ASSESSING THE EFFECTS OF RAINFALL VARIABILITY ON PLANTING DATES FOR MAIZE PRODUCTION IN SALIMA
Abstract
This study was done to assess the effects of rainfall variability on planting dates. It was done in Chipoka Extension Planning Area (EPA), Traditional Authority Ndindi in Salima district, central region of Malawi. Daily rainfall data for Salima district was analysed to come up with planting dates. The analysis was done using Instat+ version 3.37. To do this, the study used a definition of planting date as the first occasion from 1 November with 25mm rainfall or more, within a period of 3 days with no dry spell of 9 days or longer within the subsequent 21 days with a threshold value of 1mm. Results showed that the mean planting date for rainfed maize crops in Salima is 9 December with a standard deviation of 9 days. The normal planting period is between 30 November and 18 December. Variability of rainfall and planting dates was found to be minimal and the years in which planting was done very late were the years of El Nino or La Nina events. Climate change has various impacts on stability of weather elements such as precipitation and temperature. Owing to the same, rainfall variability has become an issue in rainfed agriculture in countries like Malawi where farming is the main way of making a living. This is so because agriculture depends on reliable weather patterns and it is a sector that employs a majority. The principal occupation of about 85% of Malawians is agriculture. Rainfall season in Malawi occurs during the warm-wet or summer season in the months of November to April. So, planting is done in November or December depending on the start of rainy season. The main rain bearing system during this time is Inter-Tropical convergence zone (ITCZ) which oscillates over Malawi from southern region, slowly to the central and northern regions making start of rains early in the southern region than the central and northern regions of Malawi. Therefore, planting dates are early in southern region. Another rain bearing system is congo air boundary. Having knowledge of planting dates can help farmers in planning for their farm operations including planting at the right time and avert the risk of early season dry spells.
Research summary
To do this, the study used a definition of planting date as the first occasion from 1 November with 25mm rainfall or more, within a period of 3 days with no dry spell of 9 days or longer within the subsequent 21 days with a threshold value of 1mm. Variability of rainfall and planting dates was found to be minimal and the years in which planting was done very late were the years of El Nino or La Nina events. The main rain bearing system during this time is Inter-Tropical convergence zone (ITCZ) which oscillates over Malawi from southern region, slowly to the central and northern regions making start of rains early in the southern region than the central and northern regions of Malawi. Having knowledge of planting dates can help farmers in planning for their farm operations including planting at the right time and avert the risk of early season dry spells.