Use of a standard TWAIN scanner and software for nodule number determination on different legume species

Biological nitrogen fixation by legume–Rhizobium system is the main natural source of nitrogen in agricultural fields. To measure nodule number, pea (Pisum sativum), bean (Phaseolus vulgaris) and lentil (Lens culinaris) were planted in plastic pouches. These pouches allowed root system observation. For each plant, roots were scanned, nodules hand separated, scanned and hand counted. All scanner methods of counting had correlation coefficients with hand counting above 0.85, and were highly significant.