Browsing by Author "Kok, E"

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A field experiment to evaluate the response of sugarcane varieties to waterlogging
(ASSCT, 2018) Salter, B; Park, G; Kok, E
RECENT PRODUCTIVITY REVIEWS in the Herbert and Central regions identified strong negative correlations between excessive rainfall and productivity. Waterlogging has a significant effect on sugarcane productivity. It was estimated that yield is reduced by 0.5 t/ha for every day the water-table is within 50 cm of the soil surface. Waterlogging tolerance of sugarcane varieties is not assessed in the current variety selection program. Identification of varieties that perform better under waterlogged conditions is based on anecdotal observations from the field, after a variety is released. If a variety’s tolerance to waterlogging was known closer to the time of release, growers could make informed decisions on whether particular varieties are best suited to their farm or blocks within their farm. A field experiment was conducted near Ingham where the waterlogging tolerance of eight sugarcane varieties was assessed.
Nitrogen availability from legume and past fertiliser history : ASSCT peer-reviewed paper
(ASSCT, 2019) Salter, B; Kok, E; Skocaj, DM; Schroeder, BL
It is likely that land-based activities within the Australian sugar industry have a negative effect on the quality of water in the Great Barrier Reef lagoon. Improvements to nitrogen use efficiency (NUE) are likely to require a greater understanding of processes affecting N availability, crop-N demand and uptake in sugarcane farming systems. Two issues associated with improving N management were investigated. Firstly, should fertiliser-N recommendations for ratoon crops be altered following a good legume fallow? Secondly, what contribution do past fertiliser-N management practices have on N uptake? Field experiments were established at Mackay. The first- and second-ratoon crops were fertilised at either 0 or 150 kg N/ha (0N; 150N). This followed a fallow period where a bare or soybean fallow were established and a plant crop that received 138 kg N/ha (bare fallow) or 18 kg N/ha (legume fallow). In the third and fourth-ratoon crops, due to a lack of any significant response to fallow management, the trial was altered to investigate the influence of previous N management on crop-N response. Plots either received 0N or 150N following a history of 0N or received 0N or 150N following a history of 150N. Crop-N uptake, leaf-N, soil mineral-N, crop yield and NUE data were collected. Results showed that the soybean fallow had no lasting N contribution through the crop cycle when N rates in the plant-cane crop were reduced as recommended in the SIX EASY STEPS. Based on this, fertilising ratoons at 'normal' N rates following legume fallows should be maintained. In the third-ratoon crop, where there was a history of 150N application, crop-N uptake was greater than where there was a history of 0N application. Cane yield at 0N was higher where there was history of 150N than 0N. These effects were not present in the fourth-ratoon crop. The results either showed a small fertiliser-history effect or were associated with greater N uptake by a crop in better condition.