Pub Date : 2023-01-01DOI: 10.1080/02571862.2023.2192528
T. Baloyi, F. Kutu, C. du Preez
Large areas of soils in sub-Saharan Africa are poor in organic matter and nitrogen-phosphorus-potassium (NPK) fertilisation is essential for cropping. Most farmers are smallholders who cannot afford NPK fertilisers but they could consider alternatives like commercial organic ameliorants.This applies also for commercial farmers to improve profitability. The effects of nine ameliorants on the grain yield, biomass yield and harvest index of maize were evaluated over three years at Bothaville (8% clay), Ottosdal (12% clay) and Potchefstroom (34% clay). All ameliorants were applied as manufacturers prescribe. None of the ameliorants can serve as replacement of NPK fertilisers. Active ingredients other than the small amounts of N, P and K they contain, comprised of effective microorganisms (EMs), human manure, humic acids and poultry manure, and were not able to boost crop growth as manufacturers advocated. Biozone (EMs), Gliogrow (EMs), Growmax (Human manure), K-humate (Humic acid) and Crop Care (Humic acid) that were applied with NPK fertilisation resulted in 22 to 44% instances in significantly higher grain yield (938 to 1 288 kg ha−1) compared to the NPK control; however, many inconsistencies between experimental sites and years were observed. The use of commercial organic ameliorants cannot recommended to farmers without proper evaluation.
撒哈拉以南非洲的大片土壤缺乏有机质，氮、磷、钾(NPK)施肥对种植至关重要。大多数农民都是小农，负担不起氮磷钾肥料，但他们可以考虑商业有机改良剂等替代品。这也适用于商业农民提高盈利能力。以Bothaville(8%粘土)、Ottosdal(12%粘土)和Potchefstroom(34%粘土)为试验基地，评价了9种改良剂对玉米籽粒产量、生物量产量和收获指数的影响。所有改良剂均按制造商规定使用。这些改良剂都不能代替氮磷钾肥料。除了含有少量的氮、磷和钾外，它们还含有有效微生物(EMs)、人类粪便、腐植酸和家禽粪便等有效成分，并不能像制造商所倡导的那样促进作物生长。与氮磷钾对照相比，施用Biozone (EMs)、Gliogrow (EMs)、Growmax(人粪肥)、K-humate(腐植酸)和Crop Care(腐植酸)的氮磷钾组的产量显著提高了22%至44%(938至1 288 kg ha - 1);然而，在实验地点和年份之间观察到许多不一致。未经适当的评估，不能向农民推荐商业有机改良剂的使用。
{"title":"Is the use of commercial organic ameliorants for cropping justified?","authors":"T. Baloyi, F. Kutu, C. du Preez","doi":"10.1080/02571862.2023.2192528","DOIUrl":"https://doi.org/10.1080/02571862.2023.2192528","url":null,"abstract":"Large areas of soils in sub-Saharan Africa are poor in organic matter and nitrogen-phosphorus-potassium (NPK) fertilisation is essential for cropping. Most farmers are smallholders who cannot afford NPK fertilisers but they could consider alternatives like commercial organic ameliorants.This applies also for commercial farmers to improve profitability. The effects of nine ameliorants on the grain yield, biomass yield and harvest index of maize were evaluated over three years at Bothaville (8% clay), Ottosdal (12% clay) and Potchefstroom (34% clay). All ameliorants were applied as manufacturers prescribe. None of the ameliorants can serve as replacement of NPK fertilisers. Active ingredients other than the small amounts of N, P and K they contain, comprised of effective microorganisms (EMs), human manure, humic acids and poultry manure, and were not able to boost crop growth as manufacturers advocated. Biozone (EMs), Gliogrow (EMs), Growmax (Human manure), K-humate (Humic acid) and Crop Care (Humic acid) that were applied with NPK fertilisation resulted in 22 to 44% instances in significantly higher grain yield (938 to 1 288 kg ha−1) compared to the NPK control; however, many inconsistencies between experimental sites and years were observed. The use of commercial organic ameliorants cannot recommended to farmers without proper evaluation.","PeriodicalId":21920,"journal":{"name":"South African Journal of Plant and Soil","volume":"40 1","pages":"34 - 45"},"PeriodicalIF":0.9,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45663636","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-20DOI: 10.1080/02571862.2022.2137590
H. van Zyl, C. du Preez
The sustainable production of wheat can be affected by soil acidity in the eastern Free State, South Africa. Liming of soil to appropriate acidity levels is therefore regarded as an essential farming practice. In some instances, however, planting of acid-tolerant wheat cultivars is recommended as an interim management measure. Hence, we evaluated the response (grain yield, grain protein content and hectoliter mass) of wheat cultivars with poor (Karee or Limpopo), moderate (SST 224 or Gariep) and good (Tugela DN) acid tolerance on soils (8–33% clay) over a range of lime-induced pH (KCl) values (3.7–5.7) under field conditions spanning 4 to 5 years. In Year 2 no data was collected due to staff shortages. Across the pH ranges, grain yields of the most acid-tolerant cultivars exceeded those of the moderately acid-tolerant cultivars by 29–54%, and those of the poorly acid-tolerant cultivars by 36–62%. Due to climatic conditions, larger differences in grain protein content were observed between years rather than between treatment combinations. Hectoliter mass, although influenced by treatment combinations, exceeded the threshold value of 76 kg hL−1. The results, especially of grain yield, proved the usefulness of acid-tolerant wheat cultivars during the initial stages of liming programs, until acceptable levels of soil acidity are reached.
南非自由邦东部的土壤酸度可能会影响小麦的可持续生产。因此，将土壤石灰化至适当的酸度水平被认为是一种必要的耕作方法。但在某些情况下，建议种植耐酸小麦品种作为临时管理措施。因此，我们在4 ~ 5年的田间条件下，对土壤(粘土含量为8-33%)耐酸性较差(Karee或Limpopo)、中等(SST 224或Gariep)和良好(Tugela DN)耐酸小麦品种在石灰诱导pH (KCl)值(3.7 ~ 5.7)范围内的响应(籽粒产量、籽粒蛋白质含量和千吨质量)进行了评价。在第二年，由于人员短缺，没有收集数据。在不同的pH值范围内，最耐酸品种的产量比中等耐酸品种高29-54%，较不耐酸品种的产量比中等耐酸品种高36-62%。由于气候条件的原因，籽粒蛋白质含量在不同年份之间的差异大于不同处理组合之间的差异。百升质量虽然受到处理组合的影响，但仍超过了76 kg hL−1的阈值。结果，特别是粮食产量，证明了耐酸小麦品种在石灰计划的初始阶段是有用的，直到土壤酸度达到可接受的水平。
{"title":"Response of wheat cultivars with varying acid tolerances to liming of eastern Free State soils","authors":"H. van Zyl, C. du Preez","doi":"10.1080/02571862.2022.2137590","DOIUrl":"https://doi.org/10.1080/02571862.2022.2137590","url":null,"abstract":"The sustainable production of wheat can be affected by soil acidity in the eastern Free State, South Africa. Liming of soil to appropriate acidity levels is therefore regarded as an essential farming practice. In some instances, however, planting of acid-tolerant wheat cultivars is recommended as an interim management measure. Hence, we evaluated the response (grain yield, grain protein content and hectoliter mass) of wheat cultivars with poor (Karee or Limpopo), moderate (SST 224 or Gariep) and good (Tugela DN) acid tolerance on soils (8–33% clay) over a range of lime-induced pH (KCl) values (3.7–5.7) under field conditions spanning 4 to 5 years. In Year 2 no data was collected due to staff shortages. Across the pH ranges, grain yields of the most acid-tolerant cultivars exceeded those of the moderately acid-tolerant cultivars by 29–54%, and those of the poorly acid-tolerant cultivars by 36–62%. Due to climatic conditions, larger differences in grain protein content were observed between years rather than between treatment combinations. Hectoliter mass, although influenced by treatment combinations, exceeded the threshold value of 76 kg hL−1. The results, especially of grain yield, proved the usefulness of acid-tolerant wheat cultivars during the initial stages of liming programs, until acceptable levels of soil acidity are reached.","PeriodicalId":21920,"journal":{"name":"South African Journal of Plant and Soil","volume":"39 1","pages":"360 - 369"},"PeriodicalIF":0.9,"publicationDate":"2022-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48651001","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-20DOI: 10.1080/02571862.2022.2119291
E. Ebrahimi, J. Zinkernagel
The northern part of Namibia suffers from drought and low-quality soil. The soil needs a boost of nutrients, and the water must be used in a frugal manner. Thereby, the objective of this research was to investigate the effect of sludge and treated wastewater as initial nutrient drivers in sandy loam soil by examining the dry biomass (DM), the nutrient uptake, and the heavy metal accumulation in the organs of sorghum. For this reason, sludge, chemical fertiliser, and a mixture of both were applied to a sorghum field. As a second factor, water of two different qualities was used: (a) treated wastewater (TWW), and (b) tap water. The treatment with mixed-fertiliser produced 16% more DM compared to the treatment with chemical fertiliser when irrigated with tap water. The use of TWW enhanced phosphorus uptake in the treatment with chemical fertiliser but did not increase the DM. This study suggests that sludge can be applied as an initial nutrient driver for poor soil with low organic matter and that TWW can also be an important complementary water resource for irrigation in areas affected by drought.
{"title":"Sludge as an initial nutrient driver for yield improvement in the poor soils of northern Namibia","authors":"E. Ebrahimi, J. Zinkernagel","doi":"10.1080/02571862.2022.2119291","DOIUrl":"https://doi.org/10.1080/02571862.2022.2119291","url":null,"abstract":"The northern part of Namibia suffers from drought and low-quality soil. The soil needs a boost of nutrients, and the water must be used in a frugal manner. Thereby, the objective of this research was to investigate the effect of sludge and treated wastewater as initial nutrient drivers in sandy loam soil by examining the dry biomass (DM), the nutrient uptake, and the heavy metal accumulation in the organs of sorghum. For this reason, sludge, chemical fertiliser, and a mixture of both were applied to a sorghum field. As a second factor, water of two different qualities was used: (a) treated wastewater (TWW), and (b) tap water. The treatment with mixed-fertiliser produced 16% more DM compared to the treatment with chemical fertiliser when irrigated with tap water. The use of TWW enhanced phosphorus uptake in the treatment with chemical fertiliser but did not increase the DM. This study suggests that sludge can be applied as an initial nutrient driver for poor soil with low organic matter and that TWW can also be an important complementary water resource for irrigation in areas affected by drought.","PeriodicalId":21920,"journal":{"name":"South African Journal of Plant and Soil","volume":"39 1","pages":"370 - 374"},"PeriodicalIF":0.9,"publicationDate":"2022-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41948438","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-20DOI: 10.1080/02571862.2022.2142972
Hanine Loucif, B. Bousalhih, Rebiha Chaoui, J. Drevon, M. Farissi, M. Lazali
Low phosphorus (P) availability is a major constraint for chickpea production. Consequently, P-efficient genotypes can improve productivity under conditions where the higher application of P is not economical. This study was conducted to characterise four chickpea genotypes for nutrient uptake and use efficiency under low-P conditions over two growing seasons. At flowering stage, plants were harvested and analysed for their nodulation, growth, P content and yield. Results indicate that low P availability significantly limited plant growth, nodulation and yield for all genotypes with the greatest effect on for Flip 84-92C and Flip 01-29C. The genotypes Flip 90-13C and ILC 32-79 showed the highest P uptake and use efficiency. The genotypes with high nutrient uptake had better efficiency in use of rhizobial symbiosis. It is concluded that nutrient uptake and use efficiency may be an important functional trait that may contribute to the selection of cultivars able to produce high quality seeds and efficiently fix nitrogen under conditions of low soil P.
{"title":"Genotypic variability in nutrient uptake and use efficiency in chickpea grown under low phosphorus availability in a Mediterranean climate","authors":"Hanine Loucif, B. Bousalhih, Rebiha Chaoui, J. Drevon, M. Farissi, M. Lazali","doi":"10.1080/02571862.2022.2142972","DOIUrl":"https://doi.org/10.1080/02571862.2022.2142972","url":null,"abstract":"Low phosphorus (P) availability is a major constraint for chickpea production. Consequently, P-efficient genotypes can improve productivity under conditions where the higher application of P is not economical. This study was conducted to characterise four chickpea genotypes for nutrient uptake and use efficiency under low-P conditions over two growing seasons. At flowering stage, plants were harvested and analysed for their nodulation, growth, P content and yield. Results indicate that low P availability significantly limited plant growth, nodulation and yield for all genotypes with the greatest effect on for Flip 84-92C and Flip 01-29C. The genotypes Flip 90-13C and ILC 32-79 showed the highest P uptake and use efficiency. The genotypes with high nutrient uptake had better efficiency in use of rhizobial symbiosis. It is concluded that nutrient uptake and use efficiency may be an important functional trait that may contribute to the selection of cultivars able to produce high quality seeds and efficiently fix nitrogen under conditions of low soil P.","PeriodicalId":21920,"journal":{"name":"South African Journal of Plant and Soil","volume":"39 1","pages":"331 - 339"},"PeriodicalIF":0.9,"publicationDate":"2022-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49468975","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-20DOI: 10.1080/02571862.2022.2131009
Víctor Mondragón, F. Hurtado, Daniel Francisco Jaramillo Jaramillo
Soil organic carbon (SOC) is the main element in soil organic matter (SOM) and its storage or release into the atmosphere is sensitive to changes in land use. This study evaluated SOC storage and SOM quality in the Metropolitan Regional Natural Park, Cerro El Volador, MedelIín-Colombia, in areas where plant cover was restored with plants from different functional groups consisting of secondary vegetation (SV), forest plantations of Eucalyptus globulus Labill. (EUC) and Pinus patula Schltdl. & Cham. (PIN), and pastures (PAS). Soil samples were taken at the O horizon and at two soil depths at the A horizon (0–10 and 10–20 cm). The quality of the SOM was evaluated through humification indices, spectrophotometric tests and carbon distribution in humic substances. The highest storage of SOC in the O horizon occurred in PIN, followed by EUC, SV and PAS. In descending order, the vegetation with the highest SOC values for the A horizon at both depths evaluated were EUC, PAS, PIN and SV. Humification indices showed that the SOM was mainly composed of fresh SOM with little humification. The humification process of SOM evolved towards humic acids of the P-group. These results show that the change of cover significantly affects the storage of SOC, the characteristics of SOM and the properties of the soil.
土壤有机碳（SOC）是土壤有机质（SOM）中的主要元素，其储存或释放到大气中对土地利用的变化很敏感。本研究评估了哥伦比亚MedelIín-Colombia Cerro El Volador大都会区域自然公园的SOC储量和SOM质量，这些地区的植物覆盖被不同功能组的植物恢复，包括次生植被（SV）、蓝桉人工林。（EUC）和松Cham。（PIN）和牧场（PAS）。在O层和A层的两个土壤深度（0–10和10–20 cm）。通过腐殖化指数、分光光度法和腐殖物质中碳的分布来评价SOM的质量。SOC在O水平中的最高存储出现在PIN中，其次是EUC、SV和PAS。按降序排列，在两个深度评估的A层SOC值最高的植被是EUC、PAS、PIN和SV。腐殖化指数表明，SOM主要由新鲜SOM组成，腐殖化程度很低。SOM的腐殖化过程向P族腐殖酸演化。这些结果表明，覆盖的变化对土壤有机碳的储存、有机碳的特性和土壤性质有显著影响。
{"title":"Soil organic carbon stocks and properties are affected by plant cover types in an urban ecosystem in Colombia","authors":"Víctor Mondragón, F. Hurtado, Daniel Francisco Jaramillo Jaramillo","doi":"10.1080/02571862.2022.2131009","DOIUrl":"https://doi.org/10.1080/02571862.2022.2131009","url":null,"abstract":"Soil organic carbon (SOC) is the main element in soil organic matter (SOM) and its storage or release into the atmosphere is sensitive to changes in land use. This study evaluated SOC storage and SOM quality in the Metropolitan Regional Natural Park, Cerro El Volador, MedelIín-Colombia, in areas where plant cover was restored with plants from different functional groups consisting of secondary vegetation (SV), forest plantations of Eucalyptus globulus Labill. (EUC) and Pinus patula Schltdl. & Cham. (PIN), and pastures (PAS). Soil samples were taken at the O horizon and at two soil depths at the A horizon (0–10 and 10–20 cm). The quality of the SOM was evaluated through humification indices, spectrophotometric tests and carbon distribution in humic substances. The highest storage of SOC in the O horizon occurred in PIN, followed by EUC, SV and PAS. In descending order, the vegetation with the highest SOC values for the A horizon at both depths evaluated were EUC, PAS, PIN and SV. Humification indices showed that the SOM was mainly composed of fresh SOM with little humification. The humification process of SOM evolved towards humic acids of the P-group. These results show that the change of cover significantly affects the storage of SOC, the characteristics of SOM and the properties of the soil.","PeriodicalId":21920,"journal":{"name":"South African Journal of Plant and Soil","volume":"39 1","pages":"322 - 330"},"PeriodicalIF":0.9,"publicationDate":"2022-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43628272","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-20DOI: 10.1080/02571862.2022.2125094
S. Magwaza, M. van der Laan, D. Marais
Wheat (Triticum aestivum L.) production is threatened by climate change and the decline in agricultural land available due to urbanisation, farmers switching to other crops, and environmental degradation. The aim of this study was to investigate the ecological intensification (EI) of irrigated wheat production in South Africa. Data from the long-term wheat trial at the University of Pretoria and an intensive growth analysis conducted in 2019 were used to calibrate and evaluate the APSIM model. Following adequate model performance, improved management scenarios including crop rotation, manure application, optimised inorganic nitrogen (N) fertiliser application rate, objectively scheduled irrigation, and a combination of all these improved management practices together, were tested. The adoption of all management practices simultaneously was shown to be the best practice, achieving an increase of 18% in yield and reducing deep drainage and N leaching by 31%. Whereas measured data indicated a decrease in soil organic matter (SOM) from 1.20% in 1950 to 0.58% in 2019, adopting EI measures could reduce the loss of SOM to only 0.68%. Farmers are encouraged to adopt one or more of these EI management practices as their site-specific situations allow.
{"title":"Long-term experimental data and crop modelling to inform the ecological intensification of irrigated wheat production in South Africa","authors":"S. Magwaza, M. van der Laan, D. Marais","doi":"10.1080/02571862.2022.2125094","DOIUrl":"https://doi.org/10.1080/02571862.2022.2125094","url":null,"abstract":"Wheat (Triticum aestivum L.) production is threatened by climate change and the decline in agricultural land available due to urbanisation, farmers switching to other crops, and environmental degradation. The aim of this study was to investigate the ecological intensification (EI) of irrigated wheat production in South Africa. Data from the long-term wheat trial at the University of Pretoria and an intensive growth analysis conducted in 2019 were used to calibrate and evaluate the APSIM model. Following adequate model performance, improved management scenarios including crop rotation, manure application, optimised inorganic nitrogen (N) fertiliser application rate, objectively scheduled irrigation, and a combination of all these improved management practices together, were tested. The adoption of all management practices simultaneously was shown to be the best practice, achieving an increase of 18% in yield and reducing deep drainage and N leaching by 31%. Whereas measured data indicated a decrease in soil organic matter (SOM) from 1.20% in 1950 to 0.58% in 2019, adopting EI measures could reduce the loss of SOM to only 0.68%. Farmers are encouraged to adopt one or more of these EI management practices as their site-specific situations allow.","PeriodicalId":21920,"journal":{"name":"South African Journal of Plant and Soil","volume":"39 1","pages":"309 - 321"},"PeriodicalIF":0.9,"publicationDate":"2022-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46431586","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-20DOI: 10.1080/02571862.2022.2132542
H. van Zyl, C. du Preez
Soil acidity can adversely affect wheat production in the eastern Free State, South Africa. Liming of the soils is therefore essential. The aim of this study was to establish whether extractable phosphorus (P), exchangeable calcium (Ca), magnesium (Mg) and potassium (K) concentrations and cation ratios remained within recommended ranges after liming. Incubation and field studies were done on soils of wheat fields at Kestell, Fouriesburg, Prinsloo and Melrose in the eastern Free State, South Africa. Lime was applied at different rates to induce soil acidity ranges for determination of Bray 1 extractable P and ammonium acetate (NH4OAc) exchangeable Ca, Mg and K concentrations. Cation ratios (Ca:Mg, Mg:K and (Ca + Mg):K) and effective cation exchange capacity (ECEC) were also calculated. Apart from the Prinsloo soil, liming decreased extractable P concentration only in the incubation study. In the incubation and field studies exchangeable Ca and Mg concentrations increased while exchangeable K concentration remained unchanged. Despite liming of the soils, exchangeable Ca and Mg concentrations at Kestell and Fouriesburg were still less than the required thresholds. The Ca:Mg ratio decreased at both sites while the Mg:K and (Ca + Mg):K ratios increased with liming. Liming increased ECEC of all soils at all four sites. Our results show that liming does not always result in the recommended cation levels required for soil fertility.
{"title":"Impact of liming on extractable phosphorus, exchangeable base cations, and effective cation exchange capacity of eastern Free State soils","authors":"H. van Zyl, C. du Preez","doi":"10.1080/02571862.2022.2132542","DOIUrl":"https://doi.org/10.1080/02571862.2022.2132542","url":null,"abstract":"Soil acidity can adversely affect wheat production in the eastern Free State, South Africa. Liming of the soils is therefore essential. The aim of this study was to establish whether extractable phosphorus (P), exchangeable calcium (Ca), magnesium (Mg) and potassium (K) concentrations and cation ratios remained within recommended ranges after liming. Incubation and field studies were done on soils of wheat fields at Kestell, Fouriesburg, Prinsloo and Melrose in the eastern Free State, South Africa. Lime was applied at different rates to induce soil acidity ranges for determination of Bray 1 extractable P and ammonium acetate (NH4OAc) exchangeable Ca, Mg and K concentrations. Cation ratios (Ca:Mg, Mg:K and (Ca + Mg):K) and effective cation exchange capacity (ECEC) were also calculated. Apart from the Prinsloo soil, liming decreased extractable P concentration only in the incubation study. In the incubation and field studies exchangeable Ca and Mg concentrations increased while exchangeable K concentration remained unchanged. Despite liming of the soils, exchangeable Ca and Mg concentrations at Kestell and Fouriesburg were still less than the required thresholds. The Ca:Mg ratio decreased at both sites while the Mg:K and (Ca + Mg):K ratios increased with liming. Liming increased ECEC of all soils at all four sites. Our results show that liming does not always result in the recommended cation levels required for soil fertility.","PeriodicalId":21920,"journal":{"name":"South African Journal of Plant and Soil","volume":"39 1","pages":"351 - 359"},"PeriodicalIF":0.9,"publicationDate":"2022-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44322268","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-20DOI: 10.1080/02571862.2022.2121438
H. van Zyl, C. du Preez
Soil acidity hampers the sustainability of wheat production in the eastern Free State, South Africa. Specific guidelines for liming are needed by farmers and advisors to ameliorate this condition. In this study, soils from four representative wheat producing farms were used for incubation and field studies to generate data for the development of liming guidelines. The clay content of the soils ranged between 8 and 33%, with pH (KCl) values below 4.5 and percentage acid saturation (%AS) above 8. These parameters are regarded as thresholds for wheat cultivation. Liming of the topsoil (0–200 mm) at different rates increased pH (KCl) linearly and decreased %AS exponentially. Either the resulting pH (KCl) or %AS values can be used in the development of liming guidelines. Using these values, an equation was established that is suitable for the estimation of lime requirement of soil: y 8.320× 1 + 0.0459× 2 − 1.0370, R 2 = 0.86 where y is the lime requirement (tonnes ha−1), x 1 = ΔpH (KCl) and x 2 = clay content (%). This equation was also used to compile a look-up table from which the soils’ lime requirement can be derived. Farmers and advisors can improve liming strategies for wheat production by applying this information.
{"title":"Liming guidelines for soils under wheat cropping in the eastern Free State, South Africa","authors":"H. van Zyl, C. du Preez","doi":"10.1080/02571862.2022.2121438","DOIUrl":"https://doi.org/10.1080/02571862.2022.2121438","url":null,"abstract":"Soil acidity hampers the sustainability of wheat production in the eastern Free State, South Africa. Specific guidelines for liming are needed by farmers and advisors to ameliorate this condition. In this study, soils from four representative wheat producing farms were used for incubation and field studies to generate data for the development of liming guidelines. The clay content of the soils ranged between 8 and 33%, with pH (KCl) values below 4.5 and percentage acid saturation (%AS) above 8. These parameters are regarded as thresholds for wheat cultivation. Liming of the topsoil (0–200 mm) at different rates increased pH (KCl) linearly and decreased %AS exponentially. Either the resulting pH (KCl) or %AS values can be used in the development of liming guidelines. Using these values, an equation was established that is suitable for the estimation of lime requirement of soil: y 8.320× 1 + 0.0459× 2 − 1.0370, R 2 = 0.86 where y is the lime requirement (tonnes ha−1), x 1 = ΔpH (KCl) and x 2 = clay content (%). This equation was also used to compile a look-up table from which the soils’ lime requirement can be derived. Farmers and advisors can improve liming strategies for wheat production by applying this information.","PeriodicalId":21920,"journal":{"name":"South African Journal of Plant and Soil","volume":"39 1","pages":"340 - 350"},"PeriodicalIF":0.9,"publicationDate":"2022-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48710942","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-04DOI: 10.1080/02571862.2022.2107244
Jacobus FN Smith, A. Hardie
Previous research on the effect of soil liming on rooibos tea growth was limited to short-term greenhouse trials. This is the first long-term field study to investigate the effect of lime application on rooibos tea production. Micro-fine and class A calcitic lime with similar levels of purity were applied at rates of 0, 0.5, 1.0, 2.0 and 5.0 tonnes ha−1 to a depth of 15 cm on an acid (pHKCl 4.4), sandy soil in Clanwilliam, prior to planting. Soil pH and electrical conductivity (EC), rooibos mortality and yields were then measured over a period of 4 years. Foliar nutrients were determined in Year 4. Micro-fine lime resulted in significantly higher soil pH values (0.5 pH units) than class A lime. Both limes achieved maximum soil pH and EC values in Year 2, but these values declined significantly in Years 3 and 4. This is most likely due to leaching and exhaustion of the most soluble lime fractions. Although micro-fine lime had positive effects on foliar nitrogen and calcium concentrations and bush survival, liming appeared to have a negative effect on rooibos tea yields. Yields tended to decline with increasing lime application rate. Thus, it appears that under the Clanwilliam field conditions in the present study, liming is unnecessary.
{"title":"Long-term effects of micro-fine and class A calcitic lime application rates on soil acidity and rooibos tea yields under Clanwilliam field conditions","authors":"Jacobus FN Smith, A. Hardie","doi":"10.1080/02571862.2022.2107244","DOIUrl":"https://doi.org/10.1080/02571862.2022.2107244","url":null,"abstract":"Previous research on the effect of soil liming on rooibos tea growth was limited to short-term greenhouse trials. This is the first long-term field study to investigate the effect of lime application on rooibos tea production. Micro-fine and class A calcitic lime with similar levels of purity were applied at rates of 0, 0.5, 1.0, 2.0 and 5.0 tonnes ha−1 to a depth of 15 cm on an acid (pHKCl 4.4), sandy soil in Clanwilliam, prior to planting. Soil pH and electrical conductivity (EC), rooibos mortality and yields were then measured over a period of 4 years. Foliar nutrients were determined in Year 4. Micro-fine lime resulted in significantly higher soil pH values (0.5 pH units) than class A lime. Both limes achieved maximum soil pH and EC values in Year 2, but these values declined significantly in Years 3 and 4. This is most likely due to leaching and exhaustion of the most soluble lime fractions. Although micro-fine lime had positive effects on foliar nitrogen and calcium concentrations and bush survival, liming appeared to have a negative effect on rooibos tea yields. Yields tended to decline with increasing lime application rate. Thus, it appears that under the Clanwilliam field conditions in the present study, liming is unnecessary.","PeriodicalId":21920,"journal":{"name":"South African Journal of Plant and Soil","volume":"39 1","pages":"270 - 277"},"PeriodicalIF":0.9,"publicationDate":"2022-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48795199","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-04DOI: 10.1080/02571862.2022.2092659
NZ Sosibo, E. Dube, P. Muchaonyerwa, TJ Tsilo
While conservation agriculture (CA) has largely been successful in many areas, some reports suggest that certain farmers have not realised the benefits they had hoped for, especially in Africa. The benefits of CA could depend on the cropping sequences involved. This study determined the short-term effects of wheat (Triticum aestivum L.)/ maize (Zea mays L.) and wheat/ soybean (Glycine max L.) cropping sequences on fractions of soil organic carbon (SOC), inorganic phosphorus and other soil quality parameters in the 0–200 and 200–400 mm depths on CA farms. Water-soluble carbon (C) and available phosphorus (P) (NaHCO3 Pi) were significantly higher and NaOH I Pi was lower in maize/wheat than in soybean/wheat sequences. SOC, extractable P, and NaHCO3 Pi were significantly higher in the 0–200 mm than in the 200–400 mm depth. Extractable P correlated positively with particulate organic carbon (OC) fractions under both sequences. In addition, soil pH, exchangeable potassium (K), calcium (Ca), magnesium (Mg) and cation exchange capacity (CEC) were significantly higher while acid saturation and Ca:Mg was lower in maize/wheat than in soybean/wheat sequences. The findings imply that short-term cropping sequences do not affect SOC sequestration but a wheat crop preceded by maize could benefit from higher soil pH and labile C fractions making P more available, with the additional benefit of available K in these CA systems.
虽然保护性农业在许多领域基本上取得了成功，但一些报告表明，某些农民没有实现他们所希望的好处，尤其是在非洲。CA的好处可能取决于所涉及的种植顺序。本研究确定了小麦（Triticum aestivum L.）/玉米（Zea mays L.）和小麦/大豆（Glycine max L.）种植顺序对土壤有机碳（SOC）、无机磷和其他土壤质量参数在0–200和200–400范围内的短期影响 CA农场的深度为mm。玉米/小麦序列的水溶性碳（C）和有效磷（P）（NaHCO3 Pi）显著高于大豆/小麦序列，而NaOH I Pi低于大豆/小麦。SOC、可提取P和NaHCO3 Pi在0–200 mm mm深度。在两个序列下，可提取P与颗粒有机碳（OC）组分呈正相关。此外，玉米/小麦序列的土壤pH、交换性钾（K）、钙（Ca）、镁（Mg）和阳离子交换容量（CEC）显著高于大豆/小麦序列，而酸饱和度和Ca:Mg则低于大豆/小麦。研究结果表明，短期种植顺序不会影响SOC固存，但玉米之前的小麦作物可能受益于更高的土壤pH值和不稳定的C组分，使P更有效，在这些CA系统中，有效K也有额外的好处。
{"title":"Influence of cropping sequences on labile carbon and phosphorus fractions in a wheat-based conservation agriculture system","authors":"NZ Sosibo, E. Dube, P. Muchaonyerwa, TJ Tsilo","doi":"10.1080/02571862.2022.2092659","DOIUrl":"https://doi.org/10.1080/02571862.2022.2092659","url":null,"abstract":"While conservation agriculture (CA) has largely been successful in many areas, some reports suggest that certain farmers have not realised the benefits they had hoped for, especially in Africa. The benefits of CA could depend on the cropping sequences involved. This study determined the short-term effects of wheat (Triticum aestivum L.)/ maize (Zea mays L.) and wheat/ soybean (Glycine max L.) cropping sequences on fractions of soil organic carbon (SOC), inorganic phosphorus and other soil quality parameters in the 0–200 and 200–400 mm depths on CA farms. Water-soluble carbon (C) and available phosphorus (P) (NaHCO3 Pi) were significantly higher and NaOH I Pi was lower in maize/wheat than in soybean/wheat sequences. SOC, extractable P, and NaHCO3 Pi were significantly higher in the 0–200 mm than in the 200–400 mm depth. Extractable P correlated positively with particulate organic carbon (OC) fractions under both sequences. In addition, soil pH, exchangeable potassium (K), calcium (Ca), magnesium (Mg) and cation exchange capacity (CEC) were significantly higher while acid saturation and Ca:Mg was lower in maize/wheat than in soybean/wheat sequences. The findings imply that short-term cropping sequences do not affect SOC sequestration but a wheat crop preceded by maize could benefit from higher soil pH and labile C fractions making P more available, with the additional benefit of available K in these CA systems.","PeriodicalId":21920,"journal":{"name":"South African Journal of Plant and Soil","volume":"39 1","pages":"248 - 259"},"PeriodicalIF":0.9,"publicationDate":"2022-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46016703","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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