Dickson Quality Index Research Articles

Seedling growth of Schizolobium parahyba on different substrates and irrigation levels

Abstract The present study aimed to assess the behavior of seedlings of Schizolobium parahyba (Vell.) Blake growing on different substrates and irrigation levels, and to study the use of urban waste compost in substrates. The experiment was carried out in the College of Agricultural Sciences, Universidade Estadual Paulista (UNESP), Department of Agricultural Engineering, Jaboticabal Campus, state of São Paulo, Brazil. The experimental design used was completely randomized, consisting of 30 treatments in a factorial design with 15 substrates and two irrigation levels in four replicates. The substrates were composed of different materials: urban waste, Plantmax(r), dry cattle manure, vermiculite and soil. For the study of seedling growth, the following characteristics were evaluated: height (H), root-collar diameter (D), number of leaves, shoot dry weight, root dry weight, total dry weight, H/D ratio, Dickson's quality index, and the ratio between height and shoot dry weight (H/SDW). Assessments of the first three characteristics were carried out 20, 35, 50 and 65 days after sowing. Results showed that urban waste compost increased the growth of Schizolobium parahyba. There were significant differences for the irrigation levels tested; with better results for 150% ET compared to 100% ET irrigation level.

Utilização de vermicomposto como substrato na produção de mudas de Eucalyptus grandis e Corymbia citriodora

The aim of this work was to evaluate the vermicompost efficiency in the seedlings of two eucalyptus species production. The experiment was developed in greenhouse conditions, substrate constituted by different vermicompost proportions and peat for the E. grandis and C. citriodora seedling production. The experimental design was entirely casualized with seven treatments and eight repetitions. After 100 days of experiment were evaluated: seedling height, fresh and dry biomass of aerial part, root volume, dry biomass of the root and Dickson quality index (DQI). The treatment constituted by 80% vermicompost and 20% peat presented the highest results in height, root volume and dry mass of the aerial part and roots. For the species C. citriodora was observed that the vermicompost addition to the peat in the proportions from 40% to 80% was shown efficient in the seedlings growth. The treatment constituted by 80% vermicompost and 20% peat provided highest height and dry mass of the aerial part seedlings and the treatment constituted by 60% vermicompost and 40% peat provided highest root volume. The proportions 60% and 80% vermicompost added to the peat increase the E. grandis and C. citriodora seedlings production. doi: 10.4336/2011.pfb.31.66.75

Estimates of genetic gains for growth traits in young plants of Eucalyptus urophylla S. T. Blake

The objective of this study was the selection of superior genotypes for growth traits, correlating them to initial height growth in the field, at age eight months. A random block design was used in the nursery, with eight clones, three replicates and four plants per plot. And a random block design was also used in the field, with eight clones, four replicate blocks and nine plants per plot. Data being analyzed in the nursery at age 120 days included: height of field seedling, at age eight months (Hc), height of nursery seedling (Hm), root collar diameter (Dc), shoot diameter (Db), shoot dry matter (PMSPA), root dry matter (PMSR), total dry matter (PMST), ratio of shoot dry matter to root dry matter (PMSPA/PMSR), Dickson quality index of root collar diameter (IQD-Dc), Dickson quality index of shoot diameter (IQD-Db). Analyses of variance showed that significant genetic differences exist among clones for all traits and, given the high heritability values found, the estimated genetic gains were generically very high. As for predicted indirect genetic gain, selection in nursery seedlings for Dc, PMSPA/PMSR, IQD-Dc provided the highest values of indirect gain in field seedling height.

Desenvolvimento inicial de mudas de jatobazeiro do cerrado em Aquidauana-MS

A busca por uma alimentação saudável tem aumentado o consumo de frutas e hortaliças, proporcionando maior aceitação das fruteiras do cerrado no mercado. Visando à obtenção de mudas de qualidade, este trabalho avaliou a formação de mudas do jatobazeiro-do-cerrado em diferentes ambientes protegidos e substratos, na UEMS, Aquidauana, no período de novembro de 2008 a março de 2009. Foram utilizados três ambientes protegidos: estufa plástica de polietileno transparente, viveiro de tela de sombreamento e viveiro telado com malha termorrefletora; e seis substratos: solo, Plantmax®, fibra de coco fina, fibra de coco chips, vermiculita e composto orgânico. O delineamento experimental foi o inteiramente casualizado, com esquema de parcelas subdivididas (split-plot) e dez repetições. Houve interação entre ambiente de cultivo e substrato na formação de mudas de jatobá-do-cerrado. Na estufa agrícola, indica-se a utilização do Plantmax® e, nos telados, recomenda-se a vermiculita. O Plantimax® promoveu crescimento uniforme das mudas, em todos ambientes, especialmente na estufa agrícola. O substrato com 100% de composto orgânico não é indicado na formação de mudas de jatobá-do-cerrado. O Índice de Qualidade de Dickson é um bom indicador do padrão de qualidade das mudas.

Influência da contaminação do solo por cobre no crescimento e qualidade de mudas de açoita-cavalo (<i>Luehea divaricata</i> Mart. & Zucc.) e aroeira-vermelha (<i>Schinus therebinthifolius</i> Raddi)

A contaminação do solo por cobre tem se tornado comum em áreas de mineração e de viticultura no Rio Grande do Sul. O trabalho objetivou avaliar o efeito de doses de cobre sobre o crescimento e qualidade de mudas de açoita-cavalo e aroeira-vermelha. O delineamento foi inteiramente casualizado num fatorial (2 x 5), sendo as duas espécies florestais e cinco doses de cobre: 0, 64, 128, 192 e 256 mg kg-1 de solo, com cinco repetições. Avaliaram-se altura da planta, diâmetro do colo, peso da matéria seca radicular e da parte aérea, comprimento e área superficial específica radicular, e os índices de qualidade de mudas: relação entre altura da parte aérea e diâmetro do coleto; altura da parte aérea e peso da matéria seca da parte aérea e o Índice de Qualidade de Dickson. Os resultados revelaram que as doses testadas de cobre não alteraram a qualidade de mudas de aroeira-vermelha, enquanto que o açoita-cavalo apresentou melhor qualidade com aplicação de 64 mg kg-1 de Cu. O cobre afeta primeiramente o sistema radicular das mudas de açoita-cavalo e aroeira-vermelha. A aroeira-vermelha é mais tolerante a elevadas doses de cobre do que o açoita-cavalo.

Physic nut plants present high mycorrhizal dependency under conditions of low phosphate availability

The physic nut (Jatropha curcas L.) is a perennial tree that occurs naturally in the tropical and subtropical regions of Brazil. Fruits of physic nut present an oil content of 28% on a dry weight basis. Although the plant has adapted to diverse soil conditions such as low fertility, the correction of soil acidity and the addition of fertilizer are essential for highly productive plants. Thus, the response of the physic nut to different soil phosphorus levels (P) and arbuscular mycorrhizal fungi (AMF) inoculation must be characterized. Hence, the objective of the present study was to evaluate the response of physic nut seedlings to arbuscular mycorrhizal fungi (AMF) inoculation at different levels of soil P. Experiment was carried out in a greenhouse encompassing AMF treatments (inoculation with Gigaspora margarita or Glomus clarum, and the non inoculated controls), and phosphorus treatments (0, 25, 50, 100, 200 and 400 mg kg-1 added to soil). At low soil P levels, arbuscular mycorrhizal fungi inoculation had a significant positive effect on plant growth, shoot and root dry matter content, plant height, number of leaves, total leaf area, leaf area per leaf and the Dickson quality index. The root:shoot ratio and the leaf area ratio were also affected by mycorrhizal inoculation and the level of P addition. Physic nut plants exhibited high mycorrhizal dependency at soil P additions up to 50 mg kg-1.

Correlations between growth variables and the Dickson quality index in forest seedlings

This study aims to identify correlations between growth variables and the Dickson quality index in seedlings of Eucalyptus grandis and Pinus elliottii var. elliottii. The experiment was conducted in a greenhouse and the following variables were observed: stem base diameter, shoot height, number of leaves, leaf dry matter, stem base dry matter, root dry matter, shoot dry matter, total dry matter, ratio of shoot dry matter to root dry matter and ratio of shoot height to stem base diameter in E. grandis 60, 75, 90, 105 and 120 days after seedling emergence, and in P. elliottii 25, 50, 75, 100, 125, 150 and 175 days after seedling emergence. Using Pearson correlation and also path and regression analyses, correlations were analyzed between observed variables according to day after emergence and the Dickson quality index. Stem base diameter was found to have stronger correlation with days after emergence in comparison to shoot height, in both species. Root dry matter was found to have stronger correlation with the Dickson quality index. Stem base diameter was the most suitable parameter to indicate seedling quality due to its higher correlation level with the Dickson quality index. Shoot height was only effective to indicate seedling quality if analyzed together with stem base diameter. Variables relating to dry matter showed the highest correlations with the Dickson quality index (DQI), followed by stem base diameter. Conversely, number of leaves showed the poorest correlations with DQI, followed by seedling height.

Crescimento e qualidade de mudas de Senna macranthera (collad.)irwin et barn. em resposta à calagem

Este trabalho foi desenvolvido com o objetivo de verificar a influência da saturação por bases do substrato no crescimento inicial e qualidade de mudas de Senna macranthera (fedegoso). O delineamento utilizado foi em blocos ao acaso com quatro repetições por tratamento. Como substrato foram empregados três diferentes solos, sendo para cada um deles a saturação por bases original elevada para os seguintes valores: Argissolo Vermelho-Amarelo 50, 60 e 70%, Latossolo Vermelho-Amarelo distrófico 30, 50 e 70% e Latossolo Vermelho-Amarelo álico 25, 45 e 65%. Foram avaliados os parâmetros morfológicos das mudas, suas relações e o índice de qualidade de Dickson. As mudas de fedegoso não apresentaram diferença significativa para nenhuma das características avaliadas no Argissolo Vermelho-Amarelo. Já no Latossolo Vermelho-Amarelo distrófico e no Latossolo Vermelho-Amarelo álico houve diferença significativa para todas as características avaliadas, exceto para a altura da parte aérea no primeiro e para o peso de matéria seca da parte aérea no segundo solo. As saturações por bases que forneceram as melhores mudas foram de 60% para Argissolo Vermelho-Amarelo, 70% para o Latossolo Vermelho-Amarelo distrófico e de 65% para Latossolo Vermelho-Amarelo álico.

Survival and growth of drought hardened Eucalyptus pilularis Sm. seedlings and vegetative cuttings

Forestry requires low mortality of transplanted seedlings. Mortality shortly after planting is often associated with inadequate hydration of transplants. Seedlings can be hardened to the drought conditions they may experience after transplanting by exposing them to controlled drought conditions in the nursery. Eucalyptus pilularis Sm. seedlings were drought hardened by providing nil (severe treatment) or half (mild treatment) the daily irrigation routinely received (control treatment) for up to two non-consecutive days per week during the last 4 weeks of growth in the nursery. Drought hardening reduced stem diameter, seedling leaf area, leaf area per root biomass and seedling quality measured by the Dickson quality index, but increased root:shoot ratio. Hardened seedlings had lower stomatal conductance and leaf water potential on the days they received less irrigation that the control treatment. Hardened seedlings had greater stomatal conductance and were less water stressed than seedlings experiencing drought for the first time indicating hardened seedlings had adjusted physiologically to drought. Survival after transplanting in the controlled drought environment in a glasshouse was enhanced by the hardening treatments. Non hardened seedlings that had had their upper leaves manually removed immediately prior to transplanting to reduce leaf area (top-clipped) had similar survival to hardened seedlings. Stomatal conductance and leaf water potential after transplanting were higher in hardened and top-clipped seedlings than unhardened control seedlings or vegetative cuttings. Survival in the field trial was over 95% for all treatments, possibly as rain fell within 4 days of planting and follow-up rain occurred in the subsequent weeks. Neither the hardened or top-clipped seedlings planted in the field trial had reduced growth, increased propensity to form double leaders or worse stem form than control seedlings when measured at age 3 years.

Crescimento de mudas de jacaré (Piptadenia gonoacantha J.F. Macbr.) em diferentes tipos de solos e fontes e doses de nitrogênio

Este trabalho foi realizado com o objetivo de avaliar o crescimento e qualidade de mudas de Piptadenia gonoacantha (jacaré) em resposta a fontes e doses de nitrogênio produzidas em amostras de três diferentes tipos de solo. O delineamento estatístico adotado foi em blocos casualizados (DBC), analisados em esquema fatorial (3 x 5 x 3), correspondendo a três fontes (nitrato de amônio, nitrato de cálcio e sulfato de amônio) e cinco doses de nitrogênio (0, 50, 100, 150 e 200 mg/dm³ de N, aplicadas como solução em quatro porções iguais aos 25, 50, 75 e 100 dias após a semeadura) e três tipos de solos (latossolo, argissolo e cambissolo), com quatro repetições. Foram analisados os parâmetros morfológicos, o índice de qualidade de Dickson e a nodulação do sistema radicular ativa e total e suas relações. Os substratos argissolo e cambissolo e a aplicação do sulfato de amônio proporcionaram maiores médias com relação às características morfológicas avaliadas. Quanto às doses de N utilizadas neste estudo, as melhores médias dos parâmetros morfológicos foram adquiridas com a aplicação variando de 151 a 200 mg/dm³ de N.

Quality of maritime pine (Pinus pinaster Ait.) seedlings using waste materials as nursery growing media

The use of peat as a growing media in forestry nurseries is decreasing due to high costs and environmental considerations. Furthermore, diverse waste products are being used as organic amendments in certain soils before afforestation. In this study, combinations of both of these resources are considered and seven different materials were used to make mixtures of growing media used for maritime pine tree production in a forestry nursery. Pine bark, Sphagnum peat and paper mill sludge were mixed with sewage sludge, sewage activated sludge, municipal solid waste with activated composted sludge and inorganic fertilizer to fill containers where pine seeds were sown. Germination was monitored 30–50 days after sowing. Needle samples from each treatment were taken and physical parameters (height, stem diameter, aerial dry weight, main root dry weight, total dry weight) were measured along with several morphological attributes. Foliar nutrient content was also determined (N, P, K, Ca, Mg, Fe, Cu, Mn and Zn). The highest values for germination percentage were obtained for 75% pine bark + fertilizer and for sewage sludge treatments. Seedlings grown in paper mill sludge + activated sewage sludge + peat and in paper mill sludge + activated sewage sludge + pine bark mixtures presented the best physical parameter values. Municipal solid waste and composted sludge were the most useful amendments for morphological attributes. After linking morphological indexes and foliar nutrient content, the best Dickson Quality Index values correspond with higher values of N, Ca, Mg, Cu and Zn and lower values of P, K, Fe and Mn.

Effects of a deep container on morpho-functional characteristics and root colonization in Quercus suber L. seedlings for reforestation in Mediterranean climate

In the last decades, reforestation and afforestation programs are being carried out mainly with containerized seedlings. Container design determines the morphological and physiological characteristics of seedlings. However, container characteristics are often the same for plant species with very different growth strategies. The most commonly used nursery containers are relatively shallow and limit tap root growth; consequently, species relying on the early development of a long tap root to escape drought, such as those of the Quercus genus, might need to be cultivated in deep containers. The aim of this paper was to compare the morphological and physiological characteristics of Quercus suber L. seedlings cultivated in shallow containers (CCS-18, depth 18 cm) with seedlings cultivated in deep containers (CCL-30, depth 30 cm). Both container types used were made of high-density polyethylene, cylindrical in shape, open-bottomed, with a diameter of 5 cm, two kinds of vertical ribs on the inside wall showing a cultivation density of 318 seedlings/m 2. At the end of nursery culture, the seedlings cultivated in the CCL-30 deep container presented a longer tap root, higher shoot and root biomass and higher Dickson Quality Index (DQI). Moreover, the CCL-30 seedlings showed a higher root growth capacity (RGC), they reached deep substrate layers faster and they presented higher root hydraulic conductance. These morpho-functional advantages improved the CCL-30 seedling water status, which was expressed by higher stomatal conductance during an imposed drought period.

Avaliação da especificidade de rizobactérias isoladas de diferentes espécies de Pinus sp.

Testou-se a especificidade das rizobactérias promotoras de crescimento em mudas de P. taeda L., P. oocarpa, P. elliottii Engelm. e P. caribaea var. hondurensis. Os isolados de rizobactérias UFV-AL9, UFV-AM5, UFV-AM2, UFV-F3, UFV-G2, UFV-G4, UFV-Z1, UFV-F6 e UFV-X2 foram inoculados por meio da aplicação de inóculo de rizobactérias em substrato de produção de mudas. Aos 150 dias de semeadura, avaliou-se o peso de matéria seca de raízes e da parte aérea das mudas, bem como o índice de qualidade de Dickson. Foram constatadas interações significativas dos isolados e das diferentes espécies de pinus. Os incrementos da biomassa da parte aérea e do sistema radicular variaram conforme o isolado e a espécie de pinus, porém, de modo geral, foram observados maiores médias das mudas de P. taeda. As mudas de P. taeda, inoculadas com os isolados UFV-Z1 e UFV-AM5, apresentaram ganhos significativos de biomassa da parte aérea, do sistema radicular e do índice de qualidade de Dickson, em relação à testemunha. Nas mudas de P. elliottii, observou-se também aumento significativo da biomassa da parte aérea, quando inoculadas com o isolado UFV-AM5 e do sistema radicular com os isolados UFV-X2, UFV-G2 e UFV-AM5. O isolado UFV-AM5 não se mostrou específico para essas variáveis, nas duas das quatro espécies estudadas (P. taeda e P. elliottii).

03/02006 Influence of industrial air pollutants on growth and physiological state of Douglas fir ( Pseudotsuga menziesii) in Estonia : Mandre, M. and Ots, K. Indian Journal of Agricultural Sciences, 2002, 72, (5), 263–266

An experiment was conducted during 1990-97 (0 study growth, biomass and vitality of Douglas fir [Pseudotsliga mellziesii (Mirb.) Franco], to assess its tolerance to ellvironmental changes and prospects of cultivation to increase the forest biodiversity in Estonia. Two-year-old seedlings of Douglas fir were planted in sample plots affected hy a cement plant and by oll-shah: processing enterprises and in an unpolluted control sample plot in 1990. At the end of the experiment (1917) serious inhibition in tree growth and development was indicated by an increase of the sturdiness quotient (27-31 %) and a decrease in the Dickson quality index (54-76%) in industrial areas compared with the control trees. However, an increasing proportion of needles and roots as a percentage of the total biomass in polluted areas indicated arise of compensatition mechanisms in trees to increase the assimilative mass and to improve water and nutnent availability to survive under stress.

ECOPHYSIOLOGICAL STUDY OF SUITABILITY OF PICEA MARIANA L. FOR AFFORESTATION IN ALKALIZED TERRITORIES IN NORTHEAST ESTONIA

The present paper is based on experiments carried out with black spruce (Picea mariana (Mill.) B.S.P.) in an industrial area in Northeast Estonia. Two-year-old seedlings of black spruce were planted in a sample plot affected by a cement plant and in an unpolluted control sample plot in 1990. At the end of the experiment in 1997 it was ascertained that the impact of industrial alkaline air pollution complexes resulting in the alkalization and chemical deviations of growth conditions decreases the content of carbohydrates and disbalances the mineral element composition in different organs of trees. Changes in the physiology of trees retard the growth and bring about a decrease in total biomass. The sturdiness quotient was higher and the Dickson quality index was lower than the control, indicating serious damages of trees in the polluted area. Increasing share of needles in the total biomass in polluted areas in comparison with control trees suggests that compensation mechanisms were started in trees to increase the assimilating mass in order to survive under stress.

Padrão de qualidade de mudas de Trema micrantha (L.) Blume, produzidas sob diferentes períodos de sombreamento

O objetivo deste trabalho foi verificar a influência do período de permanência das mudas sob sombreamento nos parâmetros empregados na avaliação da qualidade das mudas de Tremamicrantha (crindiúva). O delineamento experimental foi o inteiramente casualizado, com quatro repetições por tratamento, contendo 88 plantas cada. Foram realizadas três avaliações, aos 90, 120 e 150 dias após a emergência. Os tratamentos na avaliação I foram 45, 60, 75 e 90; na avaliação II, 45, 60, 75, 90, 105 e 120; e na avaliação III, 45, 60, 75, 90, 105, 120, 135 e 150 dias de permanência sob sombreamento com 48% de retenção da radiação, respectivamente. Foram avaliados os parâmetros morfológicos das mudas, suas relações e o índice de qualidade de Dickson. As mudas desenvolvidas sob maiores períodos de sombreamento, embora tenham alcançado maiores alturas das partes aéreas e áreas foliares, apresentaram as piores qualidades, com redução do diâmetro do coleto, da massa seca do sistema radicular e do índice de qualidade de Dickson e aumento da relação altura da parte aérea/diâmetro do coleto e da relação parte aérea/sistema radicular. Nas três avaliações, o período de permanência das mudas sob sombreamento não influenciou significativamente os parâmetros área foliar, massa seca das folhas, massa seca da parte aérea e massa seca total. As mudas apresentaram melhores padrões de qualidade e condições de plantio no campo a partir dos 120 dias de idade, quando crescidas sob 45 e 60 dias de sombreamento. O índice de qualidade de Dickson foi bom indicador do padrão de qualidade das mudas.

Soil water content and water relations in planted and naturally regenerated Pinus halepensis Mill. seedlings during the first year in semiarid conditions

The capacity of Aleppo pine (Pinus halpensis Mill.) seedlings to overcome the planting shock in dry conditions was assessed by firstly studying the survival and water status during the first year after planting in relation to soil water content. In spite of receiving only 177 mm rainfall during the year studied, survival of planted Aleppo pine was very high (88.5%). Soil water during summer months (after receiving 67 mm rainfall in winter and spring) was only available at 30–60 cm depth, with tension values of −1.1 and −1.3 MPa in July and August respectively; in these conditions, July predawn xylem water potential measured was −2.5 MPa, and midday potential was −3.6 MPa. According to different authors, these values don't jeopardize the survival of Aleppo pine. In addition, acclimation of outplanted seedlings to environmental conditions was followed by comparing their water relations with those of naturally regenerated seedlings on the site. Predawn and midday xylem water potential showed differences in favour of outplanted seedlings since June, indicating an adjustment to this dry site. Compared to naturally regenerated trees, nursery grown stock of the same age before field planting had much more biomass and higher N and P concentrations and contents; although shoot:root balance and Dickson quality index were not significantly different. Finally, planted seedlings acclimation level during first year was also evaluated by Transplant Stress Index, which value (−0.1278) indicated a slight planting impact.

Clonal differences in planting stock quality of sitka spruce

Morphological indices of planting stock quality, (shoot: root ratio, sturdiness quotient and Dickson's quality index) were calculated for six clones taken from half sibling families of Picea sitchensis (Bong.) Carr. in Scotland, UK. The clones were grown from stem cuttings and were lifted from the nursery in February. There were significant ( P = 0.05) clonal differences in all morphological indices of quality, and in root length, root tip frequency (number of tips per unit root length) and total number of root tips. By contrast, there was little variation in the number of first-order lateral roots produced per cutting. Significant clonal differences in root growth potential (RGP) were found, which demonstrated the opportunity to select for this important trait. Although plants of the largest clone were twice as heavy as plants from the smallest clone, RGP for these clones differed by a factor of 7. Root growth potential was significantly correlated ( P = 0.05) with the morphological indices of quality, and clones with the largest numbers of root tips had the largest RGP values.

Evaluación del residuo de cáscara de nuez (<i>Juglans regia</i> L.) en la producción de plántulas de <i>Pinus patula</i>, en vivero

Para producir plantas de calidad en vivero, se utilizan sustratos comerciales como el Peat Moss, agrolita y vermiculita, cuyo costo es eleva- do y reduce significativamente los márgenes de utilidad; por lo anterior, se necesita buscar sustratos alternativos. La cáscara de nuez (Juglans regia L.) es un residuo sin aprovechamiento en producción; sin embargo, cuenta con importantes elementos nutritivos para ser aprovechados por los organismos vegetales. Se evaluó el crecimiento inicial de Pinus patula producido en vivero, con composta de cáscara de nuez con agrolita y vermiculita, mediante sustitución paulatina del Peat Moss. Con un diseño experimental completamente al azar, se estudiaron 4 tratamientos a base de cáscara de nuez + agrolita y vermiculita, en proporciones que variaron desde 0% hasta 80% de cáscara de nuez, y la mezcla de sustratos comerciales. A los 7 meses y medio, las plántulas que se desarrollaron en el tratamiento 1, mezcla testigo (Peat Moss 33% + vermiculita 33% + agrolita 33%) y el tratamiento 4 (Cáscara de nuez 33% + vermiculita 33% + agrolita 33%) presentaron valores más altos en las variables: altura, diámetro, peso seco aéreo, peso seco radicular y peso seco total. La relación aérea/raíz y el índice de esbeltez no presentaron diferencias entre los 4 tratamientos. El valor más alto del índice de calidad de Dickson fue para el testigo (0,25 g.cm-1), seguido por el tratamiento 4 (0,24 g.cm-1), sin diferencias estadísticas. La cáscara de nuez permite producir plántulas sanas, por lo que es útil como sustrato alternativo para la producción de plantas en vivero, lo que reduce los costos de producción además de contribuir con el sector productivo forestal.