Cut Intervals Research Articles

Foliage yield of fluted pumpkin (telfairia occidentalis hook f.) As influenced by organic manure and cutting frequencies on soil of calabar, nigeria.

Field experiment was conducted in the 2019 and 2020 early cropping seasons at the University of Calabar Teaching and Research Farm, Calabar, to assess the foliage yield of fluted pumpkin (Telfairia occidentalis Hook F.) as affected by organic manure and cutting frequency on soil of Calabar. The experiment was a factorial combination of four poultry manure rates (0, 3, 6 and 9 tonnes per hectare) and three cutting frequency (2, 3 and 4 weekly intervals), laid out in randomized complete block design (RCBD) with three replications. Data were collected on vine length, number of leaves, internode length, fresh leaves, dry matter weights and soil physico-chemical properties, and analyzed. Significant means were compared using Fisher’s Least Significant Difference (FLSD) at 5 % probability. Results indicated that the sand proportions decreased after harvest while the silt and clay proportions, the soil pH, total nitrogen, organic carbon, organic matter, potassium, magnesium, effective cation exchange capacity (ECEC) and base saturation all increased after harvest in both cropping years. There were significant (p <.0. 05) effects of PM, cutting frequency and their interactions on vine length, number of leaves, internode length, fresh leaves and leaves dry matter weights in both years of study. Plots treated with 9 t/ha of PM produced the longest vines, higher number of leaves, heavier fresh leaf and leaf dry matter. This was followed by plots treated with 6 t/ha of PM while the lowest was the plot with zero PM treatment. Foliage harvest at 3-weekly cut intervals produced the highest cumulative number of leaves, fresh leaf and leaf dry matter weights, followed by the 4-weekly cut intervals while the lowest was the 2-weekly cut intervals. The interaction of 9 t/ha PM with 3-weekly cut intervals produced the best effect and is therefore recommended.

Developing bulk arrival queuing models with the constant batch policy under uncertainty data using (0 - 1) variables

This paper delves into some significant performance measures (PMs) of a bulk arrival queueing system with constant batch size b, according to arrival rates and service rates being fuzzy parameters. The bulk arrival queuing system deals with observation arrival into the queuing system as a constant group size before allowing individual customers entering to the service. This leads to obtaining a new tool with the aid of generating function methods. The corresponding traditional bulk queueing system model is more convenient under an uncertain environment. The $alpha$-cut approach is applied with the conventional Zadeh's extension principle (ZEP) to transform the triangular membership functions (Mem. Fs) fuzzy queues into a family of conventional bulkqueues. This new model focus on mixed-integer non-linear programming (MINLP) tenders a mathematical computational approach is known as (0 -1) variables. To measures the efficiency of the method, the efficient solution strategy plays a crucial role in the adequate application of these techniques. Furthermore, different stages of the $alpha$-cut intervals were analyzed and the final part of the article gives a numerical solution of the proposed model to achieve practical issues.

Optimizing Water Injection Performance by Using Sector Modeling of the Mishrif Formation in West Qurna-1 Oil Field, Southern Iraq

The regular job of a reservoir engineer is to put a development plan to increase hydrocarbon production as possible and within economic and technical considerations. The development strategy for the giant reservoir is a complex and challenging task through the decision-making analysis process. Due to the limited surface water treatment facility, the reservoir management team focuses on minimizing water cut as low as possible by check the flow of formation and injected water movement through the Mishrif reservoir. In this research, a representative sector was used to make the review of water injection configuration, which is considered an efficient tool to make study in a particular area of the entire field when compared with the full-field model on the basis of time-consuming and computational analysis. The sector model was neighboring by extra grid blocks and three pseudo wells as injector wells to realize the pressure on the sector boundary, which attained an acceptable history matching. The fluid model and physics model were introduced by using Pressure Volume Temperature data of well involved in the study area and two relative permeability curves. Fourteen wells were utilized in this work, four wells are injectors, and the rest are producer. The development scenarios were implemented by setting various targets of oil production and different water injection rates required for pressure maintenance operations. Optimization of water cut has been applied by adjustment of production and injection rates and shut off the high water cut intervals. The results obtained from this study showed that the inverted 9-spot has a good recovery which is illustrated in the case_2C, the production rate was (49,000 STB/D) with minimum water cut (27.5%) as compared with a five-spot pattern.

Effect of cutting frequency and nitrogen application on herbage yield and nitrogen content of a degraded Panicum maximum pasture.

The effects of cutting frequency and levels of nitrogen on revitalization of a run-down pasture were investigated in 2000 and 2001 at Nsukka, Nigeria. Grass swards were cut at intervals of 3, 6, 9 and 12 weeks and received 0, 150, 300 and 450 kg N ha' nitrogen. Grass dry matter yield was increased from 52 to 75% at the 3 and 6 weeks intervals of cutting, respectively. Weed proportion was reduced from 48 to 25% with 6-weekly cuts compared with more frequent cutting at 3 weeks interval between cuts. Cutting interval did not affect the total herbage yield. The dry matter yields of leaf blade, stem and inflorescence fractions increased significantly with increase in interval between cuts in the second year. The percentage nitrogen content was highest with 3-weekly interval of cut and decreased with high interval of cuts in the second year. Crude protein yield (kg ha') was highest with 6- and followed by 3- and 9-weekly intervals of cut and decreased with lar cutting of 12-weekly interval. Fertilizer-N treatment significantly increased total annual herbage dry matter yield from 3,460 kg ha yrl where no fertilizer N was applied to 5,233 kg ha-yr' with application of 450 kg N ha-'. Grass dry matter as proportion of the total herbage dry matter was increased from 57 to 80% with the highest N rate of 450 kg Nha compared with where N was not applied, while the weed dry matter as proportion of the total herbage dry matter was reduced from 43 to 20% with the highest N rate of 450 kg N ha compared with where N was not applied at the second year. A combination of 6-weeks interval of cutting with 450 kg N ha' gave the highest dry matter yield. It was also adequate in suppressing weed. Frequent cutting at higher levels of fertilizer N (300 - 450 kg ha'') increased the nitrogen and crude protein percentages of forage foliage while 6-weekly interval of cuts when combined with higher N levels gave the highest crude protein yield per hectare per year in the foliage herbage.

Canopy structure and morphogenesis of Italian ryegrass intercropped with red clover under cutting intervals determined by thermal sum

ABSTRACT: The canopy structure and morphogenesis of ryegrass (Lolium multiflorum Lam.) was investigated after it was over seeded with Tifton 85 (Cynodon spp.) and intercropped with red clover (Trifolium pratense L.). Time intervals between cuts were determined by different thermal sums (125, 250, 375, and 500 degree-days [DD]). Cuts were conducted at a height equivalent to 50% of the average canopy height. Morphogenic and structural data were collected from July to October of 2016 and 2017, from a completely randomized block experimental design. Canopy height, extended tiller height, pseudostem length, and forage mass were fitted to linear equations according to the thermal sums. Interaction of ryegrass with red clover was the highest (12.1%) for longer cut intervals (375 and 500 DD). The leaf appearance rate (0.0080 leaf/DD), phyllochron value (128.8 DD), and senescence rate (0.10 cm/DD) of ryegrass were comparable between the different intervals. The slowest elongation rate (0.06 cm/DD) with the shortest interval duration between cuts (171.6 DD) was observed in the 125 DD interval. According to the findings from this 2-year experiment, the use of a 250 DD cut interval was recommended between grazing events, taking into account the efficiency of forage use, ryegrass leaf, stem ratio, and interactions with red clover in the canopy under rotational stocking.

Productivity and nutritional value of BRS capiaçu grass (Pennisetum purpureum) managed at four regrowth ages in a semiarid region.

The objective of this study was to evaluate the productivity, productive efficiency, and nutritional value of the elephant grass cultivar BRS capiaçu (Pennisetum purpureum Schum.), managed at four regrowth ages during winter in the semiarid region of northern Minas Gerais, Brazil. A completely randomized design with the elephant grass cultivar BRS capiaçu was submitted to four cut intervals (30, 60, 90, and 120days) in the winter with ten replications, for a total of 40 plots, each with a useful area of 6 × 5m. There was a linear increase of 76.25% (P < 0.01) in the height of BRS capiaçu grass when cut from 30 to 120days. Green matter production (P < 0.01) and dry matter production (P < 0.01) increased daily by 1081kg/ha and 237kg/ha, respectively. The annual dry matter production was 72t/ha. Efficiency in water use changed (P < 0.01) from 7.91kg of dry matter (DM)/mm at 30days to 57.59kg of DM/mm at 120days of regrowth. There was a reduction in the ash content (P < 0.01), crude protein (P < 0.01), and the total digestible nutrient content (P < 0.01) with the increase in the age of the cut. The readily soluble fraction of DM (fraction A, P < 0.01), degradation rate "c" of insoluble fraction "B" (P = 0.01), potential degradability (PD; P < 0.01), and degradability (ED; P < 0.01) decreased linearly as the regrowth age increased. Harvesting is recommended at 90days of regrowth during the winter season in this semiarid region.

Rendimiento de forraje y valor nutritivo de alfalfa a diferentes intervalos de corte

&#x0D; El objetivo fue determinar el efecto en intervalos de corte sobre el rendimiento de materia seca, relación hoja-tallo, proteína y digestibilidad in situ en hoja y tallo de alfalfa cv ‘San Miguelito’, en el Altiplano Mexicano. Se establecieron cuatro intervalos de corte (3, 4, 5 y 6 semanas para primavera-verano y 4, 5, 6 y 7 semanas para otoño-invierno) distribuidos aleatoriamente bajo un diseño experimental completamente al azar, con 4 repeticiones. Los intervalos de 6 y 7 semanas (p&lt; 0.05), produjeron el mayor rendimiento de materia seca por corte con 4 393 kg MS ha-1; sin embargo, también obtuvieron los menores valores de la relación hoja-tallo (0.74), proteína en hoja y tallo (26.9 y 11.7%) y digestibilidad en hoja y tallo (79.8 y 64.3%). Con la finalidad de obtener un balance apropiado entre rendimiento y calidad del forraje se concluye que la alfalfa se debe cosechar, a intervalos de corte de seis semanas en otoño e invierno, de cuatro semanas en primavera y de cinco semanas en verano.

PRODUÇÃO E VALOR NUTRITIVO DA CANARANA ERECTA LISA (Echinocloa piramidalis Lam.) EM RESPOSTA A INTERVALOS DE CORTE

The objective of this study was to compare and explain the variations in the production and nutritive value of canarana erecta lisa grass ( Echinocloa pyramidalis Lam.) at different harvest intervals. The treatments corresponded to the cut intervals of 20, 27, 34, 41, 48, 55, 62, and 69 days. The experimental design was a randomized complete block design with three replications. Each experimental unit had 6m² (3m ×2m). The variables studied included forage production, canopy height, and nutritive value o harvested forage. Forage production varied from 11517 to 12324 kg ha -1 ; Plant heights from 48.8 to 234 cm; Neutral detergent fiber (NDF) from 68.8% to 71.13%; Acid detergent fiber (ADF) from 36.20% to 44.15%; Crude protein (CP) from 11.43% to 5.85% and in in vitro dry matter digestibility (IVDMD) from 63.30% to 47.42%. These values indicated that the nutritive value of canarana erecta lisa was reduced at longer harvest intervals. It is recommended to harvest the grass at 35 days of regrowth favoring productivity, nutritive value and forage digestibility. Keywords: ages of regrowth, canopy height, digestibility, herbage accumulation

PRODUCTION AND NUTRITIVE VALUE OF CANARANA ERECTA LISA (Echinocloa piramidalis Lam.) IN RESPONSE TO HARVEST INTERVALS

Abstract The objective of this study was to compare and explain the variations in the production and nutritive value of canarana erecta lisa grass (Echinocloa pyramidalis Lam.) at different harvest intervals. The treatments corresponded to the cut intervals of 20, 27, 34, 41, 48, 55, 62, and 69 days. The experimental design was a randomized complete block design with three replications. Each experimental unit had 6m2 (3m ×2m). The variables studied included forage production, canopy height, and nutritive value o harvested forage. Forage production varied from 11517 to 12324 kg ha-1; Plant heights from 48.8 to 234 cm; Neutral detergent fiber (NDF) from 68.8% to 71.13%; Acid detergent fiber (ADF) from 36.20% to 44.15%; Crude protein (CP) from 11.43% to 5.85% and in “in vitro” dry matter digestibility (IVDMD) from 63.30% to 47.42%. These values indicated that the nutritive value of canarana erecta lisa was reduced at longer harvest intervals. It is recommended to harvest the grass at 35 days of regrowth favoring productivity, nutritive value and forage digestibility.

Life cycle reliability analysis using imprecise failure data

Imprecise life data of machine element represent precise values along with it’s variation proportional to its degree of impreciseness. In this paper, it is attempted to develop a fuzzy Weibull model, where model parameters are in the form of fuzzy variable, with an objective to perform reliability analysis of life cycle data with simultaneous estimation of epistemic uncertainty and deterministic result. Imprecise life data of machine component is modeled as a fuzzy set with triangular membership function. Then entire range of the fuzzy variable is decomposed into a set of $$\alpha$$ -cut intervals corresponding to a various degree of impreciseness. Using these intervals, Weibull model parameters are estimated through the interval least square fitting method. The estimated parameters are in interval form. Integration of these estimated intervals of the model parameters construct a fuzzy variable. Detailed methodology including all processes involved is demonstrated for ball bearing life cycle data.

Nacre-inspired design of CFRP composite for improved energy absorption properties

Discontinuous unidirectional fiber-reinforced composites are shown to possibly exhibit pseudo-ductile failure that is lacking in continuous fiber composites. The aim of this paper is to use a discontinuous and interdigitated design strategy which mimicks the nacre structure to improve the specific energy absorption (SEA) of a carbon/expoxy composite tube. Quasi-static axial compressive experiment is combined with a digital image correlation system to analyze the failure process of the specimens. Four kinds of tubular specimens which are based on different ply cut intervals and distributions are fabricated and crushed. The load-crushed displacement curves and the SEA values are obtained showing that circular shaped continuous ply cuts result is the highest fluctuation of the compressive force. Moreover, the tubes with helical and nacre mimicking ply cut structures result in a flatter load-crushed displacement curve. This work demonstrates that in a crush process, unidirectional composites with a well-designed discontinuity at the ply level can improve the SEA over 51% as compared to the unidirectional continuous tubes.

Características produtivas e estruturais de genótipos de palma forrageira irrigada em diferentes intervalos de corte

A palma forrageira, recebendo aporte adicional de água, pode se constituir em alternativa alimentar para os rebanhos da região semiárida brasileira, entretanto são escassas as informações sobre as respostas produtivas e estruturais dos genótipos, assim como do intervalo de cortes da planta. Esta pesquisa teve o objetivo de avaliar as características produtivas e estruturais de genótipos de palma forrageira em diferentes intervalos de corte. O delineamento experimental foi em blocos completos casualizados com parcelas subdivididas tendo os genótipos dispostos nas parcelas e os intervalos de corte nas subparcelas, com quatro repetições por tratamento, totalizando 48 unidades experimentais. O experimento foi realizado no período de maio de 2014 a setembro de 2015, com três genótipos de palma forrageira, a Orelha de Elefante Mexicana (OEM) (Opuntia stricta (Haw.) Haw.), IPA 20 (Opuntia ficus indica (Mill)) e a Miuda (Nopalea cochenillifera Salm. Dyck) e intervalos de corte de 4, 8, 12 e 16 meses após o plantio. A OEM aos 16 meses apresentou maior massa de forragem (t de matéria seca/ha e matéria verde/ha) em comparação com a Miuda e IPA 20 nos diferentes intervalos de corte, tendo ainda maior taxa de acúmulo de forragem e melhor eficiência de uso da água. A Miuda teve maior número de cladódios e cladódios mais leves. A OEM juntamente com a Miuda apresentaram maiores índices de área de cladódio a partir de oito meses após o plantio comparada à IPA 20. Os genótipos assim como o intervalo de corte afetam as características produtivas e estruturais da palma forrageira.

ÍNDICE DE HORIZONTALIDADE E REMOÇÃO DE TECIDOS DO CAPIM-MARANDÚ

Resumo É possível que a maior disponibilidade de nutrientes no solo promova modificação mais acentuada da forma de crescimento da planta forrageira sob alta frequência de desfolhação. Para testar essa hipótese, caracterizaram-se as modificações na forma de crescimento da Brachiaria brizantha cv. Marandu syn. Urochloa brizantha cv. Marandu (capim-marandu) submetida aos intervalos de corte e à adubação, bem como avaliou-se o efeito dessas modificações sobre as forragens removida e remanescente do corte. O trabalho foi realizado em dois períodos experimentais. Em cada período, experimentos independentes, porém com natureza semelhante, foram realizados. No Experimento 1, de outubro de 2013 até fevereiro de 2014, o capim-marandu foi adubado com 70 kg.ha-1 de N e 50 kg.ha-1 de P2O5 e foram avaliados intervalos de corte (sete, 14, 28, 56 e 112 dias), em delineamento em blocos casualizados, com quatro repetições. No Experimento 2, de novembro de 2014 até março de 2015, além dos mesmos intervalos de corte avaliados no Experimento 1, também foram estudadas duas condições de adubação, sendo uma baixa (50 kg.ha-1 de P2O5 e de 75 kg.ha-1 de N) e outra alta (100 kg.ha-1 de P2O5 e 300 kg.ha-1 de N). No Experimento 2, utilizou-se o esquema fatorial, com dois níveis de adubação e cinco níveis de intervalos de corte, e o delineamento em blocos casualizados, com quatro repetições. No Experimento 1, os maiores índices de horizontalidade (IH) ocorreram (p&lt;0,05) nas plantas sob intervalos de corte de sete, 14 e 28 dias, em relação às plantas cortadas a cada 56 e 112 dias. No Experimento 2, apenas a planta cortada a cada sete dias apresentou (p&lt;0,05) aumento do IH (de 1,3 para 1,5) com a melhoria da alta condição de adubação. A massa de forragem remanescente aumentou (p&lt;0,05) com o intervalo de corte, de 412 para 483 g.m-2 e de 412 para 571 g.m-2 nos Experimentos 1 e 2, respectivamente. No Experimento 2, ocorreu aumento (p&lt;0,05) da massa de forragem remanescente (de 447 para 505 g.m-2) e da percentagem de colmo vivo (de 23 para 33%) com a adubação em todos os intervalos de corte. Em ambos os experimentos, os maiores intervalos de corte incrementaram (p&lt;0,05) a massa de forragem removida (de 95 para 840 g.m-2 e de 44,8 para 843 g.m-2 nos experimentos 1 e 2, respectivamente) e o índice de área foliar (IAF) removido (de 1,0 para 4,3 e de 0,4 para 3,9 nos experimentos 1 e 2, respectivamente). No Experimento 2, a melhoria da condição de adubação resultou em aumento (p&lt;0,05) da massa de forragem removida (de 261,3 para 391,8 g.m-2) e do IAF removido (de 1,6 para 2,1). No Experimento 2, quando a condição de adubação foi alta, houve (p&lt;0,05) menor percentagem de folha viva removida nos dosséis sob cortes intermediários (28 e 56 dias). Quando a desfolhação é muito frequente, a maior disponibilidade de nutrientes no solo contribui para que o capim-marandu modifique sua forma de crescimento de ereta para prostrada, em comparação à condição de menor disponibilidade de nutrientes no solo. O aumento do intervalo de corte e a adubação incrementam a remoção da forragem do capim-marandu.

Effects of cutting frequency and nitrogen fertilizer application on yield, proportion of crop fractions and leaf to stem ratio in guinea grass (Panicum maximum) pasture

In a sandy loam soil at Nsukka, the effects of fertilizer-N application and cutting management on the yield and proportions of crop fractions of Panicum maximum sown pasture were investigated in 2001 through 2004. The experiment was a 4 × 4 factorial laid out in a randomized complete block design with three replications. Treatments comprised four levels of nitrogen of 0, 150, 300 and 450 kg N ha-1 and four harvesting frequencies of 3-, 6-, 9- and 12-weekly intervals, resulting in sixteen treatment combinations per block. Increase in cutting interval and incremental application of N reduced the proportion of leaf to stem in the total grass dry matter yield. The proportion of inflorescence increased significantly (P < 0.05) with increase in interval between cuts in all the years. Nitrogen treatment increased significantly (P < 0.05) the proportion of inflorescence in 2002 and 2004 compared with the control. Leaf blade yield was significantly (P < 0.05) higher where N application at the 300 kg N ha-1 was combined with cutting at 6- and 12-weekly intervals in 2003 and 2004, respectively compared with when the 3-weekly interval of cut was combined with 0 kg N ha-1. Inflorescence dry matter was significantly (P < 0.05) higher where 12-weekly cutting interval was combined with 300 kg N ha-1 in 2004, compared with the 3-weekly interval of cuts at any N rate. On the whole, herbage dry matter yield was highest with 12-weekly cutting interval and with the higher N rates. Key words: Panicum maximum, fertilizer N, cutting interval, dry matter yield, leaf to stem ratio, inflorescence, crop fractions.

Optimization of an improved single-column chromatographic process for the separation of enantiomers

This work addresses optimization of an improved single-column chromatographic (ISCC) process for the separation of guaifenesin enantiomers. Conventional feed injection and fraction collection systems have been replaced with customized components facilitating simultaneous separation and online monitoring with the ultimate objective of application of an optimizing controller. Injection volume, cycle time, desorbent flow rate, feed concentration, and three cut intervals are considered as decision variables. A multi-objective optimization technique based on genetic algorithm (GA) is adopted to achieve maximum productivity and minimum desorbent requirement in the region constrained by product specifications and hardware limitations. The optimization results along with the contribution of decision variables are discussed using Pareto fronts that identify non-dominated solutions. Optimization results of a similar simulated moving bed process have also been included to facilitate comparison with a continuous chromatographic process.

Características morfogênicas, estruturais e acúmulo de forragem do capim-tanzânia submetido a duas alturas e três intervalos de corte

Avaliaram-se as características morfogênicas e estruturais e o acúmulo de forragem do capim Panicum maximum, cv. Tanzânia, submetido a duas alturas de corte (25 e 50 cm) e três intervalos de corte (correspondentes ao surgimento de duas, três e quatro folhas por perfilho). Utilizou-se um arranjo fatorial 2 × 3 em delineamento de blocos completos casualizados, com três repetições. A taxa de aparecimento de folhas diminuiu e o filocrono aumentou com a redução da frequência de desfolhação. De modo geral, o comprimento final da folha foi menor na altura de corte 25 cm que na de 50 cm. A taxa de senescência de folhas e a taxa de alongamento de colmos tenderam a aumento quando o intervalo de corte variou de duas para três folhas por perfilho. A taxa de mortalidade de perfilhos aumentou ao longo do período de avaliação. As altas taxas de mortalidade e de aparecimento de perfilhos caracterizaram um padrão intenso de renovação (turnover) da população de perfilhos. A altura pré-desfolhação diminuiu com o aumento da frequência de corte, enquanto a massa de forragem tendeu a ser maior nas menores frequências de corte. O acúmulo de colmos só variou entre as alturas de corte no segundo corte e foi menor no intervalo de duas folhas em comparação aos de três e quatro folhas surgidas por perfilho, também no mesmo corte. O intervalo de cortes do capim-tanzânia não deve exceder o tempo necessário para o aparecimento de duas a três folhas por perfilho.

Avaliação de cultivares do gênero &lt;em&gt;Cynodon&lt;/em&gt; com e sem nitrogênio

Chemical composition, in vitro digestibility of dry matter (IVDDM), organic matter (IVDOM) and cell wall (IVDCW), green dry matter production (GDMP), plant re-growth (PR) and stem/leaf ratio (S/L) of five cultivars of the genus Cynodon at two levels of N fertilization (0 and 400 kg/ha) in the summer and spring are provided. CP did not differ (P > 0.05) from other grasses in chemical composition. However differences (P ≤ 0.05) occurred due to nitrogen level and cut intervals. Values for ADF and NDF were affected (P ≤ 0,05) by grass, nitrogen level and cut intervals. Grasses showed statistical differences (P ≤ 0.05) for IVDDM, IVDOM and IVDCW. Tifton 44 showed the highest digestibility for all parameters, while Estrela Porto Rico the lowest digestibility for IVDCW. Other grasses did not differ from each other. There were no differences (P > 0.05) among the fertilized cultivars for GDMP. Under no fertilization GDMP of Tifton 85 cultivar was higher than that of Tifton 44 and coast cross cultivars. Under N application PR of Tifton 85 was higher than that of Estrela Porto Rico and purple star grasses. S/L ratio of the Tifton 85 cultivar was different (P < 0.05) from Estrela Porto Rico e purple star grasses ratios. Application of N increased GDMP, PR and S/L of the cultivars.

Morfofisiologia de &lt;em&gt;Andropogon gayanus&lt;/em&gt; Kunth sob adubação mineral e orgânica em três estratos verticais

Morphophysiology of Andropogon gayanus Kunth with organic and mineral fertilization in three vertical layers. The morphophysiological characteristics of the andropogon grass, Andropogon gayanus Kunth cv. Planaltina (Poaceae) with four manure treatments (control; 25 kg N/ha/cutting date; 50 kg N/ha/cutting date and 20 t/ha of cattle manure applied after each cut), were evaluated. There were 28 and 42-day cut intervals within two evaluation periods (84 and 168 days), sampled in three layers (0.20-0.40 m; 0.40-0.60 m; >0.60 m). Complete randomized block design in a split-split-plot arrangement has been used. Highest values of total dry mass and dry mass of stem were reported in the lowest layer (0.20- 0.40 m). The upper layers had higher leaf dry mass (0.40-0.60 m and >0.60 m), higher leaf area and consequently higher leaf/stem ratio. The four fertilization treatments were not significantly influential on the characteristics of the grass analyzed in this research.

Effect of anhydrous magnesium sulphate fertilizer and cutting frequency on yield and chemical composition of Panicum maximum

Effect of anhydrous magnesium sulphate fertilizer on Panicum maximum yield and chemical composition of the resultant herbage harvested at 3, 4 and 5 weeks of age was investigated. The treatments were labeled T1 to T6. T1 was fertilized and harvested at 3 weeks cutting interval, T2 was fertilized and harvested at 4 weeks cutting interval, T3 was fertilized and harvested at 5 weeks cutting interval, T4 was not fertilized but harvested at 3 weeks cutting interval, T5 was not fertilized but harvested at 4 weeks cutting interval and T6 was not fertilized but harvested at 5 weeks cutting interval. The results showed significant differences (P grass and the intervals of cuttings. Although, there was no significant difference (P>0.05) between the treated and the untreated grass at the same cutting interval, there was a marginal increase with the treated showing superiority in all the cases. Also observed was increase in yield as the cutting interval increased in both cases of treated and untreated grass. It was also found that there was no interaction between fertilizer application and cutting frequency. The crude protein contents of both the treated and untreated grass at different cutting intervals was significantly (P 0.05) different was consistently higher than that of the untreated. It was also found that the crude protein content of the grass declined as the plant aged. The NDF contents were higher in the untreated grass than the treated grass. The magnesium fractions of the treated grass at the cutting intervals were significantly (P 0.05). The herbage magnesium content between the treated and the untreated at the same cutting intervals were different as the magnesium contents in treated grass were consistently higher than the untreated at the same cutting intervals. In the treated grass, the magnesium contents of the herbage grass did not show a definite pattern as the cutting interval increased but did decrease in the untreated grass as the grass matured. The calcium contents of treated and untreated grass at different cutting intervals were similar (P>0.05) in T1 and T3 but different (P cases of treated and untreated grass. The potassium content of both the treated and untreated grass was similar (P>0.05). In both the treated and the untreated grass, the potassium contents of the grass decreased with age.

Effects of cutting management and N-fertilizer application on plant height, tiller production and percentage dry matter in a run-down &lt;i&gt; Panicum maximum &lt;/i&gt; pasture

In a sandy loam soil at Nsukka, the effects of cutting management and fertilizer-N treatment on revitalization of a run-down pasture were investigated in 2000 and 2001. Grass swards were cut at intervals of 3, 6, 9 and 12 weeks and received 0, 150, 300 and 450 kg N/ha. Increasing the interval between harvests from 3 to 12 weeks increased plant height from 31.5 cm to 139.2 cm and from 25.2 cm to 72.6 cm in 2000 and 2001, respectively but reduced the number of grass tillers. The dry matter percentage increased from 28.0 to 35.4% with 9-weekly cut compared with 3-weekly interval in 2000 and increased from 23.6 to 32.9% with 12-weekly interval of cut compared with 9-weekly interval in 2001. Tiller number per square metre generally decreased with increase in cutting interval up to 9-weeks interval. Plant height and grass tiller number were increased with increase in N application. Plant height increased from 48.4 to 91.5 cm, or from 42.6 to 68.9 cm when fertilizer N was increased from 0 to 450 kg N/ha applications in 2000 and 2001, respectively. The dry matter percentage was decreased from 32.4 to 31.2% with incremental application of N from 150 to 450 kg N/ha in 2000 and decreased from 28.7 to 25.2% with 0 to 450 kg N/ha application in 2001. Plant height, tiller number and dry matter yields of crop fractions tended to pick up early in the season, increased with season and decreased at the late season. The dry matter percentage tended to increase with advancing season. Cutting of 12 weeks interval gave the highest plant height when combined with 450 kg N/ha while fertilizing at 450 kg N/ha produced the highest tiller number when combined with cutting at 6-weekly interval. Harvesting at 9-weekly interval gave the highest percentage dry matter when combined with 300 kg N/ha. Keywords: Grass height, Tiller population, Dry matter content, Interval between cut, N – Fertilizer.Agro-Science Vol.42 (2) 2005: pp. 28-33