Growth analysis and roots morphology of forage legumes submitted to nitrogen fertilization at planting

Abstract

The hypothesis of this work is that nitrogen (N) supply at planting can influence plant growth and root morphology of forage legumes. Two experiments were carried out in a greenhouse at the Instituto de Zootecnia (IZ) in Nova Odessa, SP, Brazil, and evaluated in the first experiment (Experiment 1), in a 3 x 3 factorial scheme, forage legume species Macrotyloma axillare, Neonotonia wightii and Arachis pintoi submitted to zero doses, 40 and 80 kg/ha of N, applied in the planting and the second one (Experiment 2), in a factorial scheme 3 x 3 x 3 considering the same species and doses of nitrogen as the previous experiment and the cutting plants in the vegetative, flowering and reproductive stages. Experiment 1 was conducted in 2015/2016 with legume planting in 37 kg soil/each boxes and cut at the maturation stage of Experiment 2 in 2016/2017 in pots of 5.1 kg of soil/each, both randomized block design experiments with four and three replicates for experiments 1 and 2, respectively. The number and production (DM) of the shoots, the shoot leaf and branches or stolons and of roots were determined in the cuts. Part of the roots will be followed for analysis in the SAFIRA program to determine the total mass, length, area, specific surface, specific length and root mean diameter. For analysis of growth will be considered the relation leaf/branch, specific leaf area, leaf area ratio, leaf mass ratio and shoot/root ratio. In the leaves and branches or stolons samples will be analyzed the nitrogen content and the micronutrients Fe, Mn, Cu, Zn, B and in the soil samples, in the plants tissues will be determined ammoniacal nitrogen (N-NH4 +), nitric (N-NO3-) and micronutrients. (AU)