The Use of Mathematical Model to Predict Levels of N and K for Optimum Yield

Sometimes, yield from a commercial plantation is reduced because of inadequate availability of fertilisers to the plant due to various reasons such as poor quality of fertilizers used, loss of fertilizers in the field during cultivation due to natural causes etc. One way of preventing such loss in yield is to apply remedial fertiliser doses in the field in an intermediate stage of cultivation. To implement such a method effectively, a mathematical model has been proposed in this work. The model first determines the amount of fertilisers needed at the beginning of cultivation to optimize yield. It then ascertains at an intermediate stage of cultivation whether the plant receives adequate fertilisers for producing optimum yield. In case it is found out that required fertilisers are not available to the plant, the model decides how much more remedial fertilizer doses should be applied at the intermediate stage so that yield will not be affected. A potato plantation has been considered to illustrate the applicability of the proposed mathematical model.

Natural regeneration, composition and structure in a secondary Atlantic Forest fragment and in an abandoned Eucalyptus saligna Smith. (Myrtaceae) commercial plantation / Regeneração natural, composição e estrutura em um fragmento em sucessão secundária de Mata Atlântica e em reflorestamento comercial de Eucalyptus saligna Smith. (Myrtaceae) abandonado à regeneração

The litter horizon on forests ecosystems acts on the nutrient cycling and on the soil’s microclimate conditions. However, to reforestation ecosystems the litter attributes can conduct to alterations that can diminish the seedling establishment, as well can act on the herbivory rates. In this context, this study aimed to verify the differences and relationships between woody species diversity, the herbivory index, the litter attributes, and the canopy openness among a fragment of Atlantic Forest on secondary succession and commercial plantation of Eucalyptus saligna Smith abandoned to regeneration. This study was conducted at the Klabin’s Company “Ecological Reserve”, at Telêmaco Borba – PR, Brazil. There weren’t observed differences on the species richness and abundance among the studied sites. Litter mass and thickness were higher in E. saligna environment. However, the litter attributes only presented relationship with the woody vegetation at the Atlantic Forest site, such as abundance and species richness with litter mass (r2=0.53 and r2=0.40, respectively) and abundance with litter thickness (r2=0.63). The herbivory index was greater on the forest patch. The canopy openness was superior in the E. saligna site. At this site, the herbivory index presented a positive relation with the canopy openness (r2=0.48) and a negative with abundance (r2=0.48). Abundance also presented a negative relation with the canopy openness (r2=0.58) in the E. saligna environment. The litter horizon on the E. saligna plantation doesn’t seem to offer restrictions to regeneration of the woody vegetation. However, at this site, the higher canopy openness and the herbivory pressure over the woody vegetation may lead to a lower rate of secondary succession compared to the Atlantic Forest fragment.

Outbreak of Lauritrioza alacris (Flor, 1861) (Hemiptera, Triozidae) in a commercial plantation of bay laurel (Laurus nobilis L., Lauraceae) in Brazil

An attack of Lauritrioza alacris (Flor, 1861) (Hemiptera: Triozidae) was recorded in a commercial plantation of bay laurel (Laurus nobilis L., Lauraceae) in the municipality of Dois Lajeados, Rio Grande do Sul state (RS), Brazil. The immature triozids induced galls on the attacked leaves consisting of the thickened margins that became folded downward, forming an elongated tube-shaped roll that sheltered the immatures. All developmental stages (egg, immatures, and adults) of the psyllid were found on young leaves of bay laurel. Lauritrioza alacris is an introduced pest in Brazil that was detected in Pelotas, RS in 1949 and Rio de Janeiro, Rio de Janeiro state in 1953. Therefore, we are reporting the third record of L. alacris; however, it is the first documented information of an infestation in a commercial bay laurel plantations by L. alacris in Brazil. Information on taxonomy, biological aspects, distribution, and damage caused by the laurel psyllid is also provided.

DEVELOPMENT OF NEOLAMARCKIA CADAMBA (KELEMPAYAN) TISSUE CULTURE TECHNIQUES FOR SUSTAINABLE SUPPLY OF PLANTING MATERIALS FOR COMMERCIAL PLANTATION

Neolamarckia cadamba (kelempayan) is a multipurpose and fast growing timber species. The tree is grown for timber, paper-making and as ornamental plant. It is reported that its barks and leaves possesed medicinal values and its flowers are used in perfumes. The species is also known to be suitable for plywood, packing case, toys and short-fibred pulp. Therefore, mass production of high quality planting material of N. cadamba is important to support plantation program of this species. Here we presented mass production of N. cadamba through tissue culture techniques. Nodal segments derived from in vitro germinated seeds were used and induced direct organogenesis to produce shoots and roots using MS media (1962) and plant growth regulators (BAP and IBA) that are relatively cheaper than previously used methods. The tissue culture technique of N. cadamba developed may help in ensuring supply of planting materials that are feasible for commercial plantation purposes.

Biomass assessment, volume equations and crown architecture of Eucalyptus pellita F. Muell in a commercial plantation in Mexico

En un ensayo de procedencia se seleccionaron seis árboles de Eucalyptus pellita F. Muell, de diferentes clases de diámetro; para obtener el peso verde en campo cada árbol fue separado en sus componentes: tallo, hojas, ramas. Se llevaron a cabo regresiones lineales para obtener modelos de biomasa para el componente aéreo, utilizando el diámetro a la altura del pecho (DAP) como la variable independiente. Posteriormente se realizaron análisis para obtener la cantidad de carbono (C) y el dióxido de carbono (CO2) almacenado en una plantación de 2.5 años de edad. En general, se obtuvo un promedio de 27.04 kg de carbono almacenados en el tallo y 10.44 kg de carbono en el follaje, que representa un reservorio de 99.23 kg de CO2 almacenados en el tallo y 38.32 kg de CO2 en el follaje. En la literatura, no hay muchos estudios sobre desarrollo de copa; el presente trabajo relaciona altura de la copa, diámetro de copa y altura total en 4 índices que describen una determinada estructura del árbol (cobertura copa (CC), índice de la Copa (CI), forma de copa (CS), sombra de copa (CSd)). Los resultados muestran, para los seis individuos evaluados, un valor relativamente alto para CC, el cual presenta el valor más bajo para el diámetro más pequeño; la cobertura de copa indica que la especie, en este grupo de edad, todavía está en crecimiento de manera exponencial y que su área fotosintética necesita todavía ser alta para sostener tal crecimiento. En cuanto al índice de forma de copa, entre mayor sea el diámetro, mayor es el valor que se obtiene, lo que indica que el crecimiento en diámetro puede estar relacionado positivamente a CS; deduciéndose un desarrollo sano de la copa entre mayor sea este valor. Los valores de CSd confirman esta afirmación al mantenerse la relación.