Abstract
A field experiment was conducted during 1998-2002 to evaluate different micro-irrigation systems against basin irrigation in terms of growth, yield, fruit quality, and water use of Nagpur mandarin (Citrus reticulata Blanco) under the sub-humid tropical climate of Central India. Four treatments, viz., 4 L h-1 dripper (pressure compensating, 4 plant-1), microjet 300° (Rayjet, 2 plant-1), microjet 180° (Ejet, 2 plant-1), and basin (ring) irrigation replicated six times were tested in a randomized complete block design in a Vertic Ustochrept. Annual increase in mean canopy volume was observed with different micro-irrigation methods (5.93-9.15 m3) compared to the basin method of irrigation (4.04 m3), despite a comparatively higher quantity of irrigation water being consumed under basin irrigation (51-167 L day-1 plant-1) than micro-irrigation systems (36-131 L day"1 plant"1) during the 8th to 10th year of tree age. Fruit yield with different micro-irrigation systems was significantly (P < 0.05) higher (48.23-58.93 kg tree-1) over basin irrigation (32.30 kg tree-1) with corresponding water use efficiency of 0.194- 0.238 t ha-1 compared to 0.109 t ha-1. Leaf nutrient status was significantly (P < 0.05) higher with microjet 180° (1.77-2.51% N, 0.13-0.16% P, and 1.21-2.38% K) over the basin method of irrigation (1.62-2.16% N, 0.16-0.13% P, and 1.19-2.04% K). Similar differential response on fruit quality parameters was also observed indicating minimum promise of basin irrigation compared to micro-irrigation systems. Of the different micro-irrigation systems, microjet 180° proved to be most efficient.
