Browsing by Author "Silwana, Sibongiseni"
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- ItemWheat and canola establishment in the Western Cape : openers, nitrogen placement and planting depth(Stellenbosch : Stellenbosch University, 2019-04) Silwana, Sibongiseni; Swanepoel, Pieter Andreas; Le Roux, M. R.; Stellenbosch University. Faculty of Agrisciences. Dept. of Agronomy.ENGLISH ABSTRACT: Wheat, the main cereal crop and canola, the main oilseed crop are the two most prominent crops established in the Western Cape under dryland conditions. Tine openers are most commonly used to establish these crops, but disc – and double chute openers are emerging as viable alternatives. The suitable planting depth for each opener has not yet been evaluated in the Western Cape. These openers place nitrogen (N) fertiliser at different depth in soil. Tine openers place N below the seed and disc openers mix N with seed and place it at the same depth. The double chute places N fertilser in between two twin rows of seed. The aim of the study was to determine the efficiency of establishment of wheat and canola using a tine, disc, and double chute openers, with different fertiliser placement.This study was divided into three trials, each with a specific objective: i) The first trial was conducted in a growth room to determine the effect of N rate on wheat and canola sown at different depths (1, 2, 4, and 8 cm) and in different soil types. ii) The second trial was conducted in the field to evaluate the effectiveness of a tine or disc opener to establish canola and wheat at different depths. iii) The third was another field trial to evaluate the efficiency of tine, disc, and double chute openers on wheat and canola establishment. There was no clear effect of N rate in almost all soil types for wheat and canola, but planting depth had an effect (Objective i). Most established well when sown at depths of 1 or 2 cm. Though overall canola seed establishment was poor in most soils, it is possible that the canola seeds or seedlings were damaged by coming into contact with the N fertiliser since it was previously observed that canola seeds are sensitive to N fertiliser. The tine opener planted the seed acurate at a deeper depth (Objective ii), while the disc opener planted the seed well at a shallower depth, particularly for wheat. In contrast, for canola, planting depth was not successfully controlled by either tine or disc opener. Wheat and canola seeds were affected by the N fertiliser placement (Objective iii). When the double chute and tine openers were used in placing N fertiliser, the differences were significant in comparison to when N was broadcasted or placed using the disc opener. Plant population and biomass production was determined after 30, 60, 90 and 120 days of plant emergence, while the leaf area index (LAI) was only determinedafter 30, 60 and 90 days of plant emergence. Yield was also quantified. In most cases there were no differences between broadcasted N (control) and the disc opener for plant population, biomass production and LAI; yet, there were noticeable differences to double chute and tine opener with regard to plant population, biomass production and LAI. No yield differences were observed between the various openers.