Reynolds, Robert Douglas2025-01-222025-01-222007https://hdl.handle.net/10182/17995Dry matter production of kale (Brassica oleracea) and turnips (Brassica campestris) was studied in the Lees Valley, Canterbury, during one cropping season. The rainfall over the summer period was very low, and so moisture stress had a large influence on dry matter yields. Peak yields were 3.6 and 6.2 t DM/ha for turnips and kale respectively. There was no significant effect of nitrogen or phosphate treatments on yield of turnips; however nitrogen significantly increased the leaf yield of kale at one harvest date by 42.7%. This was a nitrogen response of 72.3 kgDM/ha/kgN. Radiation interception changed over time due to changes in the leaf canopies caused by environmental factors. The drought combined with insect damage caused much leaf senescence at first, resulting in a low radiation interception. The leaf canopies redeveloped after autumn rain and so radiation interception increased, until winter frosts caused a decline in leaf dry matter. At all stages of growth kale intercepted more radiation than turnips. The yield changed over time according to pressures imposed on the crops by drought and frost. Turnip yield decreased by 32% between 28/02/07 and 08/05/07 due to drought. The yield then increased by 32% as it recovered in late autumn, but then decreased by 47% due to frost in winter. Kale yield continued to increase throughout the drought, but decreased by 32% in winter. The turnip population declined over time from 48 plants/m² on 21/03/07 to 28 plants/m² on 25/07 /07, due to drought and frost damage. The leaf to bulb ratio of turnips also declined significantly over time from a high of 1.81 on 21/03/07 to a low of 0.43 on 25/07/07. Drought decreased leaf dry matter and had a minimal effect on bulb weight, while frost reduced leaf dry matter more than it reduced bulb weight. Both drought and frost damage resulted in a decline in leaf to bulb ratio. In a dryland environment that is likely to encounter significant summer drought kale will probably deliver a greater dry matter yield than turnips. Nitrogen should be applied if the soil cannot provide enough N for the yield potential of the site.x, 58 pageshttps://researcharchive.lincoln.ac.nz/pages/rightsBrassica campestris L.Brassica oleraceadroughtdry matter accumulationGreen Globeradiation interceptionyieldSovereignDissertationDigital thesis can be viewed by current staff and students of Lincoln University only. If you are the author of this item, please contact us if you wish to discuss making the full text publicly available.ANZSRC::300406 Crop and pasture improvement (incl. selection and breeding)ANZSRC::300802 Horticultural crop growth and developmentANZSRC::300201 Agricultural hydrology