Assessment of Carrots Leaf N Percent By Processing a Hand Held Color Camera Photography.

Techniques to measure the nitrogen status of plants can assist in fertilization management.

This study was conducted to identify and quantify nitrogen contents in carrot leaves. Carrot (Daucus carota) was grown on loess soil at five nitrogen (N) application rates to establish total yield, total %N and canopy N weight per hectare.

Results show a perfect correlation between leaves N weight obtained by standard laboratory analysis (N_lab) versus N weight determined by image processing (N_photo). This correlation enabled us to determine a continuous logistic decay curve: Nc=a/[1+(W/W₀)^b] where a and b are the correlation coefficients and W is the dry matter weight of leaves. This  provides a critical N (Nc) at each W.  Notice that the correlation equation between %N_lab and %N_photo had a unit slope but a regression coefficient of 0.36.  It was concluded that N weight (= dry leaves weight * N fraction) is suitable for the determination of nitrogen status in carrot and the availability of  N_photo data is faster, timely and less expensive than that of N_lab.