Pub Date : 2022-10-04DOI: 10.1080/02571862.2022.2104946
Z. A. Belay, N. E. Nyamende, O. J. Caleb
Cold plasma technology has been used within the food industry for surface decontamination. Therefore, this study investigated the efficacy of low-pressure cold plasma (CP) treatment to decontaminate sodium alginate-coated and packaged ‘Monterey’ strawberries. Cold plasma treatment was carried out at 80 kV for 5 min. After treatments, samples were stored at 5 °C for six days, and samples were taken at regular intervals for microbial and visual quality analysis. Results obtained showed that coated strawberries without CP treatment packed in clamshell trays had a better visual appearance than the other treatments and control at the end of storage. Application of sodium alginate coating and CP treatment on strawberries resulted in ≈2 Log reduction in yeast and mould counts at the end of storage in comparison to the control (p < 0.05).
{"title":"Impact of cold plasma-mediated treatment on coated and packaged ‘Monterey’ strawberries during cold storage","authors":"Z. A. Belay, N. E. Nyamende, O. J. Caleb","doi":"10.1080/02571862.2022.2104946","DOIUrl":"https://doi.org/10.1080/02571862.2022.2104946","url":null,"abstract":"Cold plasma technology has been used within the food industry for surface decontamination. Therefore, this study investigated the efficacy of low-pressure cold plasma (CP) treatment to decontaminate sodium alginate-coated and packaged ‘Monterey’ strawberries. Cold plasma treatment was carried out at 80 kV for 5 min. After treatments, samples were stored at 5 °C for six days, and samples were taken at regular intervals for microbial and visual quality analysis. Results obtained showed that coated strawberries without CP treatment packed in clamshell trays had a better visual appearance than the other treatments and control at the end of storage. Application of sodium alginate coating and CP treatment on strawberries resulted in ≈2 Log reduction in yeast and mould counts at the end of storage in comparison to the control (p < 0.05).","PeriodicalId":21920,"journal":{"name":"South African Journal of Plant and Soil","volume":"39 1","pages":"302 - 307"},"PeriodicalIF":0.9,"publicationDate":"2022-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45676559","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-04DOI: 10.1080/02571862.2022.2103192
S. Laurie, WM Mphela
In South Africa, the processing of sweet potatoes has a high potential for economic gain, therefore, chips were prepared from six sweet potato cultivars with varying flesh colours for consumer preference evaluation. Scoring was based on colour, crispness, taste and overall ranking by four groups of a total of 159 people at distinct locations. Instrumental assessment included colour measurement of chips, and dry mass and total carotenoid content of fresh roots. Analysis of variance, principal component analysis and Pearson correlation analysis were performed. Significant differences were found in taste/flavour, crispness and overall consumer ranking as well as for all instrumental measurements among chips made from the different cultivars. Orange-fleshed cultivars Bophelo, W-119 and Beauregard had values of 108.27, 112.37 and 113.33 µg/g for total carotenoids, respectively. The six cultivars were grouped into three clusters based on overall consumer rating, crispness, carotenoid content, colour a*, taste/flavour, oxidation and dry mass, colour L* and appearance. The results indicate that cultivars Beauregard and Bophelo can be recommended for making fried chips for South African consumers.
{"title":"Consumer acceptability of fried chips made from South African sweet potato cultivars","authors":"S. Laurie, WM Mphela","doi":"10.1080/02571862.2022.2103192","DOIUrl":"https://doi.org/10.1080/02571862.2022.2103192","url":null,"abstract":"In South Africa, the processing of sweet potatoes has a high potential for economic gain, therefore, chips were prepared from six sweet potato cultivars with varying flesh colours for consumer preference evaluation. Scoring was based on colour, crispness, taste and overall ranking by four groups of a total of 159 people at distinct locations. Instrumental assessment included colour measurement of chips, and dry mass and total carotenoid content of fresh roots. Analysis of variance, principal component analysis and Pearson correlation analysis were performed. Significant differences were found in taste/flavour, crispness and overall consumer ranking as well as for all instrumental measurements among chips made from the different cultivars. Orange-fleshed cultivars Bophelo, W-119 and Beauregard had values of 108.27, 112.37 and 113.33 µg/g for total carotenoids, respectively. The six cultivars were grouped into three clusters based on overall consumer rating, crispness, carotenoid content, colour a*, taste/flavour, oxidation and dry mass, colour L* and appearance. The results indicate that cultivars Beauregard and Bophelo can be recommended for making fried chips for South African consumers.","PeriodicalId":21920,"journal":{"name":"South African Journal of Plant and Soil","volume":"39 1","pages":"290 - 298"},"PeriodicalIF":0.9,"publicationDate":"2022-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47939258","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-04DOI: 10.1080/02571862.2022.2104945
M. Mabika, N. Mapope, CC Chinheya, E. Ngadze, E. Carstens
Pests associated with the fruit pathway are the determining factor in market access negotiations. Unconfirmed records of the occurrence and distribution of a pest in a country can lead to disputes. A report published in 1980 indicated that Monilinia fructicola is present in Zimbabwe and therefore hindering both market access and negotiations for access to new export markets for fresh stone fruit. To confirm this report, as stone fruit exports are an important foreign exchange earner for Zimbabwe, detection surveys were conducted in 2019 in the stone fruit production areas. The identities of fungal isolates were verified by using morphological and molecular characterisation. None of the fungal isolates tested positive for Monilinia species. This study confirmed that M. fructicola is not present in Zimbabwe and that stone fruit rot in Zimbabwe is not caused by Monilinia species. Therefore, the status of M. fructicola in Zimbabwe can be reported as: ‘Absent: pest records invalid’.
{"title":"Monilinia fructicola is not the causal agent of stone fruit rot in Zimbabwe","authors":"M. Mabika, N. Mapope, CC Chinheya, E. Ngadze, E. Carstens","doi":"10.1080/02571862.2022.2104945","DOIUrl":"https://doi.org/10.1080/02571862.2022.2104945","url":null,"abstract":"Pests associated with the fruit pathway are the determining factor in market access negotiations. Unconfirmed records of the occurrence and distribution of a pest in a country can lead to disputes. A report published in 1980 indicated that Monilinia fructicola is present in Zimbabwe and therefore hindering both market access and negotiations for access to new export markets for fresh stone fruit. To confirm this report, as stone fruit exports are an important foreign exchange earner for Zimbabwe, detection surveys were conducted in 2019 in the stone fruit production areas. The identities of fungal isolates were verified by using morphological and molecular characterisation. None of the fungal isolates tested positive for Monilinia species. This study confirmed that M. fructicola is not present in Zimbabwe and that stone fruit rot in Zimbabwe is not caused by Monilinia species. Therefore, the status of M. fructicola in Zimbabwe can be reported as: ‘Absent: pest records invalid’.","PeriodicalId":21920,"journal":{"name":"South African Journal of Plant and Soil","volume":"39 1","pages":"299 - 301"},"PeriodicalIF":0.9,"publicationDate":"2022-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49665458","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-30DOI: 10.1080/02571862.2022.2079741
Trevan Flynn, Liesl Wiese, Andrei Rozanov
The change from grasslands and natural shrubs to afforested arable land has a major impact on soil organic carbon (SOC) stocks. Grasslands are known to be SOC sinks as seen in the Chernozems of North America, Eurasia and South Africa. However, determining the SOC stocks of soils can be financially costly as each location must be sampled in depth increments. This study aimed to estimate the SOC stocks for the Mvoti catchment (30° 48′ E and 29° 18′ S) in Kwa-Zulu Natal, South Africa by developing depth functions on a limited number of soil samples and expanding these functions to known land-uses and soil types. The results showed that splines captured the short-term vertical distribution of SOC better than exponential decay functions, which has major implications on arable lands. Long-term forest plantations showed a positive correlation with SOC stocks (32.7 kg m−2), while annual crop cultivation (27.0 kg m−2) showed a negative correlation when compared to natural grasslands (28.8 kg m−2). The Cubist algorithm predicted the total SOC stock of the catchment area at between 12 248 and 17 624 Mg depending on the depth function used. Soils with yellow-brown subsoils tend to have higher SOC stocks and the lowest degree of uncertainty.
从草地和天然灌木到人工造林耕地的变化对土壤有机碳(SOC)储量有重要影响。在北美、欧亚大陆和南非的黑钙土中可以看到，草原是已知的碳汇。然而，确定土壤的有机碳储量在经济上是昂贵的，因为每个地点都必须以深度增量的方式采样。本研究旨在通过在有限数量的土壤样本上开发深度函数，并将这些函数扩展到已知的土地利用和土壤类型，估计南非夸祖鲁纳塔尔省Mvoti流域(东经30°48′和南纬29°18′)的有机碳储量。结果表明，样条曲线比指数衰减函数更能反映土壤有机碳的短期垂直分布，这对耕地土壤有机碳具有重要意义。长期人工林与土壤有机碳储量呈正相关(32.7 kg m−2)，而常年作物栽培与自然草地(28.8 kg m−2)呈负相关(27.0 kg m−2)。根据深度函数的不同，Cubist算法预测集水区SOC总储量在12 248 ~ 17 624 Mg之间。黄褐色底土的土壤有机碳储量较高，不确定度最低。
{"title":"Soil carbon stock assessment using depth and spatial models on afforested arable lands","authors":"Trevan Flynn, Liesl Wiese, Andrei Rozanov","doi":"10.1080/02571862.2022.2079741","DOIUrl":"https://doi.org/10.1080/02571862.2022.2079741","url":null,"abstract":"The change from grasslands and natural shrubs to afforested arable land has a major impact on soil organic carbon (SOC) stocks. Grasslands are known to be SOC sinks as seen in the Chernozems of North America, Eurasia and South Africa. However, determining the SOC stocks of soils can be financially costly as each location must be sampled in depth increments. This study aimed to estimate the SOC stocks for the Mvoti catchment (30° 48′ E and 29° 18′ S) in Kwa-Zulu Natal, South Africa by developing depth functions on a limited number of soil samples and expanding these functions to known land-uses and soil types. The results showed that splines captured the short-term vertical distribution of SOC better than exponential decay functions, which has major implications on arable lands. Long-term forest plantations showed a positive correlation with SOC stocks (32.7 kg m−2), while annual crop cultivation (27.0 kg m−2) showed a negative correlation when compared to natural grasslands (28.8 kg m−2). The Cubist algorithm predicted the total SOC stock of the catchment area at between 12 248 and 17 624 Mg depending on the depth function used. Soils with yellow-brown subsoils tend to have higher SOC stocks and the lowest degree of uncertainty.","PeriodicalId":21920,"journal":{"name":"South African Journal of Plant and Soil","volume":"39 1","pages":"235 - 247"},"PeriodicalIF":0.9,"publicationDate":"2022-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48259820","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-19DOI: 10.1080/02571862.2022.2086308
JR van der Nest, A. Hardie, J. Labuschagne, Paul Swanepoel
No-tillage systems and slow movement of surface-applied limestone can lead to stratification of soil acidity. Incorporation of lime by tilling soil is not preferred by producers following conservation agriculture practices. There is limited research on ways to facilitate lime movement without soil disturbance. This study aimed to determine the effects of form, fineness and calcium carbonate equivalent (CCE) of calcitic lime on its movement in soil with or without different soil disturbance actions and consequent effects on productivity of barley (Hordeum vulgare L.) and canola (Brassica napus L.). A field trial was established in the Western Cape province, South Africa. Ten treatments included a control, lime with different forms and fineness, and tillage practices. Due to the slow movement and reactivity of lime in soil, it was unlikely that growth responses from barley or canola would be detected within the first two years following liming. A once-off strategic tillage action promoted crop growth. This was attributed to deeper redistribution of lime in the soil (15–30 cm depth), among secondary agronomic responses to tillage. Strategic once-off tillage may address the stratification of both soil acidity and nutrients, such as calcium (Ca) and magnesium (Mg), and could be considered as an option to incorporate into management of no-tillage production systems.
{"title":"Effects of form, fineness and placement of lime with and without soil tillage on barley and canola growth and development","authors":"JR van der Nest, A. Hardie, J. Labuschagne, Paul Swanepoel","doi":"10.1080/02571862.2022.2086308","DOIUrl":"https://doi.org/10.1080/02571862.2022.2086308","url":null,"abstract":"No-tillage systems and slow movement of surface-applied limestone can lead to stratification of soil acidity. Incorporation of lime by tilling soil is not preferred by producers following conservation agriculture practices. There is limited research on ways to facilitate lime movement without soil disturbance. This study aimed to determine the effects of form, fineness and calcium carbonate equivalent (CCE) of calcitic lime on its movement in soil with or without different soil disturbance actions and consequent effects on productivity of barley (Hordeum vulgare L.) and canola (Brassica napus L.). A field trial was established in the Western Cape province, South Africa. Ten treatments included a control, lime with different forms and fineness, and tillage practices. Due to the slow movement and reactivity of lime in soil, it was unlikely that growth responses from barley or canola would be detected within the first two years following liming. A once-off strategic tillage action promoted crop growth. This was attributed to deeper redistribution of lime in the soil (15–30 cm depth), among secondary agronomic responses to tillage. Strategic once-off tillage may address the stratification of both soil acidity and nutrients, such as calcium (Ca) and magnesium (Mg), and could be considered as an option to incorporate into management of no-tillage production systems.","PeriodicalId":21920,"journal":{"name":"South African Journal of Plant and Soil","volume":"39 1","pages":"260 - 269"},"PeriodicalIF":0.9,"publicationDate":"2022-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46138768","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-07-15DOI: 10.1080/02571862.2022.2087922
G. J. van Coller, F. Kloppers, V. Coetzee, Toinette van Rooyen, L. Rose, S. Lamprecht, A. Viljoen
Chemical control of a yield-limiting, quality-reducing wheat disease like Fusarium head blight (FHB) is an important management strategy; however, no fungicides are registered against it in South Africa. The aim of this study was to determine foliar fungicides and seed treatment efficacy for FHB management. Three commercial fungicides and two seed treatments were evaluated in a naturally infested field during 2011 and 2012. Significant interactions between the seed treatments and the foliar fungicides were obtained for FHB incidence and yield. When the fungicide Abacus® was sprayed in combination with either of the two seed treatments, FHB incidence was significantly decreased compared with use of the fungicide alone. Prosaro® sprayed in combination with Galmano® Plus as a seed treatment significantly decreased yield compared with the use of Prosaro alone or in combination with Vitavax® Plus as a seed treatment. The fungicide treatments significantly reduced FHB incidence and the percentage of Fusarium-damaged kernels (%FDK) when compared with control treatments, and significantly increased the yield. A weak but significant correlation was recorded between deoxynivalenol (DON) and %FDK. Strong negative correlations were observed between hectolitre mass (HLM) and FHB incidence and %FDK, respectively, and between yield and %FDK. These results indicate that the chemical control of FHB of wheat can be used to manage the disease in South Africa. Future research, therefore, must focus on integrating chemical control with host resistance to obtain optimal results.
小麦赤霉病(Fusarium head blight, FHB)是一种限制产量、降低品质的小麦病害，化学防治是一项重要的管理策略。然而，在南非没有杀菌剂登记。本研究的目的是确定叶面杀菌剂和种子处理对FHB管理的效果。2011年和2012年在自然侵染地对3种商业杀菌剂和2种种子处理进行了评价。种子处理与叶面杀菌剂对赤霉病发病率和产量有显著的交互作用。当杀菌剂Abacus®与两种种子处理中的任何一种联合喷洒时，与单独使用杀菌剂相比，FHB发病率显著降低。与单独使用Prosaro或与Vitavax®Plus联合使用相比，Prosaro®与Galmano®Plus联合喷洒作为种子处理显著降低了产量。与对照处理相比，杀菌剂处理显著降低了赤霉病发病率和赤霉病损粒率(%FDK)，显著提高了产量。脱氧雪腐镰刀菌烯醇(DON)与%FDK之间存在微弱但显著的相关性。百升质量(HLM)与赤霉病发生率、%FDK、产量与%FDK呈显著负相关。这些结果表明，小麦赤霉病的化学防治可用于南非小麦赤霉病的防治。因此，未来的研究必须注重将化学防治与宿主抗性结合起来，以获得最佳效果。
{"title":"Foliar fungicides provide chemical control of Fusarium head blight of wheat in South Africa","authors":"G. J. van Coller, F. Kloppers, V. Coetzee, Toinette van Rooyen, L. Rose, S. Lamprecht, A. Viljoen","doi":"10.1080/02571862.2022.2087922","DOIUrl":"https://doi.org/10.1080/02571862.2022.2087922","url":null,"abstract":"Chemical control of a yield-limiting, quality-reducing wheat disease like Fusarium head blight (FHB) is an important management strategy; however, no fungicides are registered against it in South Africa. The aim of this study was to determine foliar fungicides and seed treatment efficacy for FHB management. Three commercial fungicides and two seed treatments were evaluated in a naturally infested field during 2011 and 2012. Significant interactions between the seed treatments and the foliar fungicides were obtained for FHB incidence and yield. When the fungicide Abacus® was sprayed in combination with either of the two seed treatments, FHB incidence was significantly decreased compared with use of the fungicide alone. Prosaro® sprayed in combination with Galmano® Plus as a seed treatment significantly decreased yield compared with the use of Prosaro alone or in combination with Vitavax® Plus as a seed treatment. The fungicide treatments significantly reduced FHB incidence and the percentage of Fusarium-damaged kernels (%FDK) when compared with control treatments, and significantly increased the yield. A weak but significant correlation was recorded between deoxynivalenol (DON) and %FDK. Strong negative correlations were observed between hectolitre mass (HLM) and FHB incidence and %FDK, respectively, and between yield and %FDK. These results indicate that the chemical control of FHB of wheat can be used to manage the disease in South Africa. Future research, therefore, must focus on integrating chemical control with host resistance to obtain optimal results.","PeriodicalId":21920,"journal":{"name":"South African Journal of Plant and Soil","volume":"39 1","pages":"278 - 289"},"PeriodicalIF":0.9,"publicationDate":"2022-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45601530","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-05-27DOI: 10.1080/02571862.2022.2069874
Zoleka Ncoyini-Manciya, M. J. Savage, S. Strydom, A. Clulow
Global warming is widely recognised, and its effects are becoming apparent throughout the world. Evaporation and evapotranspiration, the key components of the hydrological cycle, are generally expected to increase due to the rise in air and surface temperatures. However, previous studies suggest a decrease in these phenomena despite the observed global warming. The decreasing evaporation and evapotranspiration have been attributed to various factors. In this study, reference evapotranspiration (ETo) trends estimated using the Penman-Monteith method were studied over the KwaZulu-Natal midlands area of South Africa for the period 1997–2017. This study employed the Mann–Kendall test and linear regression model to analyse annual and seasonal ETo trends. In addition, the trends of climate parameters and their contribution towards ETo variation were analysed. The results indicate a generally decreasing ETo trend for most weather stations studied over the study period. The climate variables analysed indicate an average decreasing trend in wind speed, solar irradiance, and relative humidity while average air temperature exhibited no significant change. Relative humidity and solar irradiance were found to greatly influence ETo variation in the study area. We therefore conclude that atmospheric condition studies should consider both local and global climate phenomena to understand the actual drivers of change in any atmospheric factor.
{"title":"Long-term reference evapotranspiration trend and causative factors analysis in the sugarbelt area of the midlands of KwaZulu-Natal, South Africa","authors":"Zoleka Ncoyini-Manciya, M. J. Savage, S. Strydom, A. Clulow","doi":"10.1080/02571862.2022.2069874","DOIUrl":"https://doi.org/10.1080/02571862.2022.2069874","url":null,"abstract":"Global warming is widely recognised, and its effects are becoming apparent throughout the world. Evaporation and evapotranspiration, the key components of the hydrological cycle, are generally expected to increase due to the rise in air and surface temperatures. However, previous studies suggest a decrease in these phenomena despite the observed global warming. The decreasing evaporation and evapotranspiration have been attributed to various factors. In this study, reference evapotranspiration (ETo) trends estimated using the Penman-Monteith method were studied over the KwaZulu-Natal midlands area of South Africa for the period 1997–2017. This study employed the Mann–Kendall test and linear regression model to analyse annual and seasonal ETo trends. In addition, the trends of climate parameters and their contribution towards ETo variation were analysed. The results indicate a generally decreasing ETo trend for most weather stations studied over the study period. The climate variables analysed indicate an average decreasing trend in wind speed, solar irradiance, and relative humidity while average air temperature exhibited no significant change. Relative humidity and solar irradiance were found to greatly influence ETo variation in the study area. We therefore conclude that atmospheric condition studies should consider both local and global climate phenomena to understand the actual drivers of change in any atmospheric factor.","PeriodicalId":21920,"journal":{"name":"South African Journal of Plant and Soil","volume":"39 1","pages":"204 - 212"},"PeriodicalIF":0.9,"publicationDate":"2022-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48625523","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-05-27DOI: 10.1080/02571862.2022.2043470
D. Du Toit, P. Swanepoel, A. Hardie
Little information is available regarding the liming efficiency of various local lime sources and products currently available in South Africa. Recently, granulated micro-fine limes are being widely marketed as being superior to class A limes. Therefore, the aim of this study was to compare the effectiveness of various local, commercially available hydrated, calcitic and dolomitic lime sources (i.e., from different quarries) and forms (class A, micro-fine and granulated micro-fine) at increasing soil pH over time (365 days) under controlled conditions in two contrasting acid soils (sand and loam). Liming materials were applied adjusted for calcium carbonate equivalence (CCE) to achieve a target pHKCl of 5.5 and incubated at 85% field capacity. Micro-fine calcitic limes and hydrated limes increased pH the fastest (first 30–60 days), but the difference between these materials and class A limes attenuated over time. The difference in performance between class A limes was relatively minor (0.5 pH units), if applied based on CCE. Chemical purity (Ca%, CCE) was the main factor controlling liming effectiveness and particle fineness only related to the short-term reaction (4–7 days). Granulated limes showed the poorest performance in terms of pH correction attributed to poor solubility and spatial zonation of liming effects.
{"title":"Effect of lime source, fineness and granulation on neutralisation of soil pH","authors":"D. Du Toit, P. Swanepoel, A. Hardie","doi":"10.1080/02571862.2022.2043470","DOIUrl":"https://doi.org/10.1080/02571862.2022.2043470","url":null,"abstract":"Little information is available regarding the liming efficiency of various local lime sources and products currently available in South Africa. Recently, granulated micro-fine limes are being widely marketed as being superior to class A limes. Therefore, the aim of this study was to compare the effectiveness of various local, commercially available hydrated, calcitic and dolomitic lime sources (i.e., from different quarries) and forms (class A, micro-fine and granulated micro-fine) at increasing soil pH over time (365 days) under controlled conditions in two contrasting acid soils (sand and loam). Liming materials were applied adjusted for calcium carbonate equivalence (CCE) to achieve a target pHKCl of 5.5 and incubated at 85% field capacity. Micro-fine calcitic limes and hydrated limes increased pH the fastest (first 30–60 days), but the difference between these materials and class A limes attenuated over time. The difference in performance between class A limes was relatively minor (0.5 pH units), if applied based on CCE. Chemical purity (Ca%, CCE) was the main factor controlling liming effectiveness and particle fineness only related to the short-term reaction (4–7 days). Granulated limes showed the poorest performance in terms of pH correction attributed to poor solubility and spatial zonation of liming effects.","PeriodicalId":21920,"journal":{"name":"South African Journal of Plant and Soil","volume":"39 1","pages":"163 - 174"},"PeriodicalIF":0.9,"publicationDate":"2022-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44259158","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-05-27DOI: 10.1080/02571862.2022.2059115
Trevan Flynn, A. Rozanov, F. Ellis, W. D. de Clercq, C. Clarke
This study involved the evaluation of farm-scale digital soil classification in the Sandspruit catchment of the Western Cape Province, South Africa. The study aimed to evaluate a digital soil mapping (DSM) method, from feature selection, spatial predictions and sample design. The results showed that feature selection with the least absolute shrinkage and selection operator (LASSO) technique is a robust method as it had a high relative efficiency and achieved the highest accuracy for three out of the four soil classes predicted. This implies that covariate selection is the most notable aspect in DSM at the farm-scale. The top-performing predictive models achieved satisfactory results for soil associations (kappa = 0.64, accuracy = 74%), presence of a bleached topsoil (kappa = 0.64, accuracy = 74%) and soil depth (kappa = 0.48, accuracy = 74%), whereas only moderate results were achieved for soil texture (kappa = 0.43, accuracy = 66%). Lastly, the expert sampling locations had a higher average probability of occurrence (geographic and feature space distribution coverage) yet achieved similar performance to conditioned Latin hypercube sampling (cLHS).
{"title":"Farm-scale digital soil mapping of soil classes in South Africa","authors":"Trevan Flynn, A. Rozanov, F. Ellis, W. D. de Clercq, C. Clarke","doi":"10.1080/02571862.2022.2059115","DOIUrl":"https://doi.org/10.1080/02571862.2022.2059115","url":null,"abstract":"This study involved the evaluation of farm-scale digital soil classification in the Sandspruit catchment of the Western Cape Province, South Africa. The study aimed to evaluate a digital soil mapping (DSM) method, from feature selection, spatial predictions and sample design. The results showed that feature selection with the least absolute shrinkage and selection operator (LASSO) technique is a robust method as it had a high relative efficiency and achieved the highest accuracy for three out of the four soil classes predicted. This implies that covariate selection is the most notable aspect in DSM at the farm-scale. The top-performing predictive models achieved satisfactory results for soil associations (kappa = 0.64, accuracy = 74%), presence of a bleached topsoil (kappa = 0.64, accuracy = 74%) and soil depth (kappa = 0.48, accuracy = 74%), whereas only moderate results were achieved for soil texture (kappa = 0.43, accuracy = 66%). Lastly, the expert sampling locations had a higher average probability of occurrence (geographic and feature space distribution coverage) yet achieved similar performance to conditioned Latin hypercube sampling (cLHS).","PeriodicalId":21920,"journal":{"name":"South African Journal of Plant and Soil","volume":"39 1","pages":"175 - 186"},"PeriodicalIF":0.9,"publicationDate":"2022-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47057938","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-05-27DOI: 10.1080/02571862.2022.2062623
Samuel Kofi Tutu, H. R. Mloza Banda, C. Tfwala
Uncertainties about the effects of nutrient amendment on the culinary attributes of sweetpotato have limited fertiliser use in Eswatini. The study was carried out at a moist and dry location of Eswatini to investigate the culinary and nutritional attributes of sweetpotato cultivated with no amendments, cattle manure and/or inorganic fertiliser. Treatments were replicated three times in a 3 × 5 factorial arrangement using a randomised complete block design. Three sweetpotato varieties used: Ligwalagwala, Kenya White, and Lamngititi, with five nutrient amendments: no fertiliser/manure, 450 kg ha−1 NPK, 6 t ha−1 manure, 3 t ha−1 manure + 225 kg ha−1 NPK, and 4.5 t ha−1 manure + 112.5 kg ha−1 NPK. Yield differences of 59.8% and 47.3% over the control were recorded with Kenya White and 3 t ha−1 manure + 225 kg ha−1 NPK, and 4.5 t ha−1 manure + 112.5 kg ha−1 NPK at Malkerns and Luve, respectively. Protein, calcium, and magnesium content of the varieties improved under 4.5 t ha−1 manure + 112.5 kg ha−1 NPK amendments. Taste, flavour, palatability, and acceptability accounted for the greatest amount of culinary variability while soil amendments contributed the least. The present study suggests that nutrient amendments contribute to the agronomic performance and nutritional quality of sweetpotato.
营养改良对红薯烹饪特性影响的不确定性限制了斯威士兰的化肥使用。这项研究是在斯威士兰潮湿干燥的地方进行的，目的是调查不添加改良剂、牛粪和/或无机肥料种植的红薯的烹饪和营养特性。在3 × 使用随机完全区组设计的5因子排列。使用的三个红薯品种：Ligwalagwala、Kenya White和Lamngtiti，有五种营养改良剂：无肥料/粪肥，450 kg ha−1 NPK，6 t ha−1粪肥，3 t ha−一粪肥 + 225 kg ha−1 NPK和4.5 t ha−1粪肥 + 112.5 kg ha−1 NPK。与对照相比，肯尼亚白和3 t ha−1肥料的产量差异分别为59.8%和47.3% + 225 kg ha−1 NPK和4.5 t ha−1粪肥 + 112.5 kg ha−1 NPK。施用4.5t ha−1肥料后，改良品种的蛋白质、钙和镁含量 + 112.5 kg ha−1 NPK修正案。味道、风味、适口性和可接受性是烹饪变化最大的原因，而土壤改良剂的影响最小。本研究表明，营养改良有助于甘薯的农艺性状和营养品质。
{"title":"Yield, nutritional composition, and consumer acceptability of sweetpotato cultivars cultivated with soil amendments in the Middleveld of Eswatini","authors":"Samuel Kofi Tutu, H. R. Mloza Banda, C. Tfwala","doi":"10.1080/02571862.2022.2062623","DOIUrl":"https://doi.org/10.1080/02571862.2022.2062623","url":null,"abstract":"Uncertainties about the effects of nutrient amendment on the culinary attributes of sweetpotato have limited fertiliser use in Eswatini. The study was carried out at a moist and dry location of Eswatini to investigate the culinary and nutritional attributes of sweetpotato cultivated with no amendments, cattle manure and/or inorganic fertiliser. Treatments were replicated three times in a 3 × 5 factorial arrangement using a randomised complete block design. Three sweetpotato varieties used: Ligwalagwala, Kenya White, and Lamngititi, with five nutrient amendments: no fertiliser/manure, 450 kg ha−1 NPK, 6 t ha−1 manure, 3 t ha−1 manure + 225 kg ha−1 NPK, and 4.5 t ha−1 manure + 112.5 kg ha−1 NPK. Yield differences of 59.8% and 47.3% over the control were recorded with Kenya White and 3 t ha−1 manure + 225 kg ha−1 NPK, and 4.5 t ha−1 manure + 112.5 kg ha−1 NPK at Malkerns and Luve, respectively. Protein, calcium, and magnesium content of the varieties improved under 4.5 t ha−1 manure + 112.5 kg ha−1 NPK amendments. Taste, flavour, palatability, and acceptability accounted for the greatest amount of culinary variability while soil amendments contributed the least. The present study suggests that nutrient amendments contribute to the agronomic performance and nutritional quality of sweetpotato.","PeriodicalId":21920,"journal":{"name":"South African Journal of Plant and Soil","volume":"39 1","pages":"187 - 197"},"PeriodicalIF":0.9,"publicationDate":"2022-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48000066","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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