Pub Date : 2023-11-14DOI: 10.1080/02571862.2023.2248056
Pippa A Karsen, Elmi Lötze, Alexander J Valentine, Eleanor W Hoffman
AbstractTo ensure a high-quality, sustainable supply of South African indigenous honeybush (Cyclopia spp.) tea to domestic and international markets, a shift from wild harvesting practices to true-to-type clonal material is required. This study investigated the impact of stock plant rejuvenation period and seasonality, and the harvesting position of cutting material on stock plants, on the rooting success of four genotypes of Cyclopia subternata Vogel, the most widely cultivated honeybush species. Cutting rooting success varied between 65–94% in summer and 49–91% in autumn, whilst winter-rooted cuttings showed poor rooting success (0–7%). Cutting dry weight was positively correlated with rooting percentage (r = 0.647; p ≤ 0.001). The rooting success of cuttings was strongly impacted by internal stock plant factors, such as clonal effects, cutting position and rejuvenation period. The use of terminal, semi-hardwood cuttings collected in autumn, following 15 months of regrowth, is recommended to achieve acceptable-to-high rooting success. This study confirms that the clonal propagation of C. subternata via cuttings could be a viable option for the sustainable production of high-quality honeybush tea, provided the selection criteria of the stock plant material used as the cutting source is carefully considered.Keywords: cuttingclonesselectionphenologyrejuvenation AcknowledgementsThe authors are grateful for the funding provided by the Western Cape Department of Agriculture. Thank you to Dr Cecelia Bester from the Agricultural Research Council for the C. subternata plant material used in this research.
{"title":"Rooting potential of the ‘vleitee’ honeybush ( <i>Cyclopia subternata</i> ) as affected by growth season and the manipulation of stock plant characteristics","authors":"Pippa A Karsen, Elmi Lötze, Alexander J Valentine, Eleanor W Hoffman","doi":"10.1080/02571862.2023.2248056","DOIUrl":"https://doi.org/10.1080/02571862.2023.2248056","url":null,"abstract":"AbstractTo ensure a high-quality, sustainable supply of South African indigenous honeybush (Cyclopia spp.) tea to domestic and international markets, a shift from wild harvesting practices to true-to-type clonal material is required. This study investigated the impact of stock plant rejuvenation period and seasonality, and the harvesting position of cutting material on stock plants, on the rooting success of four genotypes of Cyclopia subternata Vogel, the most widely cultivated honeybush species. Cutting rooting success varied between 65–94% in summer and 49–91% in autumn, whilst winter-rooted cuttings showed poor rooting success (0–7%). Cutting dry weight was positively correlated with rooting percentage (r = 0.647; p ≤ 0.001). The rooting success of cuttings was strongly impacted by internal stock plant factors, such as clonal effects, cutting position and rejuvenation period. The use of terminal, semi-hardwood cuttings collected in autumn, following 15 months of regrowth, is recommended to achieve acceptable-to-high rooting success. This study confirms that the clonal propagation of C. subternata via cuttings could be a viable option for the sustainable production of high-quality honeybush tea, provided the selection criteria of the stock plant material used as the cutting source is carefully considered.Keywords: cuttingclonesselectionphenologyrejuvenation AcknowledgementsThe authors are grateful for the funding provided by the Western Cape Department of Agriculture. Thank you to Dr Cecelia Bester from the Agricultural Research Council for the C. subternata plant material used in this research.","PeriodicalId":21920,"journal":{"name":"South African Journal of Plant and Soil","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134900827","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 : 2023-10-19DOI: 10.1080/02571862.2023.2240736
Abraham S Steyn, Tshedza Matladi
AbstractSouth Africa is subject to large rainfall variability, with El Niño–Southern Oscillation (ENSO) being the most important driver across the summer rainfall region. The aim of this study was to relate ENSO phase to historical rainfall variability over the densely populated and economically important Gauteng province of South Africa. Monthly rainfall totals for the period 1960–2021 were used to calculate Standardised Precipitation Index (SPI) values at different timescales for five stations. The Oceanic Niño Index (ONI) was used to classify seasons according to ENSO phase. For each station, the number of wet, near-normal or dry seasons falling in a particular ENSO phase was tallied and used to calculate probabilities of occurrence. Results revealed spatial inhomogeneities despite the study area being relatively small. Analysis of 3- and 6-month periods revealed that dry conditions occur more frequently during spring and autumn El Niño events, but are very unlikely during summer and autumn La Niña events. Analysis of 12-month periods revealed that near-normal conditions occur most frequently regardless of ENSO phase, with an increased chance of experiencing wet as opposed to dry conditions under La Niña. This information can aid various decision-makers to make better use of seasonal climate predictions.Keywords: Oceanic Niño Index (ONI)probabilityStandardised Precipitation Index (SPI) AcknowledgementsClimate data supplied by the South African Weather Service (SAWS). The authors wish to extend their thanks to the Statistical Consultation Unit at the University of the Free State for their input.Conflict of interestThe authors declare that they have no conflict of interest.
{"title":"Assessing the influence of the El Niño–Southern Oscillation phase on rainfall variability in the Gauteng province of South Africa","authors":"Abraham S Steyn, Tshedza Matladi","doi":"10.1080/02571862.2023.2240736","DOIUrl":"https://doi.org/10.1080/02571862.2023.2240736","url":null,"abstract":"AbstractSouth Africa is subject to large rainfall variability, with El Niño–Southern Oscillation (ENSO) being the most important driver across the summer rainfall region. The aim of this study was to relate ENSO phase to historical rainfall variability over the densely populated and economically important Gauteng province of South Africa. Monthly rainfall totals for the period 1960–2021 were used to calculate Standardised Precipitation Index (SPI) values at different timescales for five stations. The Oceanic Niño Index (ONI) was used to classify seasons according to ENSO phase. For each station, the number of wet, near-normal or dry seasons falling in a particular ENSO phase was tallied and used to calculate probabilities of occurrence. Results revealed spatial inhomogeneities despite the study area being relatively small. Analysis of 3- and 6-month periods revealed that dry conditions occur more frequently during spring and autumn El Niño events, but are very unlikely during summer and autumn La Niña events. Analysis of 12-month periods revealed that near-normal conditions occur most frequently regardless of ENSO phase, with an increased chance of experiencing wet as opposed to dry conditions under La Niña. This information can aid various decision-makers to make better use of seasonal climate predictions.Keywords: Oceanic Niño Index (ONI)probabilityStandardised Precipitation Index (SPI) AcknowledgementsClimate data supplied by the South African Weather Service (SAWS). The authors wish to extend their thanks to the Statistical Consultation Unit at the University of the Free State for their input.Conflict of interestThe authors declare that they have no conflict of interest.","PeriodicalId":21920,"journal":{"name":"South African Journal of Plant and Soil","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135779399","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 : 2023-07-26DOI: 10.1080/02571862.2023.2212191
V. White, P. Raath, A. Hardie, V. van der Berg, GF Sutton
Soil titratable acidity (TA) is determined through extraction with an acetate-buffered salt solution (potassium sulphate, K2SO4) and is routinely used to predict the soil lime requirement using the Eksteen method. Soil TA is not always reported by commercial soil testing laboratories, but rather exchangeable acidity (1M KCl) is determined. Therefore, a need exists to use other routinely determined soil properties in a model to derive TA. In this study, routine soil-analysis results from a commercial laboratory (n = 5 915 measurements) were used to generate various model structures to calculate a theoretical value of TA and to evaluate the accuracy thereof. Measured TA was found to be significantly correlated to the calculated TA using the Eksteen R-value, soil pH, organic carbon percentage, exchangeable Ca2+ and Mg2+, and a function of the interaction between pH and organic carbon. Soil TA could be calculated most accurately using these factors in multivariate adaptive regression splines model (r 2 = 0.69, mean absolute error = 0.16) at TA values of < 2 cmolc kg−1. However, the exponential model calculations remained stable over a larger range of actual TA values up to 4 cmolc kg−1. Given the ease of use and interpretability, it is recommended that an exponential function model is used to calculate TA.
{"title":"Calculating soil titratable acidity from routine soil analyses of cultivated South African soils using various model structures","authors":"V. White, P. Raath, A. Hardie, V. van der Berg, GF Sutton","doi":"10.1080/02571862.2023.2212191","DOIUrl":"https://doi.org/10.1080/02571862.2023.2212191","url":null,"abstract":"Soil titratable acidity (TA) is determined through extraction with an acetate-buffered salt solution (potassium sulphate, K2SO4) and is routinely used to predict the soil lime requirement using the Eksteen method. Soil TA is not always reported by commercial soil testing laboratories, but rather exchangeable acidity (1M KCl) is determined. Therefore, a need exists to use other routinely determined soil properties in a model to derive TA. In this study, routine soil-analysis results from a commercial laboratory (n = 5 915 measurements) were used to generate various model structures to calculate a theoretical value of TA and to evaluate the accuracy thereof. Measured TA was found to be significantly correlated to the calculated TA using the Eksteen R-value, soil pH, organic carbon percentage, exchangeable Ca2+ and Mg2+, and a function of the interaction between pH and organic carbon. Soil TA could be calculated most accurately using these factors in multivariate adaptive regression splines model (r 2 = 0.69, mean absolute error = 0.16) at TA values of < 2 cmolc kg−1. However, the exponential model calculations remained stable over a larger range of actual TA values up to 4 cmolc kg−1. Given the ease of use and interpretability, it is recommended that an exponential function model is used to calculate TA.","PeriodicalId":21920,"journal":{"name":"South African Journal of Plant and Soil","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2023-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44712962","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 : 2023-07-26DOI: 10.1080/02571862.2023.2212190
Firmin N Anago, E. C. Agbangba, Brice T. C. Oussou, G. Dagbénonbakin, L. G. Amadji
The aim of this study was to assess the effects of magnesium (Mg) and zinc (Zn) on the response of rice to nitrogen (N), phosphorus (P), and potassium (K) application. Two sets of field experiments were carried out in Benin. A Box Behnken Design with eight replications per year with treatments of N, P, potassium (K), Mg, and Zn was used for the first experiment, while a randomised complete block design with five treatments varying in Mg and Zn was used for the second experiment. Co-application of major nutrients with Mg and/or Zn significantly increased rice yield and nutrient use efficiencies. Co-application of N and Mg increased grain yield, filled grain rate, and 1 000 grains weight by 53.5, 7.10, and 7.34%, respectively. Likewise, the co-application of N with Zn increased rice yield, panicles per plant, and spikelets per panicle by 35.69, 14.78, and 6.06%, respectively. When P was co-applied with Zn, grain yield, spikelets per panicle, and the 1 000 grains weight increased by 27.21, 5.71, and 6.20%, respectively. The co-application of K with Mg led to an increase of grain yield and filling of grain by 24.28, and 5.71%, respectively. This study revealed the positive effects of Mg and Zn on rice yield response to the application of N, P, and K.
{"title":"Magnesium and zinc fertilisation improves rice yield and yield component responses to nitrogen, phosphorus, and potassium","authors":"Firmin N Anago, E. C. Agbangba, Brice T. C. Oussou, G. Dagbénonbakin, L. G. Amadji","doi":"10.1080/02571862.2023.2212190","DOIUrl":"https://doi.org/10.1080/02571862.2023.2212190","url":null,"abstract":"The aim of this study was to assess the effects of magnesium (Mg) and zinc (Zn) on the response of rice to nitrogen (N), phosphorus (P), and potassium (K) application. Two sets of field experiments were carried out in Benin. A Box Behnken Design with eight replications per year with treatments of N, P, potassium (K), Mg, and Zn was used for the first experiment, while a randomised complete block design with five treatments varying in Mg and Zn was used for the second experiment. Co-application of major nutrients with Mg and/or Zn significantly increased rice yield and nutrient use efficiencies. Co-application of N and Mg increased grain yield, filled grain rate, and 1 000 grains weight by 53.5, 7.10, and 7.34%, respectively. Likewise, the co-application of N with Zn increased rice yield, panicles per plant, and spikelets per panicle by 35.69, 14.78, and 6.06%, respectively. When P was co-applied with Zn, grain yield, spikelets per panicle, and the 1 000 grains weight increased by 27.21, 5.71, and 6.20%, respectively. The co-application of K with Mg led to an increase of grain yield and filling of grain by 24.28, and 5.71%, respectively. This study revealed the positive effects of Mg and Zn on rice yield response to the application of N, P, and K.","PeriodicalId":21920,"journal":{"name":"South African Journal of Plant and Soil","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2023-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47464079","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 : 2023-07-20DOI: 10.1080/02571862.2023.2196448
D. Beukes, LD Wiese-Rozanov, M. Kidson
A rainfed rehabilitation trial on mechanically reconstructed soil, following strip coal mining, was laid out in the Mpumalanga Province of South Africa. It was used to evaluate seven rehabilitation treatments with four different depths of topsoil on coal spoil over three experimental seasons. A strip plot design was used to apply the treatments. The test crop was a grass mixture comprising of annual and perennial species. Trial measurements included soil physical, chemical and microbiological measurements, as well as growth and composition of the grass stand. Monthly rainfall was very variable with annual totals below the long-term values. Statistical significance was proved for most measurements. Relatively high soil bulk densities, stratified with depth, were measured, indicating undesirable soil compaction. Infiltration rates increased while soil strength decreased dramatically with increased topsoil thickness. A reciprocal interaction of profile water content and biomass yield was observed with water content decreasing as biomass yield increased. A large variation in soil chemical properties was observed as a function of the treatments. This study highlights the fact that the monitoring of soil and plant properties should be a prerequisite in any rehabilitation study. Similar trials on different soils and in different rainfall regions should be considered to expand our knowledge of the impacts of different soil treatments in a range of ecosystems.
{"title":"Comparison of rehabilitation treatments on mechanically reconstructed soils following strip coal mining activities: effects on soil properties","authors":"D. Beukes, LD Wiese-Rozanov, M. Kidson","doi":"10.1080/02571862.2023.2196448","DOIUrl":"https://doi.org/10.1080/02571862.2023.2196448","url":null,"abstract":"A rainfed rehabilitation trial on mechanically reconstructed soil, following strip coal mining, was laid out in the Mpumalanga Province of South Africa. It was used to evaluate seven rehabilitation treatments with four different depths of topsoil on coal spoil over three experimental seasons. A strip plot design was used to apply the treatments. The test crop was a grass mixture comprising of annual and perennial species. Trial measurements included soil physical, chemical and microbiological measurements, as well as growth and composition of the grass stand. Monthly rainfall was very variable with annual totals below the long-term values. Statistical significance was proved for most measurements. Relatively high soil bulk densities, stratified with depth, were measured, indicating undesirable soil compaction. Infiltration rates increased while soil strength decreased dramatically with increased topsoil thickness. A reciprocal interaction of profile water content and biomass yield was observed with water content decreasing as biomass yield increased. A large variation in soil chemical properties was observed as a function of the treatments. This study highlights the fact that the monitoring of soil and plant properties should be a prerequisite in any rehabilitation study. Similar trials on different soils and in different rainfall regions should be considered to expand our knowledge of the impacts of different soil treatments in a range of ecosystems.","PeriodicalId":21920,"journal":{"name":"South African Journal of Plant and Soil","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2023-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43928280","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 : 2023-06-15DOI: 10.1080/02571862.2023.2206166
K. Konan, Kouadio I Kouassi, B. S. Bonny, B. T. S. Doubi, B. Zoro, D. O. Dogbo
The objective of this study was to propose a profitable cropping association date between cassava (Manihot esculenta) and Bambara groundnut (Vigna subterranea, also known as voandzou) through the examination of competition indices. The association of the cassava varieties Allada agba, Bonoua, Six mois and Yacé with the bouquet and creeping morphotypes of Bambara groundnut was tested at different cassava sowing dates: 0, 15 and 30 days after sowing of the bouquet Bambara groundnut and 0, 15, 30, 45 and 60 days after sowing the creeping Bambara groundnut. These cropping association systems were evaluated through competition indices in Côte d’Ivoire: the area–time equivalent ratio (ATER), the competitiveness rate (CR) and the relative dominance coefficient (K). ATER and K values were greater than unity when cassava was sown 15 to 30 days after sowing the bouquet Bambara groundnut and 30 to 45 days after sowing the creeping Bambara groundnut. Cassava varieties were more competitive than the Bambara groundnut morphotypes (CRC > CRV). The best results in terms of efficient land use (ATER > 1) and yield gain (K > 1) were obtained when cassava was sown 30 days after Bambara groundnut. However, for the Bonoua–Bambara groundnut creeping association, the yield gain was obtained when cassava was sown 45 days after Bambara groundnut.
{"title":"The efficiency of cassava–Bambara groundnut intercropping according to the sowing date of cassava","authors":"K. Konan, Kouadio I Kouassi, B. S. Bonny, B. T. S. Doubi, B. Zoro, D. O. Dogbo","doi":"10.1080/02571862.2023.2206166","DOIUrl":"https://doi.org/10.1080/02571862.2023.2206166","url":null,"abstract":"The objective of this study was to propose a profitable cropping association date between cassava (Manihot esculenta) and Bambara groundnut (Vigna subterranea, also known as voandzou) through the examination of competition indices. The association of the cassava varieties Allada agba, Bonoua, Six mois and Yacé with the bouquet and creeping morphotypes of Bambara groundnut was tested at different cassava sowing dates: 0, 15 and 30 days after sowing of the bouquet Bambara groundnut and 0, 15, 30, 45 and 60 days after sowing the creeping Bambara groundnut. These cropping association systems were evaluated through competition indices in Côte d’Ivoire: the area–time equivalent ratio (ATER), the competitiveness rate (CR) and the relative dominance coefficient (K). ATER and K values were greater than unity when cassava was sown 15 to 30 days after sowing the bouquet Bambara groundnut and 30 to 45 days after sowing the creeping Bambara groundnut. Cassava varieties were more competitive than the Bambara groundnut morphotypes (CRC > CRV). The best results in terms of efficient land use (ATER > 1) and yield gain (K > 1) were obtained when cassava was sown 30 days after Bambara groundnut. However, for the Bonoua–Bambara groundnut creeping association, the yield gain was obtained when cassava was sown 45 days after Bambara groundnut.","PeriodicalId":21920,"journal":{"name":"South African Journal of Plant and Soil","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2023-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48423008","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 : 2023-03-15DOI: 10.1080/02571862.2023.2196733
Neliswa A. Matrose, Z. A. Belay, Obikeze Kenechukwu, L. Mokwena, O. J. Caleb
This study investigated the effect of processing and freeze-drying on targeted volatile compounds (terpenes) of Helichrysum odoratissimum (L.) Sweet. Air-dried plant material was processed to obtain: (i) roughly ground leaves and stems (RGMHO); (ii) finely ground leaves and stems (FGMHO); and (iii) wool-like fraction (WLMHO). Terpene content of the air-dried samples, crude ethanol extract (CE, filtrate), sediments and freeze-dried (FDE) powders from the different processed fractions were analysed using gas chromatography-mass spectrometry (GC-MS). Results showed that the highest α-pinene (91.3 µg l−1) was obtained in the CE compared to the freeze-dried (≈3.0 µg l−1) extracts (p ≤ 0.05). Eucalyptol was significantly higher in the air-dried leaves (27.3 µg l−1) than were CE and FDE (4.0 and 0.9 µg l−1 respectively), while β-caryophyllene, pulegone and humulene contents were significantly higher in the FDE samples (p ≤ 0.05). These results demonstrated that processing had significant impact on the concentration of targeted terpenes in H. odoratissimum. This study is the first report on the identification and quantification targeted terpenes in H. odoratissimum (L.) Sweet.
{"title":"Bioprospecting for active compounds: impact of milling, extract fractions and freeze-drying on targeted terpene compounds of Helichrysum odoratissimum (L.) Sweet","authors":"Neliswa A. Matrose, Z. A. Belay, Obikeze Kenechukwu, L. Mokwena, O. J. Caleb","doi":"10.1080/02571862.2023.2196733","DOIUrl":"https://doi.org/10.1080/02571862.2023.2196733","url":null,"abstract":"This study investigated the effect of processing and freeze-drying on targeted volatile compounds (terpenes) of Helichrysum odoratissimum (L.) Sweet. Air-dried plant material was processed to obtain: (i) roughly ground leaves and stems (RGMHO); (ii) finely ground leaves and stems (FGMHO); and (iii) wool-like fraction (WLMHO). Terpene content of the air-dried samples, crude ethanol extract (CE, filtrate), sediments and freeze-dried (FDE) powders from the different processed fractions were analysed using gas chromatography-mass spectrometry (GC-MS). Results showed that the highest α-pinene (91.3 µg l−1) was obtained in the CE compared to the freeze-dried (≈3.0 µg l−1) extracts (p ≤ 0.05). Eucalyptol was significantly higher in the air-dried leaves (27.3 µg l−1) than were CE and FDE (4.0 and 0.9 µg l−1 respectively), while β-caryophyllene, pulegone and humulene contents were significantly higher in the FDE samples (p ≤ 0.05). These results demonstrated that processing had significant impact on the concentration of targeted terpenes in H. odoratissimum. This study is the first report on the identification and quantification targeted terpenes in H. odoratissimum (L.) Sweet.","PeriodicalId":21920,"journal":{"name":"South African Journal of Plant and Soil","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2023-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"59237600","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 : 2023-03-15DOI: 10.1080/02571862.2023.2236075
Sibongiseni Silwana, Azwimbavhi Reckson Mulidzi, Nebo Jovanovic
AbstractCover crops are used in sustainable agricultural practices to improve soil quality and minimise the effect of climate change, water restrictions and drought. The South African citrus industry produces and exports a diverse range of citrus fruits; however, knowledge of cover crops in citrus orchards in South Africa is limited. This review focuses mostly on evaluating cover crop selection, effects on the soil microbial community, weed control, citrus yield and fruit quality. In terms of cover crop selection, legumes seem to be preferred over non-legume cover crops. The reviewed literature reported that legume cover crops increased nitrogen by 67 to 209 kg N ha−1 through the nitrogen fixation process. Additionally, the cultivation of legume cover crops substantially improved the cost savings of nitrogen fertiliser. The fruit yield improved by 7.6 to 64%, while fruit quality improved by 2.3 to 12.4% fruit weight and 2.4 to 5.8% Bx. This demonstrates that the benefits of cover crops to South African citrus growers include improved soil quality and fruit yields and decreased costs.Keywords: fruit yieldlegumesnitrogen fixationorganic carbonorganic mattersoil microbial communitySouth Africatree shading
覆盖物作物被用于可持续农业实践，以改善土壤质量并最大限度地减少气候变化、水资源限制和干旱的影响。南非柑橘产业生产和出口各种柑橘类水果;然而，对南非柑橘果园覆盖作物的了解有限。本文主要从覆盖作物的选择、对土壤微生物群落的影响、杂草控制、柑橘产量和果实品质等方面进行综述。在覆盖作物选择方面，豆类似乎比非豆类覆盖作物更受青睐。据文献报道，豆科覆盖作物通过固氮过程增加氮素67 ~ 209 kg N ha - 1。此外，豆科覆盖作物的种植大大提高了氮肥的成本节约。果实产量提高7.6 ~ 64%，果实品质提高2.3 ~ 12.4%，单果重提高2.4 ~ 5.8%。这表明覆盖作物对南非柑橘种植者的好处包括改善土壤质量和水果产量以及降低成本。关键词:果实产量豆科植物固氮有机碳有机质土壤微生物群落南非树木遮荫
{"title":"Evaluating the effects and benefits of cover crops in citrus orchards: a review","authors":"Sibongiseni Silwana, Azwimbavhi Reckson Mulidzi, Nebo Jovanovic","doi":"10.1080/02571862.2023.2236075","DOIUrl":"https://doi.org/10.1080/02571862.2023.2236075","url":null,"abstract":"AbstractCover crops are used in sustainable agricultural practices to improve soil quality and minimise the effect of climate change, water restrictions and drought. The South African citrus industry produces and exports a diverse range of citrus fruits; however, knowledge of cover crops in citrus orchards in South Africa is limited. This review focuses mostly on evaluating cover crop selection, effects on the soil microbial community, weed control, citrus yield and fruit quality. In terms of cover crop selection, legumes seem to be preferred over non-legume cover crops. The reviewed literature reported that legume cover crops increased nitrogen by 67 to 209 kg N ha−1 through the nitrogen fixation process. Additionally, the cultivation of legume cover crops substantially improved the cost savings of nitrogen fertiliser. The fruit yield improved by 7.6 to 64%, while fruit quality improved by 2.3 to 12.4% fruit weight and 2.4 to 5.8% Bx. This demonstrates that the benefits of cover crops to South African citrus growers include improved soil quality and fruit yields and decreased costs.Keywords: fruit yieldlegumesnitrogen fixationorganic carbonorganic mattersoil microbial communitySouth Africatree shading","PeriodicalId":21920,"journal":{"name":"South African Journal of Plant and Soil","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135747771","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 : 2023-01-01DOI: 10.1080/02571862.2023.2168077
Muketiwa Chitiga, G. Soropa, T. Dube, Progress Sengera
A decline in sugarcane yields from Block G (∼400 ha) of GreenFuel’s Chisumbanje Estate in south-eastern Zimbabwe prompted a study on spatial variability of the soil physico-chemical parameters in the 2017–2018 farming season. Using a systematic gridding schema, 123 geo-located soil samples from 16 sub-blocks were extracted from a depth of 0.3 m and analysed for various parameters. The results showed that pH was slightly acidic to alkaline (6.13–7.95) and had the lowest variability (CV ±15%). Low (N, P, Fe and Zn) and adequate (K and Cu) levels of mineral nutrients were also observed. However, some nutrients were highly variable, with P, Fe and Zn revealing the largest variability (CV ±35%). Semivariogram analysis showed a weak (clay, soil organic matter and N), moderate (pH, P, Mn and Zn) or strong (K, Fe and Cu) spatial correlation between the measured and predicted values. To optimise soil fertility and reduce variations, it is recommended that the estate employ variable-rate fertiliser application technologies, nutrient-monitoring systems, and precision satellite-based guidance for machinery. The study generated soil fertility maps using ordinary kriging; this will serve as a future reference for soil test-based fertiliser recommendations, soil fertility monitoring, and identifying spatial variability on the estate.
{"title":"Spatial interpolation of vertisol physico-chemical properties through ordinary kriging in south-eastern Zimbabwe","authors":"Muketiwa Chitiga, G. Soropa, T. Dube, Progress Sengera","doi":"10.1080/02571862.2023.2168077","DOIUrl":"https://doi.org/10.1080/02571862.2023.2168077","url":null,"abstract":"A decline in sugarcane yields from Block G (∼400 ha) of GreenFuel’s Chisumbanje Estate in south-eastern Zimbabwe prompted a study on spatial variability of the soil physico-chemical parameters in the 2017–2018 farming season. Using a systematic gridding schema, 123 geo-located soil samples from 16 sub-blocks were extracted from a depth of 0.3 m and analysed for various parameters. The results showed that pH was slightly acidic to alkaline (6.13–7.95) and had the lowest variability (CV ±15%). Low (N, P, Fe and Zn) and adequate (K and Cu) levels of mineral nutrients were also observed. However, some nutrients were highly variable, with P, Fe and Zn revealing the largest variability (CV ±35%). Semivariogram analysis showed a weak (clay, soil organic matter and N), moderate (pH, P, Mn and Zn) or strong (K, Fe and Cu) spatial correlation between the measured and predicted values. To optimise soil fertility and reduce variations, it is recommended that the estate employ variable-rate fertiliser application technologies, nutrient-monitoring systems, and precision satellite-based guidance for machinery. The study generated soil fertility maps using ordinary kriging; this will serve as a future reference for soil test-based fertiliser recommendations, soil fertility monitoring, and identifying spatial variability on the estate.","PeriodicalId":21920,"journal":{"name":"South African Journal of Plant and Soil","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49395879","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 : 2023-01-01DOI: 10.1080/02571862.2022.2160881
Johannes Stephanus Theron, G. J. van Coller, L. Rose, J. Labuschagne, P. Swanepoel
Conservation agriculture relies on residue retention, crop rotation and reduced tillage. Crop rotation determines residue type, while tillage affects residue load and distribution. Although crop residue retention is often beneficial, residues can create challenges, including obstruction of planters during establishment and stubble-borne diseases. This study determined the effects of crop rotation and tillage on the residue decomposition and response of wheat (Triticum aestivum L.) in the Western Cape Province, South Africa. Wheat response was investigated to determine relationships between residue decomposition and its agronomic performance. Crop rotations in long-term trials in areas of the Swartland and southern Cape consisted of the following: wheat–medics, lupin–wheat–canola–wheat, canola–wheat–lupin–wheat, and a wheat monoculture. Crops were established with four tillage practices: conventional tillage (CT: chisel plough followed by soil inversion/ploughing, tine planter establishment), minimum tillage (MT: chisel plough, tine planter establishment), no-tillage (NT: direct drilling with tine planter) and zero tillage (ZT: direct drilling with double disc planter). Crop rotation had no effect on residue decomposition but increased wheat leaf area and grain yield when rotated with medics, lupin and canola when compared with monoculture wheat. ZT increased residue load and improved seedling establishment. ZT (50.9%) and NT (51.1%) increased residue decomposition compared with CT (34%). Faster residue decomposition could be achieved with less soil disturbance.
{"title":"The effect of crop rotation and tillage practice on residue decomposition and wheat performance in the Western Cape, South Africa","authors":"Johannes Stephanus Theron, G. J. van Coller, L. Rose, J. Labuschagne, P. Swanepoel","doi":"10.1080/02571862.2022.2160881","DOIUrl":"https://doi.org/10.1080/02571862.2022.2160881","url":null,"abstract":"Conservation agriculture relies on residue retention, crop rotation and reduced tillage. Crop rotation determines residue type, while tillage affects residue load and distribution. Although crop residue retention is often beneficial, residues can create challenges, including obstruction of planters during establishment and stubble-borne diseases. This study determined the effects of crop rotation and tillage on the residue decomposition and response of wheat (Triticum aestivum L.) in the Western Cape Province, South Africa. Wheat response was investigated to determine relationships between residue decomposition and its agronomic performance. Crop rotations in long-term trials in areas of the Swartland and southern Cape consisted of the following: wheat–medics, lupin–wheat–canola–wheat, canola–wheat–lupin–wheat, and a wheat monoculture. Crops were established with four tillage practices: conventional tillage (CT: chisel plough followed by soil inversion/ploughing, tine planter establishment), minimum tillage (MT: chisel plough, tine planter establishment), no-tillage (NT: direct drilling with tine planter) and zero tillage (ZT: direct drilling with double disc planter). Crop rotation had no effect on residue decomposition but increased wheat leaf area and grain yield when rotated with medics, lupin and canola when compared with monoculture wheat. ZT increased residue load and improved seedling establishment. ZT (50.9%) and NT (51.1%) increased residue decomposition compared with CT (34%). Faster residue decomposition could be achieved with less soil disturbance.","PeriodicalId":21920,"journal":{"name":"South African Journal of Plant and Soil","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43226748","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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