Arima and Arimax Analysis on The Effect of Variability of Rainfall, Temperature, Humidity on Some Selected Crops in Nasarawa State

International Journal of Research and Innovation in Applied Science (IJRIAS) | Volume VI, Issue IX, September 2021|ISSN 2454-6194

Arima and Arimax Analysis on The Effect of Variability of Rainfall, Temperature, Humidity on Some Selected Crops in Nasarawa State

Musa, Salisu Auta¹; Dr. Yahaya, Baba Usman²; Musa, Ganaka Kubi³; Ahmad, Nafisatu Tanko⁴ and Saidu, Ibrahim Baba^5
1-5Department of Mathematics and Statistics, Federal Polytechnic, Nasarawa, Nasarawa State, Nigeria

Abstract: Crops production are highly sensitive to climate change. They are affected by long-term trends in average rainfall temperature and humidity. This study examines the effects of the variability of rainfall, temperature and humidity on some selected crops (rice and yam) in Nasarawa using autoregressive integrated moving averages (ARIMA) and autoregressive integrated moving averages with exogenous variables (ARIMAX). This research compare ARIMA modeling method which make forecast in univariate data and ARIMAX as multivariate method which include independent variables such as rainfall, temperature and humidity. The data for the study were collected from the Nasarawa Agricultural Development programme (NADP) for the period of twenty-three years from (1998 – 2020). The data collected were analyzed using ARIMA and ARIMAX models. The results from the analysis indicates that rainfall and humidity has negative and significant effect on yam production. However, rainfall and humidity has insignificant effect on rice production. Also, the forecast performance evaluation revealed that ARIMAX model performed better in modelling production of yam while the ARIMA model performed better in modelling production of rice in the study area.

Keyword: ARIMA, ARIMAX, Forecasting, NADP, Modeling, variability

I. INTRODUCTION

Agriculture is the main economic activity in Nasarawa state. Nasarawa state agricultural development programme observes that farming in the state is subsistence and generally rain fed cultivation of annual crops (Victor, 2018). Crops grown include grains such as rice, wheat, soybeans, maize and millet and tubers crops such as yam and cassava. The bulk of crop production in Nasarawa state is undertaken by small scale farmers most of whose labour force, management and capital originate from the household. Agriculture employs the large percentage of working population in the state. However, Climate change and variability are becoming a strong threat for food security in the twenty first century, particular for the agriculture dependent Sub-Saharan African countries (Eva, 2019).
Crop production is highly sensitive to climate change. It is affected by long-term trends in average rainfall temperature, intern-annual climate variability, shocks during specific phonological stages, and extreme weather events (ICPP, 2012). Some crops are more tolerant than other to

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