ABSTRACT

Rainfall is one of the key determinants of agricultural productivity in the tropics and the Bamenda Highlands of Cameroon in particular. This study, therefore, sets out to assess the incidence of rainfall variability in agricultural productivity in Jakiri Sub-Division. Jakiri Sub-Division seems to be predominantly hilly, restricting the cultivation of certain crop in these high altitude areas. Agriculture is carried out in the different topographic units extending from Wahsi to Vekovi, with diverse farming activities in each ecological zone. It is hypothesised that there is a positive relationship between rainfall variability and crop yields. In order to achieve this, both qualitative and quantitative data sources were collected from primary and secondary sources. The main primary data sources were questionnaires administered to farmers in all the ecological zones of the study area. Corresponding rainfall data was also collected from three stations (Ndop, Jakiri and Oku) that represent the three ecological zones. The results of the Coefficient of Variation (CV) revealed that rainfall is still reliable in all the agro-ecological zones with values of 14.15%, 13.81 and 20.72% for the lowland, mid-altitude and highland zones respectively. The main indicator of rainfall variation in Jakiri Sub-Division employed for this study is the Rainfall Anomaly Index (RAI). The RAI is increasing for all the ecological zones. An increasing RAI shows increasing dry conditions are recurrent. Recurrent long dry spells mean that rainfall is generally decreasing. Beans, cocoyam, vegetable, plantain and egusi are increasing, but a slight decrease in maize solanum potato and yams. In order to ensure sustainable crop productivity and effective agricultural planning in Jakiri Sub-Division both conventional and indigenous adaptation strategies have been employed by farmers. Not all the adaptive strategies are effective. These strategies are limited by environmental, political, socio-cultural and economic constraints. With these, it is recommended that farmers should be more receptive to innovations in terms of farming techniques and planting materials. They should not only stick to indigenous techniques that were handed to them by their ancestors. There is need for a blend of indigenous and conventional adaptation strategies. Farmers should diversify their sources of livelihoods, rather than depending solely on crop cultivation. Such alternatives are bee farming, fish farming, mushroom cultivation, petty trading and other sustainable income generating activities. The local government (council) and Sub-Divisional Delegation of Agriculture and Rural Development should make it a duty to follow up farmers groups and assist them with innovations and weather proof planting materials to enhance climate-smart agriculture.

Keywords:Rainfall variability and agricultural planning.

CHAPTER ONE

GENERAL INTRODUCTION

1.1 Background to the study

The cultivation of crops and rearing of animals on slopes has been considered a historical livelihood sustaining activities in the different parts of the world. Agricultural activity is a function ofphysical, Human and economicfactors. Climate is the main factor influencing crop cultivation around the world and considering that the world is divided into three different climatic zones (temperate, polar and tropical climatic zones). The climatic zones are marked by peculiar climatic parameterswhichinfluenceagriculture. In the tropics, rainfall is the main climatic parameter influencing agriculture while temperature is the main climatic factor influencing crop and animal production in thetemperateworld (Jeffrey et al,2000). This study further explains that agriculture is the main economic activity in the developing countries and a source of food security in the world. Agriculture in developed countries is highly mechanized with heavy investment in the sector to maintain food supply and security. This sector is a necessity for man to survive since we need food to live. Ludi (2009), acknowledgedthat agriculture is important in Africa and remains very crucial for poverty alleviation and economic growth the study further added that in most African countriesabout 70-80% of the total population depend solely on agriculture for sustainable livelihood.

Climate change stresses the global food system.Climate change is already making food insecurity worse, it has reduced the global yield growth of maizeas well as the yields of many other crops in Africa and elsewhere.Developing countries are experiencing 20% more extreme heat than in the late 1990s (Searchinger et al., 2019).And the number of undernourished or food-insecure people grew by between 37 million and 122 million to more than 800 million between 2014 and 2017,partly because of climate shocks.Additional climate change will exacerbate great challenges already faced by the global food system. These challenges include a likely 50% increase in global demand for food between 2010 and 2050 and even larger increases in the world’s most food-insecure regions-about a threefold increase in sub-Saharan Africa.

The complexity of climate as a biophysical process does not reveal precision and prediction on the future climatic conditions because of current dynamics of anthropogenic activities (IPCC, 2014). Climate variability is a global challenge facing socio-economic systems, health, livelihoods and food security. Climate variability has significant impacts on agricultural production worldwide, especially in developing countries such as, Ghana, Chad, Nigeria, East and South Africa, including Cameroon among others which are dominantly rain-fed production systems. Climate variability and change is a socio-ecological system which cannot be understood and evaluated by relying on physical sciences alone because its effects are considered at the micro level of the society, particularly in rural communities (Tume and Tanyanyiwa, 2018). Agrarian communities rely on climate-sensitive sectors that include agriculture, natural water sources and other primary activities for their livelihoods, especially in developing countries like Cameroon where rainfall has declined by 2% since 1961, Kenya that has experienced recurrent droughts of about 5% increases since 1960, Zimbabwe where average temperatures have increased by 1.9^oC since 1972, Nepal where temperatures have increased by 0.74^oC since 1985 and East Himalayas where rainfall has declined by 20 mm since 1990 (Tume and Tanyanyiwa, 2018).

 Rainfall variability incidence on agricultural production comes from two dimensionsmostly, the extreme events of floods and drought which were severely recorded in 2010-2012 with pronounce impacts on agriculture (IPCC, 2014). Extremes in temperature and rainfall affect crops yields, crops pests,pasture production and hazardous fire conditions. Heavy floods damages crops wash away productive topsoil and destroy crop at all young growing stage (Anyamba et al.,2014). Rainfall variability and agriculture have close similarities influenced by natural occurrences and human activities.Variations in climatic parameters especially rainfall is a significant threat to food sustainability and security,sustainable development, with severe consequences on agriculture in developingcountries (Abeysinghe, 2013) as population is increasing, land becomes scarce,water and vegetation resources are progressively degraded through prolonged misuse (Kolawole et al., 2012).The earth’s climatic system has witnessed certain changes due to human activities and natural occurrences. Climate variability which is perceived as yearly variation in climatic elements such as rainfall,temperature, hours of sunshine remains remarkable especially in the Sub-Saharan African countries. Climate varies over seasons and years instead of day-to-day like weather.Persistencevariation results in climate change (Dinse, 2011). Variation in rainfall destabilizes the agricultural calendar of activity thereby posing difficulties in agricultural planning. According to Intergovernmental Panel on Climate Change (2007), estimated a global temperature change from 0.3˚C to 0.7˚C by 2050 despite spatial variation in temperature in some regions of the world. Although there is uncertainty in changes in temperature in some regions of the world.

Rainfall variation in Asia during summer is likelyto increasein Northern Asia, East Asia, South Asia and most of South-East Asia, but is likelyto decrease in Central Asia (Hartmann, 1994). There is likelyto be an increase in the frequency of intense precipitation events in parts of South Asia, and in East Asia. Extreme rainfall and winds associated with tropical cyclones are likelyto increase in East Asia, Southeast Asia and South Asia (Potter and Colman, 2003). This variation affects agricultural productivity depending on the intensity and magnitude resulting in floods and droughts. Precipitation in boreal winter is very likelyto increase in northern Asia and the Tibetan Plateau, and likelyto increase in Eastern Asia and the southern parts of South-East Asia.

In Africa, annual rainfall has been decreasing in much of the Mediterranean Basin of Africa and the Northern Sahara, with a greater likelihood of decreasing rainfall as along the Mediterranean coast of Africa (Christensen et al., 2007; Potter and Colman, 2003; IPCC, 2007). Rainfall in Southern Africa has also been decreasing. Between 2010-2011, the main corn producing regions of South Africa known as ‘the maize triangle’ received heavy rainfall during the 2010-2011 La Nina. This abundant rainfall was combined with colder temperatures and created favorable growing conditions throughout the region, thereby warming the moister tropics (Leary et al., 2007, Anyamba et al.,2014).

In East Africa, mean annual rainfall has been increasing recently although in past 8 years or thereabout experienced below normal rainfall from early 2010 through mid-2011 (IPCC, 2014).Rainfall in 2010 in most parts of East Africa was 85% below normal recording a peak in drought in this region during the 2010-2011 La Nina period that led to sharp decline in agricultural production particularly sorghum. Somaliarecorded only 25 kilotons of sorghum in 2011 which is lowest and below normal for the last decades. Drought diminished the productivity of pasture and caused wide spread famine and high mortality in livestock throughout the region (Anyamba et al.,2014)

The situation of rainfall in the West African Sahel and the Guinean Coast has not been clear since the 1990s (Hartmann, 1994). Although recent research has been able to come out with the impacts of climate variability in the Guineasavanna andSudano-Sahelian belt of Africa which are located in West Africa. The early months of 2007 farming season (mid-May to June) was affected mostly in the Guineasavanna and Sudano-Sahelian belts,with Northern Ghana severely affected due to prolonged dry season (Yengoh et al., 2010). When the rains resumed many farmers replanted crops that were washed away by extensive floods which caused a decline in agricultural productivity (Yengoh et al.,2010).

The Agricultural systems of Cameroon are becoming more vulnerable to rainfall variability and rainfall trends have been decreasing over time Cameroon experienced particularly low rainfall in 2003 and 2005. There is insufficient daily precipitation data available to determine trends in daily rainfall extremes. Mean annual temperature on the other hand has increased by 0.7˚C since 1960, an average rate of 0.15˚C per decade (Ngakfumbe, 2001). The rate of increase is most rapid at 0.19˚C per decade, such thatNorthern parts of Cameroon are exposed to intense warming that accelerate soil moisture loss as temperature is presumed to have increased between 0.2^oC and 0.4^oC per decade (McSweeney et al., 2006). There has been continuous increase in extreme weather events, such as floods and increasing dry spells especially during the dry seasons in the Western Highlands and Northern parts of Cameroon.This has resulted in declining output of both food and cash crop output (Ndoh et al., 2015; Amawa et al., 2015, Kimengsi and Botanga, et al., 2016; Munang and Rivington, 2009). With these vulnerabilities, there is need for healthy adaptationstrategies. The Geographical location of Cameroon permits almost complete range of intertropical climates, which are influenced by the Harmattan and the Atlantic Monsoon winds. This diversity of climate in Cameroon makes it suitable for studying climate variation and changing precipitation which results to significant impacts on agriculture. It is therefore important to examine the significance of variation in monthly temperature and precipitation (Molua, 2006).

Climate  variation related impacts in the Northwest Region of Cameroon include temperature fluctuations from year to year, desiccation of natural habitats, more frequent dry spell and floods meaning rainfall variation is high since the region experience extension  of the  dry season and reduction in the period of rainfall althoughwith high intensity thus leading to destruction of crops. Such varaitions have a negative impact on agricultural production and food security. The seasonality with mean annual precipitation from 2400 to 3000 mm in an average year (Ndoh et al., 2016). Increasing temperature and decreasing rainfall are highly detrimental to agricultural productivity.

Bui Division is dominantly a tropical savannah environment. It is an ‘Aw’ climatic type, with two marked seasons, the dry season and the wet season. Sporadic rainfall experience in some driest month is less than 600mm (Ahrens, 2008). The dry season lasts for four to five months (November to March) while the wet season lasts for eight months (April to October). During the dry seasons characterized by increase in temperatures and practically no rainfall, farmers around main stream banks and those cultivating around the swampy valleys may sustain the cultivation of some food crops (mostly market gardening crops through irrigation and wetland rice cultivation) but lately, there has been enormous compliant about drying up of some main rivers and reduction of water tables rendering the marshy zones dry resulting to a reduction in outputs of those crops.The dry season is also characterized by dry harmattan winds, which lack moisture and rather facilitate the drying out of the environment such that the soils are thirsty and dry (Tume, 2008).

Agriculture in Jakiri Sub-Division is rain-fed as farmers depend on the onset of the first rains for sowing. Rainfallamongst other climatic elements of hours of sunshine, temperature, relative humidity, wind speed and direction, as well as evapotranspiration explain the spatio-temporal variability and occurrence of agricultural activities within the Jakiri landscape. In a similar way, these climatic elements are critical at various phases of the agricultural calendar and in all stages of the crop production cycle, especially in Jakiri Sub-Division. The low altitude zone such as the Wahsi-Ber, which is noted for rice cultivation, area have great agro-pastoral potentials within this zone tubers and grains are highly produced in Mbokam,Ber,Tan.This zoneconstitutes conflict zones for farmers and graziers as well as the Kinkolong Valley in Nkwanso appear to be flood prone at the peak of the rainy season. The flood intensity seems to be responsible for a declining trend in agricultural output.The transitional altitude zone such as Jakiri, Wainamah Nkar, Sop and entire Upper Dzekwa present high potentials for mixed cropping, while the high altitude zone such as Kinsenjam and Vekovi, Mvem, Ntohti have great potentials for temperature crops such as solanum potato and vegetables and market gardening in General and other cereals. The timing and planning of agricultural activities in Jakiri Sub-Division is determined by rainfall seasonality in relation to the alteration of the onset rain and cessation of the wet season.

1.3 Research questions

1.3.1 Main research question

The main question guiding this study is,

How does rainfall variability incidence influence agricultural planning in Jakiri-Sub division?

The study was guided by the following specific questions:

• Specific research questions

1) How does rainfall incidence controle variation in the agro-ecological in Jakiri Sub-Division?

2)How does rainfall variability affect crop cultivation and productivity in Jakiri Sub-Division?

3) What are the farmersplanning adjustment to fluctuations in rainfall patterns within the agrarian ecological zones?

1.4 Research objectives

1.4.1 Main research objectives

The main aim of the study is to determine rainfall variability incidence on agricultural planning in Jakiri Sub-Division.

The following specific objectives were formulated to guide the study.

1.4.1 Specific Research Objectives

• To examine the spatial variation of rainfall in Jakiri Sub-Division
• To assess the incidence of rainfall variability on cropproductivity in Jakiri Sub-Division.
• To identify farmers’ adaptation and planning adjustments to rainfall variability.