Effect of combined application of organic P and inorganic N fertilizers on post harvest quality of carrot

Abstract

A study was undertaken to assess the effect of combined application of organic-P and inorganic-N fertilizers on post harvest quality of carrot (Daucus carota l.) stored at 1°C and ambient conditions (8.6 -
24.8°C). For the fertilizer treatments, 309 kg orga ha-1 (for P) in combination with each of six rates of urea (0, 68.5, 267.2, 274, 342.5 and 411 kg urea ha-1) was used. Carrot shelf life assessment was carried out in a factorial experiment with pre-harvest fertilizer treatments as one-factor and storage conditions as another factor. Pre-harvest fertilizer and post harvest storage treatments significantly affected the post harvest quality of carrot. The weight loss, contents of ascorbic acid, reducing sugar, total sugar, as well as titrable acidity and percentage marketability of carrot were significantly (p < 0.05) affected by the different pre-harvest combinations of fertilizer treatments both at harvest and during the storage period of 28 days at 1°C and ambient storage conditions. The storage temperature also showed
significant (P < 0.01) influence on the weight loss, ascorbic acid, total soluble solids, total sugar, pH, titratable acidity and percentage marketability of carrots. After 28 days carrots subjected to 1°C storage
had 51.4% less weight loss, 17.1% more ascorbic acid, 15.0% lower total soluble solids, 20.7% more total sugar and 30.1% more marketable compared to carrots stored under ambient conditions. This
indicated that shelf life of carrots stored at 1°C exceeded that of samples stored under ambient conditions. Significant interaction was also observed between pre-harvest fertilizer treatments and
post-harvest storage conditions in most of the quality parameters of carrot. The pre-harvest combined application of orga with urea at 309 kg ha-1 and 274 kg ha-1, respectively, and post harvest storage at
1°C is recommended for better postharvest quality maintenance of carrot.