Pub Date : 2022-10-24DOI: 10.2989/10220119.2022.2125578
Diana Marcela Valencia-Echavarría, Y. Granja-Salcedo, David Felipe Nieto-Sierra, Piedad Yanneth Martínez-Oquendo, Gonzalo de Jesús Restrepo-Castañeda, Lucas Esteban Cano-Gallego, O. Mayorga-Mogollón
{"title":"Effect of botanical composition calibration on the accuracy of undisturbed sward height and comparative yield method techniques for herbage mass estimation in tropical heterogeneous pastures","authors":"Diana Marcela Valencia-Echavarría, Y. Granja-Salcedo, David Felipe Nieto-Sierra, Piedad Yanneth Martínez-Oquendo, Gonzalo de Jesús Restrepo-Castañeda, Lucas Esteban Cano-Gallego, O. Mayorga-Mogollón","doi":"10.2989/10220119.2022.2125578","DOIUrl":"https://doi.org/10.2989/10220119.2022.2125578","url":null,"abstract":"","PeriodicalId":50841,"journal":{"name":"African Journal of Range & Forage Science","volume":"11 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82077071","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-21DOI: 10.2989/10220119.2022.2133171
V. Dakos
This book is not a textbook nor practical guide on how to tackle ecosystem collapse or recovery. It is rather an extensive, thorough account of a topic that has recently attracted a lot of attention, seen from a variety of angles. It is noteworthy that it references over 1 200 citations on a subject that, one would assume, is relatively new or rather limited. This wealth of information actually reflects the fact that the book is written by integrating viewpoints from a variety of disciplines, among them that of theoretical ecology and of conservation biology. Typically, ecosystem collapse is related to the existence of alternative stable states and tipping points, a rather theoretical concept that is hard to prove. Lately, however, ecosystem collapse has also found a place in conservation science featured under the IUCN Red List of Ecosystems. This is reflected in the book, which reviews the variety of ways that different communities have defined these two terms. Yet, although the terms and the topic sound self-explanatory, there is no formal definition of ecosystem collapse or recovery. In the book, the definition adopted for ecosystems collapse is a transformation of identity, a loss of defining features and a replacement by a different ecosystem type. Ecosystem recovery is the reverse process. Chapter 1 includes the aims of the book and marks the boundaries of what the book covers. A series of questions that address what ecosystem collapse is, why it occurs, what are the implications, whether it is possible to provide early-warning for collapse to be prevented, as well as what are the mechanisms of recovery and whether they are the same across ecosystems, are few examples of what the book is after. The reader finds potential answers to these questions in the last chapter of the book (Conclusions). Chapter 2 presents the subject from a more theoretical perspective. Notions of ecological disturbance, succession, state-and-transition models, bifurcation theory, planetary boundaries, critical thresholds, resilience and even ecological networks and extincion cascades are covered. At places, the connection between these concepts appears hard to establish. It, however, reflects the different starting points of different communities on the topic, as well as the intention of the book to stress the connection between species communities and ecosystem responses, while emphasising less consciously the perspective of ecosystem functioning and collapse. The following two chapters switch to the empirical side of the topic. Chapter 3 travels to past, deep time examples from the fossil record. It covers the big five mass extinctions on the paleological record, the loss of Australian megafauna, and the relatively more recent examples of extinctions in New Zealand and Madagascar following human colonisation, as well as the transformation of the green Sahel to the present desert state. Chapter 4 provides current case studies that motivate the idea that ecosystem
{"title":"Ecosystem Collapse and Recovery","authors":"V. Dakos","doi":"10.2989/10220119.2022.2133171","DOIUrl":"https://doi.org/10.2989/10220119.2022.2133171","url":null,"abstract":"This book is not a textbook nor practical guide on how to tackle ecosystem collapse or recovery. It is rather an extensive, thorough account of a topic that has recently attracted a lot of attention, seen from a variety of angles. It is noteworthy that it references over 1 200 citations on a subject that, one would assume, is relatively new or rather limited. This wealth of information actually reflects the fact that the book is written by integrating viewpoints from a variety of disciplines, among them that of theoretical ecology and of conservation biology. Typically, ecosystem collapse is related to the existence of alternative stable states and tipping points, a rather theoretical concept that is hard to prove. Lately, however, ecosystem collapse has also found a place in conservation science featured under the IUCN Red List of Ecosystems. This is reflected in the book, which reviews the variety of ways that different communities have defined these two terms. Yet, although the terms and the topic sound self-explanatory, there is no formal definition of ecosystem collapse or recovery. In the book, the definition adopted for ecosystems collapse is a transformation of identity, a loss of defining features and a replacement by a different ecosystem type. Ecosystem recovery is the reverse process. Chapter 1 includes the aims of the book and marks the boundaries of what the book covers. A series of questions that address what ecosystem collapse is, why it occurs, what are the implications, whether it is possible to provide early-warning for collapse to be prevented, as well as what are the mechanisms of recovery and whether they are the same across ecosystems, are few examples of what the book is after. The reader finds potential answers to these questions in the last chapter of the book (Conclusions). Chapter 2 presents the subject from a more theoretical perspective. Notions of ecological disturbance, succession, state-and-transition models, bifurcation theory, planetary boundaries, critical thresholds, resilience and even ecological networks and extincion cascades are covered. At places, the connection between these concepts appears hard to establish. It, however, reflects the different starting points of different communities on the topic, as well as the intention of the book to stress the connection between species communities and ecosystem responses, while emphasising less consciously the perspective of ecosystem functioning and collapse. The following two chapters switch to the empirical side of the topic. Chapter 3 travels to past, deep time examples from the fossil record. It covers the big five mass extinctions on the paleological record, the loss of Australian megafauna, and the relatively more recent examples of extinctions in New Zealand and Madagascar following human colonisation, as well as the transformation of the green Sahel to the present desert state. Chapter 4 provides current case studies that motivate the idea that ecosystem ","PeriodicalId":50841,"journal":{"name":"African Journal of Range & Forage Science","volume":"1 1","pages":"244 - 245"},"PeriodicalIF":1.4,"publicationDate":"2022-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88492923","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-19DOI: 10.2989/10220119.2022.2133170
J. Roff
{"title":"Lessons from Plants","authors":"J. Roff","doi":"10.2989/10220119.2022.2133170","DOIUrl":"https://doi.org/10.2989/10220119.2022.2133170","url":null,"abstract":"","PeriodicalId":50841,"journal":{"name":"African Journal of Range & Forage Science","volume":"35 1","pages":"242 - 243"},"PeriodicalIF":1.4,"publicationDate":"2022-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73156772","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-05DOI: 10.2989/10220119.2022.2119277
F. Müller, Letty Masemola, Stephen Modiba, Nothando Ngcobo
The South African perennial legume Calobota sericea (Thunb.) Boatwr. & B-E van Wyk has been shown to be drought tolerant as mature plants, but information on drought tolerance of seedlings is lacking. This study evaluated the impact of moisture stress on seedling emergence, survival and growth in C. sericea. In the first trial, pre-germinated seeds were planted at 100, 70, 50 and 40% of soil moisture holding capacity without additional watering. Seedling emergence and mortality was recorded daily for 14 days. In the second trial, seeds were allowed to grow under well-watered conditions for one month, after which moisture stress was imposed for 15 and 30 days. Thereafter, the seedlings were uprooted, for shoot and root measurements. Results from these trials show that C. sericea seedlings will establish even at severely reduced water-availabilities, but without subsequent watering, significant seedling mortality will occur. Calobota sericea seedlings displayed a range of morphological adaptive strategies to moisture stress including the minimisation of water loss and optimisation of water uptake. Further research into the impacts of regular cycles of moisture stress is needed to determine if changes in morphology due to prior moisture stress will result in improved adaptation to subsequent moisture stress.
南非多年生豆科植物;Boatwr。B-E van Wyk已被证明作为成熟植物具有耐旱性，但关于幼苗耐旱性的信息缺乏。本研究评价了水分胁迫对蚕豆幼苗出苗、存活和生长的影响。在第一次试验中，在土壤保水能力为100%、70%、50%和40%的情况下播种预发芽种子，不额外浇水。每天记录幼苗出苗率和死亡率，连续14 d。在第二个试验中，让种子在水分充足的条件下生长一个月，然后施加水分胁迫15天和30天。然后，将幼苗连根拔起，进行茎部和根的测量。这些试验结果表明，即使在水分利用率严重降低的情况下，蚕蛹幼苗仍能生长，但如果没有后续的浇水，幼苗将会出现明显的死亡。花椰菜幼苗对水分胁迫表现出一系列形态适应策略，包括水分损失最小化和水分吸收优化。需要进一步研究有规律的水分胁迫周期的影响，以确定由于先前的水分胁迫引起的形态变化是否会导致对后续水分胁迫的适应改善。
{"title":"Seedling establishment and early growth in Calobota sericea subjected to moisture stress","authors":"F. Müller, Letty Masemola, Stephen Modiba, Nothando Ngcobo","doi":"10.2989/10220119.2022.2119277","DOIUrl":"https://doi.org/10.2989/10220119.2022.2119277","url":null,"abstract":"The South African perennial legume Calobota sericea (Thunb.) Boatwr. & B-E van Wyk has been shown to be drought tolerant as mature plants, but information on drought tolerance of seedlings is lacking. This study evaluated the impact of moisture stress on seedling emergence, survival and growth in C. sericea. In the first trial, pre-germinated seeds were planted at 100, 70, 50 and 40% of soil moisture holding capacity without additional watering. Seedling emergence and mortality was recorded daily for 14 days. In the second trial, seeds were allowed to grow under well-watered conditions for one month, after which moisture stress was imposed for 15 and 30 days. Thereafter, the seedlings were uprooted, for shoot and root measurements. Results from these trials show that C. sericea seedlings will establish even at severely reduced water-availabilities, but without subsequent watering, significant seedling mortality will occur. Calobota sericea seedlings displayed a range of morphological adaptive strategies to moisture stress including the minimisation of water loss and optimisation of water uptake. Further research into the impacts of regular cycles of moisture stress is needed to determine if changes in morphology due to prior moisture stress will result in improved adaptation to subsequent moisture stress.","PeriodicalId":50841,"journal":{"name":"African Journal of Range & Forage Science","volume":"28 1","pages":"292 - 297"},"PeriodicalIF":1.4,"publicationDate":"2022-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90913452","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-05DOI: 10.2989/10220119.2022.2121941
Ayanda Nyambali, J. Tjelele, M. Mndela, C. Mapiye, P. Strydom, E. Raffrenato, K. Dzama, V. Muchenje, N. Mkhize
Feed scarcity is a major challenge facing free-range beef farming in semi-arid areas. Specifically, low quality and quantity of forage in rangelands and higher feeding costs are the main constraints limiting smallholder free-range beef farmers’ participation in mainstream beef markets. Using farmers’ participatory approaches, this study identified major locally available forage resources (LAFRs) and evaluated their nutritional value. A total of 40 free-ranging commercially orientated smallholder beef farmers were interviewed using semi-structured questionnaires and tasked to identify LAFRs in the Cradock and Middelburg areas of the Eastern Cape, South Africa. Chemical analysis was conducted for the most cited forages such as African sheepbush (Pentzia incana), sweet thorn (Vachellia karroo) leaves and pods, reed (Phragmites australis), lucerne (Medicago sativa) hay, natural pasture grasses (NPGs) and barbary fig, or prickly pear cactus, (Opuntia ficus-indica) cladodes collected from twelve participants’ farms. Feed shortage was ranked by more than 53% respondents as the main constraint to smallholder beef production. Regardless of the farming area, crude protein content of V. karroo leaves and pods averaging 18.8 and 19.5%, respectively, was higher than other LAFRs. However, V. karoo pods had relatively low ash content than other forages in both farming areas. Opuntia ficus-indica attained high in vitro neutral detergent fibre digestibility at 12, 24 and 48 hr incubation periods, due to low neutral detergent fibre, acid detergent fibre and acid detergent lignin. Integration of participatory inventory and chemical analysis proved to be reliable in identifying LAFRs, with V. karroo leaves and O. ficus-indica cladodes being the main potential forage resources for inclusion in beef cattle diets. Further research is recommended to substantiate their supplementary nutritive value and level of inclusion in beef cattle finishing diets.
{"title":"Participatory inventory and nutritional evaluation of local forage resources for smallholder free-range beef production in semi-arid areas of South Africa","authors":"Ayanda Nyambali, J. Tjelele, M. Mndela, C. Mapiye, P. Strydom, E. Raffrenato, K. Dzama, V. Muchenje, N. Mkhize","doi":"10.2989/10220119.2022.2121941","DOIUrl":"https://doi.org/10.2989/10220119.2022.2121941","url":null,"abstract":"Feed scarcity is a major challenge facing free-range beef farming in semi-arid areas. Specifically, low quality and quantity of forage in rangelands and higher feeding costs are the main constraints limiting smallholder free-range beef farmers’ participation in mainstream beef markets. Using farmers’ participatory approaches, this study identified major locally available forage resources (LAFRs) and evaluated their nutritional value. A total of 40 free-ranging commercially orientated smallholder beef farmers were interviewed using semi-structured questionnaires and tasked to identify LAFRs in the Cradock and Middelburg areas of the Eastern Cape, South Africa. Chemical analysis was conducted for the most cited forages such as African sheepbush (Pentzia incana), sweet thorn (Vachellia karroo) leaves and pods, reed (Phragmites australis), lucerne (Medicago sativa) hay, natural pasture grasses (NPGs) and barbary fig, or prickly pear cactus, (Opuntia ficus-indica) cladodes collected from twelve participants’ farms. Feed shortage was ranked by more than 53% respondents as the main constraint to smallholder beef production. Regardless of the farming area, crude protein content of V. karroo leaves and pods averaging 18.8 and 19.5%, respectively, was higher than other LAFRs. However, V. karoo pods had relatively low ash content than other forages in both farming areas. Opuntia ficus-indica attained high in vitro neutral detergent fibre digestibility at 12, 24 and 48 hr incubation periods, due to low neutral detergent fibre, acid detergent fibre and acid detergent lignin. Integration of participatory inventory and chemical analysis proved to be reliable in identifying LAFRs, with V. karroo leaves and O. ficus-indica cladodes being the main potential forage resources for inclusion in beef cattle diets. Further research is recommended to substantiate their supplementary nutritive value and level of inclusion in beef cattle finishing diets.","PeriodicalId":50841,"journal":{"name":"African Journal of Range & Forage Science","volume":"54 1","pages":"62 - 70"},"PeriodicalIF":1.4,"publicationDate":"2022-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74248237","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-22DOI: 10.2989/10220119.2022.2103585
JM Goodall, E. Witkowski
Herbicide trials on pompom weed Campuloclinium macrocephalum (Less.) DC. (Asteraceae) were carried out in grasslands with xeric and hydric soils, at sites in Gauteng, South Africa, from 2005 to 2008. The rust fungus Puccinia eupatorii Dietel, an established self-perpetuating biocontrol agent on C. macrocephalum, caused significant damage to shoots in late summer and autumn. Herbicide efficacy was significantly better on foliage that did not already present symptoms and that was sprayed in early summer compared with on infected plants treated in autumn, at both the xeric (F = 36.71, p < 0.001) and hydric (F = 3.59, p = 0.031) sites. This pathogen has reduced the time available for effective chemical weed control from six months to three months. However, none of the herbicide treatments achieved commercially acceptable mortality rates of ≥80%, and after three annual applications none succeeded in extirpating C. macrocephalum from the plots. Regression analyses of count data showed that metsulfuron-methyl at 45 g ha–1 (USD 20.05 ha–1), picloram at 252 g ha–1(USD 25.47 ha–1) and 2,4-D/dicamba/MCPA at 540/360/474 g ha–1 (USD 45.41 ha–1) required five annual treatments in summer to eradicate C. macrocephalum, whereas 2,4-D amine at 1 440 g ha–1 (USD 13.65 ha–1) and MCPA at 1 200 g ha–1 (USD 14.46 ha–1) required six treatments. Hence, there is a trade-off between the use of slightly more effective herbicides against the lower costs of other selective herbicides.
玉米蓬草(Campuloclinium macrocephalum)除草剂试验直流。2005 ~ 2008年，在南非豪登省干湿土壤草地上进行了菊科植物的研究。在夏末和秋末两季，大头藤(C. macrocephalum)的芽部受到锈病菌(Puccinia eupatorii Dietel)的显著损害。在旱地(F = 36.71, p < 0.001)和旱地(F = 3.59, p = 0.031)，初夏施药对未出现症状的叶片的除草剂药效显著优于秋季施药。这种病原体使有效化学除草的时间从6个月减少到3个月。然而，没有一种除草剂处理达到商业上可接受的≥80%的死亡率，并且在每年施用三次后，没有一种除草剂能成功地从地块中清除巨头草。计数数据回归分析表明，45 g ha-1 (20.05 ha-1)、252 g ha-1 (25.47 ha-1)、2,4- d /麦草畏/MCPA (540/360/474 g ha-1) (45.41 ha-1)夏季需5次处理才能根治巨头线虫，而1 440 g ha-1 (13.65 ha-1)和1 200 g ha-1 (14.46 ha-1)的2,4- d胺需6次处理。因此，在使用效率稍高的除草剂与成本较低的其他选择性除草剂之间存在权衡。
{"title":"Herbicide trials on Campuloclinium macrocephalum (Asteraceae) during adverse conditions reveal incompatibility with biocontrol and a narrow window of opportunity for chemical control","authors":"JM Goodall, E. Witkowski","doi":"10.2989/10220119.2022.2103585","DOIUrl":"https://doi.org/10.2989/10220119.2022.2103585","url":null,"abstract":"Herbicide trials on pompom weed Campuloclinium macrocephalum (Less.) DC. (Asteraceae) were carried out in grasslands with xeric and hydric soils, at sites in Gauteng, South Africa, from 2005 to 2008. The rust fungus Puccinia eupatorii Dietel, an established self-perpetuating biocontrol agent on C. macrocephalum, caused significant damage to shoots in late summer and autumn. Herbicide efficacy was significantly better on foliage that did not already present symptoms and that was sprayed in early summer compared with on infected plants treated in autumn, at both the xeric (F = 36.71, p < 0.001) and hydric (F = 3.59, p = 0.031) sites. This pathogen has reduced the time available for effective chemical weed control from six months to three months. However, none of the herbicide treatments achieved commercially acceptable mortality rates of ≥80%, and after three annual applications none succeeded in extirpating C. macrocephalum from the plots. Regression analyses of count data showed that metsulfuron-methyl at 45 g ha–1 (USD 20.05 ha–1), picloram at 252 g ha–1(USD 25.47 ha–1) and 2,4-D/dicamba/MCPA at 540/360/474 g ha–1 (USD 45.41 ha–1) required five annual treatments in summer to eradicate C. macrocephalum, whereas 2,4-D amine at 1 440 g ha–1 (USD 13.65 ha–1) and MCPA at 1 200 g ha–1 (USD 14.46 ha–1) required six treatments. Hence, there is a trade-off between the use of slightly more effective herbicides against the lower costs of other selective herbicides.","PeriodicalId":50841,"journal":{"name":"African Journal of Range & Forage Science","volume":"9 1","pages":"263 - 272"},"PeriodicalIF":1.4,"publicationDate":"2022-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74742965","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-15DOI: 10.2989/10220119.2022.2106304
Lindokuhle X Dlamini, M. Tedder, K. Kirkman
Species-rich grasslands provide important ecosystem services, and in South Africa, approximately 40% of these grasslands are degraded. Vetiver grass (from India) is often used during rehabilitation efforts to restore soil function without a thorough understanding of the potential negative ecological impacts. Hence, a study was initiated to investigate vetiver’s ecological impacts during grassland rehabilitation. Firstly, a field survey was conducted using a contiguous quadrat method to evaluate the extent of grass secondary succession in these rehabilitated sites. Secondly, the effect of vetiver competition and seed sowing method on the recruitment of two native grasses (Eragrostis curvula and Megathyrsus maximus) was examined using pot trials. The field survey results showed no evidence of grass secondary succession, but rather the abundance of bare ground around vetiver, and a marked increase in grass species richness with increasing distance from planted vetiver. Subsequently, in the pot trial, vetiver facilitated emergence in both native grasses, and soil surface sowing of indigenous grass seeds showed greater emergence than other sowing methods. However, vetiver inhibited native grass seedling establishment, even when root competition was excluded. This study suggests that areas rehabilitated using vetiver are unlikely to become productive grasslands with good grazing, because vetiver inhibits colonisation by native grasses.
{"title":"Do native grasses emerge and establish in areas rehabilitated using vetiver grass?","authors":"Lindokuhle X Dlamini, M. Tedder, K. Kirkman","doi":"10.2989/10220119.2022.2106304","DOIUrl":"https://doi.org/10.2989/10220119.2022.2106304","url":null,"abstract":"Species-rich grasslands provide important ecosystem services, and in South Africa, approximately 40% of these grasslands are degraded. Vetiver grass (from India) is often used during rehabilitation efforts to restore soil function without a thorough understanding of the potential negative ecological impacts. Hence, a study was initiated to investigate vetiver’s ecological impacts during grassland rehabilitation. Firstly, a field survey was conducted using a contiguous quadrat method to evaluate the extent of grass secondary succession in these rehabilitated sites. Secondly, the effect of vetiver competition and seed sowing method on the recruitment of two native grasses (Eragrostis curvula and Megathyrsus maximus) was examined using pot trials. The field survey results showed no evidence of grass secondary succession, but rather the abundance of bare ground around vetiver, and a marked increase in grass species richness with increasing distance from planted vetiver. Subsequently, in the pot trial, vetiver facilitated emergence in both native grasses, and soil surface sowing of indigenous grass seeds showed greater emergence than other sowing methods. However, vetiver inhibited native grass seedling establishment, even when root competition was excluded. This study suggests that areas rehabilitated using vetiver are unlikely to become productive grasslands with good grazing, because vetiver inhibits colonisation by native grasses.","PeriodicalId":50841,"journal":{"name":"African Journal of Range & Forage Science","volume":"24 1","pages":"273 - 291"},"PeriodicalIF":1.4,"publicationDate":"2022-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77006176","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-08-05DOI: 10.2989/10220119.2022.2086620
A. Marquart, E. Slooten, FP Jordaan, M. Vermeulen, K. Kellner
Large-scale bush encroachment within rangelands is of increasing concern for land users. The aggressive encroachment of the woody shrub Seriphium plumosum (L.) Thunb. (Asteraceae), previously known as Stoebe plumosa, has resulted in a reduction in productivity, causing large socio-economic challenges, such as loss of productive land. In this study, we evaluated the efficacy of four herbicides in combination with mechanical removal of S. plumosum. We measured shrub mortality, regrowth and examined the grass species richness and cover after the execution of the control methods. Furthermore, we compared the productivity of the paddock where S. plumosum had been controlled with a neighbouring unencroached paddock. Five months after herbicide application, the total mortality of all shrubs was recorded. Grass species richness and cover were higher when shrubs had been mechanically removed before herbicide application. Additionally, the use of the non-speciesspecific herbicide (tebuthiuron) resulted in lower species richness and cover, compared to application of a speciesspecific herbicide (metsulfuron-methyl). The productivity of the treated area increased in the year after application. Our results show that when controlling S. plumosum the manual removal of shrubs before applying herbicides can improve the regeneration of the grass layer. This combination of mechanical and chemical control is effective in combating S. plumosum encroachment and increases forage yields in semi-arid rangelands.
{"title":"The control of the encroaching shrub Seriphium plumosum (L.) Thunb. (Asteraceae) and the response of the grassy layer in a South African semi-arid rangeland","authors":"A. Marquart, E. Slooten, FP Jordaan, M. Vermeulen, K. Kellner","doi":"10.2989/10220119.2022.2086620","DOIUrl":"https://doi.org/10.2989/10220119.2022.2086620","url":null,"abstract":"Large-scale bush encroachment within rangelands is of increasing concern for land users. The aggressive encroachment of the woody shrub Seriphium plumosum (L.) Thunb. (Asteraceae), previously known as Stoebe plumosa, has resulted in a reduction in productivity, causing large socio-economic challenges, such as loss of productive land. In this study, we evaluated the efficacy of four herbicides in combination with mechanical removal of S. plumosum. We measured shrub mortality, regrowth and examined the grass species richness and cover after the execution of the control methods. Furthermore, we compared the productivity of the paddock where S. plumosum had been controlled with a neighbouring unencroached paddock. Five months after herbicide application, the total mortality of all shrubs was recorded. Grass species richness and cover were higher when shrubs had been mechanically removed before herbicide application. Additionally, the use of the non-speciesspecific herbicide (tebuthiuron) resulted in lower species richness and cover, compared to application of a speciesspecific herbicide (metsulfuron-methyl). The productivity of the treated area increased in the year after application. Our results show that when controlling S. plumosum the manual removal of shrubs before applying herbicides can improve the regeneration of the grass layer. This combination of mechanical and chemical control is effective in combating S. plumosum encroachment and increases forage yields in semi-arid rangelands.","PeriodicalId":50841,"journal":{"name":"African Journal of Range & Forage Science","volume":"12 1","pages":"316 - 321"},"PeriodicalIF":1.4,"publicationDate":"2022-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87563535","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-08-03DOI: 10.2989/10220119.2022.2080269
H. Mohamed, S. M. Ahmed, A. D. Mohamed
The performance of rainfed-based Megathyrsus maximus (syn. Urochloa maxima and Panicum maximum) was investigated in the semi-arid pastures of Sudan. Split-plot complete design experiments with three replications were applied for two consecutive seasons (2020–2021). The treatments were two in situ rainwater harvesting systems [i.e. ridges plus terraces (RD) and terraces (TR)], three seeding rates (i.e. 1.5, 2.5 and 3.5 kg ha−1) and two urea fertilisation rates [0 kg ha−1 (Z) and 95 kg ha−1 (F)]. These treatments were compared to a control (a flat, unfertilised and zero-tillage plot). Hydrological, biological and chemical indicators were used in the assessment. The results showed that the adopted RWH improved semi-arid pastures, with the RD treatment providing the best results for sustaining biomass production, water use efficiency, nutritional quality and soil quality. The highest plant density (112 000 plants ha−1) was associated with the RD3.5 treatment. The FSR1.5-RD treatment resulted in the greatest plant length (63.5 cm) and number of leaves per plant (34.59), whilst the FSR3.5-RD resulted in both the highest fresh biomass (25.9 t ha−1) and dry biomass (6.3 t ha−1). The chemical compositions of M. maximus (i.e. crude protein, organic matter and nitrogen contents) were also substantially improved by fertilisation. The water use efficiency of M. maximus was plant-, management- and climate-dependent.
研究了苏丹半干旱草原上雨养大巨蟒(巨蟒和巨蟒)的生长状况。连续两个季节(2020-2021年)进行了3个重复的分块完全设计试验。处理方法为两种就地雨水收集系统[即垄沟加梯田(RD)和梯田(TR)]，三种播种率(即1.5、2.5和3.5公斤公顷- 1)和两种尿素施肥率[0公斤公顷- 1 (Z)和95公斤公顷- 1 (F)]。这些处理与对照(平坦，未施肥和免耕的地块)进行比较。采用水文、生物和化学指标进行评价。结果表明:采用RWH处理改善了半干旱牧场，RD处理在维持生物量产量、水分利用效率、营养品质和土壤质量方面效果最好。RD3.5处理的植株密度最高(11.2万株ha - 1)。FSR1.5-RD处理的植株长度(63.5 cm)和单株叶数(34.59)最大，而FSR3.5-RD处理的鲜生物量(25.9 t ha - 1)和干生物量(6.3 t ha - 1)均最高。施肥也显著改善了大孢霉的化学成分(即粗蛋白质、有机质和氮含量)。柽柳的水分利用效率与植物、管理和气候有关。
{"title":"Rainfed-based production of Megathyrsus maximus in sub-Saharan Africa: the case of the semi-arid environment of Sudan","authors":"H. Mohamed, S. M. Ahmed, A. D. Mohamed","doi":"10.2989/10220119.2022.2080269","DOIUrl":"https://doi.org/10.2989/10220119.2022.2080269","url":null,"abstract":"The performance of rainfed-based Megathyrsus maximus (syn. Urochloa maxima and Panicum maximum) was investigated in the semi-arid pastures of Sudan. Split-plot complete design experiments with three replications were applied for two consecutive seasons (2020–2021). The treatments were two in situ rainwater harvesting systems [i.e. ridges plus terraces (RD) and terraces (TR)], three seeding rates (i.e. 1.5, 2.5 and 3.5 kg ha−1) and two urea fertilisation rates [0 kg ha−1 (Z) and 95 kg ha−1 (F)]. These treatments were compared to a control (a flat, unfertilised and zero-tillage plot). Hydrological, biological and chemical indicators were used in the assessment. The results showed that the adopted RWH improved semi-arid pastures, with the RD treatment providing the best results for sustaining biomass production, water use efficiency, nutritional quality and soil quality. The highest plant density (112 000 plants ha−1) was associated with the RD3.5 treatment. The FSR1.5-RD treatment resulted in the greatest plant length (63.5 cm) and number of leaves per plant (34.59), whilst the FSR3.5-RD resulted in both the highest fresh biomass (25.9 t ha−1) and dry biomass (6.3 t ha−1). The chemical compositions of M. maximus (i.e. crude protein, organic matter and nitrogen contents) were also substantially improved by fertilisation. The water use efficiency of M. maximus was plant-, management- and climate-dependent.","PeriodicalId":50841,"journal":{"name":"African Journal of Range & Forage Science","volume":"14 1","pages":"247 - 256"},"PeriodicalIF":1.4,"publicationDate":"2022-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80814460","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-08-01DOI: 10.2989/10220119.2022.2086299
Ethan Britz, L. Cyster, Clement F Cupido, M. Igshaan Samuels, Thamsanqa DE Mpanza, F. Müller
Calobota sericea (Thunb.) Boatwr. & B.-E.van Wyk (Fabaceae) is a native legume from the semi-arid rangelands of South Africa. The species has been prioritised as a forage for water-limited agro-ecological areas. No information regarding the nutritional quality of C. sericea forage harvested at different phenological stages is currently available, limiting our knowledge as to the best time to harvest the forage. The aim of this study was to determine the nutritional quality of C. sericea forage harvested at five phenological stages. Results from the study show that crude protein, fibre, energy and digestibility of the forage decreased with plant maturity, but not all mineral nutrients showed the same trend. In general, C. sericea forage harvested at non-reproductive, early flower bud and full flower stages could provide sufficient energy and protein to maintain livestock condition. At these stages, the neutral detergent fibre and digestibility of the harvested materials are also good, indicating that intake and processing of these forage would not be a problem for the livestock. At these phenological stages most of the mineral nutrients were also sufficiently high to meet the minimum requirements of small stock. Thus, C. sericea forage harvested at the appropriate phenological stages could provide a useful source of forage for resource poor farmers.
{"title":"Nutritional quality of Calobota sericea fodders harvested at different phenological stages – opportunities for inclusion in fodder flow programs for extensive livestock farmers","authors":"Ethan Britz, L. Cyster, Clement F Cupido, M. Igshaan Samuels, Thamsanqa DE Mpanza, F. Müller","doi":"10.2989/10220119.2022.2086299","DOIUrl":"https://doi.org/10.2989/10220119.2022.2086299","url":null,"abstract":"Calobota sericea (Thunb.) Boatwr. & B.-E.van Wyk (Fabaceae) is a native legume from the semi-arid rangelands of South Africa. The species has been prioritised as a forage for water-limited agro-ecological areas. No information regarding the nutritional quality of C. sericea forage harvested at different phenological stages is currently available, limiting our knowledge as to the best time to harvest the forage. The aim of this study was to determine the nutritional quality of C. sericea forage harvested at five phenological stages. Results from the study show that crude protein, fibre, energy and digestibility of the forage decreased with plant maturity, but not all mineral nutrients showed the same trend. In general, C. sericea forage harvested at non-reproductive, early flower bud and full flower stages could provide sufficient energy and protein to maintain livestock condition. At these stages, the neutral detergent fibre and digestibility of the harvested materials are also good, indicating that intake and processing of these forage would not be a problem for the livestock. At these phenological stages most of the mineral nutrients were also sufficiently high to meet the minimum requirements of small stock. Thus, C. sericea forage harvested at the appropriate phenological stages could provide a useful source of forage for resource poor farmers.","PeriodicalId":50841,"journal":{"name":"African Journal of Range & Forage Science","volume":"37 1","pages":"257 - 262"},"PeriodicalIF":1.4,"publicationDate":"2022-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85434842","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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