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Interaction effect of seaweed extract and inoculation on growth, nodulation and nutritional quality of two cowpea varieties (Vigna unguiculata L. Walp)
Get PDFThesis (M.Sc. Agriculture (Agronomy)) -- University of Limpopo, 2015Two studies (field and tunnel house experiments) were conducted during the 2012/2013 growing season to assess the effect of a commercial seaweed extract (Technikelp) and Bradyrhizobia inoculation on growth, nodulation, yield and nutritional quality of cowpea. The field experiment was laid out as a 3-way factorial arrangement, and fitted into a randomized complete block design (RCBD) with three factors: i) Two cowpea varieties (Brown landrace and Bechua na white), ii) Two Inoculation levels (with and without Bradyrhizobium inoculation) and iii) Three seaweed extract concentrations to water (1:100, 1:500 and no seaweed extract as the control). The treatments were combined and replicated four times. Cowpea seeds were sown at an intra-row spacing of 20 cm and inter- row spacing of 60 cm with a plot size of 3 m x 3.6 m (10.8 m2) with each plot having six rows and a plant population of 96 plants per plot. Six litres (6000 ml) of each of the diluted seaweed extract levels was applied per plot as root drench at planting, 14 and 28 days after planting (DAP). The seaweed extract was applied immediately after irrigation. The tunnel house experiment was also laid out as a 3-way factorial experiment and fitted into a randomized complete block design (RCBD) with three factors: i) Two cowpea varieties (Brown cowpea landrace and commercial variety; Bechuana white), ii) Two Inoculation levels (with and without Bradyrhizobium inoculation) and iii) Three seaweed extract concentrations to water (1:100, 1:500 and no seaweed extract as the control). The factors were combined and replicated four times. Nine litre (9 L) nursery bags with a dimension of 175 x 150 x 350 mm were filled with 5 kg of sandy loam Hutton soil obtained from the University of Limpopo experimental farm. Analysis of variance revealed that the variation in genetic composition dictated the growth and yield performance of the two cowpea varieties. The current study revealed that all three factors had a significant effect of growth, nodulation, yield as well as the uptake of several mineral nutrients. The results showed that the Brown landrace took longer to reach flowering (60.45 days) and physiological maturity (142.02 days) compared to Bechuana white variety which took 57.18 days to reach 50% flower and 121.11 days to reach physiological maturity. In both the field and tunnel house experiments, the application of 1:100 v/v seaweed extract resulted in a 81-88% increase in the number of effective nodules when compared to the control. Variety, seaweed extract and inoculation had a significant (p≤ 0.05) effect on grain yield. The Bechuana white variety recorded grain yield of 1915 kg ha-1 compared to the 1021 kg ha-1 by the Brown landrace variety. The application of 1:500 v/v seaweed extract increased grain yield by 9.5% while the application of 1:100 v/v resulted in a 29.9% increase. The application of Bradyrhizobia inoculation increased grain yield by up to 40% when compared to the uninoculated treatment. In both the field and tunnel-house experiments, correlation analysis revealed a positive relationship between chlorophyll content and number of effective nodules per plant. In the tunnel house experiment, correlation analysis gave an R2 value of 0.80 while an R2 value of 0.70 was recorded in the field experiment, indicating a strong relationship between chlorophyll content and nodulation. Furthermore, a positive relationship was also observed between nodulation and pod formation with an R2 value of 0.69. Correlation analysis also revealed a positive relationship between pod formation and grain yield with a R2 value of 0.62. Statistical analysis revealed a significant variety x inoculation effect on the number of days to 50% flowering, as well as the yield components and seed nutritional quality. The application of seaweed extract in the presence of inoculation improved nodulation and chlorophyll content, yield components, as well as leaf and grain nutritional quality. Response of variety to seaweed extract was observed on shelling percentage, as well as leaf K and Fe content, and seed B content. The combination of seaweed extract x inoculation x variety had a significant effect on the number of pods per plant, grain yield, shelling percentage as well as harvest index.
Economic analysis revealed that the application of both inoculation and seaweed extract are highly profitable. The application of inoculation resulted into greater profit of R32818/ha relative to uninoculated treatments while the application of 1:100 v/v seaweed extract concentration resulted into greater profitability of R32191/ha and ultimately resulted into higher returns to investment in the technology. Overall, the results from this study suggest that the adoption of application of inoculants and seaweed extract will not only improve yield and nutrition of cowpea, but has the potential to improve the livelihoods of small scale farmers due to their high marginal returns.National Research Foundation (NRF
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Soil types, water and heat stress affect seed qualities of three maize varieties grown under variable conditions
Get PDFPhD (Agriculture with Agronom), North-West University, Mahikeng CampusFood security in Sub-Saharan Africa is threatened by the increasing incidence of extreme weather events like heat waves and drought. These stressors reduce the yield of maize (Zea mays L.), which is the most important staple food and the highest single source of calories in Sub-Saharan Africa. Therefore, improving maize yield under a stress environment will contribute towards promoting food security in the region. The aim of this research was to study the response of maize plants grown with different soil amendments to heat stress and combined water and heat stresses, as well as the effects of the stress on maize seed qualities and progeny. Two repeated greenhouse and a repeated field trials were performed.
The first greenhouse experiment was a 2 × 3 × 3 × 2 factorial in a completely randomized design with four replications. The factors were: environment, heat-stress (HS) and non-heat-stress (NHS); maize variety: WE3128, WE5323, and ZM1523; soil amendment: poultry manure (PM), mineral fertilizer (MF), and complementary (50:50) application of poultry manure/mineral fertilizer; and soil type: sandy clay loam (SCL) and loamy sand (LS). The following growth, phenological and yield attributes were measured: plant height (PH), leaf area (LA), leaf chlorophyll content (LCC), number of leaves (NoL), plant stem diameter (SD), number of days to tassel appearances (DT), number of days silk appearances (DS), tassel silk interval (TSI), stover dry weight in grams (SDWt), dry biomass yield (DBY), harvest index (HI), cob number per plant (NoC) cob length (CL), cob width (CW), cob weight (CWt), grain weight (GWt), shelling percentage (SP), number of grains (GN) and 100-seed weight (SWt). The seeds were analysed for macro and micro mineral concentrations using inductively coupled plasma mass spectrometry. The second greenhouse experiment involved a 3 × 3 × 2 × 3 factorial in a completely randomized design with four replications. Three water stress levels; non-water stress (NS), moderate water stress (MS), and terminal water stress (TS), three soil amendments (PM, MF and MPM), two soil types (SCL and LS), and three drought–tolerant maize varieties were combined to create 54 treatment interactions with four replications. The 54 treatment interactions were grown in a HS environment. The same data were collected in the two greenhouse experiments. Data from ninteen morphological attributes from the two experiments were analysed using Pearson's correlation coefficient, principal component analysis, and path coefficient analysis to assess these attributes’ contributions to GWt under NHS, HS, and combined heat and moderate water stress (HWS) conditions. To determine if the parental growth conditions influenced progeny performance, seeds from the first greenhouse experiments were evaluated in the field for two summer planting seasons. A randomised complete block design experiment with three replications was used to grow the
progenies. The progenies were examined for nineteen morphological and yield-related attributes.
The first greenhouse experiment results showed better growth and yield from SCL soil over LS soil. WE5323 and ZM1523 amended with PM produced the highest yields in the NHS and HS environments, respectively. Heat stress exerted a depressive effect on maize growth and yield attributes. HS reduced the LCC, LA, PH, SD, DBY, HI, CWt, GWt, GN, and SDWt by 35, 36, 35, 41, 59, 78, 64, 73, 69, and 23%, respectively. GN, GWt, and CWt were the most informative yield attributes.
The second greenhouse experiment results demonstrated a depressive effect of water stress on the maize LA, LCC, SD, DBY, and HI due to the increasing severity of water stress, with the HI dipping by 30.3 and 92.9% in MS and TS plants, respectively. TS reduced CWt, GWt, GN, and SWt by 96, 97, 97, and 63%, respectively. The GGEbiplot explained 96.6% of the yield variation in the treatment interactions. While GN had the most discriminatory power among the maize attributes studied, CWt was the most representative attribute. The maize varieties were ranked WE5323 ≥ ZM1523 > WE3128 in terms of average performance and stability. The NS treatments together with three MS treatments performed better than the population mean following the ranking of the treatment interactions. Under HS and MS conditions, the PM amendment performed well for varieties WE5323 and ZM1523, while the MF amendment performed best for variety WE3128. Compared to the inorganic amendment, the organic amendment had a greater ameliorative capacity for grain yield under combined heat and water stress conditions.
Under NHS, HS, and HWS, the correlation results revealed that eight traits consistently produced a significant and positive relationship with GWt. The principal component analysis explained 59.37% of the variation under NHS, 55.12% for HS, and 57.14% under HWS. The path coefficient analyses revealed that in the NHS, HS, and HWS conditions, five traits consistently had a positive direct effect on the GWt. Given the magnitude of the positive direct effects, increasing DBY, HI, and GN in the NHS; increasing GN, HI, and CW in the HS; and increasing HI, DS, LCC, and GN in the HWS will improve GWt. Under various abiotic stress conditions, maize phenotypic expression varied.
Except for the main effect of maize variety on grain yield, the results showed significant main and interaction effects of the three factors on grain yield, grain macro, and trace minerals (Mo, Mn, Fe, Zn). The highest grain Zn was obtained with the MF amendment, while the highest grain Fe and yield were obtained from the MPM amendment. When compared to the NHS environment, the HS environment reduced grain yield while increasing grain Fe and Zn
concentrations. WE5323 had the highest concentrations of macro minerals, followed by ZM1523 and WE3128. The correlation result revealed that a proportional relationship between Fe/Zn and grain yield tends to decrease the grain Fe/Zn concentrations.
The first and second principal component axes explained 69.51% of the variation in the progenies’ yield attributes. The most informative attributes were GWt and CWt. The GWt and CWt of the progenies were unaffected by the parental heat stress conditions or maize variety, but the progenies' CWt and GN were significantly influenced by the parental soil amendment. Clusters II and III contained the best-performing treatment interactions for each maize variety. WE3128 and ZM1523 had their highest yields from PM amendments in the NHS environment, while WE5323 produced its highest yield from the MPM amendment in the HS environment. The findings from this study revealed that soil type, water and heat stress affected maize seed qualities when grown under varied conditions.Doctora
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Effect of plant density on growth and yields of six soybean (Glycine max L. Merril) cultivars grown at three localities in South Africa
Get PDFMSc (Crop Science), North-West University, Mafikeng CampusAgronomic field trials were conducted at Potchefstroom, Rustenburg and Bethlehem during
the 2013/4 planting season to investigate the effect of plant density on growth and productivity
of six commercial soybean cultivars. Treatments consisted of six plant densities (200 000, 250
000, 300 000, 350 000, 400 000 and 450 000 plants ha-1) planted at three inter-row spacing (90,
75, and 45 cm) for the six different roundup ready soybean cultivars (LS 6240R, PAN1454R,
PAN 1654R, PAN 1500R, LS 6164R, and PAN 1614R). The trial at each locality was laid out
in a split-split plot arrangement and fitted into a randomized complete block design (RCBD).
Growth and phenological data were collected from the trials and data collected were tested for
comparable magnitude using Shapiro-Wilk's test for assessment of deviation from the
normality. Weighted combined analysis of variance and pair-wise comparisons were also
carried out using the Fishers least square means of significant (LSD) test at a probability level
of 5%.
Soybean grain yield was significantly affected by plant density, locality x density, locality x
cultivar, and density x cultivar interaction effects. Grain yield at Potchefstroom was higher ( 4
389.5 kg ha-1) than either Rustenburg (3 553.1 kg ha-1) or Bethlehem (3 409.5 kg ha- 1). The
cultivar that performed the best at Potchefstroom was PAN 1500R (5 820.2 kg ha- 1) at a plant
density of 400 000 plants ha-1 and a row spacing of 45 cm. The protein content of soybean
grains was significantly affected by plant density, cultivar variation, locality x density and
locality x cultivar interaction effects. Grains harvested from Rustenburg had the highest protein
content (44.1 %) than either Bethlehem (41.1 %) or Potchefstroom (40.9%). The plant density
that gave the highest grain protein (44.5%) content was 400 000 plants ha-1 at 75 cm row
spacing. The cultivar LS 6164R had grain with the highest protein content (45.3%) at
Rustenburg. The oil content of soybean grain trial was significantly affected by plant density,
cultivar and locality x cultivar interaction effects. Grain harvested from Potchefstroom had the
highest oil content (21.0%). The highest seed oil content of 21.9% was obtained in cultivar LS
6240R grain harvested at Potchefstroom while cultivar PAN 1664R at Bethlehem had the least
oil content of 19.3%.Master
Effect of composted Phalaborwa ground phosphate rock on performance of grain sorghum grown on variable soil conditions
Get PDFMSc (Crop Sciences), North-West University, Mafikeng CampusGrain sorghum (Sorghum bicolor [L.] Moench), is a cereal crop that is indigenous to Africa. The desire to reduce the negative impact of industrial wastes on the environment through the use of inorganic fertilisers and promote harmony between nature and the earth inhabitants calls for identification of viable and cheaper alternative non-hazardous fertiliser source for maintaining soil fertility and increasing crop yields on farmlands. This can also help farmers to manage on-farm wastes as wealth resources. It also minimizes the waste removal costs and serves as way of increasing income. This study assessed soil phosphorus (P) and other soil nutrients availability when using cheaper and locally available P-rich organic-based fertiliser sources for increased grain sorghum yields. Compost preparations, greenhouse and field trials were conducted at the North-West University experimental farm in Mahikeng. The P-enriched compost produced contained adequate levels of nutrients including P, which was 68.37 g/kg but with high level of Cd that was above the threshold level of 39 mg/kg it may pose serious threats for agricultural soils. The most common threats caused by Cd are stunting and chlorosis in plants. Evaluation of growth, yield, nutrient and nutritional contents of grain sorghum were carried out under greenhouse and field conditions following application of variable rates of the P-enrich composts. Two greenhouse trials consisted of factorial arrangements. The first greenhouse trial consisted of two soil textural classes (loam and a sandy loam) and seven compost rates (i.e. unamended control, 5, 10, 20, 40, 80, 160 t/ha) and inorganic NPK rate as a positive control while the second trial consisted of two soil types (Hutton and Coega) and seven compost tea rates. The compost tea rates included unamended control, 250 ml fortnightly, 250 ml weekly, 250 ml bi-weekly, 500 ml fortnightly, 500 ml weekly and 500 ml bi-weekly. In addition, a laboratory incubation study on phosphorus release from the P-enriched co-composted manures was conducted to quantify and compare P availability from co-composted GPR in two soils with variable textural characteristics. Results from the first greenhouse trial revealed that all measured sorghum growth parameters performed better under loam soil than the sandy loam. Higher compost application rates promoted early flowering first observed in the 80 t/ha rate at 49 days. However, biomass accumulation in the inorganic NPK fertilizer rate was higher (53.63 g) than any of the P-rich compost rates. However, the 27.48% grain protein content obtained at 40 t/ha P-rich compost treatment was significantly higher. Similarly, the 0.65% grain P content obtained from the 10 t/ha compost rate was the highest suggesting possible optimum compost rates. On the other hand, results of the compost tea trial revealed that compost tea application had beneficial effects on growth and yield of sorghum grain with the 500 ml bi-weekly application rate producing better growth than any other rates in both soils. However, the obtained highest grain yield of 16.93 g/ panicle was from the 250 ml weekly treatment in the Hutton soil. Higher P-use efficiency (PUE) values of 4.66 and 4.23, respectively for grain and biomass obtained from Coega soil compared to the -0.44 (grain) and -0.208 (biomass) in the Hutton soil. Compost tea application can be a useful fertilizer source for sorghum
Results of the field trials revealed that 5 and 10 t/ha treatments gave the highest yields at 5490.1 and 5301.6 kg/ha, respectively. The highest total N (2.05%), crude protein (12.90%) and P (0.46%) contents from grain samples obtained from the 80 t/ha treatment. In addition, the 80 t/ha gave the lowest bulk density across all the treatments and resulted in the highest porosity. Although the 80 t/ha compost rate resulted in increased sorghum grain P uptake, reduced bulk density and favourably improved soil total porosity, the potential risks of exchangeable cation (EC) build-up following short and long term application of such rate makes it undesirable. Finally, the results of the laboratory incubation study revealed that P released over the 49-day period showed similar trends in both soils during the first 2 weeks and the third to the sixth weeks. However, the different P trend in loam soil decreased from the third week to the fifth week and the sandy loam soil showed a continuous increase in P from the first to the fourth week but decreased steadily starting from the fifth week. The final measured mineralized P in sandy loam (561.67 mg/kg) and loam (475.05 mg/kg) soils showed a P increase as a result of P-rich compost from the initial P values of 80 mg/kg (sandy loam) and 75 mg/kg (loam). However, there was non-significance effect on the cumulative P as affected by soil texture but the interaction between soil texture and compost rates had significance effect on cumulative P. The 10% compost tea rate containing 1574 mg/kg cumulative P in the sandy loam soil was non-significant while similar 10% rate containing 1236 mg/kg cumulative P in the loam soil was significant. The compost rate and soil texture played important role on compost mineralization. The findings in this study suggest the potential for possible improvement of soil P availability in sorghum fields using cheaper and locally available P-rich organic-based fertiliser source for increased sorghum yields.Master
Assessing the productivity of grain cowpea under variable conditions using low-input agricultural production practices
Get PDFMSc (Crop Science), North-West University, Mafikeng Campus, 2019The adoption of low-input agricultural practices can play a vital role towards ensuring food security. Cowpea is an indigenous crop that is highly adaptive and has numerous benefits. However, its production in South Africa is still very low with smallholder farmers being the largest producers of the crop in the country. The study focused on efforts to maximise the production of cowpea, particularly for smallholder farmers using low-input agricultural practices, which could ensure sustainable production and enhance food security. The aim of
this study was to investigate the impact of low-input agricultural practices on the productivity of grain cowpea grown under tunnel house and dryland conditions. Phospho-compost prepared at the Molelwane experimental farm of North-West University using animal manure (cattle, sheep and poultry) and sawdust through co-composting with ground phosphate rock in heap was used for tunnel house and field trials. A repeated 2:x2x6 factorial trial was carried out under tunnel house conditions with one field trial conducted under dryland conditions (these were all done at Molelwane): The tunnel house trials treatment factors consisted of six phosphorus (P) fertilizer rates, two soil types and moisture regimes, replicated three times to obtain 72 pots for both trials. The P fertilizer treatments comprised of variable phospho-compost rates (0, 10, 20, 40 and 80 t/ha) with 30 kg P/ha rate applied as single super phosphate (SSP 10.5%) included as a standard positive control. The soils used in tunnel house trial 1 were from a smallholder farmer's field in Ventersdorp (Glenrosa) and the North-West University experimental farm (Hutton) while the soils for the second tunnel house trial comprised Coega and Hutton soil types collected from the North-West University, Mafikeng Campus. The different P fertilizer rates exerted significant (p:S0.05) influence on all cowpea growth parameters, with the exception of leaf length. Variation in soil types used in the tunnel house trials exerted significant (p:S0.05) effect on stem diameter and chlorophyll content. The highest seed yield (12.51 g/pot) and (8.50) number of pods per plant were recorded in the 40 t/ha phospho-compost rate. Cowpea plants grown under the Coega and Glenrosa soil types performed better than those grown under Hutton soil. Application of 30 kg P/ha resulted in the highest mean nodule count (34.3) under tunnel house l while moisture stress exerted a depressive effect on cowpea seed yield, number of pods and fodder weight. Results obtained revealed that moisture-deprived plants
flowered and formed pods quicker The field trial was carried out during 2017-2018 summer growing season, the trial also comprised six phosphorus (P) fertilizer rates and two tillage practices (minimum and conventional). The P fertilizer treatments under the field trial also consisted of variable phospho-compost rates (0, 10, 20, 40 and 80 t/ha) with 30 kg P/ha rate applied as single super phosphate (SSP 10.5%) included as a positive control. Rainfall was used as the main source of irrigation with supplementary irrigation used only when there was a need. Application of 40 and 80 t/ha phospho-compost rates significantly increased the residual Bray P content,
organic carbon and total N soil content after harvest. Seed germination and plant emergence was quicker under minimum tillage. Tillage and different fertilizer rates significantly influence all the measured cowpea growth parameters and yield attributes. The highest grain yield (488.06 kg/ha) and nodule count (15 .36) under field conditions were produced at 40 t/ha phospho-compost rate while minimum tillage gave higher grain yield (611.66 kg/ha) and nodule count (14.39) than conventional tillage. Application of phospho-compost resulted in
significant increase soil available P and cowpea plant tissue P content. The heavy metal content of cowpea grains from the different fertilizer rates and tillage practices did not differ significantly (p>0.05) with measured values generally within the threshold level required for human consumption albeit the high Al and Fe concentrations in soil suggesting phyto-toxicity, which may have resulted in low grain yield obtained.Master
Characterisation, classification and suitability evaluation of agricultural soils of selected communities located along various river systems in Bayelsa State, Southern Nigeria
Get PDFPhD (Agronomy), North-West University, Mafikeng Campus, 2018"Abstract not copied"Doctora
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