This studies was conducted in the experimental field, Department of Horticulture, College of Agriculture, University of Baghdad, Abu- Ghraib, during at fall and spring seasons 2006-2007 by using Desiree cultivar class (A) in the fall season and class (Eilte) in spring season. The aim of this study was to investigate the effect of sources of organic manure and mulching with black polyethylene sheets on quality characters of potatoes.
Split- plot design were adapted in this experiment the first factor inculded either without black polyethylene sheet (M0) or using it (M1). The second factor was included using of 6 types of organic manure; the first without organic manure (control T0). The second chemical fertilizer (T1), The third sheep manure (T2), The forth local peatmoss (T3), The fifth dry Pow humus (T4) and the sixth liquid Humic acid.
L.S.D were used to compare the means at a 5% level of significances. The results showed that Mulching potato plants with black polyethylene (M1) increased significantly the percentage of dry matter, starch and protien in potato tubers for both seasons and the percentage to reach (14.31, 8.76, 0.94%) respectively for fall season, as compared with the control (M0) to reach (13.85, 8.35, 0.77%). While in spring season the percentage was (16.83, 11.00, 1.22%). Respectively as compared with the control the percentage to reach (15.53, 9.81, 1.01%) respectively. And Mulching with black polyethylene and chemical fertilizer (M1T1) and mulching with black polyethylene with sheep manure (M1T2) significantly increased the dry matter and starch in potato tubers in fall season the percentage in dry matter to reach (15.14 and 14.88%) respectively and the percentag in starch to reach (9.50 and 9.26%) respectively as compared with the control (M0T0) without Mulching and manuring to reach (12.26 and 6.91%) respectively, while in spring season the percentage of dry matter was (17.93 and 17.58%) and for starch was (11.98 and 11.67%) respectively. as compared with the control (M0T0) to reach (13.92 and 8.15 %) resrectively.