Assessment of input-output relationship of crop enterprises in the different climate change adaptation options among farmers in Borno State, Nigeria

The study analyzed the input-output relationship of crop enterprises in response to different climate change adaptation options among farmers in Borno State, Nigeria. The research was conducted in two agroecological zones (AEZ) within the state, employing a multi-stage sampling procedure to select 360 farmers for the study. Data analysis involved the use of means, frequencies, and multiple regression techniques. The results regarding adaptation practices in the respective AEZs revealed that in the Sudan AEZ, farmers primarily employed strategies such as multiple cropping (98.9%), early planting (63.9%), mulching/use of cover crops (36.1%), and increased fertilizer application (25.00%). In the Guinea AEZ, the most widely used adaptation strategies included multiple cropping (93.30%), utilization of new crop varieties tolerant to the evolving climate (72.20%), increased fertilizer application (47.20%), and the use of herbicides (25.00%). The production function analysis results demonstrated that approximately 85, 51, 53, 57, 81 and 65% of the variations in yields resulting from climate change adaptation strategies, such as the application of herbicides, utilization of organic manure, early planting, increased fertilizer application, mulching, and the use of cover crops, as well as the use of improved crop varieties tolerant to the new climate regime, were accounted for by the inputs. Furthermore, the coefficients of production inputs were significant and positively correlated with crop yields across different adaptation strategies and at various levels. In conclusion, the study found that farmers primarily employed technically-based adaptation strategies, and production inputs played a crucial role in determining crop yields across various adaptation approaches. It is recommended, among other measures, that adaptation materials be provided to farmers at a subsidized rate.


INTRODUCTION
The economy of Borno State is largely agrarian, with livestock husbandry, crop production and fishing dominating the economic activities of the population.Agriculture is mainly subsistent, with over 70% of her population depending on it directly or indirectly for their livelihoods.It provides the bulk of employment, income, food, and clothing for the rapidly growing population as well as supplying raw materials for agro-based industries.In Borno State, agriculture contributes up to 65% of the state's Gross Domestic Product (FAO and ICRISAT, 2019).Major cash crops are cotton, sesame and groundnut while food crops include maize, yam, cassava, sorghum, cowpea, sorghum, millet, sweet potato and rice.Cattle and other livestock also have enormous value chain growth opportunities.With the recent insecurity that worst hit Borno State, food production (crop/animal and fishing) contributes to only 5.9% of the food needs of the State.Virtually, 94% of food consumed in Borno is imported either in the form of credit or gift from nongovernmental organizations (NGOs), the World Food Program (WFP), and civil societies among others.Declining soil fertility, climate change, low farm input, limited investment, and poor infrastructure continue to hamper agricultural productivity and developments in the agricultural sector.
Climate change has adverse ecological, social, and economic impacts.Climate change affects many institutions and productive sectors including agriculture, forestry, energy, and coastal zones, across the world.The economies of developing nations will be more affected by climate change, partly due to their greater exposure to climate shocks and also because of their limited adaptive capacity.However, no country is immune, and of the developing countries, many in Africa are seen as being the most vulnerable to climate variability and change (ACCRA, 2011).Poor agricultural productivity is one of many factors driving the vulnerability of developing countries.Climate change will create large incremental risks (Bramka et al., 2020;UNDP, 2007) and a small incremental risk of more droughts can lead to large human development setbacks.Studies indicate that Africa's agriculture is negatively affected by climate change (Debay, 2010).International Monetary Fund (2022) also noted that sub-Saharan Africa is currently the most food-insecure region in the world.Climate change could aggravate the situation further unless adequate measures are put in place.For smallholder farmers in the dry land of Nigeria, the environmental and social consequences of climate change put their livelihoods at risk.
Adaptation to climate change is the adjustment of practices, processes, and structures to reduce the negative effects particularly, the unavoidable ones, and takes advantage of any opportunities associated with climate change (Noble et al., 2014).Although, African farmers have a low capacity to adapt to changing climate, however, have survived and coped in various ways over time.A better understanding of how they have done this is essential for designing incentives to enhance private adaptation.There is need to support farmers' coping strategies through appropriate public policy and investment.Thus, public and private partnership will help increase the adoption of adaptation measures which will reduce the negative consequences of predicted changes in future climate with vulnerable rural communities in Africa benefiting more (Hassan and Nhemachena, 2008a).Ojo and Baiyegunhi (2018) posited that farmers adapted to climate change in order to maximize profit by changing using mixed cropping, use of improved crop varieties and soil and water conservation practices among others.The coping strategies adopted by arable crop farmers, which are mainly initiated at the farm and village-level, are expected to enhance their farm productivities, and improve their profit as a producing unit.
A challenge for agricultural researchers is to understand adaptation measures to climate change are used by farmers and what are the driving forces of crop outputs based on climate change adaptation strategies.An understanding of the assessment of climate change adaptation strategies and the factors that influence crop outputs is therefore, important in the process of resource allocation.The study of input-output relationship of crop enterprises in the different climate change adaptation strategies among farmers in Borno State, Nigeria is therefore, pertinent owing to the persistent, severity and the huge impact of climate change (drought, desertification, high temperature, reduced/fluctuating rainfall) on crop production.The study was designed to achieve the following specific objectives: to identify adaptation strategies use by farmers in the two agroecological zones of the State; and to determine input-output relationship of crop enterprises in the different climate change adaptation strategies in the study area.

Input-output relationships of crop enterprises
Production function shows the physical relationship between one or more inputs or factors and the output obtained from them.It helps in the estimation of the marginal productivity of productive inputs and their use efficiency in production process.Several studies have been carried out in order to look at the relationship between inputs and output of crop production process.For example, Taru et al. (2011) studied technical efficiency of sole cowpea production in Adamawa State, Nigeria: A Cobb-Douglas stochastic frontier function.The model represents an improvement over the traditional average function and the deterministic functions, which use mathematical programming to construct production frontiers.The result revealed that farm size, seeds, agrochemicals and hired labour were positive and had significant effect on output at 1%.The mean technical efficiency index was 0.89 while the minimum and maximum efficiency values were 0.55 and 0.95 respectively.This implies that the farmers were not fully efficient as the observed output was 11% less than the maximum output.Bathon et al. (2016) studied the profitability of groundnut-based cropping systems among farmers in Hong local government area of Adamawa State, Nigeria.The study used multiple regression analysis in determine input-output relationships of groundnut-based cropping systems.The double-logarithm function gave the best fit; hence, was selected as the lead equation based on the number of significant variables, the plausible magnitude of the regression coefficients, the magnitude of the coefficient of determination (R 2 ) and correctness of signs of the coefficients.The production estimates indicated the relative importance of factor inputs in groundnut-based cropping systems.The coefficient of farm size, family and hired labour, herbicide, and formal education were positive and significantly related to the output of groundnut-based cropping systems.
In a study of the economic efficiency of resource use in ground nut production in Adamawa State, Taru et al. (2008) observed that farm size, seed and labour input were significant at 1% level.The study further indicates that R 2 of 0.7840 indicated that 78.40% of the variability in the output of ground nuts is accounted for by the various independent variables used.It is believed that labour will be significant for farmers who adapt to climate change through labor-intensive adaptation strategies.Perhaps, the coefficient of seed would also be significant for farmers who adapt to climate change by the use of different crop varieties.Oluwatayo et al. (2010) in their effort to examine the resource use efficiency of maize farmers in rural Nigeria: evidence from Ekiti State, observed that farm size, labour (availability and nature), pesticide, and herbicide and fertilizer usage were positively related to maize output and these variables were equally significant in determining the output of the farmers.Farmers who use fertilizer were found to obtain higher yields than those who did not use it.Fertilizer application is one of the adaptation strategies practiced by farmers.However, for farmers who use fertilizer as an adaptation strategy, the coefficient of fertilizer will be equally significant.The estimated technical efficiency of maize was found to be 0.68 indicating 68% efficiency in their use of production inputs.Kudama (2013) analysed the economics of groundnut production in the east Harghe zone of Oromia regional State, of Ethiopia.Results revealed that a total of seven independent variables entered the model three variables were significant at different levels.Whilst the seed and livestock in TLU were significant at a 1% probability level, labor was significant at 10%.All the variables included in the analysis were positive and in agreement with prior expectations.The coefficient of the individual variable indicates the elasticity of the groundnut output.The result shows that 1% increase in the quantity of seed, labor, and livestock in TLU leads to an increase of 0.739, 0.291 and 0.247% in groundnut output.The coefficient of labour was statistically significant at the level of 1% and positive.The sign of the coefficient is in agreement with prior expectations and suggests that as the quantity of labor use increases the amount of output increases, keeping other variables constant.However, such a relationship holds true if the available labor is efficiently allocated with other resources.The result of the study agrees with the findings of Katungi et al. (2011).The coefficient livestock in the Tropical Unit (TLU) was statistically significant at the level of 1% and positive.The result gives good reason for the derived implication of livestock on groundnut output since the amount of farmyard manure added to groundnut farms is dependent on the quantity of livestock the household owns.
Production function specifies the relationship between inputs and output.It was estimated to measure the relative importance of inputs used in climate change adaptation strategies and also show which production function best suits each adaptation strategy practiced by respondents.The factors considered in the selection of the best functional form were based on statistical and econometric criteria (number of variables that were significant, magnitude of F-ratio, and R 2 ).

METHODOLOGY
The study was conducted in Borno State.The State has a land area of 69, 435 square km (Amaza et al., 2007).The area lies between latitudes 12 -00N and 14, 00N and longitude 10 -00E and 14-00E of northeastern Nigeria (Figure 1).It has climatic peculiarities characterized by erratic and un-reliable rainfall patterns.The rains are of short duration followed by a long dry spell.Temperatures are high all year round, with hot season mean temperatures ranging between 39 and 40C in the northern part of the State.Data for this study were mainly from primary sources.Multi-stage sampling technique was used in selecting 360 respondents for the study.Both descriptive (means frequencies and%ages) and inferential statistics (multiple regression analysis) were used in analyzing the data.

Production function analysis
Estimation of input-output relationship was carried out using multiple regression technique.The model is expressed as follows: Where: Y = Crop yield (Kg); bs = Parameter estimates (regression coefficients); X 1 = Labour (Man Day); X 2 = Fertilizer (Kg); X 3 = Seeds (Kg); X 4 = Chemicals (Ltr); X 5 = Farm size (ha); e = error term Three functional forms of the regression model (linear, semilogarithm and double logarithm) were fitted and the lead equation was selected based on statistical and econometric criteria including number of significant variables, magnitude of the F-ratio and Rsquare estimates and the standard error as well as consistency with the a priori expectations.The functions were explicitly expressed as

Adaptation strategies practiced by farmers
The linkage of a climate system and agricultural production raises the question about available adaptation options.Adapting agriculture and farming systems to climate change is a vital policy concern for the agricultural sector.Sofoluwe et al. ( 2011) and Akhter and Olaf (2017) indicated that agriculture is negatively affected by climate change and adaptation is one of the methods to be used to reduce the impact of climate change.To respond to the perceived changes in climate, farmers are employing adaptation strategies in order to reduce the negative impacts on crops.Majority of the farmers were using more than one type of adaptation option.The farm-level adaptation strategies practiced by respondents in the two agroecological zones are presented in Table 1.In Sudan's savannah agroecological zone, the result revealed that 98.89% of the respondents adopted multiple cropping as an adaptation strategy, 63.89% practiced early planting and 36.11% of the respondents employed mulching and use of cover crops as an adaptation strategy.Twenty-five% (25.00%) of the respondents practiced increased application of fertilizer and 17.78% adopted application of organic manure.The result of adaptation strategies adopted by farmers in the Guinea savannah zone is also presented in Table 1.The result revealed that almost all (93.33%) of the respondents Early planting is an age-long adaptation strategy practiced by crop farmers.The main thrust of the strategy is to ensure that critical growth stages do not coincide with the harsh climate conditions usually experienced at the end of the wet season.Farmers reported that as soon as the rainy season starts, they sow their crops.However, the strategy requires re-sowing, as not all the seeds germinate as a result of moisture deficiency in the soil at the beginning of the rainy season.Mulching/use of cover crops is aimed at conserving the moisture content of the soil.Couple with soil characteristics, the rainfall regime in the Sudan savannah is scanty, therefore, farmers resort to adopting the strategy in order to conserve the little moisture in the soil by covering the soil either with cover crops (cowpea, groundnut) or some non-crops materials (thatch, farm waste).This will ensure the soil surface is not directly exposed to the sun's radiation thereby minimizing the rate of evaporation.
The use of new crop varieties tolerant to the new climate regimes has been practiced by farmers in the Guinea savanna agroecological zone of Borno State.New crop varieties such as maize, cowpea, and soybean are promoted by the International Institute for Tropical Agriculture (IITA), the International Fund for Agricultural Development (IFAD), and government agencies in the zone.This paved the way for farmers to adopt it as an adaptation strategy to climate change.The main thrust of using new crop varieties as an adaptation strategy could be twofold: grow fast to meet up the shortened wet season and yield high to ensure that farmers get income in the face of climate change.The use of chemicals as an adaptation strategy is gaining ground among farmers in the Guinea savannah zone evidenced from the result of the study.Chemical such as herbicides application is a substitute for labour in the farm business.Considering the cost of labour in farm business and the adverse effects of climate change on crop production, farmers lessen the cost of labour by adopting the strategy hence reducing the cost of crop production leading to increased profitability of farm business.

Production function analysis
The results of the production function are presented in Table 2.The result shows that about 85, 51, 53, 57, 81, and 65% of the variations in yields from climate change adaptation strategies such as application of herbicides, application of organic manure, early planting, increased application of fertilizer, mulching and use of cover crops and use of improved crop varieties tolerant to new climate regime respectively.The remaining variations were accounted for by other inputs such as managerial practices and peculiarities in rainfall, temperature and soil fertility in different agro-ecological zone of the study area.
The coefficients of labour (X 1 ) were significant (P≤0.01) and positive for the application of herbicides, application of organic manure, early planting, and use of improved crop varieties.The coefficients were significant (P≤0.05) and positively related to increased application of fertilizer and mulching and use of cover crops.The positive coefficients of labour in all the adaptation strategies practice by respondents suggest that an increase in labour in each of the adaptation strategies, when other explanatory variables are held constant, will bring about an increase in output.All things being equal, an increase in labour implies more managerial practice, hence more output is expected.Labour use, however, is used with caution by respondents.This is because excessive labour particularly family labor was not used which might lead to diminishing return to labour.The coefficients of fertilizer (X 2 ) were significant (P≤0.10) and positive for the application of herbicides, early planting, increased application of fertilizer, and mulching/use of cover crops.Also, the coefficients were significant (P≤0.05) and positive for the application of organic manure and mulching/use of cover crops, while the coefficient was significant (P≤0.01) and positive for the use of improved crop varieties tolerant to new climate regimes.The result implies that increased fertilizer application in each of the adaptation strategies mentioned, when other explanatory variables are held constant will increase the output.This could be because of the fact that fertilizer could boost soil fertility, thereby allowing crops to have the required nutrients and hence, better yield expected.
The coefficients of seed (X 3 ) were significant (P≤0.10) and positive for early planting, increased application of fertilizer, and mulching and use of cover crops.The coefficients were also significant (P≤0.05) and positive for the application of herbicides and the use of improved crop varieties.The positive relationship between seeds and outputs suggests that in ceteris paribus, an increase in seed rate per hectare implies a greater number of component crop stands per hectare and consequently higher output.
The coefficients of chemical (X 4 ) were significant (P≤0.10) and positive for the application of herbicides, increased application of fertilizer, and use of improved crop varieties adaptation strategies.The coefficient of chemical was found also to be significant (P≤0.05) and positively related to the application of organic manure.The positive relationship between chemical and output of crop enterprises based on adaptation strategies could be attributable to the fact that large farm sizes could be cultivated with less labour in terms of weeding.Chemicals (herbicides) are substitutes to labour hence, less labour is required consequently, and higher output is expected.The insignificant relationship between early planting and mulching and the use of cover crops could be accounted for as a result of being traditional practices and hence require fewer chemicals.
The coefficients of farm size (X 5 ) were significant (P≤0.10) and positive for the application of herbicides, application of organic manure, increased application of fertilizer, and mulching/ use of cover crop.The positive coefficient of farm size suggests that an increase in farm size in each of the five adaptation strategies when other explanatory variables are held constant, will bring about an increase in output.All things being equal, an increase in farm size implies that more input would be required, more plant stands cultivated and consequently, more output expected, if there is good management.The significant relationship between output and farm size also stresses the importance of land in peasant agriculture, where the popular mode of production is extensive instead of intensive farming.The statistically insignificant coefficient of land for improved crop variety could be attributable to the fact that respondents who practice the strategy practiced intensive agriculture.

CONCLUSION AND RECOMMENDATIONS
The study analyzed the input-output relationship of crop enterprises under various climate change adaptation strategies among farmers in Borno State, Nigeria.It concludes that farmers predominantly employ technologically-based adaptation strategies, and the yield of crops in these strategies is significantly influenced by production inputs.The study recommends: 1. Providing adaptation materials such as improved crop varieties, fertilizers, and herbicides to farmers at subsidized rates.This will enhance their capacity to adopt cost-effective and promising adaptation strategies, 2. Promoting and improving access to relevant climaterelated information for communities throughout the study area.

Figure 1 .
Figure 1.Map of Borno State showing Ecological Zones.Source: Department of Geography, University of Maiduguri (2019).

Table 1 .
Distribution of respondents based on adaptation strategies.

Table 2 .
Regression Estimates of inputs-output relationship in the different climate change adaptation strategies practiced by farmers., **, ***: Significant at P ≤0.01, P ≤0.05 and P ≤0.10 respectively.Figures in parentheses are standard errors.AH = Application of Herbicides, AOM = Application of Organic Manure, EP = Early Planting, IFA= Increased Fertilizer Application, MUCC = Mulching and Use of Cover Crops, and UICV = Use of Improved Crop Varieties tolerant to new Climate Regime.Source: Regression Extract, 2018. *