Canadian Forest Service Publications
Quinoa biomass production capacity and soil nutrient deficiencies in pastures, tree plantations and native forests in the Andean Highlands of Southern Ecuador. 2016. Chacón, G.; Gagnon, D.; Paré, D. Rev. Cienc. Vida 24: 16-28.
Available from: Laurentian Forestry Centre
Catalog ID: 37390
CFS Availability: PDF (request by e-mail)
In the high Andes of Ecuador, although expanding agricultural practices and overgrazing have had negative impacts on soil fertility, few investigations have been conducted to identify which practices are most likely to reduce fertility. Quinoa (Chenopodium quinoa Willd.) was grown in soils from native forests, Nf; pastures, Pa; Eucalyptus globulus Labill. plantations, Eg; and Pinus patula Schlecht. plantations, Pp. A bioassay study was conducted using a randomized block design with control (C), ammonium nitrate (N), triple superphosphate (P), and combined N and P (N+P) fertilizer treatments. On soils from Pp, quinoa mortality was 100% in N, 88% in C, 63% in N+P and 0% in P; P enhanced growth the most; quinoa biomass attained only 0.1 g/pot and had a P content of 0.7mg/pot. N+P enhanced quinoa growth the most on soils from Nf, Pa and Eg. Here, quinoa biomass (g/pot) averaged 0.1 in C, 0.4 in N, 1.6 in P and 7.2 in N+P; P content (mg/pot) averaged 0.9 in C, 0.6 in N, 12 in P and 38 in N+P. In all soils, PO-4 was the principal limiting factor. K deficiencies and Al toxicity probably occurred only in Pp soils. This study suggests that the studied soils cannot support production of quinoa crops without additions of combined fertilizers containing P and K as the principal elements. Pp have the least fertile soils, presumably resulting from a longer history of use after pasturing in addition to the pine effect itself.
Plain Language Summary
This study aimed to use quinoa to gain a better understanding of soil fertility in Ecuador. The soils studied were destined to various land uses. The results of the study suggest that the different soils analyzed would not be able to support quinoa cultivation without the addition of different combinations of fertilizer mainly composed of phosphorus and potassium. Study sites included natural forests, pastures, as well as eucalyptus and pine plantations, which are generally established on degraded pastures. Pine plantation soils were found to be the least fertile due to previous intensive use (deforestation, pasture, plantation) and the direct effect of pines. In addition to having low phosphorous and potassium contents, these soils may present toxic concentrations of aluminum.
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