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Search Results: 1 - 10 of 12245 matches for " Root production "
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Community Structure, Diversity, Biomass and Net Production in a Rehabilitated Subtropical Forest in North India  [PDF]
Bajrang Singh, Karunakar Prasad Tripathi, Kripal Singh
Open Journal of Forestry (OJF) , 2011, DOI: 10.4236/ojf.2011.12003
Abstract: Gangetic alluvial plain in north India constitutes significant proportions of barren sodic lands. A representative site, where afforestation was carried out during 1960s to rehabilitate the site under forest ecosystem, was selected to assess the restoration success. Three stands (S1, S2, and S3) were selected in a semi-natural subtropical forest at Banthra, Lucknow (26°45’ N, 80°53’ E) on the basis of different vegetation morphology and basal area gradient. Species composition and their growth forms were studied in overstory, understory and ground layer vegetation, in which dominants were assorted. Among the dominants few species were common in the three stands as also in different strata, which perhaps indicate their natural regeneration. Classification of individuals among the different size classes indicated ‘L’ shape distribution in which most of the individuals remained confined in younger groups. Biomass increased from the stand S1 to S3 stand in overstory, and vise versa for understory. Stand S2 consisted of predominance of ground layer biomass over the other stands. Biomass allocation in different plant components differed significantly between the overstory and understory for aerial woody components (stem and branch). Annual litter fall did not differ significantly among the stands, where as fine root biomass (up to 45 cm soil depth) decreased from S1 to S3 stands. Rainy and summer seasons contributed to two-third proportion of total annual fine root production. The state of this rehabilitated forest when compared with the degraded and reference forest of the region indicated that structural complexity, biomass and production levels have been achieved to 70% of the reference forest site even after having a different species composition.
Field Performance of Quercus bicolor Established as Repeatedly Air-Root-Pruned Container and Bareroot Planting Stock  [PDF]
J. W. Van Sambeek, Larry D. Godsey, William D. Walter, Harold E. Garrett, John P. Dwyer
Open Journal of Forestry (OJF) , 2016, DOI: 10.4236/ojf.2016.63014
Abstract: Benefits of repeated air-root-pruning of seedlings when stepping up to progressively larger containers include excellent lateral root distribution immediately below the root collar and an exceptionally fibrous root ball. To evaluate long-term field performance of repeatedly air-root-pruned container stock, three plantings of swamp white oak (Quercus bicolor Willd.) 10 to 13 years old were located that also included bareroot planting stock. Initial and final stem diameter and height and above-ground green weights were determined on randomly selected trees at each site. On a site with a sandy, excessively drained, high pH soil, trees (age 10) from container stock were 1.5 times taller, 2.3 times larger in dbh, and 2.8 times greater in green weight than trees from bareroot stock which averaged only 2.9 m tall, 3.9 cm dbh, and 16.3 kg green weight. On a site with high clay, poor internal drainage, and frequent flooding, trees (age 12) from container stock were 1.4 times taller, 1.8 times larger in dbh, and 4.1 times greater in green weight than trees from bareroot stock which averaged 4 m tall, 7.3 cm dbh, and 28 kg green weight. On an upland site with deep loess soils, there was a trend for trees (age 13) from container stock to be only slightly larger than trees from bareroot stock with each stock type averaging 9.6 m tall, 20 cm dbh, and 177 kg green weight. Repeated air-root pruning produced lateral roots immediately below the root collar that resulted in large container stock with large well-balanced root systems that were competitive on harsh or less than ideal oak sites. Although the process is relatively labor intensive, propagation of repeatedly air-root-pruned container stock is readily adaptable internationally to locally available sources of organic matter and open-bottom containers.
Desempenho e divergência genética de cenoura 'Brasília' em fun??o da procedência das sementes
Grangeiro, Leilson C;Azevêdo, Pascalle E de;Nunes, Glauber Henrique de S;Dantas, Mara Suyane M;Cruz, Claúdia A;
Horticultura Brasileira , 2012, DOI: 10.1590/S0102-05362012000100023
Abstract: the experiments were carried out at the universidade federal rural do semi-arido, in mossoró, rio grande do norte state, brazil, from august to november 2007 and 2008. the performance and genetic divergence of carrot 'brasília', depending on the source of the seeds was evaluated. the experimental design was of complete blocks design, with eight treatments and four replications. the treatments consisted of the sources of carrot seeds 'brasilia', provided by sakata, embrapa hortali?as, tecnoseed, hortec, feltrin, agristar/topseed, seminis and isla. the variables dry mass of shoot and root, total, marketable and non- marketable roots yield, staining of the roots (hue, chroma and brightness), soluble solids and genetic divergence were measured. the 'brasília' carrot presented the performance and quality standards within the cultivar, for the conditions of the experiments. however, it was different, especially in production and coloring characteristics.
树木根系碳分配格局及其影响因子
于水强?,王政权?,史建伟?,梅莉?,于立忠?
生态学报 , 2006,
Abstract: 根系作为树木提供养分和水分的“源”和消耗c的“汇”,在陆地生态系统c平衡研究中具有重要的理论意义。尽管20多年来的研究已经认识到根系消耗净初级生产力占总净初级生产力较大的比例,但是,根系(尤其是细根)消耗c的机理以及c分配的去向一直没有研究清楚。主要原因是细根消耗光合产物的生理生态过程相当复杂,准确估计各个组分消耗的c具有很大的不确定性,常常受树种和环境空间和时间异质性、以及研究方法的限制。综述了分配到地下的c主要去向,即细根生产和周转、呼吸及养分吸收与同化、分泌有机物、土壤植食动物,及有关林木地下碳分配机理的几种假说,分析了地下碳分配估计中存在的不确定性。目的是在全球变化c循环研究中对生态系统地下部分根系消耗的c以及分配格局引起重视。
Estimation of Tree Biomass, Carbon Stocks, and Error Propagation in Mecrusse Woodlands  [PDF]
Tarquinio Mateus Magalh?es, Thomas Seifert
Open Journal of Forestry (OJF) , 2015, DOI: 10.4236/ojf.2015.54041
Abstract: We performed a biomass inventory using two-phase sampling to estimate biomass and carbon stocks for mecrusse woodlands and to quantify errors in the estimates. The first sampling phase involved measurement of auxiliary variables of living Androstachys johnsonii trees; in the second phase, we performed destructive biomass measurements on a randomly selected subset of trees from the first phase. The second-phase data were used to fit regression models to estimate below and aboveground biomass. These models were then applied to the first-phase data to estimate biomass stock. The estimated forest biomass and carbon stocks were 167.05 and 82.73 Mg·ha-1, respectively. The percent error resulting from plot selection and allometric equations for whole tree biomass stock was 4.55% and 1.53%, respectively, yielding a total error of 4.80%. Among individual variables in the first sampling phase, diameter at breast height (DBH) measurement was the largest source of error, and tree-height estimates contributed substantially to the error. Almost none of the error was attributable to plot variability. For the second sampling phase, DBH measurements were the largest source of error, followed by height measurements and stem-wood density estimates. Of the total error (as total variance) of the sampling process, 90% was attributed to plot selection and 10% to the allometric biomass model. The total error of our measurements was very low, which indicated that the two-phase sampling approach and sample size were effective for capturing and predicting biomass of this forest type.
Produ??o de batata-doce adubada com esterco bovino em solo com baixo teor de matéria organica
Santos, Jo?o F dos;Oliveira, Ademar P de;Alves, Adriana U;Brito, Carlos H de;Dornelas, Carina SM;Nóbrega, José PR;
Horticultura Brasileira , 2006, DOI: 10.1590/S0102-05362006000100021
Abstract: the influence of organic fertilization on total and commercial production of sweet potato roots, rainha branca cv. was evaluated. the experiment was carried out from june to october/2004, in paraiba state, brazil. the experimental design was of randomized blocks with six treatments (0; 10; 20; 30; 40 and 50 t ha-1 of cattle manure), in four replications. the total and commercial productions of sweet potato roots were 18.5 and 14.2 t ha-1 obtained with 32 and 30 t ha-1 of cattle manure. the cattle manure level responsible for maximum economic return of commercial roots (30 t ha-1), was equal to that which allowed maximum production, represented 100% of maximum technique efficiency, constituting an indicative of the economic viability of cattle manure application in sweet potato. the estimated cattle manure levels which resulted maximum production and economic returns for commercial roots, corresponded to 13.8 g kg-1 of remaining organic matter with the extractor. in similar soils of this study, the organic fertilization for sweet potato production can be dispensed, with remaining organic matter level higher than 13.8 g kg-1 of soil.
Performance of Lotus corniculatus L. genotypes submitted to cutting interval: subsidies to a breeding program
Scheffer-Basso, Simone Meredith;Brustolin, Ricardo;Dall'Agnol, Miguel;
Revista Brasileira de Zootecnia , 2011, DOI: 10.1590/S1516-35982011000800004
Abstract: the objective of this work was to evaluate the response of five birdsfoot trefoil populations (lotus corniculatus l.), selected under severe and intense grazing (p38, p37, p9 and p3) or cutting (population corte), one rhizomatous population from morocco and two cultivars, s?o gabriel (brazil) and ars 2620 (usa), to different cutting intervals (20 and 40 days). the trial was carried out in a greenhouse for 224 days. the plants were submitted to the treatments during four months, when it was made four and two cuttings for the 20 and 40 day intervals, respectively. in the following months, aerial part of the plants was totally removed and after 70 days of regrowth, evaluation of roots and aerial section were performed. analysis of variance and multivariate analysis was performed, obtaining the mahalanobis distance (md), dendogram by upgma method and the relative contribution of the characters for genetic divergence. there was no genotype × cutting interval interaction and the genotypes presented a reduction on dry matter yield of roots, crown and aerial sections, number of stems and plant height when submitted to frequent cuttings. the most divergent genotypes were marrocos and p9 (md = 108.7) and the most similar ones were s?o gabriel and p37 (md = 7.8). the results suggest exclusion of the population p9 because of its weak performance and the utilization of the populations corte and p37 as progenitors in the birdsfoot trefoil breeding program. root dry matter accumulation and plant height were the characters that contributed most to genetic divergence and they can be used for selection works.
Características morfológicas e produtivas de leguminosas forrageiras tropicais submetidas a duas frequências de corte
Silva, Valdson José da;Dubeux Junior, José Carlos Batista;Teixeira, Vicente Imbroisi;Santos, Mércia Virgínia Ferreira dos;Lira, Mario de Andrade;Mello, Alexandre Carneiro Le?o de;
Revista Brasileira de Zootecnia , 2010, DOI: 10.1590/S1516-35982010000100013
Abstract: the objective of this research was to evaluate morphological and productive characteristics of forage legumes under two harvest frequencies (28 and 56 days) and 10 cm harvest intensity. the following legume species were evaluated: arachis pintoi (cv. amarillo), clitoria ternatea, calopogonium mucunoides, desmodium ovalifolium (cv. itabela) and stylosanthes guianensis (cvs. bandeirante, cook, mineir?o). a randomized complete design was used in a factorial arrangement (07 legumes × 02 harvest frequencies), with four replications per treatment and the following variables were analyzed: biomass accumulation, number of branches per plant, number of live leaves/plant, root dry matter, nodule number, and nodule matter. shoot and root dry matter accumulation per unit time was similar for the harvests at every 28 or every 56 days, except for arachis, clitoria, and desmodium, which showed greater shoot and root biomass when harvested every 56 days. nodule number and nodule mass differed among legumes, but a greater nodule number was observed when the legumes were harvested every 56 days. live leaf number per plant was greater at 56 days, except for arachis and calopogonium which showed similar values for both frequencies. harvest frequency affected differently the morphologic and productive characteristics of the studied legumes that indicated the need for different management among the varieties tested.
Influence of earthworm humus on sweet potato yield
Jo?o Felinto dos Santos,José Ivan Tavares Grangeiro,Luciano de Medeiros Pereira Brito,Marinevea Medeiros de Oliveira
Engenharia Ambiental : Pesquisa e Tecnologia , 2009,
Abstract: The Paraíba State is the higher producer of the northeast region and the fourth brazilian producer of sweet potato, where this crop has a very fodder, economic and social importance, promoting the creation of joy and rent, as well contributing for the fixation of man on rural zone. The purpose of the experiment was to evaluate the influence of organic fertilization on components of production and productivity of sweet potato. The experiment was carried out from May to September of 2005, at State of Paraíba, Brazil. The experimental design was randomized blocks with six treatments (0; 3; 6; 9; 12 and 15 t ha-1 of earthworm humus), in four replications. The evaluated variables were total and marketable roots number, raw yield and total and marketable yield of roots. The maximum total yield of roots, of commercial and non-commercial roots of sweet potato, estimated by models (curves) were respectively 18.76; 16.29 and 2.46 t ha-1, obtained with a dosage of 15.00 t ha-1 of earthworm humus. The maximum yield of raw sweet potato-estimated the equation was 12.82 t ha-1 obtained with 15 t ha-1 of the earthworm humus. The application of 15 t ha-1 of earthworm humus increased from 9.96 t ha-1 (109.69%) and 8.50 t ha-1 (105.20%) in total yield and commercial roots sweet potato, respectively, in relation to the treatment without fertilizer. For every R$ 1.00 invested in earthworm humus there was a return of R$ 2.17 from the sale of sweet potato roots.Key-words: Ipomoea batatas, organic fertilization, root production.
Efeito da época de colheita no crescimento vegetativo, na produtividade e na qualidade de raízes de três cultivares de mandioca
Sagrilo, Edvaldo;Vidigal-Filho, Pedro Soares;Pequeno, Manoel Genildo;Scapim, Carlos Alberto;Gon?alves-Vidigal, Maria Celeste;Maia, Rogério Rui;Kvitschal, Marcus Vinícius;
Bragantia , 2002, DOI: 10.1590/S0006-87052002000200005
Abstract: with the objective of determining the effect of harvesting time in the vegetative growth, yield and quality of storage roots of three cassava cultivars (manihot esculenta crantz), an experiment was carried out in an area of red distrophic red latosol in araruna, northwest of paraná state, from october, 1997 to may, 1999. the experimental design was a randomized complete blocks with four replications and treatments arranged in split plots. the main treatments were the cassava cultivars mico, iac 13 and iac 14 and the secondary treatments were ten monthly harvests starting from the second plant growing season. the canopy yield observed in the second season, presented an increase of 50.0%. the good development of the vegetative structure of the plants resulted in a greater accumulation of reserve material in the storage roots, increasing its yield. the highest harvest indices were observed from 19 to 21 months, with mean values superior to 54.0%. the cultivars were not significantly different in production of tuberous roots, dry matter and starch. the second phase of physiologic rest of the plants showed to be more favourable for harvesting, expressed in terms of production of storage roots (92.5%), of dry matter (125.0%) and starch (144.0%).
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