No description available.

The purpose of this study was to assess the validity, as well as to test novel approaches to improving the reliability, of mechanical response tissue analysis (MRTA). Twenty composite tibiae underwent MRTA testing on three separate days to determine intra- and inter-day reliability of bending stiffness. The bones were then subjected to three-point bending tests to directly determine elastic modulus. Within- and between-day reliability of tibial bending stiffness with MRTA was moderate (CV = 24%) and poor (CV = 74%), respectively. No relationship was observed between the two testing methods due to the wide variation in tibial bending stiffness values with MRTA. The second part of the study sought to determine within- and between-day reliability of MRTA in young women with the current testing protocol and compare the results with those from newly-designed protocols. Twelve women (23 ± 2 yr, 162 ± 7 cm, 57 ± 7kg, 19 ± 4 % fat) were tested for tibial bending stiffness with MRTA over 5 days. The current protocol was compared to protocols where day-to-day subject positioning was quantified, subjects were tested in a supine position, and various bending stiffness prediction models were used. Within- (CV = 20%) and between-day (CV = 19%) reliability of tibial bending stiffness with MRTA was moderate using the original methodology. Modifications to this protocol either resulted in similar or worse reliability. / Ph. D.

Mechanical response tissue analysis (MRTA) provides a noninvasive means of estimating the cross-sectional bending stiffness (EI) of long bones, and thus can serve as a predictor of bone strength. Estimates of bone bending stiffness are derived from the point impedance response of a long bone to low frequency (70-500Hz) stimulation according to beam vibration theory. MRTA has demonstrated the ability to reliably estimate human ulnar bending stiffness with between-test coefficients of variation of 5%, and in vivo measurements of monkey tibiae have been validated with ex vivo 3-point mechanical bending tests. Human tibial MRTA measurement has achieved between-trial coefficients of variation of only 12%, so a new physical MRTA configuration and improved computer algorithms have been developed in an attempt to improve upon this level of reliability. The new configuration removes the rigid proximal and distal tibial restraints and models the tissue behavior with a 12-parameter algorithm that accounts for free vibration at the ankle and knee joints. Initial testing with only the hardware changes and application of the 7-parameter model of tissue behavior used in earlier systems yielded unacceptable variation. Subsequent reliability testing with application of 6-, 9-, and 12-parameter models demonstrated modest improvements, prompting the development of the more robust 12-parameter model used in the present study. Evaluation of 110 college-age females (age 20.2±1.8 yr, height 163.3±5.9 cm, weight 60.7±9.3 kg, BMI 22.8±3.1 kg·m⁻²) with the current MRTA system has demonstrated an improvement in within-trial reliability for unsupported tibial EI measurement with a coefficient of variation of 11.2%. These results demonstrate the ability of the system to measure tibial response characteristics when both proximal and distal ends are free of rigid support. Long-term measurement reliability is still problematic with a coefficient of variation of 36.5% for a set of 4 measurements spanning 21 months. / Ph. D.

The relationship between soil and wine quality has been recognized for generations but has had limited scientific validation. Vineyard soils in the eastern United States are largely unstudied although proper site selection and good soil management have the potential to improve fruit composition for high-quality wine production. Soils that provide excessive plant-available nutrients and water often produce vigorous vegetative growth and negatively influence fruit chemistry. We investigated three aspects of Eastern vineyard soils, including potassium availability, methods of reducing infiltration, and the influence of topsoil on fruit chemistry. Our first goal was to determine the best soil sampling, processing, and extraction methods for predicting potassium availability in Mid-Atlantic vineyard soils. Excessive potassium can result in high pH fruit, which negatively affects wine quality, but until now the best methods for predicting soil-available potassium had not been investigated. We found that moist-extracted soil sampled from 0-38 cm appear to best be suited predicting vine tissue potassium. Our second goal was to test methods of reducing rain infiltration at critical times during the growing season. One of the soil stabilizers we tested successfully reduced infiltration in field trials. Vineyard trials in 2021 were compromised by dry weather, but further research is ongoing. Our final project involved a three-year investigation where we attempted to isolate the influence of soil properties on grapevines and fruit composition by monitoring vines and fruit in single vineyard blocks. The most consistent result was positive relationships between topsoil and fruit titratable acidity, suggesting that the fruit was ripening earlier in vines growing in thinner topsoil. Topsoil depth better explained differences in fruit titratable acidity than other explanatory variables including crop load and sunlight exposure of fruit. Overall, this research increased our understanding of the soil properties that influence vine growth and fruit chemistry in the Eastern US. The results will help growers improve sampling methods, fruit chemistry, and increase resilience to soil and climate related challenges. / Doctor of Philosophy / The relationship between grapes, wine, and soil has been acknowledged since the Middle Ages when monks recognized that vineyards in different places produced different-tasting wine. However, it is difficult to determine exactly how soil affects grapes and wine. In the eastern United States, growers knew that some soils were not the best for growing high quality grapes for wine, such as those that provide excessive nutrients or water to the vines, but there was little information or scientific research about it. We wanted to help growers by investigating soil properties that affect fruit quality as well as potential soil management strategies that could improve fruit quality. We fine-tuned the process of collecting, processing, and analyzing vineyard samples that growers use to determine the potassium status of their vines. Potassium can affect fruit quality so testing for it before it can affect fruit quality is crucial. We found that sampling soil to a deeper depth than usual and keeping the sample moist instead of drying it were the best practices. We also determined the best way to complete the lab analysis to best predict how much potassium the soil can provide to the vines. For our second project, we found that commercial material intended for stabilizing dirt roads slowed the seeping of rain into soil. Future research will see if vineyards can use the soil stabilizer to reduce soil water during mid-summer rains to improve fruit quality. Our final project involved monitoring vineyards over three years to see how differences in soil properties affected vine growth and fruit chemistry. The main difference in soil was the thickness of topsoil throughout each vineyard. Where there was thin topsoil, the vines were smaller and produced fruit that was less acidic. These results are likely because those fruit were ripening earlier, but we were not able to identify a specific soil property that was affecting the fruit chemistry. Overall, our results will help vineyard growers better manage their soil to hopefully produce better-quality fruit and wine.

The purpose of this randomized controlled trial was to investigate temporal skeletal responses to short-term high intensity physical activity. Twenty-eight normal active females [age: 20.7 +/- 2.1 yr (mean +/- SD)] were randomized into exercise (EX, n = 15) or control (CN, n = 13) groups. The exercise group trained 6 days/wk for 6 wk, which consisted of maximal isokinetic knee flexion/extension 3 days/wk, combined with 3 days/wk running. The purpose was to expose the tibiae to a period of abruptly increased loading forces. Tibial bending stiffness (EIMRTA), and serum concentrations of biochemical markers of bone formation [osteocalcin (OC)], and bone resorption [n-telopeptide of type I collagen (NTx)] were measured at baseline, 2 wks, 4 wks, and 6 wks. Isokinetic concentric knee extension/flexion peak torque, as well as total body and site-specific bone mineral density (BMD) were measured at baseline and 6 wk. After training, the exercise group significantly increased (p < 0.05) isokinetic concentric peak torque for the dominant (13.6%) and non-dominant (5.7%) quadriceps, as well as dominant (7.7%) and non-dominant (9.5%) hamstrings, compared to the controls. No differences for total body or site-specific BMD were noted. A two-way multivariate repeated measures ANOVA revealed no timeâ ¢group interactions for composite tibial bending stiffness [(EIMRTA); p = 0.57] or the biochemical markers of bone turnover [(OC and NTx); p = 0.15] across the four sampling periods. While there were no main effects for group, a trend for time (p = 0.051) for composite EIMRTA was observed. The exercise group demonstrated a 20% increase in EIMRTA from baseline (74.8 +/- 22.3 Nm2) to 6 wk (89.8 +/- 24 Nm2), compared to controls who demonstrated a 4% increase (Baseline 86.5 +/- 23.8 Nm2; 6 wk 90 +/- 23.7 Nm2). Significant group differences (p = 0.05) were noted for OC, but not NTx. Differences (p < 0.05) for OC were observed at baseline [13.2 +/- 2.4 ng/ml (CN), 15.6 +/- 2.7 ng/ml (EX)], and follow-up ANCOVA revealed no differences for subsequent sampling periods. Main effects for time were found for OC and NTx (p < 0.001). Main effects for time in OC were attributable to changes in the exercise group (p < 0.01) and NTx (p < 0.01), but not the control group. / Ph. D.

The distribution and occurrence of plant species within a given region provides insight into the many environmental properties of that region. Although much research has been conducted on plant communities and associated environmental properties, few studies have been conducted on the characteristics of individual plants within those communities. Calcareous fens are wetlands formed by the upwelling of mineral-rich groundwater and often are associated with many unique plant communities and rare species of flora and fauna. Although many studies have documented the vegetation patterns and associated environmental gradients of these fens, none have isolated the specific hydrogeochemical conditions associated with individual species, nor have any studies attempted to document and compare the individual physiological response of species to elevated environmental calcium levels. This research was conducted to estimate environmental calcium requirements for rare as well as common indicator species of calcareous fens of Massachusetts and to examine the relationship between the accumulation of calcium in the tissues of these species to calcium availability in their environment. These factors will be important when determining required conditions for fen restoration and will further the understanding of why these species often only occur in calcareous fens. Eight calcareous fen study sites at three different locations were established where calciphiles occur in western Massachusetts. In each site, data were collected on the vegetation patterns and associated soil chemistry, water chemistry, and hydrology. In addition, plant tissues were collected and analyzed for calcium. Species distributions were evaluated as to whether they increased in abundance as environmental calcium did or whether they appeared to occur only once a specific calcium threshold was met. In addition, the concentrations of calcium in the tissues were used to determine the extent to which those plants accumulated calcium and how those levels related to levels of calcium in the substrate environment and to their overall distributions. It was found that certain calciphiles are calcium specialists, i.e. they are more abundant when environmental calcium levels are elevated, absorb greater quantities of calcium and those quantities correlate to the available environmental supply. These species include Parnassia glauca, Packera aurea, Geum rivale and Carex granularis. Of these, Geum rivale and Carex granularis, as well as Carex sterilis, did not occur below calcium concentrations of 48 mg.L-1. However, other calciphiles are calcium generalists, i.e. they are tolerant of elevated calcium levels but show no other relationship with respect to growth or accumulation. These species include Carex flava, Carex hystericina, Juncus nodosus, Solidago patula, Solidago uliginosa, and Symphyotrichum puniceum. In addition, some wetland generalists maintain elevated calcium levels (Symplocarpus foetidus and Mentha arvensis) whereas most others do not (Thelypteris palustris and Fragaria vesca). Of the calciphile and wetland generalist species, some appear to increase in abundance in calcareous fens in relation to increases in accessory benefits (Dasiphora fruticosa and Juncus brachycephalus with pH; Thelypteris palustris and Carex flava with magnesium and possibly Equisetum fluviatile with iron). Combined, these findings characterize the growth habits and calcium accumulation of species that grow in calcareous fens and indicate that calciphiles have varying degrees of dependence on calcium.

Mechanical Response Tissue Analysis (MRTA) is an emerging technology for assessing maximal bending stiffness (EI) of human long bones in vivo. The MRTA variable, EI, is the product of Young's modulus of elasticity (E) and cross-sectional moment of inertia (I). EI quantifies material and architectural/geometric properties of bone. Published human research using MRTA to measure EI has been limited to the ulna; however, the tibia requires further investigation due to its central involvement in many human activities and exercise-related clinical problems, e.g. stress fracture of the lower leg. To evaluate the inter- and intra-reliability of tibial EI, 22 healthy women (X + SD: 20.8 + 1.8 yr) were assessed twice daily for three non-consecutive days. Each daily session consisted of five repeated trials. The ulnar EI protocol of McCabe et al. [J Bone and Mineral Res. 1991;6(1):53-59] was adapted to assess tibial EI via MRTA. A significant difference was not found in scores for five repeated trials taken consecutively on the same day. Mean scores for EI were higher on day 1 (59.1 &#177; 35.5 N&#183;m², p < 0.05), compared to day 2 (46.9 &#177; 22.3) and day 3 (49.9 &#177; 18.3). Individual trial mean scores for EI on each day (mean of 5 trials) were highly correlated, R² = 0.84, 0.62, and 0.79 (set 1 vs. 2, for day 1,2,3, respectively) and the average percent change between sets 1 and 2 on each day was 5.3. The inter-test (between day) reproducibility was found to be low and unacceptable, 11.7, 18.3, and 1.3%, for day 1 vs. 2, 1 vs. 3, and 2 vs. 3. Poor inter-day reliability may be a result of the inability, at the time of this study, to apply the best computational EI model. It is concluded that tibial bone stiffness measurements with the MRTA are in the range of acceptability for same day inter- and intra-trial reliability when the 7-parameter analytic model of vibratory properties developed by McCabe et al. is used. / Master of Science

Bone mineral content (BMC) and bone mineral density (BMD), measured by dual x-ray absorptiometry are used clinically to diagnose osteoporosis and estimate risk for fragility fractures. Bone mineral explains up to 70% of bone strength; however, it does not take into account bone geometry. Mechanical Response Tissue Analysis is a method of non-invasively measuring the bending stiffness (EI) of bone which is determined by the product of Young's modulus of elasticity (E) and the areal cross sectional moment of inertia (I). The aim of the current study was to determine if high intensity strength training will increase ulnar bending stiffness in young women. Forty-nine women aged 19.9 ± 1.7 yrs, trained their nondominant arm either concentrically or eccentrically in the Isokinetic modality on the Biodex® system III 3d/wk for 32 wks. The dominant arm served as the control limb (untrained). Analysis of all subjects regardless of training mode demonstrated a significant increase in ulnar EI (22% ↑, P=0.01) with no significant difference in the untrained arm. When EI results were assessed by training mode, subjects who trained eccentrically showed a significant increase for ulnar EI in the trained limb (40% ↑, P=0.01) with no significant effect on the untrained limb while concentric training demonstrated no significant gain in either the trained or untrained arm. There was no effect of time x mode of training interaction for either the trained or untrained limb. Bone mineral density and bone mineral content of the ulna increased significantly in the trained arm in both concentric and eccentric training modes (P<0.05). These findings suggest support for the hypothesis that a critical threshold of mechanical bending loads may be necessary to effect an adaptation in bone strength and thus, eccentric training may be a novel approach to increase ulnar EI in young women. / Master of Science

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The difficulty to predict the intensity of soil properties alterative by soil flooding frequently makes the interpretation of the soil analysis results inaccurate when considering nutrients availability to the plants. Complementary methods of soil analysis, as leaf tissue analysis, chlorophyll meter and the leaf color chart can be used in order to estimate plants nutritional state. The objective of this study were: 1) to verify the influence of the cultivar, development stages and part of the plant on macronutrient levels and their relation with the rice productivity and 2) to monitory nitrogen (N) during the rice cycle in different conditions of N availability and to different cultivars of flooded rice, measuring chlorophyll meter and leaf color chart. In order to accomplish this task two field experiments were developed, during the agricultural year of 2005/2006, at Federal University of Santa Maria (RS). The first experiment studied, six cultivars of flooded rice with different cycles length (BR-IRGA 409, BR-IRGA 410, IRGA 417, IRGA 421, EPAGRI 108 e HÍBRIDO 2). Parts of the plants were collected in different periods and the macronutrients were analyzed, as well, the dry matter production, nutrients storage in the plant tissue and grain productivity were determined. The second experiment was installed comparing different N rate (0, 50, 80, 120 e 160 kg N ha-1) and two ways of nitrogen (N) application in dressing (before and after flooding). The first experiment with the six cultivars of flooded rice was also used. Measurements with chlorophyll meter arid, leaf color chart and N content analyses were done in the tissue during the crop cycle. Also, the dry matter production, stored N and grain productivity in both experiments was determined. There was a macronutrient level difference among the cultivars in the plant tissue, according to the collected part of the plant and the evaluation period. The plant part collected had greater influence on N and Ca levels and little influence in the levels of P, K and Mg. The levels of macronutrients of the plant parts and the assessment period are not significantly correlated with the grain productivity. The chlorophyll meter and the leaf color chart were sensible in diagnosing the availability of N for analyzed leaf, for different conditions of N availability. The cultivars show difference of N status, when assessed by the chlorophyll meter and the leaf color chart. With lower sensibility, the leaf color chart might be an alternative method to the chlorophyll meter if the cultivar factor is taken in consideration. / A dificuldade de prever a intensidade das alterações nas propriedades do solo provocadas pelo alagamento do solo torna a interpretação dos resultados da análise de solo, muitas vezes, imprecisa para estimar a disponibilidade dos nutrientes às plantas. Métodos complementares à análise do solo, como a análise de tecido foliar, o clorofilômetro e a cartela de cores podem ser utilizados para monitorar o estado nutricional das plantas. Os objetivos deste trabalho foram: 1) verificar a influência do cultivar, estádio de desenvolvimento e parte da planta nos teores de macronutrientes e sua correlação com a produtividade de grãos de arroz e 2) monitorar o nível de nitrogênio (N) ao longo do ciclo da cultura do arroz irrigado em diferentes condições de disponibilidade de N e para diferentes cultivares de arroz irrigado, através do clorofilômetro e da cartela de cores. Para tanto, foram desenvolvidos dois experimentos a campo, conduzidos no ano agrícola de 2005/2006, na Universidade Federal de Santa Maria (RS). Para o primeiro objetivo foi instalado um experimento com seis cultivares de arroz irrigado (BR-IRGA 409, BR-IRGA 410, IRGA 417, IRGA 421, EPAGRI 108 e HÍBRIDO 2) de diferentes ciclos. Foram coletadas partes da planta dos cultivares, planta inteira, última folha, penúltima folha e folha Y, em diferentes épocas, 15 dias após a 1ª aplicação de N em cobertura, 30 dias após a 1ª aplicação de N em cobertura, diferenciação do primórdio floral, 15 dias após a diferenciação do primórdio floral e florescimento, e analisados os teores de macronutrientes e também determinada a produção de matéria seca, o acúmulo de nutrientes no tecido das plantas e a produtividade de grãos. Para o segundo objetivo foi instalado um experimento a campo com doses de N (0, 50, 80, 120 e 160 kg ha-1 de N) e dois modos de aplicação de N em cobertura (antes e depois do alagamento) sendo também utilizado o primeiro experimento com as seis cultivares de arroz irrigado. Foram realizadas avaliações com clorofilômetro, cartela de cores e análise do teor de N no tecido ao longo do ciclo da cultura e também determinada a produção de matéria seca, N acumulado e produtividade de grãos nos dois experimentos. Houve diferença entre os cultivares quanto aos teores de macronutrientes no tecido das plantas, de acordo com a parte da planta coletada e a época de avaliação. A parte da planta coletada teve maior influência nos teores de N e Ca e pouca influência nos teores de P, K e Mg. Os teores de macronutrientes das partes das plantas e épocas de avaliação não se correlacionaram significativamente com a produtividade de grãos. O clorofilômetro e a cartela de cores foram sensíveis em diagnosticar o nível de N na folha avaliada, para diferentes condições de disponibilidade de N. Os cultivares apresentaram diferenças quanto ao nível de N, quando avaliados pelo clorofilômetro e cartela de cores. Com menor sensibilidade, a cartela de cores pode ser um método alternativo ao clorofilômetro se levado em consideração o fator cultivar.

A variação na disponibilidade de nitrogênio e magnésio pode alterar as características produtivas, nutricionais e metabólicas das plantas forrageiras. O objetivo foi de avaliar o efeito das combinações de doses de nitrogênio e de magnésio na produção da parte aérea e das raízes, nas concentrações dos nutrientes nas lâminas de folhas recém-expandidas (LR) e nas raízes, na atividade da glutamina sintetase, nas concentrações das formas inorgânicas de nitrogênio e na relação nitrogênio:magnésio nas LR do capim-marandu. O experimento foi realizado em casa de vegetação, em Piracicaba SP, com a Brachiaria brizantha cv. Marandu. Foram estudadas cinco doses de nitrogênio (2; 9; 16; 23 e 30 mmol L-1) e cinco doses de magnésio (0,05; 0,70; 1,35; 2,00 e 2,65 mmol L-1) em solução nutritiva, em esquema fatorial 52 fracionado, perfazendo treze combinações: 2/0,05; 2/1,35; 2/2,65; 9/0,70; 9/2,00; 16/0,05; 16/1,35; 16/2,65; 23/0,70; 23/2,00; 30/0,05; 30/1,35 e 30/2,65. O delineamento experimental foi o de blocos ao acaso, com quatro repetições. As plantas tiveram dois períodos de crescimento, nos quais foram avaliadas as produções de massa seca, contados perfilhos e folhas, coletado material fresco para determinação da atividade da glutamina sintetase, determinada a área foliar e determinada as concentrações dos nutrientes e nitrato e amônio nas lâminas das folhas recém-expandidas. Após o segundo corte as raízes foram separadas da parte aérea sendo determinada a massa seca das raízes, o comprimento e superfície radiculares e as concentrações dos nutrientes nas raízes. As combinações de altas doses de nitrogênio e magnésio resultaram em alta produção de massa seca, número de folhas e perfilhos, área foliar, massa seca das raízes, e comprimento e superfície radicular do capim-marandu. As concentrações de nitrogênio (segundo corte) e cálcio (nos dois cortes) nas LR e a concentração de nitrogênio nas raízes aumentaram com as combinações de elevadas doses de nitrogênio e de magnésio. A concentração de potássio nas LR, nos dois cortes, e nas raízes da gramínea foi mais baixa quando se utilizaram combinações de elevadas doses de nitrogênio e magnésio. De forma isolada, o incremento nas doses de nitrogênio resultou em reduzidos comprimento e superfície específicos das raízes, mais alta concentração de nitrogênio nas LR e mais alta concentração de cálcio nas raízes e o incremento das doses de magnésio proporcionou pequenos comprimento e superfície específicos das raízes, mais alta concentração de magnésio nas LR e nas raízes e mais baixa concentração de cálcio nas raízes do capim. A concentração de nitrato nas folhas diagnósticas foi influenciada pelas combinações de doses de nitrogênio e magnésio enquanto a concentração de amônio aumentou com o incremento das doses de nitrogênio. A atividade da glutamina sintetase foi mais baixa em altas doses de nitrogênio, nos dois crescimentos da gramínea. A relação de 6,3:1 entre as concentrações de nitrogênio e de magnésio nas LR correspondeu à máxima produção de massa seca no primeiro corte do capim. / Productive, nutritional and metabolic characteristics of the forage plants may be changed by the nitrogen and magnesium availability. The objective was to study the effects of nitrogen and magnesium rates on marandu palisadegrass growth, by evaluating the shoot and root yield, leaf and root concentrations of nutrients and leaf concentration of inorganic forms of nitrogen, glutamine synthetase activity and nitrogen:magnesium ratio in recently expanded leaf laminae (RL). The experiment was carried out in a greenhouse at Piracicaba, State of São Paulo, Brazil, with the Brachiaria brizantha cv. Marandu. Five nitrogen rates (2, 9, 16, 23 and 30 mmol L-1) and five magnesium rates (0.05, 0.70, 1.35, 2.00 and 2.65 mmol L-1) were used in nutrient solutions, in a fractorial 52 factorial, resulting in the following combinations: 2/0.05, 2/1. 35, 2/2.65, 9/0.70, 9/2.00, 16/0.05, 16/1.35, 16/2.65, 23/0.70, 23/2.00, 30/0.05, 30/1.35 and 30/2.65. A randomized block design, with four replications was used. Plants had a growth and regrowth period. After the second harvest it was evaluated the dry mass yield, number of tillers and leaves, sampled fresh material to assay the glutamine synthetase activity, measured the leaf area, and determined the concentrations of nutrients, nitrate and ammonium in the recently expanded leaf laminae (diagnostic leaves). After the second harvest the roots were separated from the tops and was determined the root dry mass, total length and surface, specific length and surface, and concentrations of nutrients in such plant tissue. High nitrogen and magnesium rates resulted in high dry mass yield, leaf area, number of leaves and tillers, in both growth periods of the grass, as well as in roots dry mass, length and surface. Nitrogen (at the second harvest) and calcium (both harvests) concentrations in diagnostic leaves and nitrogen concentration in the roots was high when high rates of nitrogen nitrogen were combined with high rates of magnesium. Diagnostic leaves, in the two grown periods, and roots sampled had low potassium concentrations in plants growth with high rates of both nitrogen and magnesium. Increases in nitrogen rates increased nitrogen concentration in the diagnostic leaves and calcium concentration in the roots, and decreased root specific length and surface. Increases in magnesium rates increased magnesium concentration in the diagnostic leaves and roots, but decreased root calcium concentration and root specific length and surface. Ammonium concentration was increased by nitrogen rates and nitrate concentration was higher under magnesium deficiency. Glutamine synthetase, determined at the two growth periods, decreased with increasing nitrogen rates. Maximum dry mass yield in the first harvest of the grass was found when the nitrogen and magnesium concentrations ratio was 6.3:1 in the diagnostic leaves.