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The substrate is one of the main inputs for the production of Yerba Mate (YM) seedlings (Ilex paraguariensis A. St.-Hil.) and its properties must be adequate according to the cultivation system. The objective of this work was to analyze physical properties of substrates made with pine bark compost (CCP) and Sphagnum peat (T) and to evaluate their effects on the morphological quality of YM seedlings produced in alveolar plastic trays. The trial consisted of five treatments: 100% T; 75% T + 25% CCP; 50% T + 50% CCP; 25% T + 75% CCP and 100% CCP. The following variables were analyzed for each substrate: pH, electrical conductivity (EC), bulk density (Dap), total pore space (EPT), water retention capacity (CRA), aeration porosity (PA) and granulometry. Stem length and diameter, aerial dry mass (MSA) and root dry mass (MSR) were measured on 45 seedlings per treatment and the robustness index (IR) and Dickson quality index (ICD) were calculated. The statistical analyses used were principal component analysis, analysis of variance and Tukey's test (P < 0.05). All the substrates had pH and EC values within an adequate range (5.5 to 6.8 and < 1 dS m-1). The CRA increased and the PA decreased in response to increasing amounts of T, with significant differences among treatments (P < 0.0001). Seedlings grown under 75% T + 25% CCP, 50% T + 50% CCP and 25% T + 75% CCP had higher MSA while those under 100% T had lower MSR. The lowest IR was identified in seedlings under 25% T + 75% CCP and 100% CCP. The seedlings under 75% T + 25% CCP, 50% T + 50% CCP and 25% T + 75% CCP showed higher ICD. In conclusion, YM seedlings with the highest quality and robustness were obtained in substrates with EPT > 85%, CRA = 55%, PA = 35% and Dap = 200 kg m-3. [ABSTRACT FROM AUTHOR]

Substrates based on raw pine sawdust and composted pine bark, with controlled-release fertilizers, are an alternative for producing forest plants in nurseries. The aim of this study was to evaluate the effect of substrate, controlled-release fertilizer (FLC) and water-soluble fertilizer (FH) on the growth of Pinus cembroides Zucc. in nursery. The mixtures evaluated were composted pine bark (P. douglasiana Martinez), raw pine sawdust (P. engelmannii Carr., P. cooperi Blanco and P. durangensis Martinez) and peat moss (Sphagnum sp. ): M1 (60:0:40), M2 (35:30:35), M3 (25:50:25), M4 (15:70:15), with three fertilization schemes based on selected combinations of doses 0, 4 and 8 kg m-3 of FLC (MulticoteR), and 0.0, 0.5 and 1.0 g L-1 of FH (Triple 19R of N, P and K). The experimental design was completely randomized with a 4 x 3 factorial arrangement. The variables evaluated were: height, diameter, total biomass, Dickson's quality index, root volume (VR) and concentration of N, P and K in the foliage. The mixture of substrates and the fertilization scheme significantly affected (p£0.0001) the variables studied. The seedlings with greater height and total biomass were those treated with 4 kg m-3 FLC plus 0.5 g L-1 FH. The largest diameter and VR were obtained with 8 kg m-3 of MulticoteR. In most variables, the lower values occurred when only raw pine sawdust was applied and in mixtures with a higher proportion of sawdust. In treatments containing FLC and FH, plants with higher morphological attributes were obtained, regardless of the substrate. [ABSTRACT FROM AUTHOR]

In the nursery, the container, substrate and fertilization affect morphological and physiological characteristics of the plants. The objective of this study was to evaluate growth of Pinus greggii var. australis through interaction of containers, substrates and forms of fertilization. The experimental design was completely randomized with a 2×3×2 factorial array. The plants were produced in two types of 230 mL containers: (E1) with holes at the bottom for drainage and (E2) with lateral and bottom drainage. Three mixtures of substrates were used: larger proportion of peat moss (S1), pine bark (S2) or pine sawdust (S3). Osmocote Plus® (N-P-K 15:9:12) fertilizer was applied at a dosage of 8 g L-1 in two forms: F1 (only fertilizer 8-9 months release) and F2 (mixture, half 5-6 months release and half 8-9 months release). Seven months after sowing, the following parameters were measured: height, root collar diameter, shoot dry weight (SDW) and root dry weight (RDW). Also, the sturdiness quotient (SQ), the ratio shoot dry weight/ root dry weight, and the Dickson quality index (DQI) were calculated. The factors container and substrate were significant in all of the morphological variables (p£0.05), but fertilization was not significant. Container E1 produced taller plants with larger diameters than those produced by E2. Plants in S1 were taller and had larger root collar diameter, higher SDW, SQ and DQI. With S2 and S3, minimum suggested growth was obtained. Container design modifies plant growth. With controlled release fertilizers and pine bark and sawdust substrates, it is possible to produce good quality plants. [ABSTRACT FROM AUTHOR]

The drying disease affects plants grown in forest nurseries during the pre-emergence and post-emergence stages, constricting the stem and causing root rot. The objectives of this study were to identify the morphological and molecular characteristics of the Fusarium species that affects the nursery located in Atlangatepec, Tlaxcala, which causes the drying disease and root rot of Pinus greggii Engelm., to evaluate its effect in the germination of seeds in three substrates, and to analyse the incidence and pathogenicity of developing seedlings. The Fusarium fungus was isolated from diseased seedlings, it was purified, and, based on its morphology and molecular structure, as identified as F. circinatum Nirenberg & O'Donnell. The substrates were: peat moss, perlite, and vermiculite (S1); sawdust, bark, and peat moss (S2); and bark, sawdust, and peat moss (S3); they were evaluated in 60:20:20 ratios. The experiment had a completely randomized design, with six treatments and four repetitions per each one. The statistical analysis of the germination percentage was executed with ANOVA and the means comparison was carried out using the Duncan test (p≤0.05). The fungus produced a significant reduction in the germination of P. greggii's seeds. Disease incidence was lower in S2, during the first two months, and its post-emergence pathogenicity was proved by the induction of symptoms and reisolations of F. circinatum. [ABSTRACT FROM AUTHOR]