Effect of Climatic Variability on Maize and Soybean Yield under High Input Farming System in Copperbelt Province, Zambia

Abstract

In many developing countries, the effect of climate change on agriculture is evaluated with reference to small scale farmers, mainly under low input systems. As a result, literature on climate variability and its effect on high input farming systems are scanty. We evaluated the impact of climatic variability on maize and soybean yield under a high input management system. The objectives of the study were to: (i) assess rainfall and temeperature variability at a high input farm (ii) evaluate the effect of rainfall and temperature on maize and soybean yield under high input management system. (iii) assess the impact of El Niño and La Niña on maize and soybean yield. Data for rainfall and temperature was obtained from Zambia Meteorological Department which was complimented by records from the weather station located at the study site. Yield data for both maize and soybean was provided by ZAMBEEF farm. The analysis covered 32 years from 1980 to 2012. Time series plot was used to investigate the trend in minimum and maximum temperature and seasonal rainfall. Correlations were done in SPSS to establish the strength and direction of association between climatic variables (temperature and seasonal rainfall) and maize and soybean yield. Multiple Regression in SPSS was then used to analyze variation in maize and soybean yield due to climatic variables. Results revealed that minimum temperature had an increasing linear trend of 0.3°C to 0.5 per decade while maximum temperature showed an increasing linear trend of 0.2°C to 0.3°C per decade. On the other hand, seasonal rainfall was variable with over the period studied. The variations in maize and soybean yield explained by seasonal rainfall and temperature was not significant with only 17.2% and 20.1% of the variation explained, respectively. Although there was no significant impact of both El Niño and La Niño on the yields of both crops, regression analysis revealed a negative relationship between El Niño and soybean yield and a positive relationship with maize yield and a positive relationship was revealed between La Niña and maize and soybean yields.