Variabilidade espacial e temporal das características térmico-hídricas do solo em cultivo da Palma de óleo no leste da Amazônia.

A palma de óleo possui grande importância econômica e ambiental. O estudo térmico e hídrico do solo e a sua variabilidade espacial e temporal, torna-se importante pois os solos participam de todo o processo de troca de água e energia entre superfície, biota e a atmosfera. O objetivo do estudo foi caracterizar a variação espacial e temporal térmico-hídrica do solo, em cultivo de palma de óleo com híbrido interespecífico (Elaeis guineensis Jacq. x Elaeis oleífera (H. B. K.) Cortés), em um Latossolo Amarelo no leste da Amazônia. O estudo foi conduzido em um plantio de HIE (01º51’43.2’’S, 48º36’52.2’’O) no município de Moju, Pará, Brasil. A precipitação foi obtida por um pluviômetro instalado em uma torre de observações micrometeorológicas, e os dados microclimáticos do solo como umidade volumétrica (θ), temperatura (Tsolo) e fluxo de calor do solo (G) foram obtidos por meio de instrumentos instalados próximos à torre. Estes foram instalados verticalmente entre duas plantas (EP), em pontos localizados a distâncias crescentes a partir da estipe da planta: EP1 (0.5 m), EP2 (2 m) e EP3 (4 m). Adicionalmente, também entre duas linhas de plantas (EL). Amostras de solo foram coletadas em EP e EL, para proceder análises físicas como granulometria, densidade, porosidade e retenção de água no solo. A série temporal utilizada nesse estudo compreende o período de 2014 a 2017. Menores valores da θ foram observados em EP1, local com maior densidade de raízes que absorvem água e nutrientes. E, os maiores de θ em EP2 e EP3. É muito provável que pelo fato em EP3 ocorrer a deposição das folhas que são podadas, isso tenha promovido um efeito isolante, que pode atenuar tanto as trocas de calor com a superfície, quanto a evaporação, mantendo o solo mais úmido e com menores temperaturas. Independente do período, chuvoso (PC) ou menos chuvoso (PMC), a θ apresentou menores valores em EL do que em EP. Através da curva de retenção de água no solo (CRA), observou-se que houve menor retenção da água, maior densidade e menor porosidade total em EL do que em EP. A menor variação de Tsolo e G ocorreu especificamente em EP3, onde ocorreu a deposição das folhas podadas sobre o solo, em comparação com EL, no qual o solo estava descoberto.Oil palm has great economic and environmental importance. The thermal and water study of the soil and its spatial and temporal variability, becomes important because the soils participate in the whole process of water and energy exchange between surface, biota and the atmosphere. The objective of the study was to characterize the spatial and temporal thermal-hydric variation of the soil, in oil palm cultivation with interspecific hybrid (Elaeis guineensis Jacq. x Elaeis oleifera (H. B. K.) Cortés), in a Yellow Latosol in eastern Amazonia. The study was conducted in a HIE plantation (01º51’43.2’’S, 48º36’52.2’’O) in the municipality of Moju, Pará, Brazil. The precipitation was obtained by a rain gauge installed in a tower of micrometeorological observations, and the microclimatic data of the soil such as volumetric moisture (θ), temperature (Tsolo) and soil heat flow (G) were obtained by means of instruments installed near the tower. These were installed vertically between two plants (EP), at points located at increasing distances from the plant stem: EP1 (0.5 m), EP2 (2 m) and EP3 (4 m). Additionally, also between two lines of plants (EL). Soil samples were collected in EP and EL, to perform physical analyzes such as granulometry, density, porosity and water retention in the soil. The time series used in this study covers the period from 2014 to 2017. Lower values of θ were observed in EP1, a place with a higher density of roots that absorb water and nutrients. And, the largest of θ in EP2 and EP3. It is very likely that due to the fact that EP3 deposits the leaves that are pruned, this has promoted an insulating effect, which can attenuate both heat exchanges with the surface and evaporation, keeping the soil more humid and with lower temperatures. Regardless of the period, rainy (CP) or less rainy (PMC), θ showed lower values in EL than in EP. Through the soil water retention curve (CRA), it was observed that there was less water retention, greater density and less total porosity in EL than in EP. The smallest variation of Tsolo and G occurred specifically in EP3, where there was the deposition of pruned leaves on the soil, in comparison with EL, in which the soil was uncovered

SOIL ACIDITY AND SOY PHYTOMETRY UNDER APPLICATION OF LIMESTONE AND AGRICULTURAL GYPSUM

The soybean is one of the main agricultural crops in Brazil, because the use of its grains is an important source of protein and vegetable oil. One of the main limiting factors for obtaining high yields in soybean in tropical soils is related to the need to correct soil acidity. The objective of the study was to evaluate the development of (Glycine max (L.) Merrill) and the variation of pH values ​​of the soil under the application of limestone and agricultural gypsum. The experimental design was completely randomized, distributed in a 4x4 factorial scheme. The treatments consisted of doses of 0, 1,5, 3,0 and 4,5 t ha-1 of only limestone, only gypsum and the combination of limestone and gypsum, repeated four times, totaling 64 experimental units. The soil pH was evaluated at 30 (pH1), 45 (pH2), 60 (pH3), 75 (pH4) days before sowing. The plant variables were: number of pods (NP), shoot green mass (SGM), shoot dry mass (SDM), root green mass (RGM), root dry mass (RDM), root length (RL) and shoot / root ratio (S/RR). The variables pH4, SGM, RL and S/RR were significantly influenced by the treatments, alone or in interaction. For pH1, pH2, pH3, NP and SDM, there were isolated effects of treatments for gypsum and limestone. At the RGM the deformation was significant for limestone and gypsum interaction with limestone. For RDM, the effect of the treatment was verified only with the use of limestone. As a conclusion, the application of limestone and gypsum reduces the soil acidity, obtaining higher pH values ​​from the doses of 3000 kg ha-1, with the combination of limestone and gypsum. The use of gypsum consortium with limestone promotes significant results in the development of soybean plants.The soybean is one of the main agricultural crops in Brazil, because the use of its grains is an important source of protein and vegetable oil. One of the main limiting factors for obtaining high yields in soybean in tropical soils is related to the need to correct soil acidity. The objective of this study was to evaluate the growth of (Glycine max (L.) Merrill) and the variation of soil pH values under the application of limestone and agricultural gypsum. The experimental design was completely randomized, distributed in a 4x4 factorial scheme. The treatments consisted of doses of 0, 1.5, 3.0 and 4.5 t ha-1 of only limestone, only gypsum and the combination of limestone and gypsum, repeated four times, totaling 64 experimental units. The soil pH was evaluated at 30, 45, 60, 75 days before sowing. The growth variables were: number of pods, shoot dry mass, root dry mass, root length and shoot/root ratio. The variables pH 75 days, root length and shoot/root ratio were significantly influenced by the treatments, alone or in interaction. For pH 30, pH 45 and pH 60 days, number of pods and shoot dry mass, there were isolated effects of treatments for gypsum and limestone. In root dry mass, the effect of the treatment was verified only with the use of limestone. As a conclusion, the application of limestone and gypsum reduces the soil acidity, obtaining higher pH values from the doses of 3000 kg ha-1, with the combination of limestone and gypsum. The use of gypsum consortium with limestone promotes significant results in the growth of soybean plants