1. Results and Discussions
CLAY POT IRRIGATION AND PLANTING DENSITY EFFECT ON LETTUCE YIELD Abubakari A-H., Nyarko G. and Maalinyuur Sheila Department of Horticulture, Faculty of Agriculture. University for Development Studies, Tamale, Ghana
Introduction
Results and Discussions
Climate change and urbanisation are the most important drivers of changing quantity and quality of irrigation water
Increased domestic and industrial uses of water is already generating huge quantities of wastewater
52 % of farmers in Tamale, Ghana, depend on either wastewater or grey water for all year round vegetable production
Feacal coliform (FC) and Total coliform (TC) in Vegetables irrigated with wastewater in Tamale was found to exceed the International Commission for Microbiological Specification for Food (103 faecal coliform g-1)
Wastewater irrigation especially with watering can exposes vegetables to FC and heavy metals
WHO recommends treated wastewater for irrigation, centralised treatment and other conventional treatment methods are expensive
Low cost treatment include:
Clay pot sub-surface irrigation (CPSI)
Bucket kit irrigation
Good wastewater irrigation practices
CPSI resulted in significantly higher plant height than the watering can irrigation (Figure 1)
CPSI also resulted in higher fresh and dry weight of leaves and roots than the watering can irrigation (Figure 2 & 3, Table 1 and 2)
The 15 cm x 15 cm spacing was comparable with the 20 cm x 20 cm and the 30 cm x 30 cm in all parameters studied under CPSI
The 15 cm x 15 cm spacing was superior to 20 cm x 20 cm and 30 cm x 30 cm in all parameters measured under watering can irrigation
The superior performance of CPSI over watering can irrigation may be due to the fact that CPSI release the water gradually allowing a more stable soil moisture regime than the watering can irrigation
The poor performance of the 20 cm x 20 cm and 30 cm x 30 cm under the watering can irrigation may attributed to their inability to effectively utilise all the water provided
Preliminary vegetative sample analysis of both CPSI and water can plots did not show the presence of either FC or TC on lettuce leaves
Plate 2. Lettuce plants set up in CPSI, with mosquito net to filter sediments
Plate 3. lettuce under Water can irrigation
Figure 1. Effect of irrigation types and spacing on plant height (bars = 2 x SED).
Figure 2. Effect of irrigation types and spacing on fresh weight of leaves (bars = 2 x SED).
Objectives
To determine the appropriate wastewater irrigation type and spacing on growth and yield of lettuce
To determine the effectiveness of CPSI in reducing the level of Feacal coliform (FC) and Total coliform (TC) on wastewater irrigated lettuce
Conclusions
Methodology
Clay pot irrigation with wastewater and spacing of 15 cm x 15 cm significantly enhanced lettuce growth and yield as was reflected in parameters like plant height, fresh and dry weight of leaves and roots
It was clear from the experiment that yield parameters (fresh and dry biomass) were increased significantly by Clay pot irrigation and spacing of 15 cm x 15 cm either acting independently or in combination
Irrigation type: CPSI and watering can
Spacing (cm): 15 x 15, 20 x 20 and 30 x 30
Treatments combinations: 6
Replications: 3 Experimental Design: CRD
Container capacity (cm): 50 diameter, 20 height
Wastewater application: 500 ml of water daily
Study parameters:
Plant height , fresh weight and dry weight
Data Analysis:
ANOVA, using Genstat statistical package
Plant height, fresh and dry weight were square root transformed to normalize the error distribution before the analysis.
Study period and location:
May –July, 2010, Tamale, Ghana
Plate 4. Lettuce grown under CPSI and ready for harvesting
Recommendations
Clay pot wastewater irrigation at a spacing of 15 cm x 15 cm should be adopted by poor urban farmers
Further test should be carried out to determine pathogen reduction by CPSI
Figure 3. Effect of irrigation types and spacing on fresh weight of roots (bars = 2 x SED)
Acknowledgement
Table 1. Effect of irrigation types and spacing on the dry weight of leaves (g)
Table 2. Effect of irrigation types and spacing on the dry weight of roots (g)
International Foundation for Science (IFS), Stockholm, Sweden supported this project through a grant to Mr. Abubakari Abdul-Halim. Thanks to the CTA for providing travel funds to present this paper at CTA Annual Seminar in Johannesburg, South Africa
Irrigation type
15 × 15
Spacing (cm)
20 × 20
30 × 30
Clay pot
0.921
1.142
1.254
Water can
1.154
0.645
0.754
F probability
0.044
SED
0.392
D.F 12
REP 3
Irrigation type
15 × 15
Spacing (cm)
20 × 20
30 × 30
Clay pot
0.1821
0.2431
0.2562
Water can
0.2205
0.1520
0.1715
F probability
0.008
SED
0.0536
D.F 12
REP 3
Plate 1. set up of CPSI