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Agroecological alternatives to fight against dry and salt stress in agriculture: association between quinoa and other plants in arid conditions of Chile

Galleguillos M., Gaete C., Zúñiga G., Martinez E.A., Bazile D.. 2013. In : Proceedings of SWUP-MED Project Final Conference "Sustainable water use for securing food production in the mediterranean region under changing climate", 10-15 march, 2013, Agadir, Morocco. s.l. : s.n., p. 386-408. Conference "Sustainable water use for securing food production in the mediterranean region under changing climate", 2013-03-10/2013-03-15, Agadir (Maroc).

Quinoa (Chenopodium quinoa Wild.) is an ancestral and highly nutritional crop that provides a global foresight although yet underutilized crop in Chilean agriculture. Its broad geographic extension in Chile (17°S-47°S) implies high genetic diversity and adaptation to extreme environmental conditions. Also specific agroecological regions generated high variability under specific agricultural practices. These adaptations offer a great potential to valorize underutilized areas as dry and salty fields. In central arid Chile, agricultural soils and natural ecosystems have been colonized by the invasive species Mesembryanthemum crystallinum L. Recent efforts to recover quinoa crop cultivation in this arid zone (70 mm of annual rainfall) face the invasion of Convolvulus arvensis L. for which there are no specific herbicides that might leave quinoa alive. In laboratory and field essays quinoa was grown with and without these two invasive species in common garden experiments. Results showed that under the arid conditions tested quinoa yields improved by 42% when cultivated with M crystallinum than when grown without this invasive plant. Besides, C. arvensis was inhibited by M crystallinum thus helping quinoa growth. Also, salinity in soils with M crystallinum was reduced by 58%, as measured by electric conductivity, due to the good salt extraction capacity of this succulent species. Some allelopathic effect of M crystallinum might be responsible of the inhibition effects on the seeds as revealed by laboratory experiments showing 50% reduction of germination. From an agroecological perspective these results show that associative cultivation might be a good alternative for crops like quinoa whose dry panicles could be harvested without physical competition by M. crystallinum, a species with a creeping growth habit. In addiction soil quality might improve and M crystallinum is edible and also it has attractive flowers for bees and a potential use in cosmetics and medicine.

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