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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Improving dryland maize (Zea mays L.) water productivity in the Chokwe District of Mozambique through better nutrient management

Sitoe, Manuel Mulhuli January 2011 (has links)
The southern region of Mozambique is characterized by arid to semi-arid climatic conditions with soils of poor fertility and low water retention capacity. The rainfall season is from September to April. In some areas, the rain season accommodates two production cycles, which is augmented by extended or unexpected rains in May and June. Maize is the main crop in this region. The major limiting factors for maize production in the Chókwè District under rainfed agriculture are rainfall amount and its distribution and soil fertility. Water productivity in this region is very low. The Challenge Program on Water and Food (CPWF), for which the slogan was “more crop per drop”, has attempted to identify and address water productivity constraints throughout the Limpopo River Basin (LRB). This study considers the water productivity in dryland areas, assuming that yields may not be only limited by water, but also by soil fertility. The study was aimed at investigating the improvement of water productivity by correcting nutrient deficiencies and recommending strategies to mitigate these deficiencies. A field experiment was conducted at Chókwè Agrarian Research Centre with maize cultivar (cv. Matuba). Matuba was selected because of its high tolerance to drought. Treatments were based on the most limiting soil nutrients at the experimental site. Crop parameters measured included total dry matter, fractional interception of photosynthetically active radiation (FIPAR), leaf area and grain yield. In addition, the Soil Water Balance (SWB) model was used to simulate potential yields with no nutrient limitations. Results of this study illustrated that the application of N resulted in improvements in total dry matter yield, leaf area index (LAI), FIPAR and water use efficiency (WUE). Application of both N and P improved the grain yield, leaf area duration (LAD) and WUE. SWB model simulations indicate that in only 1 out of 5 years in Chókwè District, the simulated yields were not higher compared to actual yields (0.2 - 1 ton ha-1). In conclusion, grain yield improvements are expected if nutrition is kept at optimum levels. This implies that in most years dryland yields are in fact nutrient limited and better nutrition can be used as a strategy to improve water productivity (WP) and grain yield / Dissertation (MSc Agric)--University of Pretoria, 2011. / gm2014 / Plant Production and Soil Science / unrestricted
2

Increased water productivity in irrigated tomato production in the smallholder farming community of Giyani

Pienaar, Cornelis Jacobus 04 1900 (has links)
Thesis (MScAgric)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: The availability of water for irrigation purposes is becoming a serious concern for smallholder famers in the former homeland areas of South Africa. Not only because of global weather change and the occurrence of more erratic weather events, but also due to competition for fresh water between the agricultural, industrial and domestic sectors (Hamdy et al., 2003). Food production increases in smallholder agriculture is seen as a possible solution to the food security challenges in the rural areas of the Limpopo Province (Altman et al., 2009). Smallholder farmers in Giyani mostly use traditional furrow irrigation systems and their farm crop productivity remains very low, compared to commercial farms in the same area. The objective of this study is to utilize and test various innovation technologies aimed at increasing Water Productivity (WP) in order to facilitate better irrigation management of the available water resources. The study was conducted on two farms, Zava Cooperative Garden and Mzilela Cooperative Garden, in the rural areas of Giyani over a two year period from 2012-2013. This study seeks to achieve the objective in three distinct ways. Firstly, the use of NIR technology is used to evaluate the prediction ability of soil chemical parameters for fertilizer requirement calculations. Secondly, WP trials were conducted on smallholder tomato (Solanum lycopersicum) production for three consecutive seasons, evaluating their current tomato crop production systems and also testing new innovations for WP increases. Thirdly, applying the MonQI methodology, inputs and outputs of all crop production sites were done to monitor the cropping systems throughout the period of the research. The results from this study indicate the importance of applying new innovations amongst smallholder production systems. Important findings from the NIR technologies indicated that this innovation can improve soil nutrient management in a more affordable, user friendly manner. The results showed that good prediction models were obtained for pH (KCl), electrical conductivity (EC), P, K, Mg, Na and CEC, with R2 and RPD values larger than 0.60 and 1.4 respectively. The prediction of exchangeable Ca was less successful with a R2 value of 0.43. Results from the WP trials suggest that drip irrigation performed better than furrow irrigation in terms of yield and WP. Yield and WP were very low for all treatments, being below 32 t/ha and 5.2 kg/m-3 respectively. Improved management practices, such as soil nutrient management and mulching were introduced in the 2nd and 3rd seasons of tomato trials in order to increase WP at field level at Mzilela farm. Results showed tomato yield increased from an average of 26.5 t/ha to 120.9 t/ha and WP increases from 4.61kg/m-3 to 17.69 kg/m-3. Deep drainage of water out of the rootzone decreased with better irrigation management. The results from the monitoring of inputs and output of their cropping systems revealed that smallholder farmers, using traditional farming practices, yielded very low and mostly below 5 t/ha for all crops. Some crops were totally lost due to hail and heat-waves. NPK balances for conventional cropping by the smallholder farmers at Mzilela was in the range of 0 to -70 kg/ha. The tomato production fertilized treatment of the 1st, 2nd and 3rd WP trials, showed positive nutrient balance results for P and K in the range of 80 to 140 kg/ha. N balances were mostly negative for all plots. NFI was R2768 and R4740 for season 1 and 3 respectively, while the 2nd season results showed a loss of - R5176. With the improved yield from the WP trial sites, and the fruits being sold to the Spar, the NFI increased to R42486 in the final season. The study concludes that great improvements in yield, WP and NFI are attainable and sustainable amongst smallholder farmers in the Giyani area. / AFRIKAANSE OPSOMMING: Die beskikbaarheid van water hulpbronne vir besproeiings doeleindes onder kleinskaalse boere in die voormalige tuislande is besig om ernstige bekommernisse te wek. Nie net as gevolg van globale weer veranderinge en meer gereelde ekstreme weer toestande nie, maar ook as gevolg van die kompetisie tussen die landbou, industriële en huishoudelike sektore vir water gebruike (Hamdy et al., 2003). Verhoogde voedsel produksie onder die kleinskaalse landbou sektor word gesien as moontlike oplossing vir die voedsel sekuriteit uitdagings in die platteland areas van die Limpopo Provinsie in Suid-Afrika (Altman et al., 2009). Kleinskaalse boere in Giyani gebruik meestal tradisionele voor-besproeiings stelsels en hul produktiwiteit bly steeds baie laag wanneer dit met kommersiële boerderye vergelyk word. Die hoofdoel van hierdie studie is om Water Produktiwiteit (WP) te bestudeer en verskeie innovasie tegnologieë te toets om beter besproeiing bestuur van kosbare water bronne te fasiliteer. Die studie was uitgevoer op twee plase, naamlik Zava Koöperatiewe Tuin en Mzilela Koöperatiewe Tuin, wat in die plattelandse areas van Giyani geleë is en die studie is gedoen oor ‘n periode van twee jaar vanaf 2012 tot 2013. Om hierdie doelwit te bereik was die navorsing in drie eenhede uitgevoer. Eerstens sal Naby-Infra Rooi (NIR) tegnologie gebruik word om die voorspelling vermoë van grond chemiese eienskappe te toets vir meer effektiewe grond voedingstof bestuur deur kleinboere. Tweedens sal WP proewe uitgevoer word op kleinskaalse tamatie (Solanum lycopersicum) produksie. Die huidige tamatie gewasproduksie stelsels was getoets om die WP statusse te evalueer van hul tradisionele bestuurs praktyke van beide drip- en voorbesproeiings stelsels. Laastens, is insette en uitsette van die kleinboere se produksie stelsels met die MonQI metodologie bestudeer om die huidige produksie sisteme te evalueer, sowel as die WP proef persele, deur opbrengs, grond voedingstof balanse en netto plaas inkomste (NPI) te moniteer en te bereken vir 4 half jaar seisoene gedurende die navorsings periode. Die resultate van die navorsing voer aan dat die gebruik van innovasie tegnologieë onder kleinskaalse boerderystelsels ontsettend belangrik is vir verbeterde produksie. Hoofbevindings van die NIR tegnologie dui dat meer doeltreffende grond voedingstof bestuur moontlik is en wat goedkoper en meer gebruikersvriendelik is vir kleinboere. Hierdie tegniek het goeie voorspelbaarheid-modelle getoon vir pH (KCl), Elektriese Geleiding (EG), P, K, Mg, Na en katioon uitruilings kapasiteit (KUK) met R2 en RPD waardes hoër as 0.60 en 1.4 onderskeidelik. Die voorspelbaarheid van Ca was minder suksesvol met ‘n R2 waarde van 0.43. Die resultate van die WP toetse wys dat drip besproeiing beter as voorbesproeiing presteer het in terme van opbrengs en WP. Opbrengs en WP was baie laag vir alle behandelings van seisoen 1, met waardes laer as 32 t/ha en 5.2 kg/m-3 onderskeidelik. Verbeterde bestuurspraktyke, soos grond voedingstof bestuur asook die gebruik van ‘n deklaag, was in die 2de en 3rde seisoen toegepas om opbrengs en WP te verhoog op plaasskaal op Mziela plaas. Resultate het gewys dat opbrengs verhoog het van ‘n gemiddelde van 26.5 t/ha tot 120.9 t/ha en WP verhoging van 4.61 kg/m-3 tot 17.69 kg/m-3. In terme van die insette en uitsette van die produksie sisteme het opbrengste van alle gewasse, wat nog van tradisionele metodes gebruik, laer as 5 t/ha getoon. Soms van die totale oeste verloor deur hael of hittegolwe. Die NPK balanse vir die gewasverbouing met konvensionele kleinboer metodes was in die orde van 0 tot -70 kg/ha. Die kunsmis behandelings van die tamatie proewe van die 1ste, 2de en 3rde WP seisoene het positiewe balanse getoon vir P en K in die orde van 80 tot 140 kg/ha. Die N balanse was meestal negatief vir alle verbouings persele. Die NPI was R2768 en R4740 vir seisoen 1 en 3 onderskeidelik, terwyl die 2de seisoen verlies van -R5176 getoon het. Die verbeteringe in opbrengs met die WP proewe en met die verkoop van die tamaties aan die Spar was die NPI vir die 4de seisoen R42486. Die studie sluit dat daar groot moontlikehede is vir verhoging in opbrengs, WP en NPI onder kleinboere in die Giyani area.
3

Manejo de irrigação em diferentes fases de desenvolvimento da Calendula officinalis L. / Irrigation management in differents phases of development of Calendula officinalis L.

Aleman, Catariny Cabral 10 April 2015 (has links)
A calêndula é uma planta medicinal de grande importância para indústria cosmética e farmacêutica. Existem poucos estudos sobre as necessidades hídricas e nutricionais das plantas medicinais. O controle do potencial matricial de água no solo pode ser uma alternativa de manejo de irrigação que favoreça a qualidade e produção de metabólitos secundários. O objetivo do experimento foi avaliar a resposta fisiológica e bioquímica da Calendula officinalis L. submetida a vários níveis de potencial matricial de água no solo para manejo da irrigação em três diferentes fases de desenvolvimento. O experimento foi conduzido em ambiente protegido sem controle de temperatura e umidade na Escola Superior de Agricultura \"Luiz de Queiroz\", Piracicaba, São Paulo. O delineamento experimental foi em blocos ao acaso com 6 tratamentos e 4 repetições, totalizando 24 unidades experimentais. Foram utilizadas sementes de calêndula bonina sortida para produção de mudas. As mudas foram transplantadas para vasos de 8 L para condução do experimento. Os potenciais matriciais adotados foram: -10, -15, -30, -40, -50 e -60 kPa. Foram realizados três ensaios distintos definidos de acordo com a fase de desenvolvimento: ciclo completo, fase vegetativa e fase reprodutiva/florescimento. O controle do potencial matricial de água no solo foi realizado utilizando tensiômetros de punção previamente instalados na profundidade de 20 cm. As leituras foram realizadas uma vez por semana com auxílio de tensímetro, desde o transplantio até a senescência das plantas. As irrigações foram realizadas por sistema de irrigação por gotejamento com gotejadores autocompensantes com vazão média de 3,92 L h-1. Os parâmetros analisados foram: taxa de crescimento relativo, massa seca de parte aérea, comprimento de raiz, volume de raiz, massa seca de raiz, produção de capítulos florais, massa seca de capítulos florais, relação raiz/parte aérea, produtividade de água, teor e rendimento de flavonoides totais e concentração de prolina. Os dados obtidos foram submetidos ao teste F, ao teste de normalidade de Komogorov-Smirnov e ao teste de Scott- Knott para comparação de médias. Os parâmetros que apresentaram diferenças entre os tratamentos foram submetidos à regressão. Foi utilizado o pacote estatístico Assistat 7.7 Beta. A taxa de crescimento relativo, a massa seca de parte aérea, o volume e massa seca de raiz, e a produção de capítulos florais apresentaram diferenças significativas apenas para o ensaio com estresse hídrico durante todo ciclo de desenvolvimento da calêndula. Para essas variáveis a diminuição da disponibilidade de água no solo apresentou resultados negativos para a planta. A massa seca de capítulos florais foi superior para o potencial matricial de -10 kPa durante a fase reprodutiva e ciclo completo. A produtividade de água foi superior para os potenciais matriciais de -30 e -40 kPa no ciclo completo e fase reprodutiva. O rendimento de flavonoides e a concentração de prolina apresentaram resultados inversamente proporcionais. A redução do rendimento de flavonoides com o decréscimo da disponibilidade de água no solo favoreceu o aumento da prolina. / Calendula is a medicinal plant of great importance in cosmetic and pharmaceutical industry. There are few studies on hydric and nutritional requirement of medicinal plants. The control of water with soil matric potential can be an alternative to the irrigation management that improve the quality and production of secondary metabolites. The objective of the experiment was to evaluate the physiological and biochemical response of Calendula officinalis L. subjected to various degree of water stress soil water for irrigation management in three different stages of development. The experiment was conducted in a greenhouse without temperature and humidity control in the Escola Superior de Agricultura \"Luiz de Queiroz\", Piracicaba, São Paulo. The experimental design was a randomized block design with 6 treatments and 4 repetitions, totaling 24 experimental units. The calendula bonina sortida seed were used to produce seedlings. The seedlings were transplanted to 8 L vessels to conduct the experiment. The potential matrices adopted were: -10, -15, -30, -40, -50 and -60 kPa. Three different tests were performed according to defined stages of development: full cycle, vegetative phase and reproductive/flowering stage. The control of the matric potential of soil water was performed using punch tensiometers previously installed at a depth of 20 cm. The measurements were performed with a tensiometer once a week, beginning the transplanting until senescence of plants. The irrigation was drip irrigation system with drip with flow of 4 L h-1. The parameters analyzed were: relative growth rate, dry weight of shoot, root length, root volume, root dry weight, production of floral chapters, dry mass of flower heads, root/shoot, water productivity, content and yield of total flavonoids and concentration of proline. The data were submitted to the test F, the normality test Komogorov -Smirnov and the Scott -Knott test for comparison of means. The parameters that show differences between treatments were submitted to regression. We used the statistical package Assistat 7.7 Beta . The relative growth rate, shoot dry weight, volume and root dry weight, and the production of floral chapter showed significant differences only for test water stress throughout the marigold development cycle. For these variables, decreased water availability in the soil was negative for the plant. The dry mass of floral chapter was superior to the matric potential of - 10 kPa during the reproductive phase and full cycle. The productivity of water was higher for the matric potentials of -30 and -40 kPa in the complete cycle and reproductive phase. The yield of flavonoids and proline concentration showed inversely proportional results. The reduction in the yield of flavonoids with decreased water availability occurred an increase of proline.
4

Fertirrigação em minimelancia (citrullus lanatus) tutorada em ambiente protegido / Fertirrigation in mini watermelon (Citrullus lanatus) supported in protected environment

Nogueira, Carlos César Pereira 24 October 2008 (has links)
As minimelancias foram desenvolvidas para atender a uma demanda por frutos de menor tamanho, mais fáceis de transportar e mais adequadas ao consumo de pequenas famílias. A produção comercial de melancia sob cultivo protegido no Brasil ainda é incipiente. O cultivo vertical, mesmo que dispendioso em razão da demanda de mão-de-obra, facilita as operações nos tratos culturais e permite ganho em produtividade por meio do aumento da densidade de plantas, além de melhorar a qualidade de frutos. Para esse sistema de produção de melancia, pouco se dispõe de informações técnicas. Foram realizados dois experimentos: o primeiro visando determinar a demanda evapotranspirativa, a eficiência de uso da água e os efeitos de cinco níveis de nitrogênio e cinco níveis de potássio em de três relações N: K, na produção e qualidade de frutos; o segundo experimento teve o objetivo de avaliar os efeitos de três tratamentos de fertilizantes em três sistemas de condução de planta e a obtenção das curvas de acúmulo de massa seca e acúmulo de nutrientes. No primeiro ciclo observou-se uma tendência de a relação 1:2 ser mais produtiva e, também, de as doses próximas às mais baixas produzirem mais. Com relação à demanda evapotranspirativa, o maior consumo diário registrado foi de 1,295 L, enquanto o consumo total médio ao final do ciclo foi de 26,48 L planta-1, com eficiência de uso da água de 21,8 L kg-1, melhor que os resultados mais promissores encontrados na literatura. No segundo ciclo, os sistemas de condução de plantas 1 e 3 foram mais precoces em até 22 dias e o sistema de condução 2 proporcionou maior produtividade e maior acúmulo de massa seca para as três soluções nutritivas. Em ordem decrescente, o acúmulo de nutrientes apresentou respectivamente: K > N > Ca > P > Mg > S > Fe > Mn > Zn > B > Cu. O custo de produção de um ciclo nesse sistema foi de R$ 17.538,82, sendo 60,47 % o custo da infra-estrutura física. Baseando-se na menor produção prevista, o preço de mercado não deve ser inferior a R$ 0,77 kg-1 para o produtor cobrir seus custos. / Mini watermelon was developed to supply demand for smaller fruit size, easier to carry and more appropriate to use by small families, as a result it has high added value. Commercial production of watermelon under protected cultivation is still new in Brazil. Vertical growing is costly due to labour cost; however it facilitates cultural practices and allows higher productivity by increasing density of plants, in addition to improving fruit quality. Technical information for this production system is scarce. Two experiments were carried out, the first one determined evapotranspiration demand, water-use efficiency and effects of five levels of nitrogen and potassium with three relations N:K, as well as production and fruit quality. The second experiment evaluated effects of three fertilizers levels in three plant conduction systems and accumulation curves of dry mass and nutrients were fitted. In the first cycle the ratio 1:2 trended to be more productive and lower dosages had high production. In this cycle the maximum daily water consumption was 1295 L, while average total consumption at the end of cycle was 26.64 L/plant and water-use efficiency was 21.9 L/kg, which is upper than the best results obtained in past studies. In the second cycle, one and three types of plant conduction systems were earlier in up to 22 days, and two type of plant conduction system provided higher productivity and greater accumulation of dry mass for three nutrient solutions. In order of importance the accumulation of nutrients presented respectively: K > N > Ca > P > Mg > S > Fe > Mn > Zn > B > Cu. Production cost of one cycle in this system was US$ 11,100.00 with 60.47% of referring to cost of physical infrastructure. Based on lower production predicted, the market price should not be less than US$ 0.49 kg-1, for cover production costs.
5

Agricultural resource efficiency and reduction of impacts under land-use and climate change scenarios in Brazil / Eficiência do uso de recursos e redução de impactos da atividade agrícola sob cenários de mudança de uso da terra e climática no Brasil

Schwantes, Ana Paula 27 June 2017 (has links)
Cerrado is the second largest Brazilian biome and originally corresponded to 24% of the national territory, and since the 1970´s has been under agriculture and cattle activities. Soybean and maize are two of the most important grain-crops found in this region, with an estimated production of approximately 223 millions of tons in the Brazilian 2016/17 harvest. Changes in soil physical properties due to soil management affect productivity. Possible changes in climatic variables may also affect agricultural productivity, either per unit area (land productivity) or per unit of water volume (water productivity). One option for studying the relation between land and water productivity and how they are affected by soil hydraulic properties and climatic factors is by using an agro-hydrological model. In this study, the aim was to quantify aspects of the soil water balance and to make estimates of land and water productivity for soybean in a clay soil and maize in a medium texture in the Cerrado region using SWAP simulations for different irrigation strategies. Effects on agricultural productivity of a climatic prevision with increasing the air temperature and rainfall reduction for the years 2016-2040 were also simulated. Results show that an increase of soil porosity, resulting from a conservation tillage management, leads to a higher infiltration capacity and is shown to increase land and water productivity, when associated to irrigation scenarios. Higher water productivities were observed with only supplementary irrigation. Predicted climate changes will lead to a decrease of approximately 20% by the end of the years 2016-2040 in land productivity, under rainfed conditions. / O Cerrado é o segundo maior bioma brasileiro que originalmente, correspondia a 24% do território nacional, e desde os anos 1970 tem sido utilizado para atividades ligadas à agricultura e pecuária. Soja e milho são duas das mais importantes culturas graníferas encontradas nesta região, com uma estimativa de produtividade de aproximadamente 223 milhoes de toneladas na safra brasileira de 2016/17. Mudanças nas propriedades físicas do solo devido ao manejo do solo afetam a produtividade agrícola. Possíveis mudanças de variáveis climáticas também poderão afetar a produtividade agrícola, tanto por unidade de área (produtividade de terra) ou por unidade de volume de água (produtividade de água). Uma opção para estudar as relações entre a produtividade de água e de terra e como elas são afetadas pelas propriedades hidraulicas do solo e pelos fatores climáticos é pela utilização de um modelo agro-hidrológico. Neste trabalho, o objetivo foi quantificar os aspectos do balanço hídrico do solo e realizar estimativas da produtividade de água e de terra para soja em um solo argiloso e para milho em um solo de textura média, na região do Cerrado, utilizando simulações com o modelo SWAP para diferentes manejos de irrigação. Os efeitos na produtividade agrícola de uma previsão climática com aumento da temperatura do ar e redução da precipitação para os anos 2016-2040 foram também simulados. Os resultados mostram que um aumento na porosidade do solo, resultante de um manejo conservacionista do solo, leva a uma maior infiltração e resulta num aumento na produtividade da terra e da água, quando associado a cenários de irrigação. As maiores produtividades da água foram observadas com irrigação suplementar. As mudanças climáticas previstas levarão a uma diminuição de aproximadamente 20% na produtividade da terra ao final dos anos 2016-2040, em áreas não irrigadas.
6

Analyzing Irrigation District Water Productivity by Benchmarking Current Operations Using Remote Sensing and Simulation of Alternative Water Delivery Scenarios

van Opstal, Jonna D. 01 May 2016 (has links)
Irrigation systems are designed to deliver water to crops, but their efficacy varies widely due to operational decisions, weather variability, and water availability. The operation of an irrigation system is studied in this dissertation to determine irrigation performance and potential for improvement.Satellite remote-sensing was used to determine inter-annual variability in crop evapotranspiration and link it with weather patterns and operational decisions. A decade was studied to include several dry, wet and average years of snowfall. It was found that the irrigation district has the capacity to buffer a dry year, but crop evapotranspiration patterns indicated that the buffer capacity of the irrigation district is limited in a second dry year. Studying the current operations of an irrigation system also requires an analysis of the spatial variability within the system to identify potential areas for improvement. Achieving such information is challenging due to the spatial heterogeneity between farm fields. The Ador irrigation system simulation model is used in this study with satellite remote sensing data, which were combined in the calibration and validation process to ease the re-adjustment of management parameters. This approach provides a cost-effective and innovative method for model simulation when field observations are limited. Alternative water delivery scenarios were simulated with the Ador irrigation system simulation model to quantify changes in the water balance, irrigation performance, and water productivity. Results for implementing a minimal irrigation time indicated that irrigation events occurred with a higher frequency and reduced crop water stress. Water productivity for the irrigation district increased substantially in this scenario, whilst district water savings were achieved by diverting less irrigation water. Advantages are only achieved if farmers collectively make the decision to change. A water accounting analysis is required to examine if water savings are achieved at basin scale. There is a potential for the rebound effect to occur, which suggests that an increase of water efficiency causes the increase of water consumption. Simulation results indicated that if the efficiency is increased through improvements of the water delivery, the water consumption increased. Water savings achieved by reducing irrigation diversions did not compensate for the decrease in drainage that downstream users depend on.
7

Manejo de irrigação em diferentes fases de desenvolvimento da Calendula officinalis L. / Irrigation management in differents phases of development of Calendula officinalis L.

Catariny Cabral Aleman 10 April 2015 (has links)
A calêndula é uma planta medicinal de grande importância para indústria cosmética e farmacêutica. Existem poucos estudos sobre as necessidades hídricas e nutricionais das plantas medicinais. O controle do potencial matricial de água no solo pode ser uma alternativa de manejo de irrigação que favoreça a qualidade e produção de metabólitos secundários. O objetivo do experimento foi avaliar a resposta fisiológica e bioquímica da Calendula officinalis L. submetida a vários níveis de potencial matricial de água no solo para manejo da irrigação em três diferentes fases de desenvolvimento. O experimento foi conduzido em ambiente protegido sem controle de temperatura e umidade na Escola Superior de Agricultura \"Luiz de Queiroz\", Piracicaba, São Paulo. O delineamento experimental foi em blocos ao acaso com 6 tratamentos e 4 repetições, totalizando 24 unidades experimentais. Foram utilizadas sementes de calêndula bonina sortida para produção de mudas. As mudas foram transplantadas para vasos de 8 L para condução do experimento. Os potenciais matriciais adotados foram: -10, -15, -30, -40, -50 e -60 kPa. Foram realizados três ensaios distintos definidos de acordo com a fase de desenvolvimento: ciclo completo, fase vegetativa e fase reprodutiva/florescimento. O controle do potencial matricial de água no solo foi realizado utilizando tensiômetros de punção previamente instalados na profundidade de 20 cm. As leituras foram realizadas uma vez por semana com auxílio de tensímetro, desde o transplantio até a senescência das plantas. As irrigações foram realizadas por sistema de irrigação por gotejamento com gotejadores autocompensantes com vazão média de 3,92 L h-1. Os parâmetros analisados foram: taxa de crescimento relativo, massa seca de parte aérea, comprimento de raiz, volume de raiz, massa seca de raiz, produção de capítulos florais, massa seca de capítulos florais, relação raiz/parte aérea, produtividade de água, teor e rendimento de flavonoides totais e concentração de prolina. Os dados obtidos foram submetidos ao teste F, ao teste de normalidade de Komogorov-Smirnov e ao teste de Scott- Knott para comparação de médias. Os parâmetros que apresentaram diferenças entre os tratamentos foram submetidos à regressão. Foi utilizado o pacote estatístico Assistat 7.7 Beta. A taxa de crescimento relativo, a massa seca de parte aérea, o volume e massa seca de raiz, e a produção de capítulos florais apresentaram diferenças significativas apenas para o ensaio com estresse hídrico durante todo ciclo de desenvolvimento da calêndula. Para essas variáveis a diminuição da disponibilidade de água no solo apresentou resultados negativos para a planta. A massa seca de capítulos florais foi superior para o potencial matricial de -10 kPa durante a fase reprodutiva e ciclo completo. A produtividade de água foi superior para os potenciais matriciais de -30 e -40 kPa no ciclo completo e fase reprodutiva. O rendimento de flavonoides e a concentração de prolina apresentaram resultados inversamente proporcionais. A redução do rendimento de flavonoides com o decréscimo da disponibilidade de água no solo favoreceu o aumento da prolina. / Calendula is a medicinal plant of great importance in cosmetic and pharmaceutical industry. There are few studies on hydric and nutritional requirement of medicinal plants. The control of water with soil matric potential can be an alternative to the irrigation management that improve the quality and production of secondary metabolites. The objective of the experiment was to evaluate the physiological and biochemical response of Calendula officinalis L. subjected to various degree of water stress soil water for irrigation management in three different stages of development. The experiment was conducted in a greenhouse without temperature and humidity control in the Escola Superior de Agricultura \"Luiz de Queiroz\", Piracicaba, São Paulo. The experimental design was a randomized block design with 6 treatments and 4 repetitions, totaling 24 experimental units. The calendula bonina sortida seed were used to produce seedlings. The seedlings were transplanted to 8 L vessels to conduct the experiment. The potential matrices adopted were: -10, -15, -30, -40, -50 and -60 kPa. Three different tests were performed according to defined stages of development: full cycle, vegetative phase and reproductive/flowering stage. The control of the matric potential of soil water was performed using punch tensiometers previously installed at a depth of 20 cm. The measurements were performed with a tensiometer once a week, beginning the transplanting until senescence of plants. The irrigation was drip irrigation system with drip with flow of 4 L h-1. The parameters analyzed were: relative growth rate, dry weight of shoot, root length, root volume, root dry weight, production of floral chapters, dry mass of flower heads, root/shoot, water productivity, content and yield of total flavonoids and concentration of proline. The data were submitted to the test F, the normality test Komogorov -Smirnov and the Scott -Knott test for comparison of means. The parameters that show differences between treatments were submitted to regression. We used the statistical package Assistat 7.7 Beta . The relative growth rate, shoot dry weight, volume and root dry weight, and the production of floral chapter showed significant differences only for test water stress throughout the marigold development cycle. For these variables, decreased water availability in the soil was negative for the plant. The dry mass of floral chapter was superior to the matric potential of - 10 kPa during the reproductive phase and full cycle. The productivity of water was higher for the matric potentials of -30 and -40 kPa in the complete cycle and reproductive phase. The yield of flavonoids and proline concentration showed inversely proportional results. The reduction in the yield of flavonoids with decreased water availability occurred an increase of proline.
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Agricultural resource efficiency and reduction of impacts under land-use and climate change scenarios in Brazil / Eficiência do uso de recursos e redução de impactos da atividade agrícola sob cenários de mudança de uso da terra e climática no Brasil

Ana Paula Schwantes 27 June 2017 (has links)
Cerrado is the second largest Brazilian biome and originally corresponded to 24% of the national territory, and since the 1970´s has been under agriculture and cattle activities. Soybean and maize are two of the most important grain-crops found in this region, with an estimated production of approximately 223 millions of tons in the Brazilian 2016/17 harvest. Changes in soil physical properties due to soil management affect productivity. Possible changes in climatic variables may also affect agricultural productivity, either per unit area (land productivity) or per unit of water volume (water productivity). One option for studying the relation between land and water productivity and how they are affected by soil hydraulic properties and climatic factors is by using an agro-hydrological model. In this study, the aim was to quantify aspects of the soil water balance and to make estimates of land and water productivity for soybean in a clay soil and maize in a medium texture in the Cerrado region using SWAP simulations for different irrigation strategies. Effects on agricultural productivity of a climatic prevision with increasing the air temperature and rainfall reduction for the years 2016-2040 were also simulated. Results show that an increase of soil porosity, resulting from a conservation tillage management, leads to a higher infiltration capacity and is shown to increase land and water productivity, when associated to irrigation scenarios. Higher water productivities were observed with only supplementary irrigation. Predicted climate changes will lead to a decrease of approximately 20% by the end of the years 2016-2040 in land productivity, under rainfed conditions. / O Cerrado é o segundo maior bioma brasileiro que originalmente, correspondia a 24% do território nacional, e desde os anos 1970 tem sido utilizado para atividades ligadas à agricultura e pecuária. Soja e milho são duas das mais importantes culturas graníferas encontradas nesta região, com uma estimativa de produtividade de aproximadamente 223 milhoes de toneladas na safra brasileira de 2016/17. Mudanças nas propriedades físicas do solo devido ao manejo do solo afetam a produtividade agrícola. Possíveis mudanças de variáveis climáticas também poderão afetar a produtividade agrícola, tanto por unidade de área (produtividade de terra) ou por unidade de volume de água (produtividade de água). Uma opção para estudar as relações entre a produtividade de água e de terra e como elas são afetadas pelas propriedades hidraulicas do solo e pelos fatores climáticos é pela utilização de um modelo agro-hidrológico. Neste trabalho, o objetivo foi quantificar os aspectos do balanço hídrico do solo e realizar estimativas da produtividade de água e de terra para soja em um solo argiloso e para milho em um solo de textura média, na região do Cerrado, utilizando simulações com o modelo SWAP para diferentes manejos de irrigação. Os efeitos na produtividade agrícola de uma previsão climática com aumento da temperatura do ar e redução da precipitação para os anos 2016-2040 foram também simulados. Os resultados mostram que um aumento na porosidade do solo, resultante de um manejo conservacionista do solo, leva a uma maior infiltração e resulta num aumento na produtividade da terra e da água, quando associado a cenários de irrigação. As maiores produtividades da água foram observadas com irrigação suplementar. As mudanças climáticas previstas levarão a uma diminuição de aproximadamente 20% na produtividade da terra ao final dos anos 2016-2040, em áreas não irrigadas.
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Fertirrigação em minimelancia (citrullus lanatus) tutorada em ambiente protegido / Fertirrigation in mini watermelon (Citrullus lanatus) supported in protected environment

Carlos César Pereira Nogueira 24 October 2008 (has links)
As minimelancias foram desenvolvidas para atender a uma demanda por frutos de menor tamanho, mais fáceis de transportar e mais adequadas ao consumo de pequenas famílias. A produção comercial de melancia sob cultivo protegido no Brasil ainda é incipiente. O cultivo vertical, mesmo que dispendioso em razão da demanda de mão-de-obra, facilita as operações nos tratos culturais e permite ganho em produtividade por meio do aumento da densidade de plantas, além de melhorar a qualidade de frutos. Para esse sistema de produção de melancia, pouco se dispõe de informações técnicas. Foram realizados dois experimentos: o primeiro visando determinar a demanda evapotranspirativa, a eficiência de uso da água e os efeitos de cinco níveis de nitrogênio e cinco níveis de potássio em de três relações N: K, na produção e qualidade de frutos; o segundo experimento teve o objetivo de avaliar os efeitos de três tratamentos de fertilizantes em três sistemas de condução de planta e a obtenção das curvas de acúmulo de massa seca e acúmulo de nutrientes. No primeiro ciclo observou-se uma tendência de a relação 1:2 ser mais produtiva e, também, de as doses próximas às mais baixas produzirem mais. Com relação à demanda evapotranspirativa, o maior consumo diário registrado foi de 1,295 L, enquanto o consumo total médio ao final do ciclo foi de 26,48 L planta-1, com eficiência de uso da água de 21,8 L kg-1, melhor que os resultados mais promissores encontrados na literatura. No segundo ciclo, os sistemas de condução de plantas 1 e 3 foram mais precoces em até 22 dias e o sistema de condução 2 proporcionou maior produtividade e maior acúmulo de massa seca para as três soluções nutritivas. Em ordem decrescente, o acúmulo de nutrientes apresentou respectivamente: K > N > Ca > P > Mg > S > Fe > Mn > Zn > B > Cu. O custo de produção de um ciclo nesse sistema foi de R$ 17.538,82, sendo 60,47 % o custo da infra-estrutura física. Baseando-se na menor produção prevista, o preço de mercado não deve ser inferior a R$ 0,77 kg-1 para o produtor cobrir seus custos. / Mini watermelon was developed to supply demand for smaller fruit size, easier to carry and more appropriate to use by small families, as a result it has high added value. Commercial production of watermelon under protected cultivation is still new in Brazil. Vertical growing is costly due to labour cost; however it facilitates cultural practices and allows higher productivity by increasing density of plants, in addition to improving fruit quality. Technical information for this production system is scarce. Two experiments were carried out, the first one determined evapotranspiration demand, water-use efficiency and effects of five levels of nitrogen and potassium with three relations N:K, as well as production and fruit quality. The second experiment evaluated effects of three fertilizers levels in three plant conduction systems and accumulation curves of dry mass and nutrients were fitted. In the first cycle the ratio 1:2 trended to be more productive and lower dosages had high production. In this cycle the maximum daily water consumption was 1295 L, while average total consumption at the end of cycle was 26.64 L/plant and water-use efficiency was 21.9 L/kg, which is upper than the best results obtained in past studies. In the second cycle, one and three types of plant conduction systems were earlier in up to 22 days, and two type of plant conduction system provided higher productivity and greater accumulation of dry mass for three nutrient solutions. In order of importance the accumulation of nutrients presented respectively: K > N > Ca > P > Mg > S > Fe > Mn > Zn > B > Cu. Production cost of one cycle in this system was US$ 11,100.00 with 60.47% of referring to cost of physical infrastructure. Based on lower production predicted, the market price should not be less than US$ 0.49 kg-1, for cover production costs.
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The water footprint of selected crops within the Olifants/Doorn Catchment, South Africa

Manamathela, Sibongile Amelia January 2014 (has links)
>Magister Scientiae - MSc / Rapidly increasing global population is adding more pressure to the agricultural sector to produce more food to meet growing demands. However the sector is already faced with a challenge to reduce freshwater utilisation as this sector is currently using approximately 70% of global water freshwater resources. In South Africa, the agriculture sector utilizes approximately 62% of freshwater resources and contributes directly about5% to the Gross Domestic Product. South Africa is a water scarce country receiving less than 500mm/year of precipitation in most parts of the country, and consequently approximately 90% of the crops are grown under irrigation. Studies have evaluated irrigation practices and crop water use in the country. However information is lacking on the full impact of South African horticultural products on freshwater resources. The water footprint concept can be used to indicate the total and source (blue/green) of water used to produce the crops. Information about water footprint (WF) can be used for identifying opportunities to reduce the water consumption associated with production of vegetables and fruits at the field to farm- gate levels, including the more effective use of rainfall (green water) as opposed to water abstracted from rivers and groundwater (Blue water). It can also be used to understand water related risks associated with the production of crops and facilitate water allocation and management at catchment/water management scale. While the potential value of water footprint information is well recognized there is still inadequate knowledge on how best to determine the water footprints of various crops within a local context. The aim of this study was to determine the water footprint and the crop water productivity of navel oranges, pink lady apples and potatoes produced with the Olifant/Doorn water management area in South Africa.The water footprint of the navel oranges, pink lady apples and potatoes assessed following the water footprint network method was 125 litres/ kg, 108 litres/kg and 65 litres/ kg respectively. The study concluded that water footprint studies should be carried out on the whole catchment instead of one farm in order to assess the sustainability of the process.

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