Effect of blending fresh-saline water and discharge rate of drip on plant yield, water use efficiency (WUE) and quality of tomato in semi arid environment

Abstract

The use of alkali ground water constitutes a major threat to irrigated agriculture in semiarid parts of India. The entire arid and semiarid region in India is characterized by low rainfall and has the problems either of water scarcity or poor quality ground water and it can be better utilized for irrigation through drip irrigation system. An experiment was conducted on tomato crop at Central Institute of Post Harvest Engineering and Technology (CIPHET) Abohar, Punjab to study the effect of blending fresh and saline irrigation water on yield and quality. The good quality canal water (EC of 0.38 dS/m) and ground water (EC 19.5 dS/m) were mixed in ratio of 100% Fresh (F), 75:25 (Fresh: saline; F:S) and 50:50 (F:S). The irrigation was done through drip system with three discharge rates (1.2, 2.4 and 4.2 lph) at three irrigation levels of 0.6, 0.8 and 1.0. The plant yield decreased significantly with increase in salinity levels of irrigation water (that is, increase in proportion of saline water). The maximum plant yield (3.55 kg/plant) was recorded with fresh water irrigation while 50% saline water blending in irrigation produced the lowest yield (2.64 kg/plant). The average yield decreased significantly when the discharge rate of emitters increased from 1.2 to 2.4 lph. The quality of tomato is observed inferior in saline water treatment compared to fresh water treatment. The TSS and acidity of tomato fruits increased with increase in the saline water ratios of irrigation water. As compared to 100% fresh water treatment, the mixing of 75% fresh and 25% saline water reduced tomato yield by 11% and gave a better quality tomato fruits at the discharge rate 2.4 lph and irrigation level 0.8. Hence, saline water can be utilized through drip system for sustainable yield and quality tomato production in water scarce area having poor quality ground water.