The reported requirement for a higher weeding effort due to increased weed infestations under conservation agriculture (CA) relative to conventional mouldboard plough tillage is perceived by both smallholder farmers and extension workers as the main limiting factor to the widespread adoption of CA by smallholder farmers in southern Africa. However, proponents of CA argue that weeds are only a problem under CA in the initial two years and decline afterwards resulting in reduced labour requirements for weeding under CA. They further posit that weeds are only major problem where minimum tillage (MT) is adopted without crop residue mulching and diverse crop rotations. This thesis explores the effect of time under CA on weed population dynamics and crop growth under the recommended CA practices and actual smallholder farmer practice in semi-arid Zimbabwe. Assessment of weed and crop growth on a long-term CA experiment at Matopos Research Station revealed that the MT systems of planting basins and ripper tine were associated with higher early season weed density and biomass than conventional early summer mouldboard tillage (CONV) in both the fifth (cowpea phase) and sixth (sorghum phase) years of CA. This increased weed infestation within the first four weeks after planting in CA necessitated early weeding to provide a clean seedbed and avert significant crop yield loss. Maize mulching only suppressed early season weed growth in sorghum mostly at a mulch rate of 8 t ha-1 which is not a mulching rate that is attainable on most smallholder farms. However, the lower maize residue mulch rate of 4 t ha-1 was consistently associated with increased weed emergence and growth as from the middle of the cropping season in both crop species. The increased weed infestations under the mulch were probably due to the creation of ‘safe sites’ with moist conditions and moderate temperatures. The high weed growth under the mulch contributed to the low sorghum grain yield obtained under mulched plots. In addition, maize mulching was also associated with a less diverse weed community that was dominated by the competitive Setaria spp. and difficult to hoe weed Eleusine indica (L.) Gaertn. However, the weed community under CA was similar to that under CONV tillage with no evidence of a shift to the more difficult to control weed species. The increased early season weed growth and high weed pressure under CA meant that it was still necessary to hoe weed four times within the cropping season to reduce weed infestations and improve crop growth even after four years of recommended CA practices. Early and frequent weeding was effective in reducing weed growth of most species including Setaria spp. and E. indica demonstrating that on smallholder farms where labour is available hoe weeding can provide adequate weed control. The wider spacing recommended for use in CA contributed to the low cowpea and sorghum grain yields obtained under CA compared to CONV tillage. On smallholder farms in Masvingo District, the MT system of planting basin (PB) was the only conservation farming (CF) component adopted by farmers. There was no difference in the total seedling density of the soil weed seed bank and density of emerged weeds in the field in PB and conventional mouldboard ploughing done at first effective rains (CONV tillage). However, the first weeding in PB was done at least 15 days earlier (P < 0.05) than in CONV tillage suggesting high early season weed growth in PB relative to CONV tillage. As weed density did not decline with time in PB, weed management did not differ with increase in years under PB. Shortage of inputs such as seed and fertiliser was identified by smallholder farmers as the most limiting factor in PB crop production with the area under PB was equivalent to the seed and fertiliser provided by CARE International for most farmers. On this small area, weeds could be managed by available family labour. Double the maize grain yield was obtained in PB (mean: 2856 kg ha-1) due to improved weed management and soil fertility. However, the use of poorly stored composts was found to introduce weeds into some PB fields. The findings of this study demonstrated that weed pressure was still high and weed management were still a challenge under the practice recommended to smallholder farmers in Zimbabwe even in the sixth year of practice. There is, therefore, a need for research on the economic feasibility of using herbicides, intercropping and optimal crop density to ameliorate the high weed pressure under CA. / Thesis (PhD)--University of Pretoria, 2013. / Plant Production and Soil Science / unrestricted

MSCAGR (Plant Production) / Department of Plant Production / Bambara groundnut (Vigna subterranea) is one of the most important legumes cultivated primarily for food by smallholder farmers in Africa. It is an affordable source of protein and contributes to income generation as well as soil fertility. Despite its importance, it is cultivated largely for subsistence purposes in South Africa. Growers use landraces. The agronomic performance of the traditional varieties depends on environmental factors prevailing in a particular area. In Limpopo and Mpumalanga Provinces, there is no adequate information regarding the performance of bambara groundnut germplasm. The objectives of the study were to (i) determine the agronomic performance of Bambara groundnut across three contrasting locations in Limpopo and Mpumalanga provinces over two cropping seasons (ii) determine the genotypic variation in the seed protein level among 42 bambara groundnut genotypes. Forty-two bambara groundnut genotypes were evaluated under three different environmental conditions (Syferkuil, Thohoyandou and Nelspruit) over two (2013/2014, 2014/2015) seasons in a 7 × 6 rectangular lattice design replicated three times. Eight agronomic traits including dry shoot weight (DSW), number of pods per plant (NPP), pod length (PL), number of seed per pod (NSP), pod weight per plant (PWT), seed weight per plant (SWT), 100 seed weight (100-SWT) and seed yield (SYLD) were measured. The results showed that there were significant genotype x location interactions which demonstrated that the prevailing agro-ecological conditions at the test locations were distinct from each other. Five genotypes (‘BGN-19‘, ‘BGN-11‘, ‘BGN-12‘, ‘BGN-4‘and ‘BGN-34‘) attained >25.0% seed yield advantage over the local check ‘BGN-39‘. The results also showed that light brown coloured genotypes attained relatively higher seed yield compared to the other seed colours types. The cultivar superiority index (CSI) showed that three genotypes (‘BGN-12‘, ‘BGN-19’ and ‘BGN-34’) were the most stable across the test locations and attained >900.0 kg/ha on average. There were significantly high positive correlations between PWT and each of the three other attributes (SWT, 100 SWT and SYLD). In terms of seed protein, the results showed a poor relationship between seed yield and protein levels. ‘BGN-12’ which produced the highest seed yield, attained the lowest percent seed protein while genotype. On average, the genotypes contained 21.72% protein. The highest and lowest seed protein quantities were attained by the genotypes ‘BGN-42’ (25.17%) and ‘BGN-12’ (19.89%) respectively. / NRF

Thesis (M.Sc. Agriculture (Agronomy) -- University of Limpopo, 2019 / Erratic rainfall and insect infestation are some of the factors that limit cowpea production in Limpopo (Asiwe, 2009). Improved cowpea varieties available for dryland production in Limpopo do not meet the farmer’s needs. Specific trait crosses are needed to be made with adapted varieties for the purpose of developing high yielding, pest tolerant and adapted varieties. Varieties with desired specific traits were planted in isolation plots for outcrossing by insects. F1 lines derived from parental lines that were half sib seeds were harvested and planted as F2, and seeds obtained from F2 generation were used to develop F3 segregating population at University of Limpopo Experiential Farm, Syferkuil, and planted along with parents. This F3 generation forms the current evaluation on which this report is based. Data collected included; aphid severity (measured on a 9-point scale), number of days to 90 % maturity, grain yield, 100 seed weight and number of genotypes selected for advancement. Results showed significant variation among progeny over parents therefore expressing transgressive segregation. Genotypes derived from pedigree TX08-30-5 were five while pedigree IT98K-205-8 and IT97K-499-35 had four genotypes each that expressed early maturity (80-90 days) which are desirable for evading drought. Twenty-three genotypes from pedigree GEC and three from pedigree IT97K-499-35 obtained grain yield (>101 g/plot and >161 g/plot) that was better than their parents. Only one genotype derived from pedigree TX08-30-1 expressed high resistance to aphids better than the parent with a mean aphid score range of 1-2. Four genotypes from pedigree TX08-30-5 obtained bigger 100 seed weight (>18.6 g) compared to parent. These progeny also proved to be high yielders as they expressed heterosis for all yield attributes than their parents. Eighty-two genotypes were selected for advancement. Significant variations were observed among progeny giving opportunity to make selections. In most cases, genotypes outperformed their parents which indicate positive heterosis. The 82 promising genotypes selected will be advanced for further selections from multi location testing for stability and adaptation.

MRDV / Institute for Rural Development / This study originated from the realisation that non-conventional crops such as Bambara nuts (Vigna subterranea) were becoming increasingly important in addressing food insecurity and malnutrition in the smallholder farming sector of countries in sub-Saharan Africa. Moreover, some of the smallholder crop farmers were observed to be continuing to rely on indigenous techniques to forecast rainfall and adapt agricultural activities in response to climate variability. However, it was not clear how climate change influenced the productivity of V. subterranea. Nor were the indigenous approaches that farmers used to forecast rainfall on this phenomenon well understood. Thus, a study was carried out to identify and document indigenous approaches that smallholder farmers used to forecast rainfall and adaptation practices relating to V. subterranea. The study was conducted in Xigalo and Lambani villages located in Collins Chabane Local Municipality of Vhembe District in Limpopo Province. The villages served as case study areas that helped to compare the native approaches that the Va-Tsonga and Vha-Venda used to forecast rainfall in the course of producing V. subterranea. A multi-case study research design, which was exploratory in nature was adopted. Convenience and snowball sampling techniques were used to identify and select respondents. The triangulation of participatory methods, techniques and tools guided the collection of qualitative data. Key informant interviews, learning circles, photovoice, one-on-one interviews and narrative inquiry techniques were applied during data collection. Smallholder farmers and the elderly members of communities were the respondents. Nine key informants in Xigalo and Lambani villages were interviewed. One retired and two currently serving government extension officers were also interviewed. Separate learning circles comprising mainly elderly men and women were also organised. Each learning circle was made up of 7-10 respondents. Atlas.ti version 7.5.7 software was used to analyse the qualitative data following the thematic content analysis approach. It was observed that the respondents were aware of climate variability events that affected V. subterranea. Some of the events were shifts in rainfall patterns, heavy rainfall, extreme temperatures, scarcity of summer rainfall, the disappearance of lunar signs and the seasonal cycle variations. Eighteen types of phenological signs used to predict rainfall were identified. The most common signs included the Milky Way Galaxy of stars, musical sounds of birds and frogs, moon shapes, cumulus and cumulonimbus cloud types. A close relationship between conservation of V. subterranea and adaptation strategies was said to exist. It was evident that most commonly used conservation strategies were rainmaking ceremonies, planting after the summer rains, hoeing weeds, soaking seeds before planting, hilling or earthing up around the base of the V. subterranea plant and storing the legumes in traditional vessels and sacks. The need for integrating western scientific knowledge with native forecasts to inform the production of V. subterranea was uncovered. In addition to this, the needs of Tsonga and Venda communities should inform local policy interventions. Lastly, adaptation strategies that address food insecurity with V. subterranea being part of the agro-ecosystem deserve attention in scientific investigation and policymaking. / NRF

African leafy vegetables have been shown and suggested to have potential to contribute to human diets and alleviate malnutrition; however, their levels of utilisation are currently low especially in South Africa. This is because there is limited access to these crops due to low availability in the market. Limited access is attributed, in part, to the lack of commercialisation as a result of limited agronomic information describing optimum management options for these leafy vegetables. Availability of such information would contribute to successful commercialisation of these crops. The primary objective of this study was to establish optimum agronomic management factors for Amaranthus cruentus, Corchorus olitorius, Vigna unguiculata and Brassica juncea for irrigated commercial production in South Africa. Seeds of Amaranthus cruentus, Corchorus olitorius were obtained from the Agricultural Research Council seed bank; Vigna unguiculata were obtained from Hydrotech and Brassica juncea seeds were obtained from Stark Ayres. The project consisted of three field studies whose overall objective was to evaluate growth and yield responses of the selected African leafy vegetables to agronomic factors under irrigated commercial production. These field studies comprised of two single factors; summer trials (planting density and nitrogen on three selected crops) and a combined winter trial (nitrogen, irrigation, plant density and planting date on a winter crop). Chapter three (3) investigated the effect of plant density on growth, physiology and yield responses of Amaranthus cruentus, Corchorus olitorius and Vigna unguiculata to three plant densities under drip irrigated commercial production. The plant density levels of 100 000, 66 666 and 50 000 plants/ha were used in the 2011/12 and 2012/13 summer seasons. Parameters measured included chlorophyll content index (CCI), chlorophyll fluorescence (CF), stomatal conductance (SC), leaf number, leaf area index (LAI) and biomass. Amaranthus cruentus and Corchorus olitorius showed better leaf quality at lower plant density of 50 000 plants ha-1 than at 66 666 plants ha-1 and 100 000 plants ha-1. These results are based on bigger leaves expressed as leaf area index (LAI), better colour expressed as chlorophyll (CCI) and higher biomass per plant observed in these crops at 50 000 plants ha-1 in comparison to 66 666 plants ha-1 and 100 000 plants ha-1. In Vigna unguiculata there were no responses observed in LAI and CCI. In Amaranthus cruentus, Corchorus olitorius and Vigna unguiculata fresh and dry mass yield of leaves were higher at 100 000 plants ha-1 compared to other treatments. In A. cruentus and C. olitorius, higher leaf quality parameters (CCI, plant height, leaf number, biomass per plant and LAI) indicated that these crops can perform better at lower densities of 50 000 than at 66 666 plants ha-1 and 100 000 plants ha-1 Therefore, using 50 000 plants ha- 1 is suitable for commercial production of A. cruentus and C. olitorius. In Vigna unguiculata, a plant density of 100 000 plants ha-1 produced the highest fresh and dry mass per unit area without compromising quality in terms of the leaf size (LAI) and colour (CCI). Therefore 100 000 plants ha-1 is a density recommended for commercial production in V. unguiculata.Chapter four (4) was conducted to investigate growth, physiology and yield responses of A. cruentus, C. olitorius and V unguiculata to nitrogen application under drip irrigated commercial production. Three nitrogen treatments levels were used viz. 0, 44 and 88 kg N ha- 1 in 2011/12 season and four nitrogen treatments levels viz. 0, 50, 100 and 125 kg N ha-1 were used in 2012/13 summer season. The nitrogen levels selected for each season were based on recommendations for Amaranthaceae species, Swiss chard (Beta vulgaris L.var cicla) derived from soil analysis of the trial (field) site. Parameters measured included chlorophyll content index (CCI), chlorophyll fluorescence (CF), stomatal conductance (SC), leaf number, leaf area index (LAI) and biomass. Results showed that application of nitrogen at 44 kg N ha- 1 in 2011/12 summer season and 100 kg N ha-1 in 2012/13 summer season improved LAI, CCI, biomass per plants and yield in A. cruentus. A similar trend was observed in C. olitorius except that 44 kg N ha-1 improved stem fresh yield. Further increase in nitrogen fertiliser above 44 kg N ha-1 during the 2011/12 season and above 100 kg N ha-1 in 2012/13 summer season reduced leaf quality and yield in both crops. In V. unguiculata, nitrogen application showed a slight increase in yield values from 0 to 44 kg N ha-1 followed by decrease at 88 kg N ha-1 in 2011/12 summer season; however, this increase in yield was not significant. During the 2012/13 summer season, yield in terms of fresh weight was significantly (P<.001) reduced by applying nitrogen at various levels. However, leaf dry matter content increased significantly (P<.001) with increase in nitrogen from 0 kg up to 100 kg N ha-1, then remained unchanged at 125 kg N ha-1. Therefore, the current study recommends that C. olitorius and A. cruentus could be commercialised at 44 kg N ha-1 and 100 kg N ha-1 which were lower nitrogen application rates than those recommended for Amaranthaceae species. In V. unguiculata, 50 kg N ha-1 improved leaf number; however, this did not translate to any fresh yield advantage, implying that the optimum rate for nitrogen application might be lower than 50 kg N ha-1. Therefore, nitrogen rates less than the ones used in the current study are recommended for V. unguiculata. Chapter five (5) was conducted in winter and it was necessitated by observations made primarily in the previous studies which focused on the effects of single factors such as plant density, planting date and nitrogen deficits. Therefore, there was a need to address interactions between irrigation, nitrogen, spacing and planting date. The objective of this study was to evaluate growth, physiology and yield responses of Brassica juncea to different agronomic and management factors in the 2012 and 2013 seasons. The treatments were as follows: two planting dates in main plot (1 June and 18 July, 2012); two irrigation frequency in sub main plot (once and three times a week); three nitrogen levels (0, 50, 100 kg N ha-1) and three plant densities (133 333, 80 000, 50 000 plants ha-1) as subplots. Parameters measured included chlorophyll content index (CCI), chlorophyll fluorescence (CF), stomatal conductance (SC), leaf number, leaf area index (LAI) and biomass. Results from this study showed a significant interaction effect on plant height, LAI, CCI and CF. Crops irrigated thrice or once a week with 50 kg N ha-1 combined with 50 000 plants ha-1 produced tall plants and bigger leaves (LAI) in the early planting date (1 June) compared to other combinations. Irrigating three times a week combined with nitrogen application at 100 or 50 kg N ha-1 improved CF for late planting date (18 July) in comparison to other combinations. Irrigating once a week combined with nitrogen application at 100 kg N ha-1 increased CCI. There was no significant interaction effect on yield. Application of nitrogen at 50 and 100 kg N ha-1 significantly (P>0.05) increased yield in early and late planting dates compared to the control (0 kg N ha-1), in 2012 and 2013 winter season. Irrigating three times a week led to a significant (P<0.05) increase in yield in the late planting date (18th July) and early planting date (1st June) in 2013 season. Higher plant density of 133 333 plants ha-1 resulted in significantly (P<0.05) higher yield in terms of fresh mass and leaf number in the late planting date 18 July in 2012 and 2013 seasons. However, leaf quality parameters such as leaf size and colour was compromised at 133 333 plants ha-1 relative to 50 000 plants ha-1. Therefore, farmers are recommended to plant early, apply 50 kg N ha-1, irrigate thrice a week and utilise a spacing of 50 000 plants ha-1. The current study indicates that growth and yield of traditional leaf vegetables can be optimised through improved agronomic practise. / Agriculture and Life Sciences / D. Litt. et. Phil. (Agriculture)

African leafy vegetables have been shown and suggested to have potential to contribute to human diets and alleviate malnutrition; however, their levels of utilisation are currently low especially in South Africa. This is because there is limited access to these crops due to low availability in the market. Limited access is attributed, in part, to the lack of commercialisation as a result of limited agronomic information describing optimum management options for these leafy vegetables. Availability of such information would contribute to successful commercialisation of these crops. The primary objective of this study was to establish optimum agronomic management factors for Amaranthus cruentus, Corchorus olitorius, Vigna unguiculata and Brassica juncea for irrigated commercial production in South Africa. Seeds of Amaranthus cruentus, Corchorus olitorius were obtained from the Agricultural Research Council seed bank; Vigna unguiculata were obtained from Hydrotech and Brassica juncea seeds were obtained from Stark Ayres. The project consisted of three field studies whose overall objective was to evaluate growth and yield responses of the selected African leafy vegetables to agronomic factors under irrigated commercial production. These field studies comprised of two single factors; summer trials (planting density and nitrogen on three selected crops) and a combined winter trial (nitrogen, irrigation, plant density and planting date on a winter crop). Chapter three (3) investigated the effect of plant density on growth, physiology and yield responses of Amaranthus cruentus, Corchorus olitorius and Vigna unguiculata to three plant densities under drip irrigated commercial production. The plant density levels of 100 000, 66 666 and 50 000 plants/ha were used in the 2011/12 and 2012/13 summer seasons. Parameters measured included chlorophyll content index (CCI), chlorophyll fluorescence (CF), stomatal conductance (SC), leaf number, leaf area index (LAI) and biomass. Amaranthus cruentus and Corchorus olitorius showed better leaf quality at lower plant density of 50 000 plants ha-1 than at 66 666 plants ha-1 and 100 000 plants ha-1. These results are based on bigger leaves expressed as leaf area index (LAI), better colour expressed as chlorophyll (CCI) and higher biomass per plant observed in these crops at 50 000 plants ha-1 in comparison to 66 666 plants ha-1 and 100 000 plants ha-1. In Vigna unguiculata there were no responses observed in LAI and CCI. In Amaranthus cruentus, Corchorus olitorius and Vigna unguiculata fresh and dry mass yield of leaves were higher at 100 000 plants ha-1 compared to other treatments. In A. cruentus and C. olitorius, higher leaf quality parameters (CCI, plant height, leaf number, biomass per plant and LAI) indicated that these crops can perform better at lower densities of 50 000 than at 66 666 plants ha-1 and 100 000 plants ha-1 Therefore, using 50 000 plants ha- 1 is suitable for commercial production of A. cruentus and C. olitorius. In Vigna unguiculata, a plant density of 100 000 plants ha-1 produced the highest fresh and dry mass per unit area without compromising quality in terms of the leaf size (LAI) and colour (CCI). Therefore 100 000 plants ha-1 is a density recommended for commercial production in V. unguiculata.Chapter four (4) was conducted to investigate growth, physiology and yield responses of A. cruentus, C. olitorius and V unguiculata to nitrogen application under drip irrigated commercial production. Three nitrogen treatments levels were used viz. 0, 44 and 88 kg N ha- 1 in 2011/12 season and four nitrogen treatments levels viz. 0, 50, 100 and 125 kg N ha-1 were used in 2012/13 summer season. The nitrogen levels selected for each season were based on recommendations for Amaranthaceae species, Swiss chard (Beta vulgaris L.var cicla) derived from soil analysis of the trial (field) site. Parameters measured included chlorophyll content index (CCI), chlorophyll fluorescence (CF), stomatal conductance (SC), leaf number, leaf area index (LAI) and biomass. Results showed that application of nitrogen at 44 kg N ha- 1 in 2011/12 summer season and 100 kg N ha-1 in 2012/13 summer season improved LAI, CCI, biomass per plants and yield in A. cruentus. A similar trend was observed in C. olitorius except that 44 kg N ha-1 improved stem fresh yield. Further increase in nitrogen fertiliser above 44 kg N ha-1 during the 2011/12 season and above 100 kg N ha-1 in 2012/13 summer season reduced leaf quality and yield in both crops. In V. unguiculata, nitrogen application showed a slight increase in yield values from 0 to 44 kg N ha-1 followed by decrease at 88 kg N ha-1 in 2011/12 summer season; however, this increase in yield was not significant. During the 2012/13 summer season, yield in terms of fresh weight was significantly (P<.001) reduced by applying nitrogen at various levels. However, leaf dry matter content increased significantly (P<.001) with increase in nitrogen from 0 kg up to 100 kg N ha-1, then remained unchanged at 125 kg N ha-1. Therefore, the current study recommends that C. olitorius and A. cruentus could be commercialised at 44 kg N ha-1 and 100 kg N ha-1 which were lower nitrogen application rates than those recommended for Amaranthaceae species. In V. unguiculata, 50 kg N ha-1 improved leaf number; however, this did not translate to any fresh yield advantage, implying that the optimum rate for nitrogen application might be lower than 50 kg N ha-1. Therefore, nitrogen rates less than the ones used in the current study are recommended for V. unguiculata. Chapter five (5) was conducted in winter and it was necessitated by observations made primarily in the previous studies which focused on the effects of single factors such as plant density, planting date and nitrogen deficits. Therefore, there was a need to address interactions between irrigation, nitrogen, spacing and planting date. The objective of this study was to evaluate growth, physiology and yield responses of Brassica juncea to different agronomic and management factors in the 2012 and 2013 seasons. The treatments were as follows: two planting dates in main plot (1 June and 18 July, 2012); two irrigation frequency in sub main plot (once and three times a week); three nitrogen levels (0, 50, 100 kg N ha-1) and three plant densities (133 333, 80 000, 50 000 plants ha-1) as subplots. Parameters measured included chlorophyll content index (CCI), chlorophyll fluorescence (CF), stomatal conductance (SC), leaf number, leaf area index (LAI) and biomass. Results from this study showed a significant interaction effect on plant height, LAI, CCI and CF. Crops irrigated thrice or once a week with 50 kg N ha-1 combined with 50 000 plants ha-1 produced tall plants and bigger leaves (LAI) in the early planting date (1 June) compared to other combinations. Irrigating three times a week combined with nitrogen application at 100 or 50 kg N ha-1 improved CF for late planting date (18 July) in comparison to other combinations. Irrigating once a week combined with nitrogen application at 100 kg N ha-1 increased CCI. There was no significant interaction effect on yield. Application of nitrogen at 50 and 100 kg N ha-1 significantly (P>0.05) increased yield in early and late planting dates compared to the control (0 kg N ha-1), in 2012 and 2013 winter season. Irrigating three times a week led to a significant (P<0.05) increase in yield in the late planting date (18th July) and early planting date (1st June) in 2013 season. Higher plant density of 133 333 plants ha-1 resulted in significantly (P<0.05) higher yield in terms of fresh mass and leaf number in the late planting date 18 July in 2012 and 2013 seasons. However, leaf quality parameters such as leaf size and colour was compromised at 133 333 plants ha-1 relative to 50 000 plants ha-1. Therefore, farmers are recommended to plant early, apply 50 kg N ha-1, irrigate thrice a week and utilise a spacing of 50 000 plants ha-1. The current study indicates that growth and yield of traditional leaf vegetables can be optimised through improved agronomic practise. / Agriculture and Life Sciences / D. Litt. et. Phil. (Agriculture)

Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-05-27T13:22:22Z No. of bitstreams: 1 ANA PAULA MORAIS NEVES - DISSERTAÇÃO PPGSA PROFISSIONAL 2017..pdf: 735461 bytes, checksum: c320ee1307d508a5d5811325882d133c (MD5) / Made available in DSpace on 2018-05-27T13:22:22Z (GMT). No. of bitstreams: 1 ANA PAULA MORAIS NEVES - DISSERTAÇÃO PPGSA PROFISSIONAL 2017..pdf: 735461 bytes, checksum: c320ee1307d508a5d5811325882d133c (MD5) Previous issue date: 2016-11-29 / Uso de leguminosas como adubo verde é uma prática bastante consolidada, pelo fato de estar adicionando ao solo material vegetal rico em nitrogênio. O experimento foi conduzido na Fazenda Experimental Rafael Fernandes, no distrito de Alagoinha, zona rural de Mossoró-RN no período de agosto de 2015 a janeiro de 2016, com o objetivo de avaliar a Presença e ausência do feijão mungo sob doses de esterco bovino na viabilidade agroeconômica da alface. O delineamento experimental utilizado foi de blocos completos casualizados com os tratamentos arranjados em esquema fatorial 4 x 2, com quatro repetições. O primeiro fator foi constituído das doses de esterco bovino (1,0; 2,0; 3,0; 4,0 kg m-2 de canteiro) e o segundo fator foi constituído pela presença e ausência do adubo verde (feijão mungo). A cultivar da alface utilizada foi a “Regina”. Foram avaliadas as seguintes características: altura de planta, número de folhas planta-1, diâmetro da cabeça, produção de alface e massa seca de alface. Foram determinados alguns indicadores econômicos tais como: custo de produção, renda bruta, renda líquida, taxa de retorno e índice de lucratividade dos dois cultivos. Não houve interação entre os fatores-tratamentos para as características de produção, com produção de alface de 87,8 kg/100 m2. Houve diferença estatística no fator presença e ausência do feijão mungo com valores médios de 81,4 e 67 kg/100 m2 de alface, respectivamente. A maior eficiência econômica no cultivo da alface se deu na presença do feijão mungo na quantidade de 3,0 kg m-2, com renda bruta de 3343,75, renda líquida de 1582,40, taxa de retorno de 1,90 e índice de lucratividade de 43,42%. A utilização de feijão mungo no cultivo da alface constitui-se em uma opção viável para ser utilizado pelo agricultor. / The use of legumes as green manure is a well-established practice, because it is adding nitrogen-rich plant material to the soil. The experiment was conducted at the Fazenda Experimental Rafael Fernandes, in the district of Alagoinha, rural area of Mossoró-RN, from August 2015 to January 2016, with the objective of evaluating the Presence and absence of mung bean under doses of bovine manure in the agroeconomic viability of lettuce. The experimental design was a randomized complete block with treatments arranged in a 4 x 2 factorial scheme, with four replications. The first factor consisted of bovine manure (1.0, 2.0, 3.0, 4.0 kg m-2 of bed) and the second factor was the presence and absence of green mango (mung bean). The lettuce cultivar used was the "Regina". The following characteristics were evaluated: plant height, number of plant-1 leaves, head diameter, lettuce production and lettuce dry mass. Some economic indicators were determined such as: production cost, gross income, net income, rate of return and profitability index of the two crops. There was no interaction between the treatment factors for the production characteristics, with lettuce production of 87.8 kg / 100 m2. There was a statistical difference in the presence and absence of mung beans, with mean values of 81.4 and 67 kg / 100 m2 of lettuce, respectively. The highest economic efficiency in lettuce cultivation occurred in the presence of mung beans in the amount of 3.0 kg m-2, with gross income of 3343.75, net income of 1582.40, rate of return of 1.90 and index of profitability of 43.42%. The use of mung beans in lettuce cultivation is a viable option for the farmer to use.

Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-05-28T15:31:34Z No. of bitstreams: 1 CAMILA MARIA FORMIGA LEITE - DISSERTAÇÃO PPGSA PROFISSIONAL 2016..pdf: 1330991 bytes, checksum: 3763a8f8c7326718476ac867c8c63cb6 (MD5) / Made available in DSpace on 2018-05-28T15:31:34Z (GMT). No. of bitstreams: 1 CAMILA MARIA FORMIGA LEITE - DISSERTAÇÃO PPGSA PROFISSIONAL 2016..pdf: 1330991 bytes, checksum: 3763a8f8c7326718476ac867c8c63cb6 (MD5) Previous issue date: 2016-12-15 / O feijão-caupi representa uma fonte de alimento estratégica pelos altos teores de proteínas, carboidratos e de sais minerais e adaptação às condições ambientais adversas. Existem pragas capazes de atacar grãos/feijão armazenados, e a mais importante dessas no Brasil é o Callosobruchus maculatus (Coleoptera: Bruchidae), destacando-se por atacar sementes perfeitas, devido ao seu potencial depreciativo, trazendo má qualidade aos grãos e consumindo as reservas de nutrientes do embrião. O método de controle mais utilizado contra pragas de armazenamento é o uso de produtos químicos de distintas classes toxicológicas. Embora esses produtos tenham bastante eficiência, seu uso intensificado pode acarretar em problemas, com isso a utilização das plantas com atividade inseticida tornou-se tão importante, sendo geralmente aplicados na forma de pós, extratos ou óleos. Diante do exposto, este trabalho teve como objetivo avaliar o efeito repelente e inseticida de ervas utilizadas na cultura popular como medicinais no controle de Callosobruchus maculatus em grãos de feijão-caupi (Vigna unguiculata L.) em condições de laboratório, analisando a dose letal (DL50) e tempo letal (TL50) desses carunchos em relação ao pó dessas erva medicinais (Melissa officinalis (erva cidreira), Peumus boldus (boldo-do-chile), Maytenus ilicifolia (espinheira-santa), Mentha (hortelã). O experimento foi conduzido no laboratório de Entomologia da Universidade Federal de Campina Grande (UFCG), Campus Pombal, Paraíba, Brasil. Os grãos de feijão-caupi foram tratados com os pós nas concentrações de 5,0 g e em doses diferenciadas de 0,25, 0,50, 0,75 e 1,0 % (massa do pó/massa de grãos) e realizados testes de preferência e sobrevivência contra C. maculatus. No que se refere à repelência Erva cidreira, Boldo-do-chile e a Hortelã os insetos exibiram propriedades repelentes, melhor especificando os insetos não tiveram preferência pelas mesmas. Já com a Espinheira Santa, os insetos mostraram-se atraentes/preferentes. No que se referem à sobrevivência todas as espécies causaram mortalidade, em determinado período de tempo. / The Cowpea represents a strategic food source for the high levels of proteins, carbohydrates and mineral salts and adaptation to adverse environmental conditions. There are plagues capable of attacking grains/beans stored, and the most important of these in Brazil is the Callosobruchus maculatus (Coleoptera: Bruchidae), stand out to attack perfect seeds due to its derogatory potential, bringing bad quality grains and consuming nutrient reserves of the embryo. The most widely used control method against pests is the use of chemical products of different toxicological classes. Although these products have a lot of efficiency, its use can cause problems if it’s intensified, then the use of plants with insecticidal activity became so important, being generally applied in the form of powders, extracts or oils. On the exposed, this work aimed to evaluate the effect of insecticide and repellent herbs used in popular culture as the medical control of Callosobruchus maculatus in Cowpea beans, (Vigna unguiculata L.) under laboratory conditions, analyzing the lethal dose (Ld50) and lethal time (TL50) of these weevils in relation to those medicinal herb powder (Melissa officinalis (balm), Peumus boldus (boldo), Maytenus ilicifolia (espinheira-santa), Mentha (Mint). The experiment was conducted in the laboratory of Entomology, Federal University of Campina Grande (UFCG), Campus Pombal, Paraíba, Brazil. Cowpea beans were treated with powders at concentrations of 5.0 grams and different doses of 0.25, 0.50, 0.75 and 1.0% (mass/mass of powder grains) and preferably tests and survival against c. maculatus. As regards the Lemongrass repellency, Boldo and Mint insects exhibited repellent properties, better specifying the insects did not have the same preference. The Maytenus, the bugs proved attractive/preferences. In referring to the survival every species have caused mortality at any given period of time.

NEVES, Antônia Leila Rocha. Irrigation of cowpea with saline water at different growth stages and their effects on the plant and soil. 2008. 119 f. : Dissertação (mestrado) - Universidade Federal do Ceará, Centro de Ciências Agrárias, Departamento de Engenharia Agrícola. 2008 / Submitted by demia Maia (demiamlm@gmail.com) on 2016-06-13T14:53:10Z No. of bitstreams: 1 2008_dis_alrneves.pdf: 903212 bytes, checksum: 4298d42aacb4a0815d2c06c72d764de8 (MD5) / Approved for entry into archive by demia Maia (demiamlm@gmail.com) on 2016-06-13T14:57:22Z (GMT) No. of bitstreams: 1 2008_dis_alrneves.pdf: 903212 bytes, checksum: 4298d42aacb4a0815d2c06c72d764de8 (MD5) / Made available in DSpace on 2016-06-13T14:57:22Z (GMT). No. of bitstreams: 1 2008_dis_alrneves.pdf: 903212 bytes, checksum: 4298d42aacb4a0815d2c06c72d764de8 (MD5) Previous issue date: 2008 / The sensitivity of crops to salinity often changes from one growth stage to another. Cowpea [Vigna unguiculata (L.) Walp.] is an important crop specie cultivated in different semi-arid regions of the world. The objective of this work was to evaluate the effect of the irrigation with saline water, applied at different growth development stages of cowpea. The experiment was set up in the field, during the dry season. A completely randomized block design, with five treatments (T1, T2, T3, T4 and T5) and five repetitions, was adopted. The distance between lines and plants were 0.8 m and 0.3 m, respectively, with two plants per hole. The treatments studied were: T1 - Groundwater with electrical conductivity (ECw) of 0.8 dS m-1 during the whole crop cycle; T2 - Saline water (ECw = 5.0 dS m-1) during the whole crop cycle, starting after germination; T3 - Saline water (ECw = 5.0 dS m-1) from sowing until the 22th day after sowing (germination and initial growth) and groundwater in remaining stages of the crop cycle; T4 - Saline water (ECw = 5.0 dS m-1) from the 23th to the 42nd day after germination (intense growth and pre-flowering), and groundwater irrigation for the remaining growth stages. T5 - Groundwater from sowing to the 42nd day after sowing and saline water (ECw = 5.0 dS m-1) during flowering and pod-filling stages. Soil coverage, gas exchange, vegetative growth and crop yield were measured. The mineral concentration and quantity of nutrient removed from the soil, as well as the nutrient use efficiency and salt accumulation in soil were also determined. The irrigation with combination of groundwater and saline water reduced the salt accumulation in soil, in relation to continuous use of saline water. The continuous application of water with ECw of 5.0 dS m-1 (T2) reduced the rates of photosynthesis and transpiration, in relation to the well water (T1). Plants of the treatment 3 showed reduction in gas exchanges only in the first measurement, while the saline water application in other growth stages (T 4 and T5) did not provoke significant reductions in leaf in the gas exchanges of the plants. It was found that the continuous use of saline water inhibits plant growth, while the irrigation with saline water during germination and initial growth causes retardation in plant development. For treatments 2 and 3, reduction in the number of pods and in seed production was verified. Irrigation with saline water from the 23rd to the 42nd day (T4) and from the 43rd to the 63rd (T5) day after sowing did not affect reproductive and vegetative growth, but the saline water application in the pre-flowering (T4) caused anticipation of reproductive cycle. Cowpea plants removed the minerals analyzed in the following decreasing sequence: N > K > Cl > Ca > Na > P > Fe > Zn > Mn > Cu, but the continuous use of saline water (T2) reduced the total extracted for the most nutrients, except for Na e Cl. The minerals Na, Cl, K, Ca, Fe and Mn were distributed preferentially to vegetative plant parts, while the most of N and P were exported in the pods. The irrigation with saline water during germination and initial growth stage (T3) reduced the mineral use efficiency of most of analyzed nutrients. The continuous application of saline water (T2) reduced the agronomic efficiency of the fertilizer application (N, P and K), but it did not affect the nutrient use efficiency by the plants. / A sensibilidade à salinidade varia com o estádio de desenvolvimento da cultura. O feijão-de-corda [Vigna unguiculata (L.) Walp.] constitui uma das principais culturas, em diversas regiões semi-áridas do mundo. Avaliou-se o efeito da irrigação com água salina, aplicada em diferentes estádios de desenvolvimento de plantas de feijão-de-corda. O experimento foi conduzido no campo, e obedeceu ao delineamento em blocos ao acaso, com cinco tratamentos (T1, T2, T3, T4 e T5) e cinco repetições. O feijão-de-corda foi cultivado no espaçamento de 0,8 m entre linhas e 0,3 m entre plantas, com duas plantas por cova. Os tratamentos utilizados foram: T1 - plantas irrigadas com água do poço (CEa de 0,8 dS m-1) durante todo o ciclo; T2 - Água salina com CEa de 5,0 dS m-1, com aplicação iniciada após a germinação e permanecendo até o final do ciclo; T3 - Água salina com CEa de 5,0 dS m-1, da semeadura até 22 dias após o plantio (DAP), correspondendo às fases de germinação e crescimento inicial, e água do poço no restante do ciclo; T4 - Água salina com CEa de 5,0 dS m-1, aplicada de 23 a 42 DAP (fase de intenso crescimento vegetativo até a pré-floração), e água do poço nas demais fases do ciclo; T5 - Água do poço da semeadura até 42 DAP e água salina (CEa de 5,0 dS m- 1) aplicada a partir dos 43 DAP (floração e frutificação). Foram avaliadas a cobertura vegetal do solo, crescimento vegetativo, fotossíntese, transpiração, condutância estomática, produtividade, partição de matéria seca, os teores, os totais extraídos e a distribuição dos nutrientes na planta, a eficiência nutricional, eficiência no uso da água e o acúmulo de sais no solo. A irrigação com a combinação de água do poço com água salina reduziu o acúmulo de sais no solo, em relação ao T2. O T2 reduziu as taxas de fotossíntese e transpiração, em relação ao T1. O T3 provocou redução das trocas gasosas somente na primeira medição, enquanto, que similar aplicação nos outros estádios (T4 e T5) não provocou reduções significativas nas trocas gasosas das plantas. O T2 inibiu o crescimento vegetativo da planta, enquanto o T3 provocou retardo no desenvolvimento da planta. Os tratamentos T2 e T3 provocaram reduções significativas no número de vagens e na produção de sementes por planta, em relação aos demais tratamentos. Por outro lado, os tratamentos T4 e T5 não afetaram o crescimento e a produtividade da cultura, sendo que o T4 causou aceleração no ciclo reprodutivo da cultura. Os minerais foram extraídos pelo feijão-de-corda na seguinte ordem decrescente: N > K > Cl > Ca > Na > P > Fe > Zn > Mn > Cu, no entanto, o T2 reduziu a extração da maioria dos elementos analisados, com exceção do Na e Cl. Os minerais Na, Cl, K, Ca, Fe e Mn permaneceram preferencialmente nas partes vegetativas enquanto N e P foram exportados em maiores proporções pelos frutos. O T3 reduziu a eficiência de utilização da maioria dos nutrientes. O T2 reduziu a eficiência agronômica de utilização de N, P e K, entretanto não afetou a eficiência de utilização dos nutrientes extraídos pelas plantas.