Effect of drip irrigation and plastic mulch on performance of Nagpur mandarin (Citrus reticulata) grown in central India

Abstract

A field experiment was conducted during 2003-06 to assess the response of various drip irrigation regimes, viz 40, 60, 80 and 100% of alternate day cumulative pan evaporation with black polyethylene mulch of 400 gauge thicktness versus basin irrigation method in 1-year-old Nagpur mandarin (Citrus reticullta Blanco) trees budded on Rough lemon (Citrus jambhiri L.) root stock at Nagpur, Maharashtra. All the drip irrigation regimes with plastic mulch produced a significantly (P&lt0.05) higher annual increase in tree growth parameters over basin irrigation method. However, the highest magnitude of growth parameters was recorded in drip irrigation at 60 % of alternate day cumulative pan evaporation with plastic mulch along with 35.7% water saving over basin irrigation method. Leaf water-use efficiency (leaf photosynthesis rate / transpiration rate) under drip irrigation at 60% of alternate day cumulative pan evaporation with plastic mulch was significantly higher both in winter (1.829 µmol CO2/mmol H20) and summer (1.580 µmol CO2/ mmol H2O) compared to leaf water-use efficiency in winter (1.123 µmol C02/mmol H2O) and summer (0.961 mmol C02/mmol H20) with basin-irrigated trees. Analysis of leaf nutrients (N, P, K, Fe, Mu, Cu, and Zn) indicated that the drip irrigation at 60% cumulative day pan evaporation with plastic mulch produced a significantly higher leaf N (2.47%), K (1.99%), and Fe (113.7 ppm) over leaf N (1.34%), K (1.07%), and Fe (98.4 ppm) under basin irrigation, with other nutrients (P, Mn, Cu, and Zn) non-affected.