Growth and absorption of nutrients by onion cultivar Bola Precoce

ABSTRACT:

In Southeit was rn Brazil, the Country main onion-producing region, research is not available on the dynamics of nutrient absorption, nutritional requirement and exportation of nutrients for the seedling transplanting system, which covers over 70% of the cultivated area with this vegetable crop. The objective was to determine growth, accumulation, partitioning and nutrient absorption rates of onion cultivar Bola Precoce in the transplanting system in the Southern Brazil. This study was carried out under field conditions at the Experimental Station of Epagri, municipality of Ituporanga, Santa Catarina State, Brazil. The experimental design was randomized blocks with 18 treatments and five replications. Each treatment corresponded to a time of assessment/collect held at intervals of seven days. Each plot consisted of 27 plants and for each evaluation we collected the five central plants in each plot. It was evaluated the dry matter accumulation, absolute growth rate, content of nutrients N, P, K, Ca, Mg, Zn, Fe, Cu, B and Mn in the leaves and bulbs and determined absorption rates. Growth was slow and demand for nutrients low in the first half of the cycle up to 60 days after transplanting (DAT). During bulbification (61-119 DAT), growth and nutrient absorption were enhanced and plants accumulated 84% of the total dry matter and from 73 to 89% of the nutrients. At the end of the cycle, for an average yield of 37.34 t/ha, nutrient accumulation in descending order was N> K>Ca>P>Mg>Fe>B>Mn>Zn>Cu, with 101.4; 86.5; 46.6; 34.5; 12.1 kg/ha and 761; 221; 150; 84 and 34 g/ha, respectively. From that amount, 57.5; 52.8; 42.3; 68.5; 57.3; 37.6; 70.7; 41.9; 73.6 and 71.6%, respectively, were deposited in the bulb.

Keywords:
Allium cepa; nutrition of plant; macronutrients; micronutrients.