Growth, Yield and Microbial Contamination of Lettuce with Organic and Inorganic Fertilizer Treatments under Pipe-borne Water Irrigation Systems in Ghana

 

Tiimub, B. M.1*., Dauda, M. M.2 and Alhassan, M. K

 

Full Length Research Paper I Published December,2016

 

Journal of Physical Science and Environmental Studies Vol. 2 (4), pp. 58-66

ABSTRACT

The effect of organic (T₁- poultry manure at 2kg/m², T₂ - cattle manure at 2kg/m², T₃ - sheep manure at 2kg/m²) and inorganic fertilizer (T_4­ -DI grow green at 0.00024 l/m² and T₅ - NPK (15:15:15) and sulphate of ammonia at 25.2 g/m²) on growth, yield and microbial contamination of lettuce was elucidated in Ghana using Randomized Complete Block Design (RCBD) with three replications. The results showed that application of organic and inorganic fertilizer had not significant effect on plant establishment, number of leaves, plant height, chlorophyll accumulation leaf area, fresh weight and dry matter of the shoots and the roots (P<0.05). Poultry manure recorded the highest mean leaf counts (12.47 and 13.87 in 26 days and 33 days but was overtaken by DI grow green with 28.73 mean leaf counts in 40 days), respectively. The total coliform numbers on lettuce grown with poultry, cattle and sheep manure, D1 Grow Green, NPK/Sulphate of Ammonia and control or zero fertilization were [(7.0 x 10⁵), (9.0 x 10¹⁷), (1.0 x 10¹⁷), (1.0 x 10¹⁸), (1.0 x 10¹⁷) and (2.0 x10¹⁸)], respectively. Feacal coliform numbers in the same sequence treatments were low, [(3.11 x 10⁵), (2.18 x 10⁶), (9.36 x 10⁶), (4.57 x 10⁶), (1.39 x 10⁶) and (7.84 x 10⁶)], respectively. Similarly, Enterococci numbers on lettuce were lower, (6.52 x 10²), (90), (57), (1.03 x10²), (58) and (1.23 10²) in the same treatment order. Salmonella numbers on lettuce were much lower [(1.0 x 10⁴), (2.66 x 10⁴), (1.33 x 10⁴), (4.0 x 10⁴), (3.0 x 10⁴) and (3.33 x 10⁵)] in the order of treatments for the total coliforms. Escherichia coli numbers on lettuce were also lower than the total and faecal coliforms [(3.05 x 10⁶), (2.25 x 10⁵), (1.42 x 10⁶), (2.92 x 10⁵), (3.05 x 10⁴) and (2.91 x 10⁵)] in the same treatment order. Generally, guano yielded the highest bacteria count on the lettuce far exceeding the recommendation of the World Health organization (WHO) and International Commission on Microbial Specifications for Foods (ICMSF) standard of 103. High dependency on the guano to produce lettuce may be a contributing factor to contamination and a health threat to lettuce consumers. Intensification of innovative education on the production, processing and consumption of lettuce in and around the College of Agriculture Campus of the University of Education, Winneba at Asante Mampong is thus, a good food hygiene and safety improvement strategy.

Key words: Organic and inorganic fertilizers, Lettuce, Yield and Microbial contamination.

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