3,528 research outputs found

    Middle Pleistocene paleoenvironmental reconstruction through phytolith analysis at the Manyara Beds, northern Tanzania

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    This project is aimed at developing a detailed habitat reconstruction for hominins living at the Manyara Beds of Northern Tanzania during the early Middle Pleistocene using phytolith remains. The dissertation comprises three interlinked, but independent studies. The first study examines the phytolith assemblages from modern surface soils and plants to create a referential baseline for studying phytoliths from the Acacia-Commiphora ecosystem surrounding the Manyara Beds, the same plant regions in which our ancestors reside. Phytoliths from 21 species of plants, including 11 unstudied taxa from this ecosystem, were characterized. Twenty-five composite surface soil samples from five sites were also analyzed. Using Stromberg's 2003 classification and interpretive scheme, this study has demonstrated that the dominant phytoliths for Commiphora are polyhedral epidermal cells, and Acacia is a rare producer of blocky-faceted rectangular plate morphotypes. The second study examines phytolith assemblages from archaeological and non-archaeological sites within the six-meter zone of the uppermost part of the lower Manyara Beds. In general, phytolith assemblage from archaeological and non-archaeological sites confirms the persistence of C4 grasslands. However, varied habitats were available for the Acheulean tool-making hominins at archaeological site MK 4, which featured palms, woody dicots, sedge, and grasslands taxa, including high proportions of warm arid and moist loving C3 and C4 PACMADs and dry adapted C4 chloridoids. There is also a small presence of wet-loving panicoids. The palms, sedges, Commelinaceae, and other aquatic monocots indicate that Manyara Beds were well-watered, at least with the occurrence of freshwater springs or rivers near the Lake shores. Therefore, inferences from phytolith assemblages from the Manyara Beds are consistent with the common predictions of many Plio-Pleistocene sites near the lake shores, pointing to hominin's dependence on water and food resources such as plants and game. The third study presents the analysis of 106 stone tool residue samples from the MK4 site to understand the function of the small flake assemblage found there. Ten tools yielded phytoliths, including two flaked and eight core tools. Phytoliths revealed the exploitation of plant resources, including grasses, palms, sedges, woody dicots, and other unknown taxa

    Sequential herbicide application coupled with mulch enhances the productivity and quality of winter onion (Allium cepa L.) while effectively controlling the mixed weed flora

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    Weed control poses substantial difficulties for winter season onion (Allium cepa L.) cultivation in the north-western Indo-Gangetic Plains, primarily due to the constrained efficacy of the existing herbicides. To address this issue, a 2-year field study was conducted to assess the efficacy of pre- and post-emergence herbicides (pendimethalin, ethoxysulfuron, imazethapyr, and quizalofop-p-ethyl) individually and in combination with crop residue mulch for weed control in winter onion. The results revealed that using herbicides or mulches in isolation did not provide satisfactory weed control. However, the integration of natural mulch with pendimethalin followed by quizalofop-p-ethyl application proved to be the most effective weed control strategy, resulting in the least reduction in bulb yield (10.3%) compared to other treatments. On the contrary, combinations of pendimethalin with ethoxysulfuron or imazethapyr showed adverse effects on the onion crop and inflicted the highest yield losses among all treatments (78.6 and 83.4%, respectively). However, the combination of pendimethalin with quizalofop-p-ethyl coupled with crop mulch resulted in season-long weed control and over 80% bulb yield (36.58 t/ha) gains compared to the weed-free condition. These findings emphasize the efficacy of combining herbicides and mulches as an integrated weed management strategy for onions. By adopting such integrated approaches, farmers could improve weed control while maintaining bulb yield and quality, reducing the risks associated with herbicide resistance, and promoting sustainable onion production in the north-western Indo-Gangetic Plains

    Advanced strategies for optimization of primary nutrients requirement in rice-A review

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    The Green Revolution led to India's food independence mostly through the inclusion of supply-driven technologies, such as the introduction of high-yielding cultivars, improved access to water, agrochemicals, and mechanization. The present and future needs target agricultural sustainability without endangering the ecosystem. In this regard, the adoption of precision agriculture is required to meet this expected objective. In developed nations, precision farming has already experienced tremendous growth. However, precision farming methods have taken a while for emerging nations in Asia to comprehend, create, and embrace. Moreover, precision farming is frequently misunderstood as a sophisticated technological intervention intended for extensive agricultural fields. However, it is essentially a science that involves using the "right input" in the "right quantity," at the "right time," and in the "right place," to improve input use efficiency. In the case of primary nutrients such as nitrogen, phosphorus, and potassium, so-called recommendations for nutrient management based on soil tests have improved food grain output which increased the nutrient use efficiency up to a certain extent. Moreover, the recommendations are made for a given agroclimatic region and crops irrespective of site-specific soil fertility, cultivars, and agronomic management levels resulting in excess or scanty use to crop needs. At this juncture, assessing the nutritional requirements of plants proves to be a superior method, as it takes into account the cumulative impact of nutrient availability from various sources on plant growth at any specific stage, making it a reliable indicator of nutrient accessibility. Rice, the most important food crop, is grown in diverse agroclimatic regions at different management levels. Hence, there is an urgent need to adopt a precision nutrient management strategy to optimize the yield output. The article offers an overview of several precision instruments available for managing nutrients at specific sites and aids in choosing the most appropriate one for each circumstance

    A bio-sustainable approach for reducing Eucalyptus tree-caused agricultural ecosystem hazards employing Trichoderma bio-sustained spores and mycorrhizal networks

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    The presence of the exotic Eucalyptus tree in crop-growing soil and the accumulation of its undecomposed leaves is a significant ecological hazard. The waxy coating on the leaves and the phenolic compounds takes a long time to break down under normal conditions. It is necessary to explore various fungi that can degrade these leaves for an eco-friendly solution to this problem. In this study, spores of nine native Trichoderma strains were produced on wheat agar using a lactic acid-induced sporulation strategy (LAISS). Trichoderma biosustained spores and Serendipita indica (SI) spores were applied to a rice field with accumulated Eucalyptus leaves under continuous ponding (CP) and alternate flooding and wetting conditions (AFW). Among the strains, TI04 (Trichoderma viride) and TI15 (Trichoderma citrinoviride) showed faster (5‚ÄČdays) and massive sporulation (1.06‚Äď1.38‚ÄČ√ó‚ÄČ1011 CFU/g) in LAISS. In vitro, TI04 and TI15 biosustained on Eucalyptus leaves and improved rice seedling growth and SI infection under greenhouse conditions. In the rice-field experiment, Trichoderma-treatment had a threefold yield (percentage) increase from control, with TI04 (CP) increasing the yield by 30.79, TI04 (AFW) by 29.45, TI15 (CP) by 32.72, and TI15 (AFW) rising by 31.91. Remarkably, unfilled grain yield significantly decreased in all the Trichoderma treatments. Under AFW conditions, TI04 and TI15 showed a higher pH increase. Furthermore, TI04 and TI15 under AFW had higher water productivity (t‚ÄČha‚ąí1 cm‚ąí1) of 0.0763 and 0.0791, respectively, and the highest rates (percentage) of SI colonization of 86.36 and 83.16, respectively. According to the findings, LAISS-produced Trichoderma spores can be applied to break down persistent wastes and restore agricultural ecosystems through increased mycorrhizae networking

    Synergistic impact of nanomaterials and plant probiotics in agriculture: A tale of two-way strategy for long-term sustainability

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    Modern agriculture is primarily focused on the massive production of cereals and other food-based crops in a sustainable manner in order to fulfill the food demands of an ever-increasing global population. However, intensive agricultural practices, rampant use of agrochemicals, and other environmental factors result in soil fertility degradation, environmental pollution, disruption of soil biodiversity, pest resistance, and a decline in crop yields. Thus, experts are shifting their focus to other eco-friendly and safer methods of fertilization in order to ensure agricultural sustainability. Indeed, the importance of plant growth-promoting microorganisms, also determined as ‚Äúplant probiotics (PPs),‚ÄĚ has gained widespread recognition, and their usage as biofertilizers is being actively promoted as a means of mitigating the harmful effects of agrochemicals. As bio-elicitors, PPs promote plant growth and colonize soil or plant tissues when administered in soil, seeds, or plant surface and are used as an alternative means to avoid heavy use of agrochemicals. In the past few years, the use of nanotechnology has also brought a revolution in agriculture due to the application of various nanomaterials (NMs) or nano-based fertilizers to increase crop productivity. Given the beneficial properties of PPs and NMs, these two can be used in tandem to maximize benefits. However, the use of combinations of NMs and PPs, or their synergistic use, is in its infancy but has exhibited better crop-modulating effects in terms of improvement in crop productivity, mitigation of environmental stress (drought, salinity, etc.), restoration of soil fertility, and strengthening of the bioeconomy. In addition, a proper assessment of nanomaterials is necessary before their application, and a safer dose of NMs should be applicable without showing any toxic impact on the environment and soil microbial communities. The combo of NMs and PPs can also be encapsulated within a suitable carrier, and this method aids in the controlled and targeted delivery of entrapped components and also increases the shelf life of PPs. However, this review highlights the functional annotation of the combined impact of NMs and PPs on sustainable agricultural production in an eco-friendly manner

    Studying the impact of agrivoltaic systems across the water-energy-food (WEF) nexus

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    L'umanità sta affrontando molteplici sfide dovute alla crisi climatica, all'aumento della domanda di cibo a causa della crescita della popolazione mondiale e alla conseguente richiesta di energia. I sistemi agrivoltaici (AV), la combinazione sinergica di impianti fotovoltaici e attività agricola, rappresentano una soluzione al dibattito energia-cibo. I sistemi AV prevedono l'installazione di impianti fotovoltaici su terreni agricoli, preservando il suolo agricolo per la produzione di cibo. L'obiettivo principale di questa tesi è stato quello di studiare la crescita delle colture nei sistemi AV, la loro risposta ecofisiologica, produttiva e la conversione energetica. Lo studio è stato effettuato attraverso prove in campo e modelli di simulazione con il fine di sostenere la sicurezza alimentare e promuovere l’agricoltura sostenibile in tutto il mondo rispettando i principi connessi al nesso acqua-energia-cibo. Nei capitoli di questa tesi è stato evidenziato come il sistema agrivoltaico è in grado ottimizzare la produzione di energia elettrica e di cibo, sono stati studiati i principali tratti eco-fisiologici che influenzano la crescita delle colture sotto sistema AV, sono stati utilizzati modelli di simulazione per prevedere l'energia convertita dai sistemi AV e la resa delle colture e l'impatto dell'albedo delle colture sulla conversione energetica di sistemi AV bifacciali.Humanity is currently facing multiple challenges due to the climate crisis, the increasing in food demand due to a global population growth and the consequently increasing demand for energy. Agrivoltaic (AV) systems, the synergistic combination of photovoltaic systems and conventional agricultural practices, represent a solution to the energy-food debate. AV systems includes installing large PV systems on agricultural land while preserving the agricultural soil for food production. The main objective of this thesis was to study the growth of crops under agrivoltaic system and their response in terms of productivity, morphology, physiology and on energy conversion throughout field activity and model simulations to support food security and sustainable agriculture worldwide across the water-energy-food nexus. On the chapters of this thesis was highlighted how agrivoltaic system can optimise electricity and food production, furthermore the main eco-physiological traits that influence the crop growth under AV system were studied and finally, were used simulation models to forecast energy and crop yield and the impact of the measured crop albedo from different crops on the energy conversion of two AV systems with bifacial PV modules

    Irrigation of Agricultural Crops with Municipal Wastewater - A Review

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    Sustainable viticulture is important for socio-economic prosperity in the Western and Northern Cape provinces of South Africa. Limited natural water resources, as well as periodic droughts in these regions necessitate the need to find alternative sources of irrigation water to sustain yield and quality. The large volumes of treated municipal wastewater generated annually holds promise as an alternative water source. Despite various treatment procedures, municipal wastewater may contain high levels of Na+, B3+, Cl- and SO42-, as well as trace elements and heavy metals. However, it often contains essential plant nutrients, e.g. N, P and K+. If treated properly, municipal wastewater may be beneficial when reused for irrigating agricultural crops. Possible benefits include recycling of nutrients, fertiliser savings, the addition of organic material, a reduced pressure on fresh water sources and reduced environmental contamination. However, high salt loads, in particular Na+, can have detrimental effects on soil physical and chemical properties, as well as crop sustainability. Therefore, it is essential to implement measures that will limit damage caused by salinity and/or sodicity. The attenuation and accumulation of toxic substances should also be managed to a minimum. Most of the information regarding treated municipal wastewater has been generated through laboratory studies using simulated wastewater, or in some cases actual wastewater. No studies have yet investigated the impact of irrigation with treated municipal wastewater under the conditions that prevail in South African grape growing regions

    Plantas de cobertura inoculadas com microrganismos multifuncionais na entressafra em sistemas de produção da região do Cerrado

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    Pr√°ticas agr√≠colas, como o uso de plantas de cobertura inoculadas com microrganismos, objetivam transformar os sistemas produtivos em ecossistemas sustent√°veis, uma vez que reduzem os impactos negativos ao ambiente e os custos de produ√ß√£o e, ao mesmo tempo, incrementam a produtividade das culturas principais por meio da melhoria nos atributos do solo. Este estudo objetivou determinar o efeito da aplica√ß√£o de rizobact√©rias ben√©ficas em plantas de cobertura cultivadas na entressafra, no ac√ļmulo de nutrientes por essas plantas e no controle de plantas daninhas. Os experimentos foram conduzidos em √°rea experimental em Santo Ant√īnio de Goi√°s, Goi√°s, nas safras 2020, 2021 e 2022, com delineamento em blocos casualizados, no esquema fatorial 2x8 e quatro repeti√ß√Ķes.¬† Os tratamentos consistiram na combina√ß√£o de 8 coberturas vegetais ((1. pousio/plantas daninhas), 2. Milho, 3. Mix 1 (Tremo√ßo Branco, Trigo Mourisco, Aveia Branca, Aveia Preta, C. ochroleuca, C. Juncea, Nabo Forrageiro, Capim coracana); 4. Mix 2 (trigo Mourisco, C. spectabiliis, nabo forrageiro, aveia preta); 5. Mix 3 (Milheto, C. ochroleuca, aveita preta, aveia branca, trigo mourisco, Capim coracana); 6. Mix 4 (C. spectabilis, trigo mourisco, milheto e C. breviflora); 7. Mix 5 (Aveia, Trigo Mourisco, Milheto, Piat√£ e C. Ocholeuca); e 8. Mix 6 (Aveia preta, Nabo Forrageiro, Tremo√ßo Branco, Capim coracana, Trigo Mourisco)) com ou sem microrganismos (rizobact√©rias Serratia marcencens (BRM 32114) + Bacillus sp. (BRM 63573)). As avalia√ß√Ķes consistiram no teor de nutrientes e biomassa seca da parte a√©rea, utilizando o teste estat√≠stico LSD (p<0,05). Coberturas vegetais, com destaque para milho, mix 4 e mix 5, tratadas com rizobact√©rias ben√©ficas aumentaram a quantidade de fitomassa, aos 60 dias ap√≥s o plantio, ac√ļmulo de macronutrientes N, P, K, Ca e Mg e micronutrientes Cu, Fe e Mn em compara√ß√£o com o tratamento pousio. Maior teor de S foi encontrado nas palhadas do mix 2 e mix 4 e de Zn nas palhadas de milho, mix 4 e mix 5, independentemente do tratamento microbiano. Al√©m disso, as coberturas vegetais proporcionaram redu√ß√Ķes na incid√™ncia de plantas daninhas. Portanto, cobertura vegetal e microrganismos multifuncionais se destacam como tecnologias sustent√°veis, uma vez que a melhoria das condi√ß√Ķes nutricionais e da quantidade de biomassa seca das plantas de cobertura podem refletir diretamente na disponibilidade de nutrientes para a cultura sucessora e maior prote√ß√£o e conte√ļdo de mat√©ria org√Ęnica para o solo

    Weed dynamics and productivity of wheat (Triticum aestivum) under various tillage and weed management practices

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    The reduced yield under conventional tillage is due to more crop-weed competition and more dry matter accumulation by the weeds (Kumar et al. 2018). Due to zero weed competition, weed-free treatments yielded the highest grain yield of all weed management practices. In contrast to this, the lowest grain yield was obtained in weedy treatment due to season-long weed competition. Maximum yield under W8 is due to broadspectrum activity of these herbicides (Sharma et al. 2014, Sunil et al. 2021). The use of zero tillage reduced weed incidence and suppression, leading to higher grain yields. Therefore, zero tillage and metsulfuron 20% wp 4 g a.i./ha + clodinafop propargyl 15% wp 60 g a.i./ha should be practiced for minimizing weed growth and maximizing the yield

    Investigation into response of wheat genotypes to drought and optimum conditions in the Eastern Cape Province, South Africa

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    Wheat is generally one of the dominant crops globally, being mainly used for human food and livestock feed. Due to climate change, drought makes it challenging to produce enough wheat mostly under dryland production regions in South Africa. Drought stress has severely reduced wheat yield by up to 70 percent, and adversely compromised wheat grain quality. The adoption of drought-tolerant cultivars offers a sustainable and low-cost solution for increasing wheat yields and minimise importing the crop to meet national requirements. The main objective of this study was to investigate the response of different wheat genotypes to drought and optimum conditions in the Eastern Cape Province, South Africa. Forty diverse wheat genotypes were evaluated in this study. The specific objectives were: (i) to evaluate the response of wheat genotypes under optimum and drought-stressed field conditions; (ii) to determine the effect of terminal drought stress on wheat grain quality composition; and (iii) to identify appropriate drought tolerance indices that can be used as selection tools under field conditions. This study was conducted in the field using a 5x8 alpha lattice design, replicated twice under two water regimes (drought and optimum) over two consecutive winter seasons of 2020 and 2021 at two different sites namely University of Fort Hare Research Farm in Alice, and Zanyokwe irrigation scheme in Keiskamahoek. Drought stress was imposed from 50% flowering up to physiological maturity. Data on agro-physiological traits such as duration to heading (DTH); flowering (DTF); maturity (DTM); plant height (HT); spike length (SL); number of spikelets per spike (SPS); kernels per spike (KPS); and grain yield (GY (kg/ha)) was subjected to the analysis of variance using Genstat 18th edition. As the study took place over two sites, a combined ANOVA table revealed significant differences (p0.001) among genotypes, and all interactions such as genotype by water regime (GWR); genotype by seasons (GS) for all studied traits. Notably, the extent and severity of drought differed between geographical regions and between seasons. This necessitated the adoption of the additive main effect and multiplicative interaction analysis (AMMI) for the identification of stable genotypes under two different water regimes over two sites. Regarding grain yield, superior and/or stable genotypes included G5 (4334 kg/ha under optimum, and 2871kg/ha under drought), and G22 (4418 kg/ha under optimum, and 2624kg/ha under drought) at the UFH site. G21 (3194 kg/ha under optimum, and 2938 kg/ha under drought), G33 (2552kg/ha under optimum, and 3810 kg/ha under drought), and G35 (2688 kg/ha under optimum, and 3309 kg/ha under drought) at the ZAN site. Stable genotypes across sites included G21 and G33. There were generally weak correlations between agro-physiological traits and grain yield. From the experiment, grain quality traits such as fixed protein (PF); wet gluten (WG); hectolitre mass (HLM); and thousand kernel weight (TKW) were also examined. A combined ANOVA revealed significant differences (p0.001) among the interaction of genotypes by environments (GE) for all traits except PF. This implies that the performance of wheat genotypes across sites was also different, and therefore, necessitated separate analysis of variance for each site. Significant differences (p0.001) among genotypes (G), water regimes (WR), and the interaction of genotypes by water regime (GWR) were observed for all studied quality traits except PF in both sites. GWR showed no significant differences for TKW in the ZAN site. The stability in the performance of genotypes across water regimes was further determined. G38 was stable for wet gluten; G31 and G26 were stable for PF; G36 was stable for HLM; and G11, G15, and G29 were stable for TKW at the UFH site. G6 was stable for both WG and PF; G13 and G15 were stable for HLM; and G35, G21, and G40 were stable for TKW at the ZAN site. These results suggest that the quality of wheat grains was affected under drought stress conditions except PF. Average grain yield data under both stressed (Ys) and optimum (Yp) conditions was used to compute a number of different drought tolerance indices. These include mean productivity (MP); geometric mean productivity (GMP); harmonic mean (HM); Tolerance index (TOL), stress susceptible index (SSI), sensitive drought index (SDI), and stress tolerance index (STI). The aim was to identify appropriate drought tolerance indices that can be used as selection tools under drought stress. MP, GMP, and HM were the more appropriate indices as they had a strong and positive correlation with grain yield under both drought and optimum conditions. However, genotypes G5, G22, G8, and G21 were more tolerant and stable as they showed high mean values. Based on the results, G19, G16, G2, and G20 were more sensitive to drought as they showed low values of MP, GMP, and HM. Overall, genotype: G5, G21, G22, and G33 are recommended for production under drought and optimum conditions, as they showed stable performance across water regimes. Principal component analysis also revealed that MP, GMP, and HM were the only indices that had positive loadings into the first principal component.Thesis (MSc) -- Faculty of Science and Agriculture, 202
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