddling is concerned, it is a matter of crushing the plant remains and mixing them with the soil of the wet field. But an investigation published last year in the LIFE EBRO-ADMICLIM project showed that from October to December, the time in which mudding takes place, 70% of the total methane derived from rice cultivation is emitted. The work of this group also warned that rice grown under flood conditions is considered a major source of greenhouse gas emissions, especially methane and nitrous oxide.
In the past, in 2011, a study led by the researcher Antonio Torres, from the Institute of Animal Science and Technology – Universitat Politècnica de València (ICTA-UPV), showed that puddling was more polluting than burning. Specifically 18%, taking into account the emissions of greenhouse gases.
Stubble and agricultural residues have always burned. What happens is that before everything was not burned, but only what was left over after being assigned to livestock, adobo, fuel or even papermaking. But since the crops were massive, in October l’Horta de València was filled with flames and smoke.
It was time to burn rice straw, a technique that, in addition to eliminating waste, also helps to eliminate the seeds of weeds such as Leersia oryzoides and fungal spores. It is the simplest and cheapest alternative, but neither is it free of contaminants and substances that can have a toxic or carcinogenic effect.
In 2014 another study developed by ICTA-UPV, in collaboration with FISABIO-Salut Pública, concluded that the least harmful way to burn straw was when it was as dry as possible. That is, the more humid it is, the more it contaminates its combustion.
In addition, te study points out that it is necessary to avoid the weather conditions that direct the smoke towards the population. However, the authors insist on the need to find alternatives to this burning, giving another use to straw, less polluting and expensive for farmers, that does not cause respiratory incidences in the nearest neighborhood.
Despite being a cyclical issue that returns every autumn, the controversy over waste management was magnified last year to stem from the decision of the Ministeri d’Agricultura, Medi Ambient, Canvi Climàtic i Desenvolupament Rural (Ministery of Agriculture, Environment, Climate Change and Rural Development). Although the burning of rice straw in the vicinity of the Albufera Natural Park had previously been prohibited, the Government authorized it, exceptionally, citing phytosanitary reasons and in the absence of other viable alternatives.
The burning, however, had to be controlled. For example, between one and six in the afternoon – when the straw is drier, to avoid smoke – and only when there is not a high rate of fire hazard. The authorization was well received by the rice farmers, but not by the environmental groups, who continue to ask for less polluting alternatives.
In the search for the perfect alternative
Aware of the situation, both the City Council of Valencia and the Generalitat Valenciana have stept it out to find viable alternatives that respect the environment. As a result of the commitment acquired with the sector and with the municipalities surrounding the Albufera, in January the Ministry of Agriculture, Environment, Climate Change and Rural Development set up the Technical Commission for the Study of Alternatives to the Burning of Rice Straw. Its biggest challenge is to reduce the burning of this waste in the following campaigns until it is totally dispensable. Some of the alternatives that were cited in that first meeting were the use in composting processes of urban waste or in the production of biodegradable containers.
Another option is to transform the rice straw of La Albufera into a source of energy capable of generating heat or electricity, and also, bioproducts. This is the proposal of Rice2Rice, a project led by the Technological Institute of Enregía, with the support of the Ministry of Agriculture, Medi Ambient, Canvi Climàtic i Desenvolupament Rural, and the Conselleria d’Economia Sostenible, Sectors Productius, Comerç i Treball. L’IVACE and the ERDF were in charge of co-financing it.
On the other hand, l’Ajuntament de València contributes to the LIFE project “Climate Change mitigation through an innovative goat feed based on agricultural waste recycling”. It is an initiative of mixed public-private nature, which has a budget of 1,174,439 euros financed by 60% by the European Union. The project is coordinated by La Unió de Llauradors i Ramaders and also involve the Ajuntament de la Vall d’Uixó, the UPV, Airatec SL, La Unión de Productores de Caprino, the Low Carbon Economy Foundation and the Italian consultancy Area Europa.
According to information provided by José Castro León, project director of La Unió, some of the general objectives are the application of new practices of low emissions in agriculture and livestock with a transformational impact; the reduction of greenhouse gas emissions in citrus and rice crops by valorisation and not burning the waste generated; the reduction of greenhouse gas emissions in the enteric fermentation of dairy goat livestock (ie those that produce by digestion), through the use of new foods low in carbon; or the contribution to the implementation and development of new legislation in the mitigation of climate change in accordance with the policies of the European Union.
The other burning
L’Ajuntament de València collaborates with a project of the UPV that tries to get new materials, more sustainable and less polluting, for the construction of monumentos falleros. In fact, this year, the municipal fault has already had ninots made with rice straw as an alternative to white cork. Pere Fuset, counselor of Cultura estiva, explains to the newspaper La Veu that “this line of research is a priority to move towards cleaner and sustainable faults in the future”. In this way, emissions from the burning of straw in the rice fields and the Cremà de las Fallas would not occur, but would be unified into one.
Mercavalència, through the new agro-alimentary incubator Agro-Lab, also has in its hands find alternatives to the management of rice straw. Agro-Lab was born with the mission of contributing to the creation of a local and sustainable food system in Valencia based on the production of proximity, respect for the environment, health and consumers, and the principles of solidarity economy . With this purpose, Mercavalència, in collaboration with the Càtedra Terra Ciutadana of the UPV, Las Naves and the Regidoría d’Agricultura de València, opened a call for sustainable projects in June. One of the two award-winning initiatives seeks to give the straw another use; concretely, taking advantage of it for the production of substrates of cultures for edible and medicinal mushrooms.