Pub Date : 2021-03-15DOI: 10.1080/02571862.2021.1881633
C. V. van Huyssteen, NR Rantoa, C. du Preez
Soil classification aims to group similar soils to facilitate communication and management. Management of soil organic carbon is gaining international recognition in an attempt to manage atmospheric carbon in addressing global warming. This paper explored the soil morphological and analytical data from a land type survey of South Africa, as augmented by data from other soil surveys in the country, to establish if soil classification, especially the soil form, can indicate the expected soil organic carbon content and thus enable generalisations to be drawn. Average organic carbon in the diagnostic topsoil horizons followed a predictable pattern: organic O (9.51% OC) > humic A (3.69% OC) > melanic A (2.59% OC) > vertic A (1.49% OC) > orthic A (1.38% OC). However, the organic carbon content also differed within the same diagnostic horizon between different soil forms. These differences could largely be related to the nature of the overlying topsoil, where topsoils with higher organic carbon contents typically resulted in subsoils with higher organic carbon. The results presented here can thus be used to semi-quantitatively determine the organic carbon contents of selected soil forms.
{"title":"Organic carbon content in the diagnostic horizons and materials of South African soil forms","authors":"C. V. van Huyssteen, NR Rantoa, C. du Preez","doi":"10.1080/02571862.2021.1881633","DOIUrl":"https://doi.org/10.1080/02571862.2021.1881633","url":null,"abstract":"Soil classification aims to group similar soils to facilitate communication and management. Management of soil organic carbon is gaining international recognition in an attempt to manage atmospheric carbon in addressing global warming. This paper explored the soil morphological and analytical data from a land type survey of South Africa, as augmented by data from other soil surveys in the country, to establish if soil classification, especially the soil form, can indicate the expected soil organic carbon content and thus enable generalisations to be drawn. Average organic carbon in the diagnostic topsoil horizons followed a predictable pattern: organic O (9.51% OC) > humic A (3.69% OC) > melanic A (2.59% OC) > vertic A (1.49% OC) > orthic A (1.38% OC). However, the organic carbon content also differed within the same diagnostic horizon between different soil forms. These differences could largely be related to the nature of the overlying topsoil, where topsoils with higher organic carbon contents typically resulted in subsoils with higher organic carbon. The results presented here can thus be used to semi-quantitatively determine the organic carbon contents of selected soil forms.","PeriodicalId":21920,"journal":{"name":"South African Journal of Plant and Soil","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2021-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/02571862.2021.1881633","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46038224","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 : 2021-03-15DOI: 10.1080/02571862.2021.1903106
Yared Semahegn, H. Shimelis, M. Laing, I. Mathew
Drought is a major cause of reduced yields in dryland wheat production. This study aimed to determine the combining ability effects of selected bread wheat genotypes (Triticum aestivum L.) for yield and yield-related traits. Eight parental lines were selected and crossed using a half-diallel mating design. The parents and 28 crosses were evaluated at two sites in Ethiopia, representing drought-stressed and non-stressed conditions, using a 6 x 6 simple lattice design. The parental line ETW17302 was the best general combiner for the growth indices: days to heading, days to maturity, grain-filling period, and 1 000-kernel weight, thereby enabling direct selection for improved grain yield under a drought-stressed condition. Parent ETW17377 could also be used for improving grain yield under a drought-stress condition owing to its positive and significant general combining ability effect on grain yield. The families ETW17302 × ETW17377, ETW17396 × ETW17374, and ETW17396 × ETW17385 were the best specific combiners for improving grain yield under the drought-stressed condition. The selected parents and families are desirable genetic resources to enhance yield and yield-related traits under both drought-stressed and non-stressed conditions.
干旱是旱地小麦产量下降的主要原因。本研究旨在确定选定的面包小麦基因型（小麦）对产量和产量相关性状的配合力效应。选择8个亲本系，采用半双列杂交设计进行杂交。在埃塞俄比亚的两个地点对亲本和28个杂交种进行了评估，分别代表干旱胁迫和非胁迫条件，采用6 x 6的简单晶格设计。亲本系ETW17302是生长指数（抽穗天数、成熟天数、灌浆期和1000粒重）的最佳组合，从而能够在干旱胁迫条件下直接选择提高粮食产量。亲本ETW17377在干旱胁迫条件下也可用于提高粮食产量，因为其对粮食产量的总体配合力效应是积极而显著的。在干旱胁迫条件下，ETW17302×ETW17377、ETW17396×ETW1737 4和ETW17396ETW17385是提高粮食产量的最佳组合。所选择的亲本和家庭是在干旱胁迫和非胁迫条件下提高产量和产量相关性状的理想遗传资源。
{"title":"Combining ability of bread wheat genotypes for yield and yield-related traits under drought-stressed and non-stressed conditions","authors":"Yared Semahegn, H. Shimelis, M. Laing, I. Mathew","doi":"10.1080/02571862.2021.1903106","DOIUrl":"https://doi.org/10.1080/02571862.2021.1903106","url":null,"abstract":"Drought is a major cause of reduced yields in dryland wheat production. This study aimed to determine the combining ability effects of selected bread wheat genotypes (Triticum aestivum L.) for yield and yield-related traits. Eight parental lines were selected and crossed using a half-diallel mating design. The parents and 28 crosses were evaluated at two sites in Ethiopia, representing drought-stressed and non-stressed conditions, using a 6 x 6 simple lattice design. The parental line ETW17302 was the best general combiner for the growth indices: days to heading, days to maturity, grain-filling period, and 1 000-kernel weight, thereby enabling direct selection for improved grain yield under a drought-stressed condition. Parent ETW17377 could also be used for improving grain yield under a drought-stress condition owing to its positive and significant general combining ability effect on grain yield. The families ETW17302 × ETW17377, ETW17396 × ETW17374, and ETW17396 × ETW17385 were the best specific combiners for improving grain yield under the drought-stressed condition. The selected parents and families are desirable genetic resources to enhance yield and yield-related traits under both drought-stressed and non-stressed conditions.","PeriodicalId":21920,"journal":{"name":"South African Journal of Plant and Soil","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2021-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/02571862.2021.1903106","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45234169","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 : 2021-03-15DOI: 10.1080/02571862.2021.1888391
V. Mathinya, J. Barnard, Z. Bello, E. van der Watt
Premiums are offered for high quality grain, but producers of malting barley are often confronted with marginal soils and water scarcity. Irrigation water quality is often low, primarily due to high salt loads. This study determined the effect of irrigation water salinity (ECi) on grain quality characteristics of malt barley evaluated in a lysimeter-based trial over two seasons. The trial involved five ECi levels (1. 5, 4. 5, 6, 9 and 12 dS m−1), and two different soil types (Bainsvlei and Clovelly). Grain yields, 1 000 seed mass (TSM, g), germination characteristics, and crude proteins (CP) were determined. Salinity levels of greater than 6 dS m−1 decreased TSM but had no significant effect on germination characteristics, while CP content of the grains significantly increased above the required range (between 9% and 11.5%) for malting. Increasing ECi reduced malt extract potential for all treatments, most noticeably at 9 and 12 ECi dS m−1. There were significant relationships between salinity and germinative characteristics as well as the malt extract proxy (germination index). The study shows that premium quality barley grain cannot be produced when salinity exceeds 6 dS m−1 and that the Clovelly soil would be a better fit for producing barley irrigated with saline water.
{"title":"Response of malt barley grain quality characteristics to increasing irrigation water salinity","authors":"V. Mathinya, J. Barnard, Z. Bello, E. van der Watt","doi":"10.1080/02571862.2021.1888391","DOIUrl":"https://doi.org/10.1080/02571862.2021.1888391","url":null,"abstract":"Premiums are offered for high quality grain, but producers of malting barley are often confronted with marginal soils and water scarcity. Irrigation water quality is often low, primarily due to high salt loads. This study determined the effect of irrigation water salinity (ECi) on grain quality characteristics of malt barley evaluated in a lysimeter-based trial over two seasons. The trial involved five ECi levels (1. 5, 4. 5, 6, 9 and 12 dS m−1), and two different soil types (Bainsvlei and Clovelly). Grain yields, 1 000 seed mass (TSM, g), germination characteristics, and crude proteins (CP) were determined. Salinity levels of greater than 6 dS m−1 decreased TSM but had no significant effect on germination characteristics, while CP content of the grains significantly increased above the required range (between 9% and 11.5%) for malting. Increasing ECi reduced malt extract potential for all treatments, most noticeably at 9 and 12 ECi dS m−1. There were significant relationships between salinity and germinative characteristics as well as the malt extract proxy (germination index). The study shows that premium quality barley grain cannot be produced when salinity exceeds 6 dS m−1 and that the Clovelly soil would be a better fit for producing barley irrigated with saline water.","PeriodicalId":21920,"journal":{"name":"South African Journal of Plant and Soil","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2021-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/02571862.2021.1888391","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44637642","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 : 2021-03-15DOI: 10.1080/02571862.2021.1879285
C. Nwigwe, A. Fossey, O. de Smidt
Hybrid vigour is exploited in Eucalyptus forestry through the production of interspecific hybrids. Hybrids are deployed via cuttings that often suffer from poor rooting. Rhizospheric microorganisms have been associated with rooting enhancement, therefore knowledge of the diversity of microorganism communities, and their abundance and changes over time could be of value in commercial forestry. This knowledge could be applied when sourcing and formulating combinations of useful rhizospheric microorganisms for the treatment of Eucalyptus hybrid cutting genotypes, specifically to improve rooting in the nursery for the establishment of clonal forests. Fatty acid methyl ester (FAME) profiles were prepared for 3-month-old and 5-year-old soil samples collected from rhizospheres of Eucalyptus grandis × Eucalyptus nitens clones to characterise microbial diversity. Saturated, monounsaturated and polyunsaturated fatty acids were present in both soil age groups, although in different proportions. Proportions of saturated fatty acids in the younger samples were greater than in the older samples, while proportions of unsaturated fatty acids were fewer in the younger samples. Palmitic (C16:0) and stearic (C18:0) acids were the most prevalent. Both Shannon’s and Simpson’s indices confirmed that younger soils were more diverse. The greater proportion of polyunsaturated fatty acids in older samples, especially linoleic, α-linolenic and γ-linolenic acids, suggests increasing establishment of fungi.
{"title":"Characterisation of Eucalyptus rhizospheric communities using fatty acid methyl ester (FAME) profile analysis","authors":"C. Nwigwe, A. Fossey, O. de Smidt","doi":"10.1080/02571862.2021.1879285","DOIUrl":"https://doi.org/10.1080/02571862.2021.1879285","url":null,"abstract":"Hybrid vigour is exploited in Eucalyptus forestry through the production of interspecific hybrids. Hybrids are deployed via cuttings that often suffer from poor rooting. Rhizospheric microorganisms have been associated with rooting enhancement, therefore knowledge of the diversity of microorganism communities, and their abundance and changes over time could be of value in commercial forestry. This knowledge could be applied when sourcing and formulating combinations of useful rhizospheric microorganisms for the treatment of Eucalyptus hybrid cutting genotypes, specifically to improve rooting in the nursery for the establishment of clonal forests. Fatty acid methyl ester (FAME) profiles were prepared for 3-month-old and 5-year-old soil samples collected from rhizospheres of Eucalyptus grandis × Eucalyptus nitens clones to characterise microbial diversity. Saturated, monounsaturated and polyunsaturated fatty acids were present in both soil age groups, although in different proportions. Proportions of saturated fatty acids in the younger samples were greater than in the older samples, while proportions of unsaturated fatty acids were fewer in the younger samples. Palmitic (C16:0) and stearic (C18:0) acids were the most prevalent. Both Shannon’s and Simpson’s indices confirmed that younger soils were more diverse. The greater proportion of polyunsaturated fatty acids in older samples, especially linoleic, α-linolenic and γ-linolenic acids, suggests increasing establishment of fungi.","PeriodicalId":21920,"journal":{"name":"South African Journal of Plant and Soil","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2021-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/02571862.2021.1879285","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43367974","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 : 2021-03-15DOI: 10.1080/02571862.2020.1845831
J. Chipomho, C. Parwada, J. Rugare, S. Mabasa, R. Chikowo, A. Mashingaidze
Labour bottlenecks and multiple operations at the start of a cropping season often result in inadequate early weed control and subsequent poor crop performance. Therefore, there is a need to establish management practices that provide the best opportunities for the gains associated with weeding and nutrient management across farms. We investigated the influence of soil organic carbon (SOC), fertiliser management, and weeding regimes on weed dynamics and maize productivity on smallholder farms with contrasting SOC in eastern Zimbabwe. On each site, and for two seasons, a 2 × 5 factorial experiment laid in a randomised complete block design was used. Fertiliser management was NPK or NPK + cattle manure (CM); weeding regimes were herbicide + hoe weeding, hoe weeding thrice/twice/once, or weedy check. Principal component analysis was used to evaluate weed density. The grain yield of maize increased by 13% on the sites with higher SOC. Integrating NPK + CM increased weed density and maize grain yield by 1.32 and 1.46-times, respectively, compared with NPK application only. The increased maize yield from fertiliser-managed treatments occurred only in early frequently weeded treatments. However, fertiliser application had little effect when weeding was delayed, as maize yield instead declined by 40–80%. We concluded that higher SOC increased weed density and weed biomass. Smallholder farmers are encouraged to combine herbicide application combined with hoe-weeding options for sustainable maize production.
{"title":"Influence of soil organic carbon, fertiliser management, and weeding regime on weed dynamics and maize productivity on sandy soils in eastern Zimbabwe","authors":"J. Chipomho, C. Parwada, J. Rugare, S. Mabasa, R. Chikowo, A. Mashingaidze","doi":"10.1080/02571862.2020.1845831","DOIUrl":"https://doi.org/10.1080/02571862.2020.1845831","url":null,"abstract":"Labour bottlenecks and multiple operations at the start of a cropping season often result in inadequate early weed control and subsequent poor crop performance. Therefore, there is a need to establish management practices that provide the best opportunities for the gains associated with weeding and nutrient management across farms. We investigated the influence of soil organic carbon (SOC), fertiliser management, and weeding regimes on weed dynamics and maize productivity on smallholder farms with contrasting SOC in eastern Zimbabwe. On each site, and for two seasons, a 2 × 5 factorial experiment laid in a randomised complete block design was used. Fertiliser management was NPK or NPK + cattle manure (CM); weeding regimes were herbicide + hoe weeding, hoe weeding thrice/twice/once, or weedy check. Principal component analysis was used to evaluate weed density. The grain yield of maize increased by 13% on the sites with higher SOC. Integrating NPK + CM increased weed density and maize grain yield by 1.32 and 1.46-times, respectively, compared with NPK application only. The increased maize yield from fertiliser-managed treatments occurred only in early frequently weeded treatments. However, fertiliser application had little effect when weeding was delayed, as maize yield instead declined by 40–80%. We concluded that higher SOC increased weed density and weed biomass. Smallholder farmers are encouraged to combine herbicide application combined with hoe-weeding options for sustainable maize production.","PeriodicalId":21920,"journal":{"name":"South African Journal of Plant and Soil","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2021-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/02571862.2020.1845831","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47107858","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 : 2021-03-15DOI: 10.1080/02571862.2021.1879287
Vhuthu Ndou, Frederick Eksteen, E. Phiri, P. Pieterse
Resistance to glyphosate in plantago (Plantago lanceolata L.), a serious weed in South Africa, was confirmed in 2003. More recently, a plantago biotype that is putatively resistant to both glyphosate and paraquat was reported. Seeds from a putatively susceptible (S) plantago population and from two putatively resistant populations (R1 and R2) were subjected to glyphosate and paraquat. To investigate possible multiple resistance, sequential application of glyphosate and paraquat was explored. The results showed an LD50 of 891.89 g a.e. ha−1 and 387.75 g a.i. ha−1 for glyphosate and paraquat respectively for the S biotype. For glyphosate, the LD50 value for R1 was 3842.61 g a.e. ha−1. The LD50 for the R2 biotype to glyphosate was 2020.39 g a.e. ha−1. The paraquat LD50 values for the R1 and R2 biotypes were 785.14 and 1246.43 g a.i. ha−1 respectively, resulting in resistance indices of 2 and 3 respectively. Sequential application of glyphosate and paraquat was not effective in plantago management. The R biotypes showed resistance to both glyphosate and paraquat indicating possible multiple resistance.
车前草(plantago lanceolata L.)是南非的一种严重杂草，2003年证实其对草甘膦具有抗性。最近，一种车前草生物型被认为对草甘膦和百草枯都具有抗性。对一个推定易感的车前草种群和两个推定抗性的车前草种群(R1和R2)的种子施用草甘膦和百草枯。为了调查可能的多重抗性，对草甘膦和百草枯的顺序施用进行了探索。结果表明，S型草甘膦和百草枯的LD50分别为891.89 g a.e. ha−1和387.75 g a.i. ha−1。对于草甘膦，R1的LD50值为3842.61 g a.e. ha−1。R2型对草甘膦的LD50为2020.39 g a.e. ha−1。R1和R2生物型的百草枯LD50分别为785.14和1246.43 g a.i. ha−1，抗性指数分别为2和3。连续施用草甘膦和百草枯对车前草的治理效果不明显。R型对草甘膦和百草枯均有抗性，表明可能存在多重抗性。
{"title":"First report of glyphosate and paraquat resistance in two Plantago biotypes","authors":"Vhuthu Ndou, Frederick Eksteen, E. Phiri, P. Pieterse","doi":"10.1080/02571862.2021.1879287","DOIUrl":"https://doi.org/10.1080/02571862.2021.1879287","url":null,"abstract":"Resistance to glyphosate in plantago (Plantago lanceolata L.), a serious weed in South Africa, was confirmed in 2003. More recently, a plantago biotype that is putatively resistant to both glyphosate and paraquat was reported. Seeds from a putatively susceptible (S) plantago population and from two putatively resistant populations (R1 and R2) were subjected to glyphosate and paraquat. To investigate possible multiple resistance, sequential application of glyphosate and paraquat was explored. The results showed an LD50 of 891.89 g a.e. ha−1 and 387.75 g a.i. ha−1 for glyphosate and paraquat respectively for the S biotype. For glyphosate, the LD50 value for R1 was 3842.61 g a.e. ha−1. The LD50 for the R2 biotype to glyphosate was 2020.39 g a.e. ha−1. The paraquat LD50 values for the R1 and R2 biotypes were 785.14 and 1246.43 g a.i. ha−1 respectively, resulting in resistance indices of 2 and 3 respectively. Sequential application of glyphosate and paraquat was not effective in plantago management. The R biotypes showed resistance to both glyphosate and paraquat indicating possible multiple resistance.","PeriodicalId":21920,"journal":{"name":"South African Journal of Plant and Soil","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2021-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/02571862.2021.1879287","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47245238","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 : 2021-03-15DOI: 10.1080/02571862.2021.1881634
R. M. Moloto, F. Dakora, P. Soundy, S. Maseko
Although the application of biostimulants to soils and plants affects their phosphatase activity, this has not been shown in chickpea (Cicer arietinum L.) grown under South African conditions. In this study, chickpea genotypes were grown in silty-loam and silty-clay-loam soils and supplied with Kelpak and Bontera. The leaves, roots and rhizospheric soil were collected, processed and acid phosphatase (APase) activity assayed following the p-nitrophenol method. The ICCV92944 cultivar exhibited the highest levels of intracellular activity in both soils and extracellular APase in the silty-loam soil. Leaves of the selected genotypes revealed increased APase activity than roots. The application of Kelpak increased intracellular APase activity while Bontera enhanced extracellular APase activity. The APase activity was markedly higher in chickpea grown in the silty-clay-loam soil compared to those grown in the silty-loam soil.
{"title":"Effects of biostimulants on tissue and rhizospheric acid phosphatase activity of chickpea genotypes","authors":"R. M. Moloto, F. Dakora, P. Soundy, S. Maseko","doi":"10.1080/02571862.2021.1881634","DOIUrl":"https://doi.org/10.1080/02571862.2021.1881634","url":null,"abstract":"Although the application of biostimulants to soils and plants affects their phosphatase activity, this has not been shown in chickpea (Cicer arietinum L.) grown under South African conditions. In this study, chickpea genotypes were grown in silty-loam and silty-clay-loam soils and supplied with Kelpak and Bontera. The leaves, roots and rhizospheric soil were collected, processed and acid phosphatase (APase) activity assayed following the p-nitrophenol method. The ICCV92944 cultivar exhibited the highest levels of intracellular activity in both soils and extracellular APase in the silty-loam soil. Leaves of the selected genotypes revealed increased APase activity than roots. The application of Kelpak increased intracellular APase activity while Bontera enhanced extracellular APase activity. The APase activity was markedly higher in chickpea grown in the silty-clay-loam soil compared to those grown in the silty-loam soil.","PeriodicalId":21920,"journal":{"name":"South African Journal of Plant and Soil","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2021-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/02571862.2021.1881634","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43487077","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 : 2021-03-15DOI: 10.1080/02571862.2020.1858512
P. F. Loke, Johannes Jacobus Schimper, E. Kotzé, C. D. du Preez
This study evaluated temporal effects of wheat production management practices on soil fertility under semi-arid conditions. Treatments applied for 37 years included straw management (unburned and burned), tillage practices (no-tillage, stubble mulch, and mouldboard ploughing) and weed control methods (chemical and mechanical). Soil samples were collected from 0–50, 50–150 and 150–250 mm layers, in 1990, 1999, 2010 and 2016, and analysed for organic carbon (OC), total nitrogen, pH, phosphorus (P) and potassium (K). Supplied grain yield data were used to estimate straw yield. Uptake of N, P and K by grain (removal) and straw (recycle) were estimated across sampling periods. Results revealed that OC, C:N ratio and P generally increased from 1990 to 1999 or 2010, and that conservation tillage increased soil fertility as compared with mouldboard ploughing. The only year × treatment interaction effects were on pH and K in the soil layers 0–50 and 50–150 mm in some treatments. However, all soil fertility indicators increased from 1990 to 1999 or 2010, then declined or stabilised across all treatments. The results suggest that adoption of conservation tillage with associated straw and nutrient recycling and additions cannot enable farmers to maintain or improve soil fertility and yields over time.
{"title":"Long-term wheat production management effects on soil fertility indicators in the semi-arid eastern Free State, South Africa","authors":"P. F. Loke, Johannes Jacobus Schimper, E. Kotzé, C. D. du Preez","doi":"10.1080/02571862.2020.1858512","DOIUrl":"https://doi.org/10.1080/02571862.2020.1858512","url":null,"abstract":"This study evaluated temporal effects of wheat production management practices on soil fertility under semi-arid conditions. Treatments applied for 37 years included straw management (unburned and burned), tillage practices (no-tillage, stubble mulch, and mouldboard ploughing) and weed control methods (chemical and mechanical). Soil samples were collected from 0–50, 50–150 and 150–250 mm layers, in 1990, 1999, 2010 and 2016, and analysed for organic carbon (OC), total nitrogen, pH, phosphorus (P) and potassium (K). Supplied grain yield data were used to estimate straw yield. Uptake of N, P and K by grain (removal) and straw (recycle) were estimated across sampling periods. Results revealed that OC, C:N ratio and P generally increased from 1990 to 1999 or 2010, and that conservation tillage increased soil fertility as compared with mouldboard ploughing. The only year × treatment interaction effects were on pH and K in the soil layers 0–50 and 50–150 mm in some treatments. However, all soil fertility indicators increased from 1990 to 1999 or 2010, then declined or stabilised across all treatments. The results suggest that adoption of conservation tillage with associated straw and nutrient recycling and additions cannot enable farmers to maintain or improve soil fertility and yields over time.","PeriodicalId":21920,"journal":{"name":"South African Journal of Plant and Soil","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2021-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/02571862.2020.1858512","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42367704","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 : 2021-03-15DOI: 10.1080/02571862.2021.1891473
CF Wessels, L. van Straaten, C. du Preez, G. Ceronio
Maize is the most important crop produced for human and animal nourishment in South Africa. The crop is susceptible to zinc (Zn) deficiencies, which result in lower grain yields with poorer nutritional value. Knowledge of the nature and behaviour of Zn fertilisers is therefore important for sustainable maize production, especially in sandy soils. The aim of this incubation study was to test the effect of inorganic (ZnO, ZnCl2, ZnCO3 and ZnSO4) and chelated (ZnEDTA, ZnDTPA, ZnEDDHA and ZnHEDTA) sources of Zn applied at different rates on Zn extracted by diluted HCl, DTPA, Mehlich-1, Ambic-2 and Na2EDTA methods. Analyses showed that ZnO was the least effective source, and ZnSO4 was the most effective source at increasing the extractable Zn of sandy soils. The extractable Zn content of the soils increased almost linearly with increasing application rates of all the zinc sources. Generally, the Na2EDTA method was most efficient in extracting the applied Zn. These results must be validated with crop growth response in glasshouse and especially field studies.
{"title":"A comparison of zinc sources and extraction methods on sandy soils suitable for maize cropping","authors":"CF Wessels, L. van Straaten, C. du Preez, G. Ceronio","doi":"10.1080/02571862.2021.1891473","DOIUrl":"https://doi.org/10.1080/02571862.2021.1891473","url":null,"abstract":"Maize is the most important crop produced for human and animal nourishment in South Africa. The crop is susceptible to zinc (Zn) deficiencies, which result in lower grain yields with poorer nutritional value. Knowledge of the nature and behaviour of Zn fertilisers is therefore important for sustainable maize production, especially in sandy soils. The aim of this incubation study was to test the effect of inorganic (ZnO, ZnCl2, ZnCO3 and ZnSO4) and chelated (ZnEDTA, ZnDTPA, ZnEDDHA and ZnHEDTA) sources of Zn applied at different rates on Zn extracted by diluted HCl, DTPA, Mehlich-1, Ambic-2 and Na2EDTA methods. Analyses showed that ZnO was the least effective source, and ZnSO4 was the most effective source at increasing the extractable Zn of sandy soils. The extractable Zn content of the soils increased almost linearly with increasing application rates of all the zinc sources. Generally, the Na2EDTA method was most efficient in extracting the applied Zn. These results must be validated with crop growth response in glasshouse and especially field studies.","PeriodicalId":21920,"journal":{"name":"South African Journal of Plant and Soil","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2021-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/02571862.2021.1891473","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48811397","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 : 2021-03-15DOI: 10.1080/02571862.2020.1863485
E. Asare, O. Domfeh, S. Avicor, P. Pobee, Y. Bukari, I. Amoako-Attah
Outbreak of anthracnose of cacao (Theobroma cacao L.), covering an estimated total growing area of 248.47 hectares, occurred in parts of Ghana from July to October 2019. Disease samples were collected from the outbreak areas to isolate and identify the pathogen and establish its pathogenicity. Disease symptoms appeared on leaves as dark brown patches with yellow halo margins. Colletotrichum gloeosporioides s.l. was isolated from infected plant tissues and pathogenicity tests confirmed it as the causative agent. The disease was widespread in the Prestea-Huni Valley district of the Western Region, particularly in the Yareyeya community, where a 14.8-hectare farm was seriously affected. Anthracnose has long been known as a sporadic but minor disease of cacao in Ghana. The current shift in status and rapid spread of the disease from infected farms to new farms, though it may or may not be contiguous, cannot be readily explained. Application of copper fungicides, namely Nordox 75 WG (86% cuprous oxide), Champion (77% cupric hydroxide) and Royal Cop 50 WP (77% copper hydroxide) at 75 g, 100 g and 100 g, respectively, each in 15 litres of water, at 2-week intervals for four months, effectively managed the disease.
{"title":"Colletotrichum gloeosporioides s.l. causes an outbreak of anthracnose of cacao in Ghana","authors":"E. Asare, O. Domfeh, S. Avicor, P. Pobee, Y. Bukari, I. Amoako-Attah","doi":"10.1080/02571862.2020.1863485","DOIUrl":"https://doi.org/10.1080/02571862.2020.1863485","url":null,"abstract":"Outbreak of anthracnose of cacao (Theobroma cacao L.), covering an estimated total growing area of 248.47 hectares, occurred in parts of Ghana from July to October 2019. Disease samples were collected from the outbreak areas to isolate and identify the pathogen and establish its pathogenicity. Disease symptoms appeared on leaves as dark brown patches with yellow halo margins. Colletotrichum gloeosporioides s.l. was isolated from infected plant tissues and pathogenicity tests confirmed it as the causative agent. The disease was widespread in the Prestea-Huni Valley district of the Western Region, particularly in the Yareyeya community, where a 14.8-hectare farm was seriously affected. Anthracnose has long been known as a sporadic but minor disease of cacao in Ghana. The current shift in status and rapid spread of the disease from infected farms to new farms, though it may or may not be contiguous, cannot be readily explained. Application of copper fungicides, namely Nordox 75 WG (86% cuprous oxide), Champion (77% cupric hydroxide) and Royal Cop 50 WP (77% copper hydroxide) at 75 g, 100 g and 100 g, respectively, each in 15 litres of water, at 2-week intervals for four months, effectively managed the disease.","PeriodicalId":21920,"journal":{"name":"South African Journal of Plant and Soil","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2021-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/02571862.2020.1863485","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47313236","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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