Fertilizer Absorption Efficiency δ15n -labelled Applied to Maize Crop (Zea Mays) in Central Chile.

Nitrogen stable isotopes (δ15N) help to understand the nitrogen (N) uptake in different crop parts. This study investigates the contribution and distribution of N absorption within the different fractions/organs (leave, stem, root and grain) of the crop plant (Zea mays), and labelled N remaining into the soil (0–50cm). An experiment was carried out in an Inceptisol soil type located at Botalcura (35o 18’ 26” S; 71o 47’ 22’’W), a rural area at Maule region, Central-Chile. Three microplots of (2.5m x 1m) were fertilized with urea (NH4)2SO4 tagged with δ15N (10% excess atom) and three intercalated microplots were located as controls. Treatments were control, 50, 100, 100 and 100 kg N ha−1. Results indicate that on averages the maize store N in the leaves with 333 kg N ha−1 and less of 106 kgNha−1 came preferably from the root. From 350 kg N ha−1 as an applied fertilizer to the studied microplots, 6.3% was recovered from the leaves, 6.8% came from the stem, 7.1% came from the root, and 9% came from grain. However, most of the N store in the organs plant came from the soil reaching 409 kgNha-1 in stems and grains. Therefore, considering the recovery efficiency of N in the plant and soil a total of 95.3%; 100%; 30.3% and 100% were stored for leave, stem, root and grain, respectively. This study demonstrates the recovery efficiency of N from the fertilizer is moderate to low and remained N from the soil widely supplies the demand of the plant.