Geomorphometric tool associated with soil types and properties spatial variability at watersheds under tropical conditions

ABSTRACT The application of quantitative methods to digital soil and geomorphological mapping is becoming an increasing trend. One of these methods, Geomorphons, was developed to identify the ten most common landforms based on digital elevation models. This study aimed to make a quantitative assessment of the relationships between Geomorphons units, determined at three spatial resolutions and nine radii, and soil types and properties of two watersheds with different soil-landscape relationships in Brazil to help soil surveying and mapping under tropical conditions. The study was conducted at Lavrinha Creek (LCW) and Marcela Creek (MCW) watersheds, located in the state of Minas Gerais, Brazil. Spatial resolutions of 10, 20 and 30 m were the basis for generating Geomorphons at 9 radii of calculation for the watersheds. They were overlapped to detailed soil maps of the watersheds and a chi-square test was carried out to assess their relationship with soil types. Observation points were compared with the most highly correlated Geomorphons to also assess relationships with soil properties. Geomorphons with resolution of 30-m and radii of 20 and 50 cells, respectively for LCW and MCW, were more highly correlated with the variability of soil types, in accordance with the terrain features of these watersheds. The majority of observation points for each soil type was located in the same Geomorphon unit that was dominant when analyzing soil maps. There was less variability in soil properties between Geomorphon units, which was probably due to the highly weathered-leached stage of soils. Geomorphons can help to improve soil maps in tropical conditions when assessing soil variability due to its high correlation with tropical soil types variability

Efeito da aplicação de pó de basalto no desenvolvimento inicial de mudas de camu-camu (Myrciaria dubia)

A produção de mudas de fruteiras nativas é um importante passo para a preservação das espécies, exploração comercial sustentável e geração de emprego. Neste contexto, os fertilizantes alternativos, como pó de rocha, propiciam a obtenção de um substrato com maior fertilidade, rico em nutrientes, com redução de custos em mão de obra e com a reposição de adubação. O objetivo no presente trabalho foi avaliar o desenvolvimento inicial de mudas de camu-camu (Myrciaria dubia H.B.K. McVaugh) em função de doses de pó de basalto. O experimento foi conduzido em casa de vegetação pertencente ao CCA/UFRR. O delineamento experimental foi o de blocos ao acaso, com cinco repetições, em esquema fatorial (5x2+1), sendo seis doses de pó de basalto (0; 0,42;1,04; 2,08; 4,17 e 8,33 g kg-1), duas granulometrias (0,05 e 0,10 mm f) e uma testemunha. Vasos de polietileno de 14 litros foram as unidades experimentais e utilizou-se um Latossolo Amarelo distrófico textura média. A incubação do solo nos vasos teve duração de 120 dias e, após esse período, fez-se o transplante das plântulas. Após seis meses do plantio, foram determinados altura, diâmetro do colo, número de ramos e biomassa seca da parte aérea e de raiz das mudas. A partir destes dados, foram calculados os índices morfológicos. Os tratamentos sem pó de basalto (0 g kg-1) e a dose de 0,42 g kg-1 produziram mudas de menor qualidade em ambas as granulometrias testadas. As melhores mudas de camu-camu foram obtidas aplicando-se 4,17 e 8,33 g kg-1 de pó de basalto com a granulometria de 0,05 mm