THE EFFECT OF DIFFERENT WEED CONTROL METHODS ON THE GROWTH AND YIELD OF MAIZE (A CASE STUDY OF MAIZE FARMERS IN IKWO LOCAL GOVERNMENT AREA, EBONYI STATE)

CHAPTER ONE

INTRODUCTION

1.1 Background of the Study

Maize (Zea mays L.) is one of the most important cereal crops in Nigeria, used as human food, as livestock and poultry feed and as an industrial raw material. Ngonadi et al. (2023), citing United States Department of Agriculture figures, report that Nigerian maize production rose to 11.6 million tonnes in 2021/2022, but they also point out that the full potential of the crop cannot be attained, especially by small-scale farmers, without effective weed control.

Weeds compete with crops for space, nutrients, water and light, and maize is one of the crops that cannot compete effectively with weeds (Ngonadi et al., 2023). Imoloame (2021) notes that uncontrolled weed growth has been reported to cause yield losses of 40% to 90% in cereals in West Africa. The loss depends on how dense the weeds are and on when they appear relative to the growth of the crop, with early competition being the most damaging.

Farmers control weeds in several ways. Cultural and manual methods include hand pulling and hoe weeding; mechanical methods include slashing; chemical methods use pre-emergence and post-emergence herbicides integrated practices combine two or more of these (Ngonadi et al., 2023). Each has strengths and weaknesses. Manual weeding is slow, tiring and expensive, since hand weeding one hectare of maize may require as much as 25 to 40 person-days, which is about 50% to 80% of the total labour budget, and labour is often short at the time weeding is needed (Ngonadi et al., 2023). Imoloame (2021) adds that two well-timed hand weedings in the first six weeks after planting have been reported to give effective control, but that the dwindling labour force, the high cost of labour and the drudgery of hand weeding have made herbicides more attractive. Chemical control, on the other hand, can be expensive, can cause crop injury if wrongly applied and can harm the environment and the person applying it.

Recent work in south-eastern Nigeria shows how much the method matters. In a two-year study at Igbariam, Anambra State, Ngonadi et al. (2023) compared a weedy check, hoe weeding, pre-emergence herbicide and post-emergence herbicide on three local maize cultivars, including Oka Abakaliki, a cultivar sourced partly from Ebonyi State. They found that weed control method significantly affected plant height, stem girth and leaf area while cultivar did not: plants under pre-emergence herbicide reached about 249 cm at eight weeks after sowing, compared with about 106 cm in the weedy check, and grain yield was around 3.1 t/ha under pre-emergence herbicide against 0.7 to 0.8 t/ha in the weedy check. Pre-emergence herbicide also proved the most profitable, and hoe weeding twice was next in revenue. Alternatives to direct weeding also exist; Daryanto et al. (2020), for example, report that intercropping of grain legumes with cereals in Africa was associated with 23% lower weed biomass.

These results show that weed control method can have a large effect on growth, yield and profit, but the trials were conducted on research farms and the ranking of methods depends on cost and on the availability of labour, herbicides and knowledge, which differ between locations. What farmers in a particular area actually do, and how they judge the results, can only be learnt by asking them.

Ikwo Local Government Area is in Ebonyi State, where maize is grown by smallholders for food and sale. This study therefore used a structured questionnaire to examine the weed control methods used by maize farmers in Ikwo and their perceived effects on the growth and yield of maize.

1.2 Statement of the Problem

Maize farmers in Ikwo Local Government Area must control weeds, but the methods available to them differ greatly in cost, labour demand and effectiveness. Hoe weeding is tiring and labour-intensive, herbicides cost money and require knowledge, and uncontrolled weeds can reduce yield severely (Imoloame, 2021; Ngonadi et al., 2023). It is not known which methods farmers in Ikwo use, how they time them, or how they judge their effects on growth and yield.

The studies reviewed here were carried out on research farms in other parts of Nigeria or in other regions (Imoloame, 2021; Ngonadi et al., 2023), and the literature consulted for this study did not reveal a survey of weed control practices and perceived effects among maize farmers in Ikwo. Differences in weed species, labour availability, herbicide prices and farmers' knowledge mean that results from other locations cannot be assumed to hold in Ikwo.

As a result, farmers may be using methods that are costly or ineffective, or may be applying herbicides unsafely, and extension agents lack local information on which to base advice. This study was undertaken to provide it.

1.3 Objectives of the Study

The main objective of the study was to assess the effect of different weed control methods on the growth and yield of maize among farmers in Ikwo Local Government Area, Ebonyi 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 weed control methods and their timing currently used by the respondents in the production of maize

(iii) ascertain the respondents' perception of the effect of different weed control methods on the growth of maize ;

(iv) ascertain the respondents' perception of the effect of different weed control methods on the yield of maize

(v) identify the constraints faced by the respondents in the use of different weed control methods 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 weed control methods and their timing do the respondents use in the production of maize?

(iii) How do the respondents perceive the effect of different weed control methods on the growth of maize?

(iv) How do the respondents perceive the effect of different weed control methods on the yield of maize?

(v) What constraints do the respondents face in the use of different weed control methods, 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 weed control method.

H02: There is no significant difference in the perceived growth of maize among respondents who differ in their weed control method.

H03: There is no significant difference in the perceived yield of maize among respondents who differ in their weed control method.

1.6 Significance of the Study

The findings will give maize farmers in Ikwo information on the weed control methods used by their peers and those perceived to give better growth and yield at acceptable cost. Extension agents will obtain local information for advice on weeding and safe herbicide use, and input suppliers may better understand farmers' needs.

The study will also add to the literature on maize production in south-eastern Nigeria.

1.7 Scope and Limitations of the Study

The study covers maize farmers in Ikwo Local Government Area, Ebonyi State. It is limited to weed control methods and covers the respondents' socio-economic characteristics, weed control practices, perceived effects on growth and yield, and constraints. It does not include measurement of weed density or controlled field measurement of yield.

Limitations include reliance on respondents' recall and perception, the possible reluctance of some respondents to disclose herbicide use, 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

Weed: a plant growing where it is not wanted, which competes with the crop.

Weed control method: the practice used to prevent, remove or suppress weeds, such as hoe weeding, hand pulling or herbicide application.

Pre-emergence herbicide: a herbicide applied after planting but before the crop and weeds emerge.

Post-emergence herbicide: a herbicide applied after the crop and weeds have emerged.

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

Yield: the quantity of maize grain harvested per unit area.

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

REFERENCES

Daryanto, S., Fu, B., Zhao, W., Wang, S., Jacinthe, P.-A., & Wang, L. (2020). Ecosystem service provision of grain legume and cereal intercropping in Africa. Agricultural Systems, 178, 102761. https://doi.org/10.1016/j.agsy.2019.102761

Imoloame, E. (2021). Agronomic and economic performance of maize (Zea mays L.) as influenced by seed bed configuration and weed control treatments. Open Agriculture, 6, 445–455. https://doi.org/10.1515/opag-2021-0030

Ngonadi, E. N., Uko, I., & Okonkwo, N. J. (2023). Profitability of selected weed control methods in maize (Zea mays L. Moench) production at Igbariam in three successive months. International Journal of Agriculture, Food and Biodiversity, 2(1), 37–42. https://journals.unizik.edu.ng/ijafab/article/download/2799/2262/6729