Optimum range in potato tubers grown under plastic mulches: II. Micronutrients

For 3 years (1993-1995) Solanum tuberosum L. var. Spunta. was grown under d ifferent polyethylene [PE] sheets: (25 mu-thick, transparent PE, (T-1), 25 mu-thick, white PE, (T-2); 50 mu thick-coextruded black-and-white PE, (T-3) ; 25 mu-thick black PE, (T-4); control (not covered, (T-0). During the 4 mo nths long biological cycle, six tuber samplings were taken to determine B, Cl, Zn, Cu, Fe and Mn concentration. The optimum foliar ranges were determi ned and established for these micronutrients.