Abstract
A study was conducted at the Zambia Agriculture Research Institute (ZARI), Central Research Station, Mount Makulu (latitude: 15.550° S, longitude: 28.250° E, altitude: 1213 m), Zambia to investigate the effects of sowing date (SD), maize (Zea mays L.) cultivars and 3 N fertilizer rates on yield and yield components. Maize cultivars were planted on 12th December, 2016 (SD1), 26th December, 2016 (SD2) and 9th January, 2017 (SD3). A split-split plot design was setup with SD, maize cultivars (ZMS 606, PHB 30G19 and PHB 30B50) and nitrogen rate (67.20, 134.40 and 201.60 kg N ha-1) as the main-plot, subplot and sub-subplot, respectively. The rainfall, solar radiation (Srad) and mean temperature at the experimental site during the 2016/2017 season were 930.17 mm, 18.93 MJ m-2 day-1 and 21.83°C, respectively. Analysis of variance for Split-split plot design was used to analyze maize yield and yield components and means separated at p≤5 using Tukey’s Tests. Results showed that the treatment effect of sowing date and cultivar was significant on biomass yield, harvest index, 100-grain weight, seed number m-2, cob length, and width. Seed number m-2, 100-grain weight, grain and biomass yield reduced with delay in sowing date. The reduction in grain yield from SD1-SD2 (1.91 t ha-1), SD1-SD3 (2.90 t ha-1) and SD2-SD3 (0.99 t ha-1) were 21.04, 31.83 and 13.83%, respectively. Therefore, it was concluded that maize grain yield and yield components are affected by SD, cultivar and N. Farmers could enhance maize yield by manipulating sowing date, cultivar selection and N as the most limiting nutrient in agriculture production systems. Key words: Biomass, corn cultivars, date of sowing, grain yield, leaf area index, nitrogen, total dry matter, yield.
Highlights
Maize (Zea mays L.) is the third most important cereal crop in the world after wheat and rice and is mainly grown for food, feed and as an industrial raw material (Lukeba et al, 2013)
Computed cumulative growing degree days (GDDs), crop heat units (CHUs), solar radiation (Srad), and precipitation at vegetative and reproductive stages, grain yield, growth duration, phenothermal index (PTI) and heat use efficiency (HUE) are shown in Table 5 and Table 66
Sowing date 1 (SD1) had more GDD, CHU, cumulative Srad and cumulative precipitation compared to SD2
Summary
Maize (Zea mays L.) is the third most important cereal crop in the world after wheat and rice and is mainly grown for food, feed and as an industrial raw material (Lukeba et al, 2013). It is grown across a wide range of climate mainly in humid subtropics and warmer temperate regions. In Zambia, maize is grown by small-scale (80%) and commercial (20%) farmers (Mulenga and Wineman, 2014).
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