Crescimento e nutrição mineral de porta-enxertos de seringueira (Hcvea spp.) em função da idade.

Abstract

Abstract 1: For some time, knowledge of the nutritional requirements of the rubber tree in the nursery phase of rubber in formation and production was little known. With the increase in rubber consumption in the world, greater attention has been given to nutrition research in rubber, aiming to recommend a more adequate fertilization in the different stages of the crop. The present work aimed to determine the growth and yield of dry matter, macronutrient content and accumulation in rubber tree rootstocks, as a function of age. The experiment was carried out at Embrapa Oriental Amazonia, Belém, PA experimental field, in an Oxisol with medium texture, with good physical properties, but with low fertility. Seedlings obtained from seeds of clone IAN 873 were used. The plants were collected at two, four, six, eight and ten months after planting, and separated into leaves, stem and petiole, to determine the dry mass of the plant. macronutrient content and accumulation. The growth of rubber tree rootstocks evaluated by biomass, height, diameter and petiole was more expressive from the sixth month of age, with the largest increase in total dry mass occurred between the eighth and tenth month. The contribution of the different components to the dry mass of rubber tree rootstocks followed the following order: stem dry mass> leaf dry mass> petiole dry mass. In general, there was variation in macronutrient contents of rootstocks in leaves, stem and petiole as a function of age. The rootstocks of rubber presented satisfactory N, P, K and Ca leaf contents. The period of greatest increase in macronutrient absorption in rubber tree rootstocks occurred between the eighth and tenth month. The order of total macronutrient accumulation in rubber tree rootstocks at ten months of age is as follows: N> K> Ca> Mg> P> S. The amounts extracted from nitrogen, phosphorus, potassium and magnesium at 10 months of age. age considering 100% fertilizer efficiency corresponded to 11.1 g / urea plant, 2.3 g / triple superphosphate plant, 6.6 g / potassium chloride plant and 5.5 g / sulfate plant of magnesium.

Abstract 2: Analyzing the growth of a plant is one of the basic requirements for solving any nutritional problem, such as fertilizer application time. Thus we realize that the need to increase studies on mineral nutrition in nursery and rubber tree in formation and production. In order to verify the growth and production of dry mass in different parts of rootstocks according to the age of 2, 4, 6, 8 and 10 months of age, an experiment was carried out in an experimental area of ​​Embrapa Eastern Amazon. Belém-PA, in a Yellow Latosol with medium texture, with good physical properties, but low fertility. The samples of rubber tree rootstocks were collected, separated into different parts, placed in paper bags and placed in an oven with forced air circulation at 70oC until reaching the constant dry mass weight. Results of plant height, stem diameter, leaf number, leaflet number, stem dry mass, leaflet dry mass and total dry mass were analyzed according to age (2, 4, 6, 8 and 10 months old). There was an increase in the referent height from two to ten months of age, the largest increase occurred between the eighth and tenth month, similar to that observed for stem diameter and number of leaves of rubber tree rootstocks. The rootstocks of rubber tree showed satisfactory growth, since they reached six months and ten months of diameter in grafting conditions beyond the minimum recommended. The number of petiole increased with age, with a greater increase between the fourth and sixth month. Leaf dry mass also increased with age, with the largest increase occurring between the eighth and tenth month, and stem dry mass production showed the smallest increase at two months and the largest at ten months, similar to yield. of dry mass of the petiole. The total dry mass production of rubber rootstock showed an increase with age, where the greatest increase occurred between the eighth and tenth month.

Abstract 3: In the rubber tree culture, there were few studies on nutrition studies, where it is known that there is a need to increase mineral nutrition studies in the various stages of rubber tree cultivation. The nutrient absorption march provides information on the nutritional requirement of the plants in their different phonological stages, signaling the most favorable times for the addition of nutrients in adequate doses, favoring a good plant development. Aiming to obtain knowledge about macronutrient content and accumulation in rubber tree rootstocks aged 2 to 10 months, this field-based experiment was carried out at Embrapa Oriental Amazonia, Belém, PA, in a Yellow Latosol. Medium texture. The plants were collected at 2, 4, 6, 8 and 10 months after planting, separated in leaf, stem and petiole, and placed in paper bags and placed in a greenhouse with forced air circulation at 70oC until reaching constant weight. The material was then milled for dispatch to the Foliar Analysis Laboratory of the Federal University of Lavras, MG, for the diagnosis of macronutrient content and accumulation. The period of greatest increase in the absorption of macronutrients in rubber tree rootstock at field level was from the eighth to the tenth month. The total accumulation order of macronutrients in rootstocks It was concluded that N> K> P> Ca> Mg = S. It is concluded that rubber tree rootstock extract small amounts of nutrients from the soil up to 240 days.