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Agronomy, Vol. 11, Pages 228: Effect of Deficit Irrigation and Reduced N Fertilization on Plant Growth, Root Morphology, and Water Use Efficiency of Tomato Grown in Soilless Culture
Agronomy doi: 10.3390/agronomy11020228
Authors: Ikram Ullah Hanping Mao Ghulam Rasool Hongyan Gao Qaiser Javed Abid Sarwar Muhammad Imran Khan
This study was conducted to investigate the effects of various irrigation water (W) and nitrogen (N) levels on growth, root-shoot morphology, yield, and irrigation water use efficiency of greenhouse tomatoes in spring–summer and fall–winter. The experiment consisted of three irrigation water levels (W: 100% of crop evapotranspiration (ETc), 80%, and 60% of full irrigation) and three N application levels (N: 100%, 75%, and 50% of the standard nitrogen concentration in Hoagland’s solution treatments equivalent to 15, 11.25, 7.5 mM). All the growth parameters of tomato significantly decreased (p < 0.05) with the decrease in the amount of irrigation and nitrogen application. Results depicted that a slight decrease in irrigation and an increase in N supply improved average root diameter, total root length, and root surface area, while the interaction was observed non-significant at average diameter of roots. Compared to the control, W80N100 was statistically non-significant in photosynthesis and stomatal conductance. The W80N100 resulted in a yield decrease of 2.90% and 8.75% but increased irrigation water use efficiency (IWUE) by 21.40% and 14.06%. Among interactions, the reduction in a single factor at W80N100 and W100N75 compensated the growth and yield. Hence, W80N100 was found to be optimal regarding yield and IWUE, with 80% of irrigation water and 15 mM of N fertilization for soilless tomato production in greenhouses.