Abstract
THE NITROGEN requirement of sugarcane in South Africa has been the subject of extensive research. Results of more than 200 trials conducted over the past four decades have shown that the response to applied N can be highly variable and that N use efficiency by the crop can be influenced by ecological factors such as season, rainfall, nature of the soil as well as cultural practices that include variety, irrigation, N form, rate, timing and method of N placement. Local research results are reviewed and specific outcomes that have modified N use efficiency include: Soil specific nitrogen fertiliser recommendations for the main agro-climatic zones that are based on soil organic matter status and the potential of the soil to release N; For advisory purposes, an analytical method based on Near Infra-red Reflectance Spectroscopy (NIRS) was pioneered to rapidly measure the organic matter and nitrogen mineralisation potential of soil; A new laboratory test to predict potential ammonia volatilisation losses from surface-applied urea fertiliser; Improved N fertiliser use efficiency through fertigation; Classification of sugarcane varieties into one of three categories of N use efficiency and the impact on N recommendations; The use of the leaf and stalk N/Si ratio as a predictor of risk from stalk borer damage; Development of robust leaf N thresholds using a continuous model Fourier function and the use of DRIS to more accurately diagnose the nitrogen status of sugarcane. In general, the adoption by growers of a number of these research outcomes over the past two decades has resulted in an improvement of fertiliser N use efficiency from 2.0 kg N/t of harvested cane in 1980 to the current level of about 1.45 kg N/t cane, without compromising average cane yields. This represents an overall improvement in irrigated areas of about 28% in N fertiliser use efficiency. Introduction In South Africa as in most other sugarcane growing countries, efficient fertiliser practices have contributed greatly to sugarcane productivity. This has largely been achieved through better management practices and advances in the development of soil and leaf testing methods for predicting the macro and micro nutrient fertiliser requirement of sugarcane. Nitrogen (N) is still undoubtedly the most influential plant nutrient in global sugarcane production, as too little can impact negatively on sucrose production and too much can cause lodging, reduced cane quality and increased risk of pest and disease infestation. Predicting the correct amount of nitrogen to apply to sugarcane remains the most difficult and elusive of all
Abstract from the paper’s OpenAlex record, shown for indexing and research. Copyright remains with the authors or the publisher. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 13
Claim · model-written summary
Sugarcane response to applied nitrogen was highly variable across trials.
Verbatim
e0“the response to applied N can be highly variable”
e1“sugarcane in South Africa”
Claim · model-written summary
Sugarcane nitrogen use efficiency was influenced by season, rainfall, soil, variety, irrigation and nitrogen application practices.
- Taxon
- sugarcanee1
- Outcome
- N use efficiencye0
- Qualifier
- season, rainfall, nature of the soil as well as cultural practices that include variety, irrigation, N form, rate, timing and method of N placemente0
- Setting
- South Africae1
Not reportedDirection
Verbatim
e0“N use efficiency by the crop can be influenced by ecological factors such as season, rainfall, nature of the soil as well as cultural practices that include variety, irrigation, N form, rate, timing and method of N placement”
e1“sugarcane in South Africa”
Claim · model-written summary
A soil specific nitrogen fertilizer recommendation system was developed for sugarcane agroclimatic zones.
- Taxon
- sugarcanee1
- Outcome
- Soil specific nitrogen fertiliser recommendationse0
- Qualifier
- based on soil organic matter status and the potential of the soil to release Ne0
Not reportedComparatorValue
Verbatim
e0“Soil specific nitrogen fertiliser recommendations for the main agro-climatic zones that are based on soil organic matter status and the potential of the soil to release N”
e1“sugarcane in South Africa”
Claim · model-written summary
NIRS was pioneered as a rapid advisory measure of soil organic matter and nitrogen mineralization potential for sugarcane.
- Taxon
- sugarcanee1
- Outcome
- organic matter and nitrogen mineralisation potential of soile0
- Qualifier
- rapidly measuree0
Not reportedComparatorValue
Verbatim
e0“an analytical method based on Near Infra-red Reflectance Spectroscopy (NIRS) was pioneered to rapidly measure the organic matter and nitrogen mineralisation potential of soil”
e1“sugarcane in South Africa”
Claim · model-written summary
A laboratory test was developed to predict ammonia volatilization losses from surface-applied urea fertilizer in sugarcane management.
- Taxon
- sugarcanee1
- Treatment
- surface-applied urea fertilisere0
- Outcome
- potential ammonia volatilisation lossese0
Not reportedComparatorValue
Verbatim
e0“A new laboratory test to predict potential ammonia volatilisation losses from surface-applied urea fertiliser”
e1“sugarcane in South Africa”
Claim · model-written summary
Fertigation improved sugarcane nitrogen fertilizer use efficiency.
Not reportedComparator
Verbatim
e0“Improved N fertiliser use efficiency through fertigation”
e1“sugarcane in South Africa”
Claim · model-written summary
Sugarcane varieties were classified into three nitrogen use efficiency categories affecting nitrogen recommendations.
Verbatim
e0“Classification of sugarcane varieties into one of three categories of N use efficiency and the impact on N recommendations”
Claim · model-written summary
Leaf and stalk nitrogen to silicon ratio was used to predict stalk borer damage risk in sugarcane.
Not reportedComparatorValue
Verbatim
e0“The use of the leaf and stalk N/Si ratio as a predictor of risk from stalk borer damage”
e1“sugarcane in South Africa”
Claim · model-written summary
A Fourier function supplied leaf nitrogen thresholds for sugarcane diagnosis.
Not reportedComparatorValue
Verbatim
e0“Development of robust leaf N thresholds using a continuous model Fourier function”
e1“sugarcane in South Africa”
Claim · model-written summary
DRIS was used for more accurate diagnosis of sugarcane nitrogen status.
Not reportedComparatorValue
Verbatim
e0“the use of DRIS to more accurately diagnose the nitrogen status of sugarcane”
Claim · model-written summary
Grower adoption of research outcomes improved sugarcane fertilizer nitrogen use efficiency from 2.0 to about 1.45 kg N per tonne cane.
Verbatim
e0“improvement of fertiliser N use efficiency from 2.0 kg N/t of harvested cane in 1980 to the current level of about 1.45 kg N/t cane”
e1“sugarcane in South Africa”
Claim · model-written summary
Average sugarcane yields were not compromised during improved nitrogen efficiency.
Verbatim
e0“without compromising average cane yields”
e1“sugarcane in South Africa”
Claim · model-written summary
Irrigated areas achieved about 28% improvement in sugarcane nitrogen fertilizer use efficiency.
Verbatim
e0“an overall improvement in irrigated areas of about 28% in N fertiliser use efficiency”
e1“sugarcane in South Africa”