Effect of Different Compost Treatments on The Growth and Yield of Sweet Pepper

T. Kankam^*a, F. Kemausuor ^a+

^aDepartment of Agricultural and Biosystems Engineering, College of Engineering, KNUST, Kumasi-Ghana

Student: tesskankam@gmail.com*

Supervisor: fkemausuor.soe@knust.edu.gh

Abstract

This study was carried out on the campus of Kwame Nkrumah University of Science and Technology. An experiment was conducted from October 2018 to March 2019 to evaluate the effect of different compost treatments on the growth and yield of sweet pepper. A plot of 289 m² area (17 m × 17 m) was prepared using raised beds. A 4×4 factorial was laid out in Randomized Complete Block Design with four replications. The four treatments were; Control, 6250 kg compost per ha, 9375 kg per compost per ha and 12500 kg compost per ha. Growth indices (the number of leaves, stem girth, plant height and leaf area) and yield (fruit number and fruit weight) of sweet pepper plants were determined. The results obtained at the end of the experiment indicated that 6250 kg treatment recorded the highest number of fruits and the highest yield of 1.25 t/ha with the control recording the lowest with 0.95 t/ha.

Keywords: Compost; growth; yield; sweet pepper

Introduction

Bell pepper commonly known as sweet pepper or capsicum is a cultivar group of the species capsicum annuum. The genus capsicum belongs to the family solanaceae, originated from central and South America and have been spreading through the world since the late 1400s (Bell, 2008). Bell pepper is a highly nutritious vegetable which adds colour to dishes with a tangy taste that enhances food flavour. Bell pepper is called sweet pepper due to their less pungent smell and their fruits differ in colours, including, green, red, yellow and purple. Green bell peppers are unripe than the others when matured. They grow best in temperatures of 24-30 ˚C (Hartz et al., 2008). In tropical regions, bell peppers can be more than one season plants, but because plants are tender and are easily killed by frosts, bell peppers are most often cultivated in one growing season in temperate regions (University of Missouri Extension, 2010).

Cultivating bell pepper, and indeed most vegetables, require soils with good nutrients. When natural soil nutrients are lacking, they can be replenished with organic or inorganic fertiliser. The application of compost to agricultural soils has many advantages which include providing a whole array of nutrients to the soil (Chodak et al., 2001; Tejada et al., 2001), decreasing soil acidification, preventing soil erosion, increasing beneficial soil organisms, improving soil physical and biological properties and helping keep organic wastes out of landfills. All these effects and the suppression of pathogenic micro-organisms are advantageous for plant health (Pinamonti and Zorzi, 1996). Application recommendations for the use of compost are difficult to make because of the wide variety of feedstocks used in producing compost, and the variable effect of weather, soil type, soil microbial communities and management practices on nutrients release. It is therefore important to evaluate the effect of different compost types on crops, in order to make effective marketing decisions.

The aim of this project is to determine the effect of Jekora Ventures Limited (JVL) fortifier compost on growth and yield of green bell pepper. The specific objectives are:

• To assess the effect of JVL fortifier compost on the growth parameters (plant height, number of leaves, leaf area, and stem girth) of green bell pepper.
• To assess the effect of JVL fortifier compost on the yield of green bell pepper.

Materials and Methods

Experimental site

The experiment consisted of laboratory work and fieldwork. The fieldwork was conducted at the Department of Horticulture, KNUST in the moist semi-deciduous forest of Ghana. The forest has an average rainfall of 1500 mm. The field had a gentle slope and the soil was a well-drained sandy loam.

Soil samples were collected from the field before the layout of the experiment for the determination of the soil properties. The soil samples were collected to determine the initial soil chemical and physical properties from the experimental field. The study area is noted for bimodal rainfall pattern with two peaks that is major and minor rainfall with annual precipitation of approximately 1484 mm. The average maximum mean temperature is approximately 34.80 ˚C and a minimum mean temperature of 22.54 ˚C, with relative humidity averaging 80%.

Experimental design

The experiment was conducted in the open field, in the minor season from October 2018 to February 2019. A 4 m×4 m experiment was laid out in Randomized Complete Block Design with 16 Treatments in four (4) replications. The two factors involved in the experiment included, one (1) production system, that is an open field production system and one (1) variety of sweet pepper (sweet California wonder).

Agronomic practices

The land was sprayed with sunphosate (Glyphosate herbicide) at a rate of 150 ml/15L knapsack sprayer. At two weeks after spraying, the field was demarcated into blocks and plots. Seedlings were raised on 16th October 2018 under a shade. The seeds were sown in plastic containers (disposable cups) with three (3) seeds per cup. The cups were filled with sterilized soil. There was no application of fertilizer to the seedlings during the nursery stage. Seedlings were transplanted at 5 weeks after sowing, at 4-5 true leaf stage. The seedlings were transplanted on 23rd November 2018 at a planting distance of 60 cm within rows and 60 cm between rows per bed. Plants were irrigated using the sprinkler system of irrigation. The compost was analysed for their nutrient contents (N P K), moisture content, pH and electrical conductivity (See Table 1). Compost application was done on 30th November 2018, a week after transplanting to enhance the growth of plants. The application was done according to treatments per bed. The four treatments were; Control, 6250 kg compost per ha, 9375 kg per compost per ha and 12500 kg compost per ha. Various pests including leaf miners, thrips, whiteflies, aphids, spider mites etc. that attacked the plants were controlled as and when required using an insecticide (Orizon-trade name) from Dizengoff Ghana Limited at the rate of 25ml/15L knapsack sprayed fortnightly to reduce the rate of pest damage. Weeds were controlled using the cultural methods, which is hoeing and handpicking. Mulching was done to reduce weed growth

Data collection and analysis

Data were collected on the number of leaves, stem girth, plant height and leaf area. Five plants were randomly tagged from each plot for recording growth parameters and the averages of these five plants were recorded. The height of the plants was measured using a meter rule from the base of the plant to the apex of the leaf, the total number of leaves per plant was obtained by counting all fully opened leaves on the plants. The stem girth or diameter was measured around the base of the plants, using a string and a tape measure and leaf area were determined by measuring the length and the width of the leaf using a meter rule. During harvesting time, samples of green pepper fruits were randomly harvested from each plot to measure fruit

length, fruit diameter and average fruit weight. The total weight of fruits in each treatment was recorded by harvesting pepper fruits weekly and the total yield was calculated in tonne/ha. Data were analysed using descriptive statistics, i.e. tables and graphs. Statistical analysis was done using the One-way Analysis of Variance (ANOVA).

Table 1. Laboratory analysis of compost

Results and Discussion

Effect of Compost Treatments on growth parameters

As shown in Figure 1, it can be observed that 9375 kg/ha treatment had the highest number of leaves from week 1 to week 5 as compared to the other treatments. With regards to plant height, as can be seen in Figure 2, the 9375 kg/ha treatment kept increasing from week 1 to week 5 followed by 6250 kg/ha and the other treatments. Similar trends were observed for leaf area and stem girth. The 9375 kg/ha treatment had the highest leaf area and the highest stem girth from week 1 to week 5. The highest fruit weight per treatment replicate was significantly obtained by 6250 kg/ha, followed by 9375 kg/ha, then 12500 kg/ha, whiles control attained the lowest fruit weight as shown in Figure 3.

Statistical analysis (ANOVA)

The Tukey’s honest significance difference test was used in conjunction with an analysis of variance (ANOVA) to find the means that are significantly different from each treatment. The probability value (p-value)

=0.00147<0.05. If the p-value is < 0.05 then there is a difference between at least two of the mean of the treatments. Table 2 shows the Tukey multiple comparisons of means with a 95% family-wise confidence level. The highlighted values show a clear significance difference between the two treatments indicated.

Table 2. Significance difference between each treatment

Conclusions and recommendations

On the basis of the results obtained, it was found out that 9375 kg/ha treatment increased plant vegetative growth in terms of the number of leaves, plant height, stem girth and leaf area. However, the 6250 kg/ha treatment produced the highest yield. Based on the results, it is recommended that sweet pepper can be grown with 6250 kg/ha JVL compost application rate for increased yield. Future research should focus on lower application rates.

Acknowledgements

I thank God almighty for his divine protection and guidance from the onset of the project and my four years of stay in school. I would like to thank Jekora Ventures Limited for providing the compost at a 50% subsidy for this experiment, I am very grateful. I wish to express my sincere gratitude to my supervisor, Dr Francis Kemausuor for his patience, guidance and support throughout the project. I would like to thank Dr William Amponsah for his assistance. I also thank Mr Kwabena Afrane Okese of Agrihome Expressions for his guidance, also to Mr Bright Osei for his support during the fieldwork.

References

Alabi D. A. 2006. Effect of fertilizer phosphorus and poultry droppings treatments on growth and nutrient components of pepper (Capsicum annum L.). African Journal of Biotechnology. 5(8): 671-677.

Aliyu L. 2002. Analysis of the chemical composition of some organic manure and their effect on the yield and composition of pepper. Crop Res. 23: 362-368.

Asiegbu J. E. 1987. Effects of organic matter substrate sources and time of photosynthate – sink removal on flower and pod production in okra. Abelmoschus esculentus (L) Moench. East African Agriculture, Forestry Journal. 52(4): 293-297.

Beckman E.O. 1973. Organic fertilization vegetable farming luxury or necessity. Tech. Commun. ISHA. 29: 247.

Bray R. H. and L. T. Kurtz. 1945. Determination of total organic and available forms of phosphorus in soils, Soil Science. 5: 3-45.

About the Student Authors

Theresah Kankam will graduate in July 2019 with a bachelor’s degree in Agricultural and Biosystems Engineering from Kwame Nkrumah University of Science and Technology.