Core Ideas Erosion is decreasing the potential for food security in the Andean region. Zero tillage would be a viable and economical practice for this region. Adding N fertilizer increased the net economic returns by 22%. These practices could potentially increase the income of 200,000 farmers. The Andean region of Ecuador is critical for the country's food security; however, cultivation of high‐slope mountainous agricultural systems that experience significant precipitation is accelerating erosion of the soils and reducing the productivity and sustainability of these systems. For 5 yr we monitored tillage and crop residue management practices using a 2 × 2 factorial randomized block (Phase 1) and a 2 × 2 factorial randomized block with split plot (Phase 2) to assess the effects of tillage, crop residue management, and N fertilization on yields and economic returns. Our study found in the initial phase that for three out of the four crops zero tillage (ZT) had higher average yields than minimum tillage, and for one of these three crops, the increase was significant. Our study found in Phase 2 that when N fertilizer was added as a treatment, compared with crops that were not fertilized, yields were significantly higher in four out of five crops. Leaving the crop residue at the surface was a practice that increased the yields of one of the five crops. The higher net economic returns for Phase 1 were with ZT and with harvesting crop residue. When N was added as a treatment in Phase 2, higher net economic returns were found with ZT and residue removed and with N fertilization. Nitrogen fertilizer, crop residue removal, and zero tillage increased net economic returns by 22, 45.1, and 31.8%, respectively. There is potential to use ZT in this region of South America.

Physical and environmental vulnerability analysis conducted for the Illangama watershed located in Ecuador's Andean highlands, shows deteriorated soil quality and declining crop productivity. These problems are caused by soil erosion in steep slopes and inappropriate soil management practices. Research projects conducted from 2011 to 2014 adopted and examined the feasibility of conservation agriculture practices for potato (Solanum tuberosum L.), oat (Avena sativa L.) and vetch (Vicia sativa L.), barley (Hordeum vulgare L.), bean (Vicia faba L.), and a mixture of pastures (annual ryegrass [Lolium multiflorum Lam.], perennial ryegrass [L. perenne L.], orchardgrass [Dactylis glomerata L.], white clover[Trifolium repens L.], and red clover [T. pratense L.]). The practices included surface water deviation ditches, reduced tillage, residue retention, and application of N, all within an improved rotation. The study examined crop yields and economic returns in an effort to identify the best practices. Results indicate that crop productivity and net (of cost of production) benefits of the system were increased as much as 25 and 24%, respectively, using a feasible conservation agriculture system compared to conventional practices. This study shows that conservation agriculture increases yields and saves on production costs due to less tillage. We also found that N fertilization with these conservation agriculture practices increases yields and net returns. This study concludes that conservation agriculture practices are good alternatives for these high‐altitude Andean soils. The practices should be promoted among Andean producers to increase the productivity and sustainability of their potato–grain–pasture systems. Core Ideas The Andean region of Ecuador is critical for the country's food security. Cultivation of high‐slope mountainous agriculture is accelerating erosion. Conservation agriculture is an attractive management alternative. Implementation of reduced tillage could contribute to higher net income for farmers. These practices could benefit nearly 200,000 Ecuadorean farms.

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Core Ideas Conservation agriculture practices evaluated in this study were agronomically effective, but expensive. Reduced tillage resulted in similar yields in all crops of the potato–oat/vetch–barley–faba rotation to conventional tillage. Retaining crop and cover crops residues in the field rather than for animal fodder will make the greatest contribution to soil nutrient cycling, but likely to be the least accepted conservation agriculture practice evaluated in this study by regional farmers. The Illangama region of Ecuador's highlands is typical of much of the Andean region throughout South and Central America. Steep slopes, frequent soil disturbance and the short fallow periods threaten the sustainability of soil quality and crop production in this region. We evaluated several conservation agricultural practices, including deviation ditches, crop residue retention, and reduced tillage in the context of a potato (Solanum tuberosum L.)–oat/vetch (Avena sativa L./Vicia sativa L.)–barley (Hordeum vulgare L.)–faba bean (Vicia faba L.) rotation from 2011 to 2014 on crop productivity, crop and soil nutrient concentration, and nutrient removal from the system. Crop productivity tended to be higher in plots that had deviation ditches, and where crop and cover residues were retained in the field. Reduced tillage systems had yields similar to conventional tillage systems in all crops. Retaining crop and cover crop residues in the field had the greatest impact on recycling nutrients back to the soil, but was also the most costly conservation practice that we evaluated. Overall, conservation agricultural practices showed considerable agronomic promise for cropping systems in the Illangama region of Ecuador, but will require a longer evaluation period and a comprehensive outreach plan to help gain acceptance with regional farmers. Retaining crop and cover crops residues in the field rather than for animal fodder will make the greatest contribution to soil nutrient cycling, but likely to be the least accepted conservation agriculture (CA) practice evaluated in this study.

ResumenEn las etapas iníciales del proceso de selección clonal en caña de azúcar (Saccharum spp.) se realiza la selección indirecta para las variables toneladas de caña por hectárea (TCH) y porcentaje de sacarosa. Esta selección indirecta puede aumentar su eficiencia en la medida que se precise mejor el conocimiento acerca de la naturaleza y la magnitud de las asociaciones existentes entre las caracterís-ticas de interés y entre éstas y los indicadores de productividad. El objetivo del presente trabajo fue estimar las correlaciones genéticas entre las variables de tipo agronómico (factores causales) y las de rendimiento (variables de respuesta), además descomponer su magnitud mediante análisis de sendero. Se evaluaron cinco caracteres de interés en caña de azúcar (altura, diámetro de tallos, población de tallos por metro, TCH y sacarosa (%caña)) en cinco localidades de la zona semiseca del valle del río Cauca para 17 variedades y dos testigos (CC 85-92 y MZC 74-275) en plantilla utilizando un diseño experimental Latice. Para estimar los coeficientes de correlación genética y de sendero ('path coefficient') se utilizó el software GENES. El análisis mostró que para obtener variedades con alto TCH y alta sacarosa (%caña), primero se deben seleccionar clones con altura superior que la variedad testigo CC 85-92 (334 cm) para asegurar un contenido alto de sacarosa y posteriormente hacer un segundo tamizado por tallos gruesos de diámetro mayor que el testigo (32 mm) y alta población de tallos igual o superiores que el testigo (14 tallos/m).Palabras clave: Análisis de sendero, fitomejoramiento, Saccharum spp. AbstractIn the initial stages of clonal selection, indirect selection for variables tons of sugar cane per hectare (TCH) and sucrose (%cane) is used, based on some agronomic traits associated with TCH and sucrose (%cane). This indirect selection can increase efficiency to the extent that better knowledge about the nature and magnitude of the associations among the characteristics of interest required and, between the latter and productivity indicators. The aim was to estimate genetic correlations between agronomic traits (causal factors) and performance variables (response variables), also decompose its magnitude by path analysis. Five characters of interest, cane length, diameter, stalk population per meter, TCH and sucrose (%cane) were evaluated in five locations in the geographic area of the semi-dry valley of the Cauca River to 17 varieties and two witnesses on plant-cane using Latice experimental design. To estimate the genetic correlation coefficients and path coefficients (path coefficient) the GENES software was used. The analysis showed that for high TCH varieties and sucrose (%cane) must first be selected clones carried high above the control range 85-92 CC (334 cm) to ensure a high sucrose content, and then you can make a second screening by thick stems of larger diameter than the control (32 mm) and high stalk population equal to or higher than the control (14 stems/m).