%A"Calvache, Marcelo [Comision Ecuatoriana de Energia Atomica, Quito (Ecuador)]" %D1991 %I; Comision Ecuatoriana de Energia Atomica, Quito (Ecuador) %2 %J[] %K60 APPLIED LIFE SCIENCES, TREES, ROOT ABSORPTION, EXPERIMENTAL DATA, FERTILIZERS, HUMIDITY, NITROGEN CYCLE, NITROGEN 15, PHOSPHORUS 32, RUBIDIUM 85, SOILS, TRACER TECHNIQUES, 553002, HORTICULTURE %PMedium: X; Size: [12] p. %TRoot activity evaluation in tree crops using isotopic techniques; Evaluacion de la actividad radicular de cultivos arboreos utilizando tecnicas isotopicas %XThis paper discusses the methdology used to evalute root activity of the crops utilizing the technique of soil injection with solutions marked with isotopes. Some of the experimental data obtained with coffee, citrus and oil palm are also presented. Ovel all, these tree crops present a higher root activity in soil layers close to the surface (0-20 cm) and to a distance from the trunk which varies with age, season and variety. The most important conclusions are: 1. The isotope injection technique using {sup 3}2{sup P}, {sup 1}5{sup N}, or {sup 8}5{sup R}b, allow direct and reliable determination of root activity in these tree crops. 2. Root activity of three crops depends on age of the tree, variety, moisture content of the soil and soil type. 3. Soil moisture is the most influencial factor affecting root activity. This is turn depends on the irrigation method employed. 4. From the practical view point, the best distance from the trunk to apply fertilizer in the one wich has highest root activity closest to the soil surface. %0Miscellaneous %NINIS-mf-13449; CONF-9108235-;Other: ON: DE93616335; CNN: Project OIEA ECU-05-012; TRN: EC9200015018906 %1 %CEcuador %Rhttps://doi.org/ Other: ON: DE93616335; CNN: Project OIEA ECU-05-012; TRN: EC9200015018906 INIS %GSpanish