Estimation of concentration of chlorophyll, N, and biomass using non-destructive measurements in arugula (Eruca sativa)

Abstract

Nitrogen is an essential nutrient for plants and the most required element in leafy vegetables, so it is important to know it s levels in relation to chlorophyll formation and biomass production. The objective of this research was to estimate, using non-destructive portable meters, the concentration of chlorophyll and relate it to the levels of nitrogen and fresh biomass in arugula ( Eruca sativa L.). The research was carried out in a greenhouse where the plants were subjected to different doses of nitrogen fertilization using five N-NO3 treatments (0, 4, 8, 12 and 16 meq·L-1), based on the Steiner nutrient solution. Weekly evaluations were made on the plants up to 42 days after transplant using SPAD, atLEAF and MC-100 meters, together with laboratory determinations of the levels of chlorophyll, nitrogen and fresh biomass per plant. The results showed that the relationship between SPAD readings, nitrogen, chlorophyll and fresh matter was positive and significant, with R2 coefficients of 0.93-0.97; for atLEAF readings similar relationships were observed, with coefficients of 0.96-0.99. The relationships between SPAD, atLEAF and MC-100 readings were positive and significant, with coefficients of 0.97-0.98. This indicates that these meters are valid instruments to estimate in-situ the status of chlorophyll and nitrogen in the arugula crop in a non-destructive, fast and precise way.