Eddy-covariance (EC) CO₂ flux data were analysed and annual carbon (C) balances estimated for a four-year period (2004-2007) following clearcut harvesting of a boreal jack pine stand in northern Saskatchewan. The site was a source of C to the atmosphere for all years, with annual net ecosystem productivity (NEP) increasing from -153 g C m⁻² yr⁻¹ in 2004 to -63 g C m⁻² yr⁻¹ in 2007. This increase was mainly due to gross primary productivity (GPP) increasing significantly from 78 to 200 g C m⁻² yr⁻¹ , while ecosystem respiration (R) increased only slightly from 231 to 263 g C m⁻² yr⁻¹ over the same period. In the 2006 growing season (GS), a field campaign was conducted to investigate the relationships between monthly destructive measurements of leaf area index (LAI) and daily measurements of the normalized difference vegetation index (NDVI) and photosynthetic capacity (Amax). The latter was derived from 5-day, 16-day, 30-day and annual Michaelis-Menten light response analyses using daytime measurements of NEP and incident photosynthetically active radiation. Digital-camera data were used to evaluate the potential of using the rectilinear-lens vegetation index (RLVI) as a surrogate for NDVI of a young forest stand. Results showed that LAI was linearly related to NDVI and RLVI, which was largely the result of changes in the deciduous vegetation component across the GS. These results indicate that RLVI could be used as a surrogate for NDVI up to a GS maximum LAI of 0.91 m2 m⁻² observed in 2006. Measured mean (± 1 S.D.) GS LAI was 0.67 (± 0.24) m² m⁻² in 2006. LAI accounted for the majority of the variability in Amax at the 30-day time scale, while at shorter time scales air temperature was the dominant control. For 2004 to 2007, mean spring estimates of LAI were 0.25, 0.29, 0.38 (compared to 0.40 m² m⁻² from measurements) and 0.41 m² m⁻², respectively. Results suggest that a steady increase in the jack pine LAI component accounted for the annual increases in GPP and hence NEP over the four years.

Understanding variations in remote sensing data with illumination and sensor angle changes is important in agricultural crop monitoring. This research investigated field bidirectional reflectance factor (BRF) in crop differentiation and PROSAIL leaf area index (LAI) estimation. BRF and LAI data were collected for planophile and erectophile crops at three growth stages. In the solar principal plane, BRF differed optimally at 860 nm 60 days after planting (DAP) for canola and pea, at 860 nm 45 and 60 DAP for wheat and barley, and at 860 nm and 670 nm 45 and 60 DAP for planophiles versus erectophiles. The field BRF data helped better understand PROSAIL LAI estimation. NDVI was preferred for estimating LAI, however the MTVI2 vegetation index showed high sensitivity to view angles, particularly for erectophiles. The hotspot was important for crop differentiation and LAI. Availability of more along-track, off-nadir looking spaceborne sensors was recommended for agricultural crop monitoring. / xiii, 161 leaves : ill., map ; 29 cm

No description available.

During this study two models were developed to predict growth of Pinus radiata D.Don plantations in Canterbury, New Zealand. The first, CanSPBL(1.2), is a model for whole rotations of stands owned by Selwyn Plantation Limited in Canterbury. The second model, CanSPBL(water) is a hybrid growth model for the Selwyn estate in Canterbury that incorporates an index of root zone water balance over the simulation period. An existing stand growth and yield model CanSPBL was examined using a validation dataset of PSP measurements that were not used in model fitting. Projection bias was shown for mean top height, basal area per hectare, and residual stand stocking particularly for stands at elevations exceeding 450 metres. The new model, CanSPBL(1.2) showed an increase in precision of 4 - 46% over CanSPBL(1.0) at a stand level. The components of the stand model include mean top height, basal area per hectare, stems per hectare, and diameter distribution. The mortality model was made in conjunction with managers at CanSPBL to exclude catastrophic mortality events from model projections. Data used for model fitting was filtered using a mortality index based on the -3/2 power law. An examination of this model with an independent dataset showed little apparent bias. The new model, CanSPBL(water) was developed to include an index of water balance over the simulation period. Water balance estimates were made using a sub model for root zone water balance included in the hybrid physiological model 3-PG (Landsberg and Waring, 1997). The new model showed an increase in precision of 1 - 4% over CanSPBL(1.2) at a stand level (with the exception of the model for maximum diameter which showed a decrease in precision of 0.78%) using climatic inputs that included yearly variation. However the model showed increases of precision from 0.5 to 8% (with the exception of maximum diameter again, showing a decrease in precision of 0.13%) using long term monthly average climatic inputs. The components of the stand model also include mean top height, basal area per hectare, stems per hectare, and diameter distribution. The mortality model was also fitted with a data set filtered using a mortality severity index based on the -3/2 power law to exclude catastrophic mortality events. An examination of this model with an independent dataset showed little apparent bias. Two models to predict a one sided canopy leaf area index (LAI) of radiata pine stands in the Canterbury Plains of New Zealand were also developed. The models were fitted using non-linear least squares regression of LAI estimates against stem measurements and stand characteristics. LAI estimates were derived from digital analysis of fisheye lens photography. The models were kept simple to avoid computational circularity for physiological modelling applications. This study included an objective comparison and validation of a range of model types. The models CANTY (Goulding, 1995), CanSPBL(1.2) (Pinjuv, 2005), CanSPBL-water (Pinjuv, 2005), and 3-PG (Landsberg and Waring, 1997) were compared and validated with the main criteria for comparison being each model s ability to match actual historical measurements of forest growth in an independent data set. Overall, the models CanSPBL(water), and CanSPBL(1.2) performed the best in terms of basal area and mean top height prediction. Both models CanSPBL(water), and CanSPBL(1.2) showed a slightly worse fit in predictions of stocking than did the model CANTY. The hybrid model 3PG showed a better fit for the prediction of basal area than the statistically based model CANTY, but showed a worse fit for the prediction of final stocking than all other models. In terms of distribution of residuals, CanSPBL(1.2) had overall the lowest skewness, kurtosis, and all model parameters tested significant for normality. 3PG performed the worst on average, in terms of the distribution of residuals, and all models tested positively for the normality of residual distribution.

ABSTRACT Assessing the impact of herbivory on plant growth and reproduction is important to predict the success of biocontrol of invasive plants. Leaf area production is most important, as photosynthesis provides the foundation for all plant growth and fitness. High levels of defoliation generally reduce the productivity of plants. However, leaf area production fluctuates during the season and compensational growth may occur, which both complicate accurate estimations of defoliation impacts. Under field conditions the interaction with neighbouring species and the availability of soil nutrients need to be assessed in order to gauge long term effects of weed invasions on natural environments. In this thesis I have investigated seasonal leaf area dynamics in Buddleia davidii following repeated artificial defoliation, to quantify compensational leaf production and to understand the regulatory mechanisms involved. The impact of defoliation on photosynthesis, seed production, germination and nitrogen translocation patterns were analysed. Finally, possible facilitation between B. davidii and a native nitrogen fixer, Coriaria arborea, and the impact of B. davidii on soil nutrient availability were investigated. In defoliated B. davidii, increased node production (34%), leaf size (35%) and leaf longevity (12%) resulted in 52% greater total emergent leaf area in the short term. However, with time and diminishing tissue resources the compensation declined. No upregulation of photosynthesis was observed in pre-existing leaves. Compensational leaf area production occurred at the expense of reproduction but the germination capacity of individual seeds was unaffected. In B. davidii, nitrogen reserves are stored in old leaves. Thus, the defoliation-induced decline in tissue reserves led to changes in the remobilisation pattern and increased the importance of soil uptake but biomass production especially that of roots had declined significantly (39%). Slight facilitation effects from the neighbouring nitrogen fixer and VA-mycorrhizae were observed on B. davidii in the field, while its impact on soil chemistry during spring was negligible. Defoliation of B. davidii resulted in priority allocation of resources to compensational leaf growth and a concomitant reduction in flower and seed production. The compensational leaf production greatly increased the demand for nitrogen, while continued leaf removal decreased the pool of stored nitrogen. This led to changes in nitrogen remobilisation and an increased importance of root uptake. However, the significant decline in root growth will likely impair adequate nutrient uptake from the soil, which is especially important where B. davidii invades nutrient poor habitats and will increase the success of biocontrol of the species. While mycorrhizae increase nutrient accessibility for B. davidii, it is likely that the additional stress of defoliation will negate the small facilitative effects from nitrogen-fixing species like C. arborea. This research provides new insights into the mechanisms regulating leaf area dynamics at the shoot level and systemic physiological responses to defoliation in plants, such as nitrogen translocation. The compensation in leaf area production was considerable but only transitory and thus, the opportunity to alleviate effects of leaf loss though adjustment of light capture limited. However, to ascertain that photosynthesis at whole plant level does not increase after defoliation, more detailed measurements especially on new grown leaves are necessary. In general, defoliation had greatly reduced plant growth and performance so that an optimistic outlook for controlling this species can be given. Conclusions about the wider impacts of B. davidii on soil chemistry and community function will require further research.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniversitet, 2005. / Härtill 4 uppsatser.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The objectives of this dissertation were to determine the phyllochron, the final leaf number on the main stem and the duration of developmental stages to characterize leaf growth during the developmental cycle and to determine the tuber yield of tenadvanced potato clones of the Potato Breeding and Genetics Program of the Universidade Federal de Santa Maria (UFSM) and two potato cultivars grown in spring and fall conditions in Santa Maria, Depression Central Region of the Rio Grande do Sul State. Two field experiments were conducted during Spring 2010 and Fall 2011 at the experimental field of the, Santa Maria, RS. The advanced potato clones were: SMINIA 00017-6, SMINIA 793101-3, SMINIA 02106-11, SJSM 00211-3, SJSM 03478-37, SJSM 01212-2, SJSM 01274-4, SJSM 04503-9, SJSM 02349 - 1 and SJSM 02317-3. The two potato cultivars were Asterix and Macaca. The planting density was 3.79 hills m-2. The experiment was a complete randomized block design with seven replications. After emergence, four plants in each plot were marked and on these plants the number of leaves on the main stem were counted twice a week and on one of these plants the length of the leaves was measured once a week to determine the green leaf area index. Tuber initiation was determined by collecting four plants of each clone at the border rows. The phyllochron was calculated by the inverse of the slope of the linear regression between leaf number and accumulated thermal time. Power-like nonlinear models were used to relate leaf length and leaf area. For determining tuber yield all the hills were used. The phyllochron varied from 17.0°C to 21.5°C day leaf the in Spring and from 14.8°C to 22.1° C in the Fall. There are differences of the duration of vegetative and tuberization phases and the final leaf number among clones, cultivars and growing seasons. The evolution of leaf area index throughout the developmental cycle was different in the advanced clones and in the cultivars during the two growing seasons. The of advanced clones showed high tuber yield in both Spring and Fall growing seasons. / Os objetivos nesta dissertação foram determinar o filocrono, o número final de folhas na haste principal e a duração das fases de desenvolvimento, caracterizar o crescimento foliar durante o ciclo de desenvolvimento e determinar a produtividade de tubérculos de dez clones avançados do Programa de Genética e Melhoramento de Batata da Universidade Federal de Santa Maria (UFSM) e de duas cultivares de batata em cultivo de primavera e outono em Santa Maria, região da Depressão Central do Rio Grande do Sul (RS). Dois experimentos de campo foram conduzidos durante a primavera de 2010 e o outono de 2011, na área experimental do Departamento de Fitotecnia da UFSM, Santa Maria, RS. Foram utilizados os clones avançados SMINIA 00017-6, SMINIA 793101-3, SMINIA 02106-11, SJSM 00211-3, SJSM 03478-37, SJSM 01212-2, SJSM 01274-4, SJSM 04503-9, SJSM 02349-1 e SJSM 02317-3 selecionadas pelo Programa de Genética e Melhoramento de Batata da UFSM e as cultivares Asterix e Macaca. A densidade de plantio foi de 3,79 covas m-2. O delineamento experimental utilizado foi o de blocos ao acaso com sete repetições. Após a emergência, quatro plantas em cada parcela foram identificadas com anel colorido e nestas foram contadas, duas vezes por semana, o número de folhas na haste principal e, em uma destas plantas, semanalmente foi medido o comprimento das folhas para determinação do índice de área foliar verde. A data do início da tuberização foi determinada coletando-se a cada dois dias quatro plantas de cada clone nas linhas da bordadura. O filocrono foi calculado pelo inverso do coeficiente angular da regressão linear entre o número de folhas e a soma térmica acumulada. Obtiveram-se modelos não lineares do tipo potência para relacionar o comprimento das folhas com o índice de área foliar. Para determinação da produtividade foram utilizadas todas as covas da parcela. O filocrono variou de 17,0°C a 21,5°C dia folha-1, no cultivo de primavera, e de 14,8°C a 22,1°C dia folha-1, no cultivo de outono. Houve diferença na duração das fases vegetativa e de tuberização e do número final de folhas entre os clones avançados, as cultivares e as épocas de cultivo. A evolução do índice de área foliar foi diferente ao longo do ciclo de desenvolvimento nos clones avançados e nas cultivares nas duas épocas de cultivo. No cultivo de primavera e no cultivo de outono os clones avançados apresentaram elevada produtividade de tubérculos de batata.

Submitted by Claudia Rocha (claudia.rocha@udesc.br) on 2018-02-09T12:25:49Z No. of bitstreams: 1 PGCA15MA192.pdf: 1575532 bytes, checksum: 64b6fd74ab7e674270e1107fbb51b295 (MD5) / Made available in DSpace on 2018-02-09T12:25:49Z (GMT). No. of bitstreams: 1 PGCA15MA192.pdf: 1575532 bytes, checksum: 64b6fd74ab7e674270e1107fbb51b295 (MD5) Previous issue date: 2015-12-15 / UNIEDU / FUMDES / The pastures regrowth is a continuous event-dependent and leaf area, as this characteristic affects the growth processes. Accordingly, removal of the leaf area (frequency and magnitude) over a period occupancy must provide forage accumulation effects. Thus, the aim of this study was to evaluate the effect of defoliation on concomitant herbage accumulation of grass-Kikuyu swards (Pennisetum clandestinum Hochst. Ex. Chiov.) Under intermittent stocking, testing the hypothesis that there is a reduction in herbage accumulation during the lowering of pastures. The objective of Experiment II was to evaluate the effect of removing leaves fully expanded at the stretching expanding leaves testing the hypothesis that the leaf elongation expanding terminates immediately when all fully expanded leaves are defoliated in oat pastures (Avena strigosa). Treatments consisted of four proportions of defoliation (40, 50, 60 and 70% relative to the initial height) combined at the same height in pre-grazing (20 cm). The experimental design was a randomized complete block design with three replications. Each paddock was busy for heifers and dry cows of the Dutch race in the form of daily strip (2), with periods of occupation of 24 hours and supply of 3 kg DM / 100 kg BW above the desired residue. The rates of growth processes and herbage accumulation were determined by tillers technique marked (20 tillers / track), and the field of readings taken at four moments during the occupation (08:00, 12:00, 18:00, 8:00). In addition, 10 tillers / track were excluded from grazing (using exclusion cages) and evaluated in their morphogenetic rhythms, for the derivation of some data. The variables studied were: elongation rate; proportion of fully expanded leaves and leafless expansion; forage accumulation rate. The effects (linear, quadratic and cubic) of defoliation severity were assessed with the help of orthogonal polynomial contrasts generated by the IML procedure of SAS statistical package for treatments not equidistant. The significance level was 5%. The severity of defoliation targets were not achieved effectively, but a contrast between them was established (40, 46,54% of initial height) having some effect on the viable analyzed (P <0.05). It was found that there was a linear effect between the proportion of leaf area index removed and elongation of leaf blades a day and that consequently the greater leaf area removal negatively affect forage accumulation of pickets with the presence of animals. The percentage of leaf blades bare in treatments with higher proportion kneeling directly affected forage accumulation rate per day. It was concluded that the main determinant that affects the forage accumulation during the occupation period is the rate of IAF removed, and that the occupation reduces forage accumulation. Already with the second experiment it concluded that with the removal of all tiller leaves the fully expanded leaf elongation reduces instantly expanding leaves / A rebrotação de pastos é um evento contínuo e dependente da área foliar, uma vez que tal característica influencia os processos de crescimento de plantas forrageiras. A remoção da área foliar (frequência e magnitude) verificada durante um período de ocupação deve apresentar efeitos no acúmulo de forragem. Sendo assim, o objetivo desse trabalho foi avaliar o efeito da desfolhação no concomitante acúmulo de forragem em pastos de capim-quicuiu (Pennisetum clandestinum Hochst. Ex. Chiov.) sob lotação intermitente (experimento I). Adicionalmente, um ensaio foi realizado para testar o efeito da remoção de folhas totalmente expandidas no alongamento de folhas em expansão (experimento II). Os tratamentos do experimento I consistiram de quatro proporções de desfolhação (40, 50, 60 e 70% em relação à altura inicial) combinadas a uma mesma altura em pré-pastejo (20 cm). Os tratamentos do experimento II basearam-se na desfolhação (10 perfilhos) ou não (10 perfilhos) de todas as folhas totalmente expandidas do perfilho. O delineamento experimental foi de blocos completos casualisados com três repetições. Cada piquete foi ocupado por novilhas e vacas secas da raça Holandês na forma de faixa diária (2), com períodos de ocupação de 24 horas e oferta de 3 kg de MS/100 kg PV acima do resíduo pretendido para o experimento I. As taxas dos processos de crescimento e acúmulo de forragem foram determinadas através da técnica de perfilhos marcados, sendo as leituras de campo realizadas em quatro momentos durante a ocupação (08:00, 12:00, 18:00, 08:00). Adicionalmente, 10 perfilhos/faixa foram excluídos do pastejo (com o uso de gaiolas de exclusão) e avaliados em seus ritmos morfogênicos, para a derivação de alguns dados. As variáveis estudadas foram: taxa de alongamento; proporção de folhas totalmente expandidas e em expansão desfolhadas; taxa de acúmulo de forragem. Os efeitos (linear, quadrático e cúbico) da severidade de desfolhação foram avaliados com o auxílio de contrastes de polinômios ortogonais gerado pelo procedimento IML do pacote estatístico SAS para tratamentos não equidistantes. O nível designificância foi de 5%. As metas de severidade de desfolhação não foram efetivamente alcançadas, mas um contraste entre elas foi criado (40, 46, 48, 54% da altura inicial), apresentando efeito sobre a proporção de folhas em expansão e expandidas desfolhadas (P < 0,05). As variáveis de crescimento e produção não responderam significativamente (P > 0,05) às severidades de desfolhação alcançadas, mas variaram de acordo com a proporção do IAF removido (P < 0,05). Com o aumento da proporção de IAF removido, houve uma redução no alongamento de lâminas foliares e no acúmulo de forragem. No experimento II foi verificado que com a remoção de todas as folhas expandidas, houve uma redução na taxa de alongamento foliar nos primeiros dois dias após sua remoção. É possível concluir com o experimento I que o principal determinante que compromete o acúmulo de forragem durante o período de ocupação é a porcentagem do IAF removido, e que a ocupação reduz o acúmulo de forragem. Já com o experimento II foi possível concluir que com a remoção de todas as folhas completamente expandidas dos perfilhos o alongamento de lâmina foliar de folhas em expansão reduz instantaneamente

A relação entre o microclima e a vegetação tem sido explorada sob os mais variados pontos de vista. Raros são os trabalhos deste tipo, que consideram mais de um tipo de floresta, e em situação natural. Este trabalho avalia de forma detalhada a temperatura do ar, e sua relação com a estrutura da vegetação da maior Unidade de Conservação particular do País, a RPPN SESC Pantanal. Esta Unidade de Conservação se localiza em uma área continental tropical de grande importância para a conservação biológica, o Pantanal de Mato Grosso no centro-oeste do Brasil. Foi mensurada a estrutura de cinco formações florestais (Cambarazal, Mata com Acuri, Mata Densa, Tabocal e Mata Seca) e uma savânica (Campo com Murundus). Com uso de sensores de temperatura acoplados a data loggers e instalados dentro das formações, realizou-se comparações com um campo aberto, que funcionou como controle durante toda a amostragem. Para testar a influência da estrutura da vegetação no microclima, foram realizadas cinco regressões lineares múltiplas, onde a variável dependente era a diferença da temperatura registrada em campo aberto (delta) e de 36 unidades amostrais (6 por formação). Como variáveis preditivas foram empregados dados estruturais levantados nas mesmas. Foram observadas diferenças estruturais significativas entre as seis formações. Através dos dados de vegetação e de temperatura foi possível separar as formações vegetais em três grupos distintos; o das formações semi-abertas (Campo com Murundus, Tabocal e Mata Seca), abertas (campo aberto usado como controle dos dados meteorológicos) e das formações fechadas com coberturas de dosséis densos (Cambarazal, Mata com Acuri e Mata Densa). Foram encontradas diferenças térmicas superiores a 10ºC para todas as formações em relação ao campo aberto (exceto Campo com Murundu). As maiores diferenças foram registradas nos períodos de aquecimento e resfriamento dos dias. A explicação para isto está na grande velocidade de incremento e perda de calor do campo frente às demais formações que apresentaram maior estabilidade térmica. As regressões múltiplas revelaram um poder de explicação entre 43,3 e % e 63,8% e revelaram que o índice de área foliar (LAI) como a variável preditiva mais importantes para variações térmicas. / The relation between microclimate and vegetation has been explored under the most varied points of view. However, studies that consider more than one type of forest are rare, mainly in natural situation. This study evaluates in detail the air temperature and its relation to the vegetation structure of the largest Private Reserve of the Natural Wealth owned by de Social Service of Commerce, the RPPN SESC Pantanal. It is located in a tropical continental area of great importance for biological conservation, the Pantanal of Mato Grosso in mid-west of Brazil. The structure of five types of forest formations (Cambarazal, Mata com Acuri, Mata Densa, Tabocal e Mata Seca) and one savanna (Campo com Murundus) was measured. Temperature sensors coupled to data loggers were installed inside each of the vegetal formations as well as one station at open field to be used as control. To test influence of vegetation structure on microclimate, five multiple linear regressions were performed. The response variable was the temperature difference between recorded in open field and each of the 36 sampling units (6 by formation). Predictive variables were structural data verified at the same places. The difference in vegetation structure between the six types of vegetation was significant. The analysis of vegetation and temperature data allowed to distinguish the vegetal formations in three distinct groups: partialy open (Campo com Murundus, Tabocal e Mata Seca); open areas (open field); closed formations (Cambarazal, Mata com Acuri e Mata Densa). Thermal differences greater than 10°C were found for all vegetal formations when compared to open field (except for Campo com Murundu). The largest differences were recorded during the daily periods of warming (morning) and cooling (afternoon). The reason is the high speed of increment and loss of heat in open field relative to the other formations that showed higher thermal stability. The multiple regressions revealed a power of explanation between 43,3% and 63,8% and revealed the leaf area index (LAI) as the most important predictive variable to the thermal variations.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The water management is a major practical possibilities to achieve significant increases in productivity unchanged in terms of occupied area. For the floricultural industry despite being considered a competitive and profitable activity, studies on the optimal water needs for different species is scarce, and studies and research. Thus the present study aims to identify water management suitable for crop production Alstroemeria x hybrida in pots with substrate. Analyzing its response in yield and quality of the buds. The experiment was conducted under controlled conditions in the Floriculture Industry Polytechnic College of UFSM - RS. They were used vessels of 20 l, with one plant per pot Alstroemeria x hybrida, variety Firenze. The experimental design was completely randomized, with 16 replications and five treatments, totaling 80 experimental units. Throughout the cycle evaluations were made (destruction) of a vessel of each treatment to monitor the development of both shoot (leaf area) and the underground part (rhizomatous structure). Comparison of the results was performed by analysis of variance and regression using the software SISVAR. To evaluate the water consumption were set limits 30, 45, 60, 75 and 90% of the maximum water retention of the substrate in the vessel (CRV), and verified the measurement of moisture of each vessel by the method of weighings of each vessel individually, seven days irrigation interval. The evaluated factors of production were: length and diameter of flowering stems; fresh and dry weight, number of flowers, leaf area and root development. They also determined the reference evapotranspiration and crop coefficient (Kc) in different phenological stages. The results showed that water consumption is larger as the availability rises and is influenced by weather conditions; the crop coefficient (Kc) showed average values of 0.39 and 0.41 for the growing season and early flowering respectively 0.95 for flowering 1.51 for the full flowering and 0.74 for the fall of flowering; water availability of 90% is recommended for the production of long stems, the parameters number of flowers and diameter of the buds did not differ between treatments. The water availability changes all the root structure of Alstroemeria; It is not advised commercial cultivation of Alstroemeria on vessels of up to 20 l. / A prática de manejo da irrigação é uma das principais possibilidades para a obtenção de aumentos significativos de produtividade sem mudança em termos de área ocupada. Para o ramo da floricultura apesar de ser considerada uma atividade competitiva e rentável, os estudos sobre a necessidade ideal de água para as diferentes espécies é escasso, sendo necessários estudos e pesquisas. Assim o presente trabalho tem por objetivo identificar o manejo de água adequado para produção da cultura de Alstroemeria x hybrida em vasos com substrato. Analisando sua resposta sob rendimento e qualidade das hastes florais. O experimento foi conduzido em estufa climatizada no Setor de Floricultura do Colégio Politécnico da UFSM RS. Foram usados vasos de 20 l, com uma planta por vaso de Alstroemeria x hybrida, da variedade Firenze. O delineamento experimental foi inteiramente casualisado, com 16 repetições e cinco tratamentos, totalizando 80 unidades experimentais. Ao longo do ciclo foram feitas avaliações (destruições) de um vaso de cada tratamento para acompanhar o desenvolvimento tanto da parte aérea (área foliar) como da parte subterrânea (estrutura rizomatosa). A comparação dos resultados foi realizada através de análise de variância e regressão utilizando-se o software SISVAR. Para avaliar o consumo de água foram estipulados limites de 30, 45, 60, 75 e 90% da capacidade máxima de retenção de água pelo substrato no vaso (CRV), sendo verificada a medida da umidade de cada vaso pelo método das pesagens de cada vaso individualmente, com turno de rega de sete dias. Os fatores de produção avaliados foram: comprimento e diâmetro das hastes floríferas; massa fresca e seca, quantidade de flores, área foliar e desenvolvimento radicular. Também foram determinados a evapotranspiração de referência e o coeficiente de cultura (Kc) nos diferentes estágios fenológicos. Os resultados obtidos mostraram que o consumo de água é maior à medida que a disponibilidade se eleva e é influenciado pelas condições meteorológicas; o coeficiente da cultura (Kc) apontou valores médios de 0,39 e 0,41 para a fase vegetativa e início da floração respectivamente, 0,95 para o florescimento, 1,51 para o pleno florescimento e 0,74 para a queda do florescimento; a disponibilidade hídrica de 90% é recomendada para a produção de hastes longas, os parâmetros número de flores e diâmetro das hastes florais não diferiram entre os tratamentos. A disponibilidade hídrica altera toda a estrutura radicular da alstroemeria; não é aconselhado o cultivo comercial de alstroemeria em vasos de até 20 l.