THE EFFECT OF IRRIGATION FREQUENCY ON THE GROWTH AND YIELD OF TOMATO (A CASE STUDY OF TOMATO FARMERS IN ZARIA LOCAL GOVERNMENT AREA, KADUNA STATE)

CHAPTER ONE

INTRODUCTION

1.1 Background of the Study

Tomato (Solanum lycopersicum L., synonym Lycopersicon esculentum Mill.) is one of the most widely grown fruit vegetables in the world. It is eaten fresh and cooked in soups and stews, and is processed into paste, puree and juice. In northern Nigeria, tomato is produced on a large scale in the dry season under irrigation, and the crop is a major source of income for many smallholders who supply urban markets.

Tomato is a water-demanding crop. Patanè et al. (2011) describe processing tomato as a crop with a high water demand that requires irrigation throughout the growing season in arid and semi-arid areas. Water stress affects germination, vegetative growth, flowering, fruit set and fruit size, and too much water can encourage diseases, fruit cracking and nutrient losses. How often irrigation is applied therefore influences both how the crop grows and how much it yields.

Evidence from northern Nigeria confirms the sensitivity of tomato to water supply. Arab et al. (2025) carried out experiments at the Institute for Agricultural Research irrigation site at Kadawa in the Sudan savanna, applying full irrigation and deficit levels of 25% and 50% at different growth stages. They found that yield was significantly affected by water stress, with mean fresh yields ranging from 72.52 to 40.81 t/ha; the development and middle growth stages were the most sensitive to water stress, while the late stage was less sensitive; a 25% deficit at the development stage reduced yield by 7%, whereas a 50% deficit at the development, middle and late stages together reduced yield by 44%. The authors estimated the seasonal water requirement of tomato in the Sudan savanna at 554 mm.

Deficit irrigation can also have benefits. Patanè et al. (2011) found in a semi-arid Mediterranean environment that a 50% reduction of crop evapotranspiration, applied through the whole season or part of it, saved water and maintained high fruit quality, and that the effects of deficit irrigation on fruit quality were generally the opposite of those on fruit yield. Stoleru et al. (2020) likewise examined the yield and nutritional response of greenhouse-grown tomato cultivars to sustainable fertilization and irrigation management. These studies show that irrigation scheduling is a balance between yield, water use and quality.

For farmers, the practical question is how often to irrigate. Frequency depends on the source and cost of water, the type of soil, the weather, the method of irrigation and the labour or fuel that is available for pumping. Farmers who irrigate too rarely risk water stress, while those who irrigate too often use more water, labour and energy than may be necessary.

Zaria Local Government Area, in Kaduna State, lies in the northern Guinea savanna and is a centre of dry-season vegetable production, where tomato is irrigated from streams, wells and other sources. This study therefore used a structured questionnaire to examine the irrigation frequencies used by tomato farmers in Zaria and their perceived effects on the growth and yield of tomato.

1.2 Statement of the Problem

Tomato farmers in Zaria Local Government Area rely on irrigation for dry-season production, but water is limited and the cost of pumping and labour is high. Farmers choose irrigation frequency largely by experience and by the water and fuel they have available. Experimental work shows that yield falls when the crop is water stressed (Arab et al., 2025), but it is not clear what irrigation frequencies farmers in Zaria actually use or how they judge the effects on growth and yield.

The studies reviewed here were conducted on research stations, under controlled deficit levels, or in other regions (Arab et al., 2025; Patanè et al., 2011), and the literature consulted for this study did not reveal a survey of irrigation frequency practices and perceived effects among tomato farmers in Zaria. Results from other places depend on soil, climate and irrigation method and cannot be assumed to hold in Zaria.

As a result, farmers may be irrigating too often, wasting scarce water and money, or too seldom, losing yield. Extension agents and irrigation planners also lack local data to advise farmers on scheduling. This study was undertaken to provide such information.

1.3 Objectives of the Study

The main objective of the study was to assess the effect of different irrigation frequencies on the growth and yield of tomato among farmers in Zaria Local Government Area, Kaduna State, using a structured questionnaire. The specific objectives, each of which corresponds to a section of the questionnaire, were to:

(i) describe the socio-economic characteristics of the respondents, namely age, sex, educational level, farming experience, farm size and source of labour

(ii) identify the irrigation frequencies and water sources currently used by the respondents in the production of tomato

(iii) ascertain the respondents' perception of the effect of different irrigation frequencies on the growth of tomato ;

(iv) ascertain the respondents' perception of the effect of different irrigation frequencies on the yield of tomato

(v) identify the constraints faced by the respondents in the use of different irrigation frequencies and the measures they suggest for improvement .

1.4 Research Questions

The following research questions, which correspond to the sections of the questionnaire, guided the study:

(i) What are the socio-economic characteristics of the respondents?

(ii) What irrigation frequencies and water sources do the respondents use in the production of tomato?

(iii) How do the respondents perceive the effect of different irrigation frequencies on the growth of tomato?

(iv) How do the respondents perceive the effect of different irrigation frequencies on the yield of tomato?

(v) What constraints do the respondents face in the use of different irrigation frequencies, and what improvements do they suggest?

1.5 Research Hypotheses

The following null hypotheses were tested at the 0.05 level of significance:

H01: There is no significant relationship between the socio-economic characteristics of the respondents and their choice of irrigation frequency.

H02: There is no significant difference in the perceived growth of tomato among respondents who differ in their irrigation frequency.

H03: There is no significant difference in the perceived yield of tomato among respondents who differ in their irrigation frequency.

1.6 Significance of the Study

The findings will give tomato farmers in Zaria information on the irrigation frequencies used by their peers and on the frequencies that they perceive to give better growth and yield, which may help them save water and cost. Extension agents and irrigation project managers will obtain local information for scheduling advice.

The study will also add to the literature on dry-season tomato production in the northern Guinea savanna.

1.7 Scope and Limitations of the Study

The study covers tomato farmers in Zaria Local Government Area, Kaduna State. It is limited to irrigation frequency and covers the respondents' socio-economic characteristics, irrigation practices, perceived effects on growth and yield, and constraints. It does not include measurement of soil moisture or controlled field measurement of yield.

Limitations include reliance on respondents' recall and perception, seasonal variation in water availability and weather, and the limited number of respondents who could be reached. The findings should be applied with care outside the study area.

1.8 Definition of Terms

Irrigation frequency: the number of times water is applied to the crop within a given period.

Dry-season farming: crop production during the months without regular rainfall, which depends on irrigation.

Water stress: a condition in which the plant does not receive enough water for normal growth.

Growth: the visible development of the tomato plant, such as height, leaf number and vigour, as perceived by farmers.

Yield: the quantity of tomato fruit harvested per unit area.

Questionnaire: a structured set of written questions used to collect information from respondents.

REFERENCES

Arab, A. I., Othman, M. K., Mudiare, O. J., Ramalan, A. A., & Idris, U. D. (2025). Yield and water productivity of tomato under full and deficit irrigation in northern Nigeria. Journal of Agricultural Engineering and Technology. https://jaet.niae.net/index.php/jaet/article/view/141

Patanè, C., Tringali, S., & Sortino, O. (2011). Effects of deficit irrigation on biomass, yield, water productivity and fruit quality of processing tomato under semi-arid Mediterranean climate conditions. Scientia Horticulturae, 129(4), 590–596.

Stoleru, V., Inculet, S. C., Mihalache, G., Cojocaru, A., Teliban, G. C., & Caruso, G. (2020). Yield and nutritional response of greenhouse grown tomato cultivars to sustainable fertilization and irrigation management. Plants, 9(8), 1053. https://doi.org/10.3390/plants9081053