Investigation of the optimum planting dates for maize varieties using a hybrid approach: A case of Hwedza, Zimbabwe

Abstract

Water scarcity and unreliable weather conditions frequently cause smallholder farmers in Zimbabwe to plant maize ( Zea mays L.) varieties outside the optimum planting timeframe. This challenge exacts the necessity to develop sowing management options for decision support. The study's objective was to use a hybrid approach to determine the best planting windows and maize varieties. The combination will guide farmers on planting dates, dry spell probability during critical stages of the crop growth cycle and rainfall cessation. To capture farmer's perception on agroclimatic information, a systematic random sampling of 438 smallholders was carried out. An analysis of climatic data during 1949–2012 was conducted using INSTAT to identify the best planting criterion. The best combination of planting criterion and maize varieties analysis was then achieved by optimizing planting dates and maize varieties in the DSSAT environment. It was found that 56.2% of farmers grew short-season varieties, 40.2% medium-season varieties and 3.6% long-season varieties. It was also established that the number of rain days and maize yield had a strong positive relationship (p = 0.0049). No significant association was found amongst maize yield (p > 0.05), and planting date criteria, Depth (40mm in 4 days), the AREX criterion- Agricultural Research Extension (25 mm rainfall in 7 days) and the MET Criterion-Department of Meteorological Services (40 mm in 15 days). Highest yields were simulated under the combination of medium-season maize variety and the AREX and MET criteria. The range of simulated yields from 0.0 t/ha to 2.8 t/ha formed the basis for the development of an operational decision support tool (cropping calendar) with (RMSE) (0.20). The methodology can be used to select the best suitable maize varieties and a range of planting time.

Efficacy of Adaptation of Smallholder Maize Production to Climate Variability in Selected Countries of Kenya

“…Although affordable, smallholders may be challenged in determining when to commence planting. Mugiyo et al (2021) found that there was no consistency in the dates reported by farmers as the early planting date. The findings suggest that accurate identification of appropriate planting time could facilitate the practice of changing planting dates.…”

Onset of Rainfall and Cumulative Analysis for Sorghum Cultivation in Baringo County

“…Mhizha et al, (2014a) & Raes et al, (2004), descriptions in which they defined agricultural rain (wet) day occurs when an area receives 4.95 mm or more of rainfall, 2.95 mm or more of rainfall is a rainy day, any day that accumulates less than 2.95 mm of rain is a dry day and at least 100 mm of rain within five consecutive days is waterlogging [26]. Looking at the geographical location, a rainfall of more than 2.5 mm as a rainy day and less than 2.5 mm as a dry day was adopted in Baringo having applied the Indian Institute of Tropical Meteorology (IMD) that defined ‗dry days' as continuous period with daily rainfall equal to or less than daily mean rainfall over the area of interest [27].…”

Efficacy of Adaptation of Smallholder Maize Production to Climate Variability in Selected Countries of Kenya

“…The findings suggest that accurate identification of appropriate planting time could facilitate the practice of changing planting dates. Mugiyo et al (2021) therefore recommended the establishment of a crop calendar to facilitate the selection of planting time with respect to specific crop varieties.…”