The South African Journal of Plant and Soil最新文献

{"title":"Effect of tied ridges on grain yield response of maize (Zea mays L.) to application of crop residue and residual N and P on two soil types at Alemaya, Ethiopia","authors":"Asfaw Belay, H. Gebrekidan, Y. Uloro","doi":"10.1080/02571862.1998.10635130","DOIUrl":"https://doi.org/10.1080/02571862.1998.10635130","url":null,"abstract":"Field experiments were conducted on two soil types over a period of five years (1986–1990) to investigate the effects of tied ridges and planting systems on the grain yield response of maize to applications of crop residue and residual N and P fertilizers. Grain yields were increased by the use of tied ridges. Further increases in grain yields resulted from residual N and P and crop residue applied separately or together. Under all fertilization practices, planting in the furrow of tied ridges resulted in higher grain yields than planting on top of tied ridges. The effect of the tied ridges in increasing grain yields was generally better in the drier periods and the more so when the ends of the ridges were tied. In wetter seasons the open end tied ridges gave higher yields than the closed end tied ridges. The effect of tied ridges on grain yield response of maize to application of crop residue and residual N and P fertilizers was influenced by rainfall and by soil type.","PeriodicalId":22913,"journal":{"name":"The South African Journal of Plant and Soil","volume":"169 1","pages":"123-129"},"PeriodicalIF":0.0,"publicationDate":"1998-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85398027","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}

{"title":"Germination of Pterocarpus angolensis DC. and evaluation of the possible antimicrobial action of the phloem sap","authors":"K. Riet, L. V. Rensburg, R. Correia, L. J. Mienie, G. Krüger","doi":"10.1080/02571862.1998.10635132","DOIUrl":"https://doi.org/10.1080/02571862.1998.10635132","url":null,"abstract":"The Transvaal teak (Plerocarpus angolensis) is being over utilised in its natural habitat, although it is a protected tree in South Africa, Swaziland and Namibia. The phloem sap of this species has several traditional, medicinal uses and the wood is used primarily for furniture and fuelwood. The aim of this study was firstly, to determine which seed pre-treatments would ensure optimal germination and secondly, to evaluate the potential antimicro­ bial activity of the phloem sap. The initial germination trial was conducted by using unsterilised seeds in the dark, which resulted in low germination rates (7.78%) and high percentages of fungal infections (45.56%), primarily Aspergillus niger and a Fusarium sp. In the second experiment the seeds were sterilised with a mixture of 60 9 Thiram and 70 g Captan and germinated in an alternating light/dark environment. In both experiments the seeds were subjected to either a hormonal, heat or control pre-treatment and were allowed to germinate at three dif­ ferent temperature regimes. Different sap concentrations were tested for antimicrobial activity against both gram positive (Staphylococcus aureus) and gram negative (Escherichia coli; Pseudomonas aeruginosa) procaryotes as well as two eucaryotes (Candida albicans; Aspergillus niger), with negative results. The phloem sap was analysed by means of GC-MS and a few compounds, which have been identified, are reported. Ten spyte van hul bedreigde status word kiaat (Pterocarpus angolensis) bome steeds uit hul natuurlike habitat verwyder, waarvan die sap tradisioneel vir verskeie medisinale gebruike aangewend en die hout vir meubels en brandhout gebruik word. Die tweeledige doel van hierdie studie was eerstens, om te vas te stel walter saad voorbehandelings sal lei tot die optimale ontkieming en tweedens, om die sap van die kiaat te evalueer vir moontlike antimikrobiese aktiwiteit. Die aanvanklike lootsproef is uitgevoer met ongesteriliseerde sade in die donker wat lae kiemingspersentasies(7.78%) en hoe persentasies fungusinfeksies (45.56%), primer Aspergil­ lus niger en 'n Fusarium sp. tot gevolg gehad het. Die sade v}r die tweede eksperiment is gesteriliseer met 'n mengsel van 60 9 Thiram en 70 9 Captan en 'n veranderende lig/donker omgewing. In beide gevalle is die sade aan 'n hormoori, hitte of 'n kontrole voorbehandeling blootgestel en toegelaat om by drie verskillende temper­ atuur toestande te ontkiem. Verskillende sapkonsentrate is vir antimikrobiese aktiwiteit teen sowel gram posi­ tiewe (Staphylococcus aureus) as gram negatiewe (Escherichia coli; Pseudomonas aeruginosa) prokariote en twee eukariote (Candida albicans; Aspergi/lus niger) getoets, maar negatiewe resultate is verkry. Die sap is met behulp van 'n GC-MS geanaliseer en enkele verbindings wat ge\"identifiseer is, word aangetoon.","PeriodicalId":22913,"journal":{"name":"The South African Journal of Plant and Soil","volume":"9 14 1","pages":"141-146"},"PeriodicalIF":0.0,"publicationDate":"1998-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79823631","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}

{"title":"A comparison of HMW-GS, LMW-GS and RAPD fingerprinting for cultivar identification of some South African wheat cultivars","authors":"M. Labuschagne, H. Maartens, A. Oberholster","doi":"10.1080/02571862.1998.10635133","DOIUrl":"https://doi.org/10.1080/02571862.1998.10635133","url":null,"abstract":"Accurate identification of breeding material is very important for the plant breeder. In South Africa, high molecular weight glutenin subunits (HMW-GS) have so far been used for wheat cultivar identification. This method can often not distinguish between cultivars, and other techniques need to be investigated. The aim of this study was to compare HMW-GS, low molecular weight glutenin subunits (LMW-GS) and random amplified polymorphic DNA (RAPDs) for wheat cultivar identification. Five commercial wheat cultivars were analysed using the above three methods. The HMW-GS failed to distinguish between the five cultivars. LMW-GS could clearly distinguish between the cultivars, but banding pattern interpretation was more complicated than for HMW-GS. RAPDs could distinguish between the five cultivars with three different primers, but were expensive and would need an increased number of primers with an increase in cultivars. We concluded that HMW-GS should be used for initial cultivar identification, as it is simpl...","PeriodicalId":22913,"journal":{"name":"The South African Journal of Plant and Soil","volume":"167 1","pages":"147-150"},"PeriodicalIF":0.0,"publicationDate":"1998-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72897626","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}

{"title":"An investigation into the problems associated with revegetating chrysotile tailings","authors":"L. Rensburg, L. Pistoruis","doi":"10.1080/02571862.1998.10635131","DOIUrl":"https://doi.org/10.1080/02571862.1998.10635131","url":null,"abstract":"The present investigation was initiated because of the limited success achieved in the past at attempts to revegetate chrysotile tailings with their associated inherent environmental risk factors. The current set of experiments and surveys, as with several previous studies, were conducted at Msauli chrysotile mine, Mpumalanga Province, South Africa. All soil and leaf samples were collected, and the total percentage canopy cover, species frequency, percentage cover per species, percentage alive biomass, and phenology per species quantified. This was done in nine randomly selected 1m2 areas, on both the upper (steeper) and lower (less steep) slopes of previously revegetated slopes, with comparable samples from areas within the native vegetation serving as controis. Nine composite (consisting on average of three 500g samples) replicate soil samples per slope gradient, as well as leaf samples (ca. 5g of dried above ground leaf material) representative of the species composition, were sampled in the same plots...","PeriodicalId":22913,"journal":{"name":"The South African Journal of Plant and Soil","volume":"1 1","pages":"130-140"},"PeriodicalIF":0.0,"publicationDate":"1998-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82149739","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}

{"title":"Rootstock-dependent soil respiration in a citrus orchard","authors":"N. Keutgen, M. Huysamer","doi":"10.1080/02571862.1998.10635124","DOIUrl":"https://doi.org/10.1080/02571862.1998.10635124","url":null,"abstract":"Soil respiration is a major contributor to the carbon flux in apple orchards, but very little data exist for citrus. Daytime soil respiration, grass respiration, and grass photosynthesis were recorded in a ‘Nules’ clementine (Citrus reticulata Blanco) orchard on ‘Carrizo’ citrange or ‘X639’ rootstock in Stellenbosch, Republic of South Africa, under typically variable spring weather conditions such as cool to hot, and clear to cloudy days. The amount of CO2 contributed by the citrus roots and the Oakleaf soil type to the carbon fluxes in the orchard, was evaluated. Soil respiration rate in the citrus rows varied between 0.1 and 0.4 g CO2 m−2 h−1 and increased with temperature, with a Q10 of about 1.4. After rainfall or irrigation, soil respiration was higher, especially at elevated temperatures. The rootstocks ‘Carrizo’ and ‘X639’ were characterised by slightly different rates of soil respiration. The difference was more pronounced after irrigation, and soil respiration of ‘X639’ exceeded that of ‘Carrizo’...","PeriodicalId":22913,"journal":{"name":"The South African Journal of Plant and Soil","volume":"37 1","pages":"93-98"},"PeriodicalIF":0.0,"publicationDate":"1998-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90270965","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}

{"title":"Organic matter, pH and nutrient distribution in soil layers of a savanna Thornveld subjected to different burning frequencies at Alice in the Eastern Cape","authors":"S. Materechera, O. T. Mandiringana, P. M. Mbokodi, K. Nyamapfene","doi":"10.1080/02571862.1998.10635127","DOIUrl":"https://doi.org/10.1080/02571862.1998.10635127","url":null,"abstract":"Fire is an important tool for the management of grazed savanna grasslands in the Eastern Cape, South Africa. The aim of this study was to quantify the influence of veld burning frequency on soil properties especially organic matter, pH, exchangeable Ca, Mg, K, Na and extractable P. Soil samples were collected from different depths in plots of a 17-year old experiment where burning frequencies were: no burning (B0), annual (B1), triennial (B3) and sexennial (B6). A land under continuous grazing and not burned (G) and strips between the plots (R) were also sampled for comparison. Burning significantly (p G>B3>B6>B1>R. The trend in the distribut...","PeriodicalId":22913,"journal":{"name":"The South African Journal of Plant and Soil","volume":"1 1","pages":"109-115"},"PeriodicalIF":0.0,"publicationDate":"1998-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82925415","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}

{"title":"The effect of soil fertility on the contribution of main stem, tillers and kernel position to grain yield and grain protein content of wheat","authors":"L. A. Metho, P. Hammes, E. Beyers","doi":"10.1080/02571862.1998.10635117","DOIUrl":"https://doi.org/10.1080/02571862.1998.10635117","url":null,"abstract":"The relative contribution of main stems and tillers, as well as the relative contribution of first, second and third kernels in spikeiets to grain yield and grain protein content, is seldom quantified. The grain yield of main stems, tillers and relative mass of kernels in the spikelet by floret position were determined in a long-term fertilization and irrigation experiment at the University of Pretoria. A randomized complete block design in a split-plot arrangement with three replicates was used. Main plots consisted of two different soil fertility levels and subplots were assigned to four cultivars. Mean grain yield of main stem (MS), first tiller (T1) and second tiller (T2) for the cultivar Kariega was 1.26 g, 0.98 g and 0.53 g respectively, 1.29 g, 0.78 g and 0.40 g for Carina, 1.63 g, 0.69 g and 0.09 g for Inia and 1.71 g, 1.10 g and 0.51 g for SST 86. Within a cultivar, the respective ears (MS, T1 and T2) did not differ in mean grain protein content, but significant differences were observed among th...","PeriodicalId":22913,"journal":{"name":"The South African Journal of Plant and Soil","volume":"114 1","pages":"53-60"},"PeriodicalIF":0.0,"publicationDate":"1998-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77734477","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}

{"title":"Crop and Soil Science Challenges and Directions in the USA","authors":"B. Klepper","doi":"10.1080/02571862.1998.10635116","DOIUrl":"https://doi.org/10.1080/02571862.1998.10635116","url":null,"abstract":"","PeriodicalId":22913,"journal":{"name":"The South African Journal of Plant and Soil","volume":"56 1","pages":"49-52"},"PeriodicalIF":0.0,"publicationDate":"1998-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76766646","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}

{"title":"The response of germinating sunflower seed to heat tolerance induction","authors":"A. A. Nel","doi":"10.1080/02571862.1998.10635122","DOIUrl":"https://doi.org/10.1080/02571862.1998.10635122","url":null,"abstract":"Vigour of pre-emergent sunflower (Helianthus annuus L.) seedlings is reduced when daily peak soil temperatures exceed 44°C resulting in poor emergence. Seedlings of sorghum (Sorghum bicolor L. Moench) are known to acquire thermotolerance to temperatures of 45–50°C as a consequence of a brief pre-exposure of the imbibing seed to 40°C. The aim of this investigation was to determine whether sunflower seedlings can acquire heat tolerance. Seed of three sunflower cultivare was used to compare the response to heat shock of 2 hr at 50°C in untreated and thermotolerance induced incubated seed. Heat tolerance was induced by exposure of the imbibed seed to 40°C for I h, 24 h before the heat shock. The response was assessed by comparing germination percentages and hypocotyl lengths. Germination percentages and hypocotyl lengths of seedlings differed significantly for cultivars. Hypocotyls of seed pre-exposed to 40°C were shorter than untreated seed indicating the inability of sunflower to acquire thermotolerance.","PeriodicalId":22913,"journal":{"name":"The South African Journal of Plant and Soil","volume":"102 1","pages":"90-90"},"PeriodicalIF":0.0,"publicationDate":"1998-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75767431","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}

{"title":"A comparison of three methods of soil water content determination","authors":"K. Little, B. Metelerkamp, C. Smith","doi":"10.1080/02571862.1998.10635121","DOIUrl":"https://doi.org/10.1080/02571862.1998.10635121","url":null,"abstract":"In forestry the need to manage plantations on a sustainable site-specific basis requires the understanding and management of any growth limiting factors. Soil water regime is a factor considered to be of prime importance with respect to explaining differences in tree growth. In research studies measurement of soil water content is carried out on a regular basis and due to theft and vandalism, soil water sensing equipment cannot usually be left on site. Other rapid methods to determine soil water content therefore have to be found. The ThetaProbe and Speedy Moisture Tester were compared as alternative measures of soil water content determination in the top 10 cm of the soil to the more traditional gravimetric method. These methods were tested in KwaZulu-Natal on two contrasting soils in terms of clay content, organic carbon content and soil water content. Regression analysis performed to compare the two different methods with the gravimetric method as a reference, indicated that they were similar on a soil...","PeriodicalId":22913,"journal":{"name":"The South African Journal of Plant and Soil","volume":"29 1","pages":"80-89"},"PeriodicalIF":0.0,"publicationDate":"1998-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81306318","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}