A well-managed irrigation scheduling system needs a rapid, preCIse, simple, costeffective and non-destructive soil water content sensor. The PRl profile probe and Diviner 2000 were used to determine the timing and amount of irrigation of three cover crops (Avena sativa L., Secale cereale L. and Lolium multiflonlm Lam.), which were planted at Cedara, KwaZulu-Natal. The PRl profile probe was first calibrated in the field and also compared with the Diviner 2000. For the calibration of the PRl profile probe the factory-supplied parameters (aJ = 8.4 and ao = 1.6) showed good correlation· compared to the soil-estimated parameters (aJ = 11.04 and ao = 1.02). The factorysupplied parameters gave a linear regression coefficient (r2 ) of 0.822 and root mean square error (RMSE) of 0.062. The soil-estimated parameter showed a linear regression coefficient of 0.820 with RMSE of 0.085. The comparison between the soil water content measured using the PR1 profile probe and Diviner 2000 showed a linear regression coefficient of 0.947 to 0.964 with a range of RMSE of 0.070 to 0.109 respectively for the first 100 to 300 mm soil depths. The deeper depths (400, 600 and 1000 mm) showed a linear regression coefficient ofO.716to 0.810 with a range of 0.058 to 0.150 RMSE. These differences between the shallow and deeper depths could be due to soil variability or lack of good contact between the access tube and the surrounding soil. To undertake irrigation scheduling using the PRl profile probe and Diviner 2000, the soil water content limits were determined using field, laboratory and regression equations. The field method was done by measuring simultaneously the soil water content using the PR1 profile probe and soil water potential using a Watermark sensor and tensiometers at three depths (100, 300 and 600 mm) from a 1 m2 bare plot, while the soil dries after being completely saturated. The retentivity function was developed from these measurements and the drained upper limit was estimated to be 0.355 m3 m-3 when the drainage from the pre-wetted surface was negligible. The lower limit was calculated at -1500 kPa and it was estimated to be 0.316 m3m,3. The available soil water content, which is the difference between the upper and lower limit, was equal to 0.039 m3 m,3. In the laboratory the soil water content and matric potential were measured from the undisturbed soil samples taken from the edge of the 1 m2 bare plot before the sensors were installed. Undisturbed soil samples were taken using a core sampler from 100 to 1000 mm soil depth in three replications in 100 mm increments. These undisturbed soil samples were saturated and subjected to different matric potentials between -1 to -1500 kPa. In the laboratory, the pressure was increased after the cores attained equilibrium and weighed before being subjecting to the next matric potential. The retentivity function was then developed from these measurements. The laboratory method moved the drained upper limit to be 0.390 m3 m,3 at -33 kPa and the lower limit be 0.312 m3m-3 at -1500 kPa. The regression equation, which uses the bulk density, clay and silt percentage to calculate the soil water content at a given soil water potential, estimated the drained upper limit to be 0.295 m3m-3at -33 kPa and the lower limit 0.210 m3 m,3 at -1500 kPa. Comparison was made between the three methods using the soil water content measured at the same soil water potential. The fieldmeasured soil water content was not statistically the same with the laboratory and estimated soil water content. This was shown from the paired-t test, where the probability level (P) for the laboratory and estimated methods were 0.011 and 0.0005 respectively at 95 % level of significance. However, it showed a linear regression coefficient of 0.975 with RMSE of 0.064 when the field method was compared with the laboratory method. The field method showed a linear regression coefficient of 0.995 with RMSE of 0.035 when compared with the estimated method. The timing and amount of irrigation was determined using the PR1 profile probe and Diviner 2000. The laboratory measured retentivity function was used to define the fill (0.39 m3 m-3 ) and high refill point (0.34 m3 m-3 ). The soil water content was measured using both sensors two to three times per week starting from May 29 (149 day of year, 2002) 50 days after planting until September 20 (263 day of year) 11 days before harvesting. There were five irrigations and twenty rainfall events. The next date of irrigation was predicted graphically using, the PRl profile probe measurements, to be on 3 September (246 day of year) after the last rainfall event on 29 August (241 day of year) with 8 mm. When the Diviner 2000 was used, it predicted two days after the PRl profile probe predicted date. This difference appeared since the Diviner 2000-measured soil water content at the rooting depth was slightly higher than the PRl profile probe measurements. The amount of irrigation was estimated using two comparable methods (graphic and mathematical method). The amount of irrigation that should have been applied on 20, September (263 day of year) to bring the soil water content to field capacity was estimated to be 4.5 hand 23 mm graphically and 5.23 hand 20 mm mathematically. The difference between these two methods was caused due to the error encountered while plotting the correct line to represent the average variation in soil water content and cumulative irrigation as a function of time. More research is needed to find the cause for the very low soil water content measurements of the PRI profile probe at some depths. The research should be focused on the factors, which could affect the measurement of the PRl profile probe and Diviner 2000 like salinity, temperature, bulk density and electrical conductivity. Further research is also needed to extend the non-linear relationship between the electrical resistance of the sensor and soil water potential up to -200 kPa. This non-linear equation of the Watermark is only applicable within the range of soil water potential between -10 and -100 kPa. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2003.

The effect of continuous monoculture of sorghum, mungbean, oats, greenpanic and luceren on the nitrogen status of a brown clay soil from Narayen, South East Queensland was studied using biological and chemical methods. the soil nitrogen status was estimated by using indices of nitrogen availability i.e. waterlogged incubation method as the biological method and 2 M KCL, phosphate-borate buffer and 0.01 M CaCl_2 as rapid chemical methods. Total soil nitrogen and organic carbon were also included as estimates of soil nitrogen status. The results obtained by the waterlogged (WL) method were used to evaluate the results obtained by the three rapid chemical methods. The results show that of the three rapid chemical methods 2 M KCL was the most closely correlated with the waterlogged incubation method. Total N and organic C were also highly correlated with the WL method and they may have value as indices of nitrogen availability. The available N, total N and organic C contents in the 0-5 cm and 5-15cm layer soils were consistently higher under greenpanic and lucerne than for the annual crop treatments. The available N contents as determined by the WL method in the 0-5 cm and 5-15 cm soil layers under greenpanic and lucerne ranged from 75.6 to 126.5 ug N/g soil and 53.2 to 106.7 ug N/g soil, respectively, whereas the values under the annual crop treatments ranged from 13.2 to 75.3 ug N/g soil and 25.6 to 66.1 ug N/g soil, respectively. The total N contents in the 0-5 cm and 5-15 cm layer soils under the greenpanic and lucerne ranged from 0.29 to 0.38 % and 0.20 to 0.33 %, respectively, whereas the values under the annual crop treatments ranged from 0.17 to 0.31 % and 0.17 to 0.25 %, respectively. The availability of the total N as indicated by the available N as a percentage of the total N in the 0-5 cm and 5-15 cm layer soils under the greenpanic and lucerne ranged from 2.6 to 4.0 % and 2.1 to 3.2 %, respectively, whereas the values under the annual crop treatments ranged from 0.8 to 3.8 % and 1.5 to 2.4 %, respectively. In addition the organic C contents in the 0.5 cm and 5-15 cm layer soils under the greenpanic and lucerne range from 2.4 to 4.0 % and 2.0 to 3.5 %, respectively, whereas the values under the annual crop treatments ranged from 1.4 to 3.3 % and 1.7 to 2.7 %, respectively.

The effect of continuous monoculture of sorghum, mungbean, oats, greenpanic and luceren on the nitrogen status of a brown clay soil from Narayen, South East Queensland was studied using biological and chemical methods. the soil nitrogen status was estimated by using indices of nitrogen availability i.e. waterlogged incubation method as the biological method and 2 M KCL, phosphate-borate buffer and 0.01 M CaCl_2 as rapid chemical methods. Total soil nitrogen and organic carbon were also included as estimates of soil nitrogen status. The results obtained by the waterlogged (WL) method were used to evaluate the results obtained by the three rapid chemical methods. The results show that of the three rapid chemical methods 2 M KCL was the most closely correlated with the waterlogged incubation method. Total N and organic C were also highly correlated with the WL method and they may have value as indices of nitrogen availability. The available N, total N and organic C contents in the 0-5 cm and 5-15cm layer soils were consistently higher under greenpanic and lucerne than for the annual crop treatments. The available N contents as determined by the WL method in the 0-5 cm and 5-15 cm soil layers under greenpanic and lucerne ranged from 75.6 to 126.5 ug N/g soil and 53.2 to 106.7 ug N/g soil, respectively, whereas the values under the annual crop treatments ranged from 13.2 to 75.3 ug N/g soil and 25.6 to 66.1 ug N/g soil, respectively. The total N contents in the 0-5 cm and 5-15 cm layer soils under the greenpanic and lucerne ranged from 0.29 to 0.38 % and 0.20 to 0.33 %, respectively, whereas the values under the annual crop treatments ranged from 0.17 to 0.31 % and 0.17 to 0.25 %, respectively. The availability of the total N as indicated by the available N as a percentage of the total N in the 0-5 cm and 5-15 cm layer soils under the greenpanic and lucerne ranged from 2.6 to 4.0 % and 2.1 to 3.2 %, respectively, whereas the values under the annual crop treatments ranged from 0.8 to 3.8 % and 1.5 to 2.4 %, respectively. In addition the organic C contents in the 0.5 cm and 5-15 cm layer soils under the greenpanic and lucerne range from 2.4 to 4.0 % and 2.0 to 3.5 %, respectively, whereas the values under the annual crop treatments ranged from 1.4 to 3.3 % and 1.7 to 2.7 %, respectively.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniversitet, 2008. / Härtill 4 uppsatser.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniversitet, 2006. / Härtill 4 uppsatser.

Foram determinadas as variáveis fisiológicas (experimento 1) de três genótipos de aveia (Avena sativa L) e o valor nutricional e a cinética de produção de gases da cultivar IPR 126 (experimento 2), adubadas com níveis de 0, 180, 360 e 720 kg ha-1 de N. No experimento 1 avaliou-se a assimilação e a taxa de concentração intracelular de CO2, taxa fotossintética, teor de clorofila, relação folha/colmo, número de perfilhos/planta, número de folhas/perfilho, área foliar e a produção de biomassa dos três genótipos. O delineamento experimental utilizado foi o fatorial 3 x 4 (espécie e dose de nitrogênio), com três repetições, efetuando análise de variância e comparação de medias pelo teste de Duncan, ao nível de 5% de significância. Não houve diferença estatística entre as três cultivares para as variáveis analisadas, porém o tempo de corte apresentou diferença estatística, sendo que as melhores condições foram obtidas no segundo corte. No experimento 2 foram determinadas a composição química da cultivar IPR 126, assim como a estimativa dos parâmetros do modelo logístico bicompartimental para cinética de produção de gases (Vf1, Vf2, K1, K 2 e λ). O delineamento experimental foi blocos ao acaso, e utilizou-se o Critério de Informação de Akaike Corrigido (AICC) para a escolha da melhor matriz de variância e covariância. O nível de adubação causou aumento linear no teor de PB, e diminuição linear no teor de CT. O parâmetro λ variou de forma quadrática em função do nível de adubação. Os demais teores de nutrientes e parâmetros cinéticos não apresentaram variância significativa em função dos tratamentos. Não foi alcançada a fase assintótica da concentração de proteína, mesmo utilizando altas doses de nitrogênio. / We determined the physiological variables (experiment 1) of three oat genotypes (Avena sativa L) and the nutritional value and the gas production kinetics of cultivar IPR 126 (experiment 2), fertilized at levels of 0, 180, 360 and 720 kg N/ha. In experiment 1 we evaluated the assimilation and the rate of intracellular CO2 concentration, photosynthesis, chlorophyll content, leaf/stem ratio, number of tillers/plant, number of leaves/tiller, leaf area, and the production of biomass of the three genotypes. The experimental design was a factorial 3 x 4 (species and nitrogen dose), with three repetitions, performing variance analysis and comparison of means by Duncan test at 5% significance level. There was no statistical difference between the three cultivars for any variable, but cutting time showed statistical significance, and the best conditions were obtained in the second cut. In experiment 2 were determined the chemical composition of cultivar IPR 126 and the estimation parameters of the two-compartment logistic model for gas production kinetics (Vf1, Vf2, K1, K2 and λ). The experimental design was randomized blocks, and the Corrected Akaike Information Criterion (AICC) was used for choosing the best matrix of variance and covariance. The level of fertilization caused a linear increase in the CP content and linear reduction in TC content. The parameter λ varied in a quadratic pattern according to the level of fertilization. The other nutrient contents and kinetic parameters did not show significant variance in the treatments. The asymptotic phase of protein concentration was not reached, even using high doses of nitrogen.

Foram determinadas as variáveis fisiológicas (experimento 1) de três genótipos de aveia (Avena sativa L) e o valor nutricional e a cinética de produção de gases da cultivar IPR 126 (experimento 2), adubadas com níveis de 0, 180, 360 e 720 kg ha-1 de N. No experimento 1 avaliou-se a assimilação e a taxa de concentração intracelular de CO2, taxa fotossintética, teor de clorofila, relação folha/colmo, número de perfilhos/planta, número de folhas/perfilho, área foliar e a produção de biomassa dos três genótipos. O delineamento experimental utilizado foi o fatorial 3 x 4 (espécie e dose de nitrogênio), com três repetições, efetuando análise de variância e comparação de medias pelo teste de Duncan, ao nível de 5% de significância. Não houve diferença estatística entre as três cultivares para as variáveis analisadas, porém o tempo de corte apresentou diferença estatística, sendo que as melhores condições foram obtidas no segundo corte. No experimento 2 foram determinadas a composição química da cultivar IPR 126, assim como a estimativa dos parâmetros do modelo logístico bicompartimental para cinética de produção de gases (Vf1, Vf2, K1, K 2 e λ). O delineamento experimental foi blocos ao acaso, e utilizou-se o Critério de Informação de Akaike Corrigido (AICC) para a escolha da melhor matriz de variância e covariância. O nível de adubação causou aumento linear no teor de PB, e diminuição linear no teor de CT. O parâmetro λ variou de forma quadrática em função do nível de adubação. Os demais teores de nutrientes e parâmetros cinéticos não apresentaram variância significativa em função dos tratamentos. Não foi alcançada a fase assintótica da concentração de proteína, mesmo utilizando altas doses de nitrogênio. / We determined the physiological variables (experiment 1) of three oat genotypes (Avena sativa L) and the nutritional value and the gas production kinetics of cultivar IPR 126 (experiment 2), fertilized at levels of 0, 180, 360 and 720 kg N/ha. In experiment 1 we evaluated the assimilation and the rate of intracellular CO2 concentration, photosynthesis, chlorophyll content, leaf/stem ratio, number of tillers/plant, number of leaves/tiller, leaf area, and the production of biomass of the three genotypes. The experimental design was a factorial 3 x 4 (species and nitrogen dose), with three repetitions, performing variance analysis and comparison of means by Duncan test at 5% significance level. There was no statistical difference between the three cultivars for any variable, but cutting time showed statistical significance, and the best conditions were obtained in the second cut. In experiment 2 were determined the chemical composition of cultivar IPR 126 and the estimation parameters of the two-compartment logistic model for gas production kinetics (Vf1, Vf2, K1, K2 and λ). The experimental design was randomized blocks, and the Corrected Akaike Information Criterion (AICC) was used for choosing the best matrix of variance and covariance. The level of fertilization caused a linear increase in the CP content and linear reduction in TC content. The parameter λ varied in a quadratic pattern according to the level of fertilization. The other nutrient contents and kinetic parameters did not show significant variance in the treatments. The asymptotic phase of protein concentration was not reached, even using high doses of nitrogen.

Please read the abstract in the section 00front of this document / Dissertation (MSc Agric (Pasture Science))--University of Pretoria, 2007. / Plant Production and Soil Science / unrestricted

Para quantificar o teor de lignina em alguns cultivares de aveia, foi utilizado o método espectrofotométrico "lignina solúvel em brometo de acetila – LSBA", onde a lignina é solubilizada em uma solução a 25% de brometo de acetila em ácido acético glacial e em seguida sua absorbância lida a 280 nm; como padrão de referência foi utilizada a lignina extraída da aveia através de uma solução ácida de dioxana. A quantificação da lignina foi realizada em oito cultivares de aveia, nas frações planta inteira, caule e folha, em três estádios de maturidade (45, 55 e 65 dias de idade). Os resultados obtidos foram comparados com três métodos gravimétricos: lignina detergente ácido (LDA), lignina permanganato de potássio (LPer) e lignina Klason (LK). Os quatro métodos estudados mostraram teores de lignina diferentes entre si. Os resultados de LSBA foram superiores para quase todos os cultivares, ocorrendo o inverso para a LDA. Houve uma pequena diferença em relação aos dias de corte, com dados superiores para LSBA, onde o caule apresentou maior variação em relação às demais frações. As curvas de regressão e os espectrogramas indicaram presença de diferenças qualitativas entre as ligninas provenientes da aveia forrageira nos diferentes estádios de maturidade. / To quantify lignin content in some varieties of oat, it was employed the spectrophotometric method acetyl bromide soluble lignin – ABSL where lignin is dissolved into a 25% acetyl bromide solution in glacial acetic acid and its absorbance read at 280 nm; as a standard it was employed a, lignin extracted by mild acidic dioxane solution from the same sample. Lignin quantification was evaluated in eight oat cultivars, divided in three vegetable parts (whole plant, stem and leaf), and three different maturity stages (cuts at 45, 55 and 65 days). Obtained results were compared with three gravimetric methods: acid detergent lignin (ADL), potassium permanganate lignin (PerL) and Klason lignin (KL). All four methodologies yielded different results. Overall, ABSL yielded highest values whereas ADL yielded the lowest ones. There was a slight difference related to maturity, with higher values for ABSL, where stem fraction showed higher variation when comparing to the two other vegetable parts. Regression equations and espectrograms indicated the presence of qualitative differences between lignins from at distinct maturity stages.

El presente trabajo de investigación expone una propuesta de negocio innovadora y económicamente viable. Dentro del mercado de Lima Metropolitana se ha detectado la necesidad por el consumo de avena 100% pura, si bien en la actualidad existen productos alternativos, en el canal moderno no existe un producto de avena 100% grano entero disponible. Por parte de la población existe desconocimiento acerca de la composición del producto y los aportes nutricionales que benefician su pureza. Por ello, el objetivo de la empresa es crear conciencia en el consumidor. El 80% del mercado peruano en promedio consume avena y esto varía dependiendo el NSE al que pertenezca, en el caso NSE AB muestra 70% de consumo de avena para lo cual se busca captar mercado con un producto de mayor calidad y pureza, ya que este segmento estaría dispuesto a pagar hasta 123% más por un producto de mayor valor nutricional en comparación del resto. Bajo esa perspectiva, la empresa distribuirá y comercializará avena 100% pura desarrollando una nueva línea de productos. Para el posicionamiento y expansión de marca se plantean estrategias de gestión comercial. El modelo de negocio asegura la viabilidad de este, debido al incremento en la tendencia del consumo. Se han realizado diversos análisis cualitativos y cuantitativos, y se ha llegado a la conclusión que la demanda del segmento es inelástica, lo que es una oportunidad para la empresa y el desarrollo de la marca. / This research paper presents an innovative and economically viable business proposal. Within the Metropolitan Lima market, the need for the consumption of 100% pure oats has been detected, although there are currently alternative products, there is no 100% whole grain oat product available in the modern channel. On the part of the population there is ignorance about the composition of the product and the nutritional contributions that benefit its purity. Therefore, the objective of the company is to create awareness in the consumer. 80% of the Peruvian market on average consumes oats and this varies depending on the NSE to which it belongs, in the case NSE AB shows 70% consumption of oats for which it seeks to capture market with a product of higher quality and purity, since This segment would be willing to pay up to 123% more for a product of higher nutritional value compared to the rest. Under that perspective, the company will distribute and market 100% pure oats by developing a new product line. For the positioning and expansion of the brand, commercial management strategies are proposed. The business model ensures its viability, due to the increase in the consumption trend. Various qualitative and quantitative analyzes have been carried out, and it has been concluded that the segment's demand is inelastic, which is an opportunity for the company and the development of the brand. / Trabajo de investigación