Pub Date : 2022-03-15DOI: 10.1080/02571862.2022.2039792
L. D. Lyimo, Jackline A Bakengesa, Janeth D Mbuma
The abundance and distribution of plant-parasitic nematodes (PPN) on tomato plants grown in nine villages in the semi-arid zones of Singida and Dodoma in Tanzania were assessed in December 2020. Samples from soil and plant roots were evaluated for abundance, genera and distribution of PPN. Nematodes were extracted, counted and identified based on morphological descriptors. Ten genera of PPN were identified in both root and soil samples, with root-knot nematodes (RKN) being the most common PPN in all nine villages surveyed. The results showed that the abundance of RKN was significantly higher (p = 0.002) in soil than in tomato roots. Tutu and Chamkoroma villages had a significantly (p = 0.001) higher population density of RKN compared to other villages. In addition, RKN was associated with Penicillium and Aspergillus fungi, while the nematode genera Helicotylenchus, Aphelenchus, Scutellonema and Pratylenchus exhibited relationships with Alternaria and Fusarium fungi. The results also indicated that the abundance of RKN was significantly higher (p = 0.001) in sandy soil as compared to other types of soils. Inappropriate agronomical practices (e.g., no fallow, rotation of tomato plant with related crops) and poor phytosanitary measures were the major factors associated with high levels of abundance and distribution of RKN in soil.
{"title":"Abundance and distribution of plant-parasitic nematodes in tomatoes grown in a semi-arid agro-ecological zone in Tanzania","authors":"L. D. Lyimo, Jackline A Bakengesa, Janeth D Mbuma","doi":"10.1080/02571862.2022.2039792","DOIUrl":"https://doi.org/10.1080/02571862.2022.2039792","url":null,"abstract":"The abundance and distribution of plant-parasitic nematodes (PPN) on tomato plants grown in nine villages in the semi-arid zones of Singida and Dodoma in Tanzania were assessed in December 2020. Samples from soil and plant roots were evaluated for abundance, genera and distribution of PPN. Nematodes were extracted, counted and identified based on morphological descriptors. Ten genera of PPN were identified in both root and soil samples, with root-knot nematodes (RKN) being the most common PPN in all nine villages surveyed. The results showed that the abundance of RKN was significantly higher (p = 0.002) in soil than in tomato roots. Tutu and Chamkoroma villages had a significantly (p = 0.001) higher population density of RKN compared to other villages. In addition, RKN was associated with Penicillium and Aspergillus fungi, while the nematode genera Helicotylenchus, Aphelenchus, Scutellonema and Pratylenchus exhibited relationships with Alternaria and Fusarium fungi. The results also indicated that the abundance of RKN was significantly higher (p = 0.001) in sandy soil as compared to other types of soils. Inappropriate agronomical practices (e.g., no fallow, rotation of tomato plant with related crops) and poor phytosanitary measures were the major factors associated with high levels of abundance and distribution of RKN in soil.","PeriodicalId":21920,"journal":{"name":"South African Journal of Plant and Soil","volume":"39 1","pages":"132 - 141"},"PeriodicalIF":0.9,"publicationDate":"2022-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41984856","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 : 2022-01-01DOI: 10.1080/02571862.2021.1994046
MH Visser, A. Barnard, C. du Preez
Conservation agriculture (CA) is advocated to promote sustainable cropping. Little is known about the impact of preceding crop sequences on the growth and development of dryland wheat under CA in the eastern Free State Province of South Africa. In a criss-cross experimental design, the response of wheat planted after 25 summer and 25 winter crop sequences was evaluated. Biomass yield was a more reliable indicator than grain yield as a consequence of water and nitrogen stress in the reproductive phase as indicated by harvest index, precipitation use efficiency and nitrogen agronomic efficiency. The five best sequences that favoured wheat biomass yields were, in decreasing order: grain sorghum × maize, sunflower × dry bean, sunflower × maize, soybean × soybean, and maize × maize for summer crops (7.1–7.8 t ha−1); and fallow × vetch, fallow × wheat, fallow × fallow, vetch × fodder oat, and wheat × oat for winter crops (6.5–7.4 t ha−1). Of the grading parameters, only protein content was influenced significantly by the winter crop sequences. A single 3-year cycle comprising wheat after two seasons with preceding crop sequences was insufficient to test abiotic stress factors thoroughly to establish with certainty the best crop sequences for dryland wheat production.
保护性农业(CA)提倡促进可持续种植。在南非东部自由邦省，以前的作物序列对CA下旱地小麦生长发育的影响知之甚少。采用交叉试验设计，评价了小麦在25个夏季作物和25个冬季作物种植序列后的反应。收获指数、降水利用效率和氮素农艺效率表明，生物量产量比籽粒产量更可靠，是生殖期水分和氮胁迫的结果。最有利于小麦生物量产量的5个最佳序列依次为:高粱×玉米、向日葵×干豆、向日葵×玉米、大豆×大豆和玉米×玉米(7.1 ~ 7.8 tha−1);休耕×野豌豆，休耕×小麦，休耕×休耕，野豌豆×饲料燕麦，小麦×燕麦用于冬季作物(6.5-7.4 t / h)。在分级参数中，只有蛋白质含量受冬作物序列的显著影响。一个3年的周期，包括两个季节后的小麦和之前的作物序列，不足以彻底测试非生物胁迫因素，以确定旱地小麦生产的最佳作物序列。
{"title":"Impact of preceding crop sequences on wheat growth and development under conservation agriculture in the eastern Free State, South Africa","authors":"MH Visser, A. Barnard, C. du Preez","doi":"10.1080/02571862.2021.1994046","DOIUrl":"https://doi.org/10.1080/02571862.2021.1994046","url":null,"abstract":"Conservation agriculture (CA) is advocated to promote sustainable cropping. Little is known about the impact of preceding crop sequences on the growth and development of dryland wheat under CA in the eastern Free State Province of South Africa. In a criss-cross experimental design, the response of wheat planted after 25 summer and 25 winter crop sequences was evaluated. Biomass yield was a more reliable indicator than grain yield as a consequence of water and nitrogen stress in the reproductive phase as indicated by harvest index, precipitation use efficiency and nitrogen agronomic efficiency. The five best sequences that favoured wheat biomass yields were, in decreasing order: grain sorghum × maize, sunflower × dry bean, sunflower × maize, soybean × soybean, and maize × maize for summer crops (7.1–7.8 t ha−1); and fallow × vetch, fallow × wheat, fallow × fallow, vetch × fodder oat, and wheat × oat for winter crops (6.5–7.4 t ha−1). Of the grading parameters, only protein content was influenced significantly by the winter crop sequences. A single 3-year cycle comprising wheat after two seasons with preceding crop sequences was insufficient to test abiotic stress factors thoroughly to establish with certainty the best crop sequences for dryland wheat production.","PeriodicalId":21920,"journal":{"name":"South African Journal of Plant and Soil","volume":"39 1","pages":"56 - 65"},"PeriodicalIF":0.9,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48527040","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 : 2022-01-01DOI: 10.1080/02571862.2021.1987536
Abera Daba, Mekuria Tadesse, Selamawit Negassa Chawaka, G. Berecha
A weed population survey was carried out to assess the variability in weed species composition and abundance in the main coffee production systems and regions of Ethiopia. A total of 168 coffee fields were assessed using a quadrat count in a systematic sampling technique. Weed species composition was evaluated using frequency, abundance and dominance of species at each site. We found a total of 98 weed taxa belonging to 35 families, of which Asteraceae and Poaceae were the most abundant. The most frequent weed species were Oplismenus hirtellus (L.) P.Beauv., Galinsoga parviflora Cav., Achyranthes bidentata Blume, Impatiens balfourii Hook. F., Bidens pilosa L. and Commelina benghalensis L., with a frequency of over 40%. The density of weed species varied and the highest abundance value was recorded by O. hirtellus. Similarity indices of the 16 districts assessed ranged from 8.33% to 72.73%, while the similarity indices of the coffee production systems and altitudinal range ranged from 7.14% to 49.49% and 41.76% to 68.75%, respectively. Coffee production systems and soil properties were the main explanatory variables influencing weed species distribution and composition in the study areas. In conclusion, coffee producers should take into account these variables while designing the appropriate management strategies to curtail weeds in coffee farms.
{"title":"Weed species composition and abundance in the main coffee production systems and regions of Ethiopia","authors":"Abera Daba, Mekuria Tadesse, Selamawit Negassa Chawaka, G. Berecha","doi":"10.1080/02571862.2021.1987536","DOIUrl":"https://doi.org/10.1080/02571862.2021.1987536","url":null,"abstract":"A weed population survey was carried out to assess the variability in weed species composition and abundance in the main coffee production systems and regions of Ethiopia. A total of 168 coffee fields were assessed using a quadrat count in a systematic sampling technique. Weed species composition was evaluated using frequency, abundance and dominance of species at each site. We found a total of 98 weed taxa belonging to 35 families, of which Asteraceae and Poaceae were the most abundant. The most frequent weed species were Oplismenus hirtellus (L.) P.Beauv., Galinsoga parviflora Cav., Achyranthes bidentata Blume, Impatiens balfourii Hook. F., Bidens pilosa L. and Commelina benghalensis L., with a frequency of over 40%. The density of weed species varied and the highest abundance value was recorded by O. hirtellus. Similarity indices of the 16 districts assessed ranged from 8.33% to 72.73%, while the similarity indices of the coffee production systems and altitudinal range ranged from 7.14% to 49.49% and 41.76% to 68.75%, respectively. Coffee production systems and soil properties were the main explanatory variables influencing weed species distribution and composition in the study areas. In conclusion, coffee producers should take into account these variables while designing the appropriate management strategies to curtail weeds in coffee farms.","PeriodicalId":21920,"journal":{"name":"South African Journal of Plant and Soil","volume":"39 1","pages":"41 - 55"},"PeriodicalIF":0.9,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41876088","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 : 2022-01-01DOI: 10.1080/02571862.2021.1969692
M. Zhou
Smut, Sporisorium scitamineum (Syd.) (formerly Ustilago scitamineum), is a major disease of sugarcane causing cane yield losses of 0.25 to 0.75% for every 1% of infected stools. Breeding resistant cultivars is part of integrated smut management. The objective of this study was to determine the effects of locations and seasons on smut infection genotype in irrigated sugarcane breeding trials. Data for smut-infected stools and smut whips collected from early and late season trials at Pongola (NPG) and Mpumalanga research stations (MP) were analysed using linear mixed models. There were significant (p < 0.001) location, season, location by season, genotype, genotype by location, genotype by season and genotype by location by season interaction effects for infected stools and whips. Broad sense heritability in late season trials averaged 0.89 compared to 0.61 in early season, while that for MP (0.79) was higher than for NPG (0.69) indicating higher selection efficiency for smut resistance in late season MP trials. Genotypes had significantly (p < 0.001) higher infected stools and whips at MP than at NPG and in late than early season trials. Smut-screening using MP late season trials will increase efficiency of breeding for smut resistance in South Africa.
{"title":"Location and seasonal effects on sugarcane smut and implications for resistance breeding in South Africa","authors":"M. Zhou","doi":"10.1080/02571862.2021.1969692","DOIUrl":"https://doi.org/10.1080/02571862.2021.1969692","url":null,"abstract":"Smut, Sporisorium scitamineum (Syd.) (formerly Ustilago scitamineum), is a major disease of sugarcane causing cane yield losses of 0.25 to 0.75% for every 1% of infected stools. Breeding resistant cultivars is part of integrated smut management. The objective of this study was to determine the effects of locations and seasons on smut infection genotype in irrigated sugarcane breeding trials. Data for smut-infected stools and smut whips collected from early and late season trials at Pongola (NPG) and Mpumalanga research stations (MP) were analysed using linear mixed models. There were significant (p < 0.001) location, season, location by season, genotype, genotype by location, genotype by season and genotype by location by season interaction effects for infected stools and whips. Broad sense heritability in late season trials averaged 0.89 compared to 0.61 in early season, while that for MP (0.79) was higher than for NPG (0.69) indicating higher selection efficiency for smut resistance in late season MP trials. Genotypes had significantly (p < 0.001) higher infected stools and whips at MP than at NPG and in late than early season trials. Smut-screening using MP late season trials will increase efficiency of breeding for smut resistance in South Africa.","PeriodicalId":21920,"journal":{"name":"South African Journal of Plant and Soil","volume":"39 1","pages":"1 - 9"},"PeriodicalIF":0.9,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43973469","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 : 2022-01-01DOI: 10.1080/02571862.2021.1994047
Sphiwokuhle Shandu, E. Gasura, K. Mashingaidze, J. Derera
Increases in genetic gains are crucial to maize breeding programmes. The objectives of this study were to identify higher-yielding and stable maize hybrids across stress and non-stress environments, to identify representative test environments for testing and selection of superior maize genotypes, and to determine the contribution of temperate maize germplasm in the performance of new tropical hybrids. Respectively 42 and 72 newly developed single-cross hybrids together with check hybrids were evaluated separately for grain yield performance across stress and non-stress environments, at four locations (Potchefstroom, Cedara, Vaalharts/Taung and Makhathini) in South Africa, in the 2014/15 and 2015/16 growing seasons (seasons 1 and 2, respectively). Additive main effects and multiplicative interaction (AMMI) and genotype + genotype × environment interaction (GGE) biplots were employed. In season 1, the hybrids MO17HtHtN × CML444 and I-39 × CML444 were the most stable and high-yielding genotypes after the ideal commercial check. In season 2, the hybrids FO215W × CML444, I-42 × CML444 and U71Y × CML444 were stable and high-yielding, with FO215W × CML444 being the most ideal. These stable hybrids would be the best suited for wide adaptation across non-stress and stress environments. Hybrids containing tropical CIMMYT testers were more stable than those derived from temperate Corn Belt material. The locations Potchefstroom and Vaalharts were the most suitable environments for evaluating the performance of these genotypes across the diverse environments.
{"title":"Contribution of temperate germplasm to the performance of maize hybrids under stress and non-stress environments in South Africa","authors":"Sphiwokuhle Shandu, E. Gasura, K. Mashingaidze, J. Derera","doi":"10.1080/02571862.2021.1994047","DOIUrl":"https://doi.org/10.1080/02571862.2021.1994047","url":null,"abstract":"Increases in genetic gains are crucial to maize breeding programmes. The objectives of this study were to identify higher-yielding and stable maize hybrids across stress and non-stress environments, to identify representative test environments for testing and selection of superior maize genotypes, and to determine the contribution of temperate maize germplasm in the performance of new tropical hybrids. Respectively 42 and 72 newly developed single-cross hybrids together with check hybrids were evaluated separately for grain yield performance across stress and non-stress environments, at four locations (Potchefstroom, Cedara, Vaalharts/Taung and Makhathini) in South Africa, in the 2014/15 and 2015/16 growing seasons (seasons 1 and 2, respectively). Additive main effects and multiplicative interaction (AMMI) and genotype + genotype × environment interaction (GGE) biplots were employed. In season 1, the hybrids MO17HtHtN × CML444 and I-39 × CML444 were the most stable and high-yielding genotypes after the ideal commercial check. In season 2, the hybrids FO215W × CML444, I-42 × CML444 and U71Y × CML444 were stable and high-yielding, with FO215W × CML444 being the most ideal. These stable hybrids would be the best suited for wide adaptation across non-stress and stress environments. Hybrids containing tropical CIMMYT testers were more stable than those derived from temperate Corn Belt material. The locations Potchefstroom and Vaalharts were the most suitable environments for evaluating the performance of these genotypes across the diverse environments.","PeriodicalId":21920,"journal":{"name":"South African Journal of Plant and Soil","volume":"39 1","pages":"66 - 76"},"PeriodicalIF":0.9,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48589150","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 : 2022-01-01DOI: 10.1080/02571862.2021.2001597
KA Seetseng, L. van Rensburg, J. Barnard, C. du Preez
In South Africa canola (Brassica napus L.) is cultivated in rotation with wheat under winter rainfall in the Western Cape Province. Expansion of the crop to the other eight provinces is advocated to reduce a shortage of locally produced plant oils. Moreover, canola can serve as a rotational crop for wheat in the summer rainfall provinces. In the central Free State, agronomic information for canola production is lacking. An experiment with a line source sprinkler irrigation system was conducted to establish the influence of water application levels (175, 233, 295, 351 and 420 mm) in combination with plant densities (25, 50, 75, 100 and 125 plants m−2) on yield responses, yield components and growth parameters of canola. Seed (653–4653 kg ha−1) and stover (1983–6733 kg ha−1) yields induced by the treatment combinations proved that canola has a high level of plasticity. Over the full range of water application levels, highest seed and biomass yields were realised at densities of 25 and 75 plants m−2, respectively. The compensation of yields at lower plant densities was due to the production of more branches, pods and seeds per plant. Under full irrigation, densities of 25 and 75 plants m−2 are optimal for seed and biomass production, respectively.
在南非，在西开普省，油菜(油菜L.)在冬季降雨下与小麦轮作种植。人们提倡将这种作物扩大到其他8个省份，以减少当地生产的植物油的短缺。此外，在夏季多雨的省份，油菜可以作为小麦的轮作作物。在自由邦中部，缺乏油菜籽生产的农艺信息。通过线源喷灌系统试验，研究了施水量(175、233、295、351和420 mm)和种植密度(25、50、75、100和125株m−2)对油菜产量响应、产量构成和生长参数的影响。处理组合诱导的种子产量(653 ~ 4653 kg ha - 1)和干料产量(1983 ~ 6733 kg ha - 1)表明油菜具有较高的可塑性。在整个施水量范围内，种子和生物量产量最高的密度分别为25株和75株m - 2。低密度下产量的补偿是由于单株产生更多的枝、荚和种子。在充分灌溉条件下，25株m−2和75株m−2的密度对种子和生物量产量最适宜。
{"title":"Influence of water application levels and plant densities on the plasticity of canola in the central Free State, South Africa","authors":"KA Seetseng, L. van Rensburg, J. Barnard, C. du Preez","doi":"10.1080/02571862.2021.2001597","DOIUrl":"https://doi.org/10.1080/02571862.2021.2001597","url":null,"abstract":"In South Africa canola (Brassica napus L.) is cultivated in rotation with wheat under winter rainfall in the Western Cape Province. Expansion of the crop to the other eight provinces is advocated to reduce a shortage of locally produced plant oils. Moreover, canola can serve as a rotational crop for wheat in the summer rainfall provinces. In the central Free State, agronomic information for canola production is lacking. An experiment with a line source sprinkler irrigation system was conducted to establish the influence of water application levels (175, 233, 295, 351 and 420 mm) in combination with plant densities (25, 50, 75, 100 and 125 plants m−2) on yield responses, yield components and growth parameters of canola. Seed (653–4653 kg ha−1) and stover (1983–6733 kg ha−1) yields induced by the treatment combinations proved that canola has a high level of plasticity. Over the full range of water application levels, highest seed and biomass yields were realised at densities of 25 and 75 plants m−2, respectively. The compensation of yields at lower plant densities was due to the production of more branches, pods and seeds per plant. Under full irrigation, densities of 25 and 75 plants m−2 are optimal for seed and biomass production, respectively.","PeriodicalId":21920,"journal":{"name":"South African Journal of Plant and Soil","volume":"39 1","pages":"77 - 84"},"PeriodicalIF":0.9,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41419878","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 : 2022-01-01DOI: 10.1080/02571862.2021.1970831
Avhurengwi Shirley Mathelemuse, K. Yobo, M. Truter, P. Steyn, M. Kena, R. Sutherland
Brown leaf spot caused by Alternaria alternata (Fries) Keissler is one of the most devastating fungal diseases of potato. Management of this disease relies mostly on fungicide applications. However, fungicides are becoming less effective due to the development of fungal resistance to specific chemicals. Additionally, there is limited information on resistance in potato cultivars in South Africa against brown leaf spot. This study aims to evaluate ten commercial potato cultivars for brown leaf spot resistance using detached leaf, tuber and whole plant screening techniques under controlled conditions. The experiment was conducted in 2016 and repeated in 2017. The whole plant assay showed that Labadia, Almera, Sifra, Mondeo, Up-To-Date and Lanorma are resistant to brown spot. Resistance levels in Labadia, Almera, Sifra and Up-To-Date were consistent in the 2016 and 2017 experiments. The detached leaf assay showed Almera, Sifra, Up-To-Date and Mondeo as moderately resistant, while Innovator, Mondial and Markies were moderately susceptible. However, in the tuber assay all cultivars were highly susceptible. Cultivar resistance varied based on the screening technique used, although results suggest that the detached leaf and whole plant assays could be used in potato disease screening programs.
{"title":"Assessing resistance levels of potato cultivars in South Africa against Alternaria alternata","authors":"Avhurengwi Shirley Mathelemuse, K. Yobo, M. Truter, P. Steyn, M. Kena, R. Sutherland","doi":"10.1080/02571862.2021.1970831","DOIUrl":"https://doi.org/10.1080/02571862.2021.1970831","url":null,"abstract":"Brown leaf spot caused by Alternaria alternata (Fries) Keissler is one of the most devastating fungal diseases of potato. Management of this disease relies mostly on fungicide applications. However, fungicides are becoming less effective due to the development of fungal resistance to specific chemicals. Additionally, there is limited information on resistance in potato cultivars in South Africa against brown leaf spot. This study aims to evaluate ten commercial potato cultivars for brown leaf spot resistance using detached leaf, tuber and whole plant screening techniques under controlled conditions. The experiment was conducted in 2016 and repeated in 2017. The whole plant assay showed that Labadia, Almera, Sifra, Mondeo, Up-To-Date and Lanorma are resistant to brown spot. Resistance levels in Labadia, Almera, Sifra and Up-To-Date were consistent in the 2016 and 2017 experiments. The detached leaf assay showed Almera, Sifra, Up-To-Date and Mondeo as moderately resistant, while Innovator, Mondial and Markies were moderately susceptible. However, in the tuber assay all cultivars were highly susceptible. Cultivar resistance varied based on the screening technique used, although results suggest that the detached leaf and whole plant assays could be used in potato disease screening programs.","PeriodicalId":21920,"journal":{"name":"South African Journal of Plant and Soil","volume":"39 1","pages":"20 - 27"},"PeriodicalIF":0.9,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46559545","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 : 2022-01-01DOI: 10.1080/02571862.2021.1969693
S. Dube, P. Muchaonyerwa, F. Mapanda, J. Hughes
Liquid waste (sludge water (SW)) from treatment of drinking water contains impurities which pose disposal challenges. Irrigation with SW could be a solution for the Morton Jaffray Water Works. This study was conducted to determine the effects of SW dilution on aluminium (Al) and manganese (Mn) concentrations in (a) leachates from columns with either clay or a sandy loam soil and (b) different depths in the columns. The columns were leached with tap water (control) and 25, 50, 75 and 100% of the original SW concentration and the leachates were analysed for pH, electrical conductivity (EC), Al, and Mn. The sectioned soils (0–5, 5–10, 10–15 cm depths) were analysed for pH, exchangeable acidity, extractable Mn and total Al and Mn. Leaching with undiluted SW significantly increased EC and Al and Mn concentrations and lowered pH in leachates of the first four and two leaching events in the clay and sandy loam soils, respectively. The last two to four leaching events released additional Mn. Higher SW concentrations significantly increased retention of Mn, Al, extractable Mn and acidity, and lowered pH in the soils. In practice, irrigation with SW may retain the pollutants and acidify the soil, increasing Mn mobility, potentially causing leaching and phytotoxicity.
{"title":"Aluminium and manganese leaching and retention in two contrasting soils treated with aluminium-based sludge water in a column experiment","authors":"S. Dube, P. Muchaonyerwa, F. Mapanda, J. Hughes","doi":"10.1080/02571862.2021.1969693","DOIUrl":"https://doi.org/10.1080/02571862.2021.1969693","url":null,"abstract":"Liquid waste (sludge water (SW)) from treatment of drinking water contains impurities which pose disposal challenges. Irrigation with SW could be a solution for the Morton Jaffray Water Works. This study was conducted to determine the effects of SW dilution on aluminium (Al) and manganese (Mn) concentrations in (a) leachates from columns with either clay or a sandy loam soil and (b) different depths in the columns. The columns were leached with tap water (control) and 25, 50, 75 and 100% of the original SW concentration and the leachates were analysed for pH, electrical conductivity (EC), Al, and Mn. The sectioned soils (0–5, 5–10, 10–15 cm depths) were analysed for pH, exchangeable acidity, extractable Mn and total Al and Mn. Leaching with undiluted SW significantly increased EC and Al and Mn concentrations and lowered pH in leachates of the first four and two leaching events in the clay and sandy loam soils, respectively. The last two to four leaching events released additional Mn. Higher SW concentrations significantly increased retention of Mn, Al, extractable Mn and acidity, and lowered pH in the soils. In practice, irrigation with SW may retain the pollutants and acidify the soil, increasing Mn mobility, potentially causing leaching and phytotoxicity.","PeriodicalId":21920,"journal":{"name":"South African Journal of Plant and Soil","volume":"39 1","pages":"10 - 19"},"PeriodicalIF":0.9,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44732981","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 : 2022-01-01DOI: 10.1080/02571862.2021.1970832
L. Myeni, M. Moeletsi, AD Clulow
Data discontinuity is the major challenge that hinders the integrity of datasets from the sparse soil moisture monitoring networks in developing countries. In this study, a simplified, multi-layered soil water balance model to estimate daily soil moisture at point-scale from standard weather data and minimal physical soil properties was developed. The model requires values for soil water retentivity properties such as wilting point, field capacity and saturation of each soil layer. It also requires measurements or estimates of reference evapotranspiration (ETo ) in addition to rainfall as climate inputs. The developed model was evaluated using point-scale in-situ soil moisture measurements acquired over a minimum of two years from three well-calibrated stations representing different soil types and climatic conditions in South Africa. The results indicate that the proposed model was capable of estimating total soil moisture content at all three sites, with coefficient of determination (r 2) values greater than 0.84, index of agreement (d) values greater than 0.95 and root mean square error (RMSE) values less than 7.30 mm. The findings of this study suggest that the proposed model can be reliably used for daily estimation of soil moisture at point-scale using climate data and minimal soil physical properties, to fill in gaps, and to extend datasets in locations facing data-discontinuity.
{"title":"Development and validation of an operational multi-layered model for estimation of soil moisture at point-scale in South Africa","authors":"L. Myeni, M. Moeletsi, AD Clulow","doi":"10.1080/02571862.2021.1970832","DOIUrl":"https://doi.org/10.1080/02571862.2021.1970832","url":null,"abstract":"Data discontinuity is the major challenge that hinders the integrity of datasets from the sparse soil moisture monitoring networks in developing countries. In this study, a simplified, multi-layered soil water balance model to estimate daily soil moisture at point-scale from standard weather data and minimal physical soil properties was developed. The model requires values for soil water retentivity properties such as wilting point, field capacity and saturation of each soil layer. It also requires measurements or estimates of reference evapotranspiration (ETo ) in addition to rainfall as climate inputs. The developed model was evaluated using point-scale in-situ soil moisture measurements acquired over a minimum of two years from three well-calibrated stations representing different soil types and climatic conditions in South Africa. The results indicate that the proposed model was capable of estimating total soil moisture content at all three sites, with coefficient of determination (r 2) values greater than 0.84, index of agreement (d) values greater than 0.95 and root mean square error (RMSE) values less than 7.30 mm. The findings of this study suggest that the proposed model can be reliably used for daily estimation of soil moisture at point-scale using climate data and minimal soil physical properties, to fill in gaps, and to extend datasets in locations facing data-discontinuity.","PeriodicalId":21920,"journal":{"name":"South African Journal of Plant and Soil","volume":"39 1","pages":"28 - 40"},"PeriodicalIF":0.9,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47575124","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 : 2021-10-20DOI: 10.1080/02571862.2021.1958939
Vhuthu Ndou, E. Phiri, F. H. Eksteen, P. Pieterse
Globally glyphosate is the most widely used herbicide. The alternative in many cropping situations is paraquat. After many years of success, neither herbicide could control plantago (Plantago lanceolata L., also ‘English plantain’) in Robertson. A survey was carried out by sending a questionnaire to agrichemical personnel to document the areas with poor plantago control using glyphosate and paraquat in the Western Cape province of South Africa. Recipients were asked to list localities with plantago not eliminated by glyphosate and paraquat, plantago populations that are not controlled by other herbicides apart from glyphosate and paraquat, other herbicides apart from glyphosate and paraquat that eliminate plantago, the history of herbicides applied in those areas and the total number of hectares involved. Survey data were obtained for 21 areas, which spanned over 6 583 ha. There were minimal differences in the type of herbicides applied in the different areas across the province. Most of the respondents reported that both glyphosate and paraquat were failing to control plantago. It appears as if the occurrence of difficult-to-control plantago is more widespread than initially thought. In future, a more detailed survey encompassing the entire country should be carried out to assess the extent of this problem. This will allow weed management strategies to be prioritised to deal with the troublesome plantago weed.
{"title":"Occurrence of putatively resistant plantago in the winter rainfall region of South Africa: a survey","authors":"Vhuthu Ndou, E. Phiri, F. H. Eksteen, P. Pieterse","doi":"10.1080/02571862.2021.1958939","DOIUrl":"https://doi.org/10.1080/02571862.2021.1958939","url":null,"abstract":"Globally glyphosate is the most widely used herbicide. The alternative in many cropping situations is paraquat. After many years of success, neither herbicide could control plantago (Plantago lanceolata L., also ‘English plantain’) in Robertson. A survey was carried out by sending a questionnaire to agrichemical personnel to document the areas with poor plantago control using glyphosate and paraquat in the Western Cape province of South Africa. Recipients were asked to list localities with plantago not eliminated by glyphosate and paraquat, plantago populations that are not controlled by other herbicides apart from glyphosate and paraquat, other herbicides apart from glyphosate and paraquat that eliminate plantago, the history of herbicides applied in those areas and the total number of hectares involved. Survey data were obtained for 21 areas, which spanned over 6 583 ha. There were minimal differences in the type of herbicides applied in the different areas across the province. Most of the respondents reported that both glyphosate and paraquat were failing to control plantago. It appears as if the occurrence of difficult-to-control plantago is more widespread than initially thought. In future, a more detailed survey encompassing the entire country should be carried out to assess the extent of this problem. This will allow weed management strategies to be prioritised to deal with the troublesome plantago weed.","PeriodicalId":21920,"journal":{"name":"South African Journal of Plant and Soil","volume":"38 1","pages":"411 - 415"},"PeriodicalIF":0.9,"publicationDate":"2021-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47932518","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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