Vermicompost and millicompost as a resource in sustainable agriculture in semiarid: decomposition, nutrient release, and microstructure under the action of nitrogen and organic-mineral fertilizers.

With the expansion of organic agriculture, research is needed to indicate economically and ecologically viable fertilizer options, especially in semiarid regions, with low soil organic matter and nitrogen content. In the Brazilian semiarid region, vermicomposts are widely used by farmers and are scientifically investigated; however, there is no information for millicompost, a new type of organic compound that has shown very promising results in other regions. Thus, this study aimed to analyze the decomposition rate, nutrient release, and microstructure evaluation of vermicomposts from different sources and of millicompost produced from plant residues, with the application of mineral nitrogen-urea and organo-mineral fertilizer in the Brazilian semiarid region. The experimental design was a randomized block in a 4 × 3 factorial scheme, with four replicates; four organic composts (millicompost, commercial vermicompost, vermicompost from bovine manure, vermicompost from goat manure); and three types of fertilization (without fertilizer, with mineral-urea and organo-mineral fertilizer). The organic composts were decomposed using litterbags at the soil surface. The variable's decomposition rate and the nutrient release were evaluated at six-time intervals (0, 30, 60, 90, 120, and 150 days), and microstructure was evaluated at the beginning and the end of the experiment, with scanning electron microscopy (SEM). The highest decomposition was verified for commercial vermicompost rich in macro and micronutrients and with lower P contents. The lignin:N ratio and the initial P content were more important in the permanence of the organic compost in the field than the C:N ratio. Regardless of the organic composts, the use of urea as a mineral fertilizer stimulated decomposition more than the organo-mineral fertilizer. The initial composition of the nutrients was decisive in the dynamics of nutrient release, mass loss, and decomposition of C. There was no pattern in the release order of macronutrients. However, for the micronutrients, the release order was Cu > Fe > Mn, in all treatments. Microstructure analysis is a visual analysis where differences are detected through microphotographs and the biggest difference occurred with millicompost, which showed elongated fibers and fiber bundles, forming a relatively open structure characteristic of the presence of fulvic acid. However, the addition of organo-mineral fertilizer formed agglomerates in compacted micro-portions, helping the mineralization of C and N.

Ethnopedology in production units at Canto da Ilha de Cima, São Miguel do Gostoso-RN, Brazil / Etnopedologia em unidades de produção canto da ilha de cima, São Miguel do Gostoso, RN, Brasil

Ethnopedological studies in family units tend to contribute to the academy with respect to the importance of knowledge exchange, allowing the understanding on the local reality of a community. The objective of this study was to conduct an ethnopedological study in production units at the Settlement Project Canto da Ilha de Cima ­ RN, Brazil, and to infer on their interrelationships of knowledge. Participatory workshops and transverse walks were carried out and soils were classified by means of Ethnopedology. The soils were classified using etic and emic approaches, respectively: Inceptisol - CAMBISSOLO HÁPLICO Carbonático típico (Terra Boa or Malhada de Boi) (P1); Oxisol - LATOSSOLO AMARELO Eutrófico típico(Terra de Arisco) (P2); Ultisol - ARGISSOLO VERMELHO AMARELO Eutrófico típico (Terra de Arisco Branco Amarelado) (P3); Oxisol - LATOSSOLO AMARELO Eutrófico típico (Terra de Piçarro) (P4); Ultisol - ARGISSOLO AMARELO Eutrófico abrúptico (Terra de Arisco) (P5) and Inceptisol - CAMBISSOLO HÁPLICO Tb Eutrófico típico (Terra Boa or Velha Chica) (P6 and P7). In the emic survey, farmers described as fertile and better for agricultural activities the soils in the following areas: "Terra Boa" or "Malhada do Boi" (P1) and "Velha Chica" or "Terra Boa" (P6 and P7), corroborating the etic classification, based on the parent material. The soils in these areas were classified as Inceptisols(CAMBISSOLOS), which have higher natural fertility.

Estudos etnopedológicos em unidade familiar tendem a contribuir com academia sobre a importância da troca de saberes, proporcionando a compreensão da realidade local de uma comunidade. Objetivou-se a realização de estudo etnopedológico no Projeto de Assentamento Canto da Ilha de Cima ­ RN, em unidades de produção e inferir sobre as suas inter-relações dos conhecimentos. Foram realizadas oficinas participativas e caminhadas transversais e a classificação dos solos por meio da Etnopedologia. Os solos foram classificados de forma eticista e emicista, respectivamente: CAMBISSOLO HÁPLICO Carbonático típico ­ Inceptisol (Terra Boa Malhada de Boi) (P1); LATOSSOLO AMARELO Eutrófico típico ­ Oxisol (Terra de Arisco) (P2); ARGISSOLO VERMELHO AMARELO Eutrófico típico ­ Ultisol (Terra de Arisco Branco Amarelado) (P3); LATOSSOLO AMARELO Eutrófico típico ­ Oxisol (Terra de Piçarro) (P4); ARGISSOLO AMARELO Eutrófico abrúptico ­ Ultisol (Terra de Arisco) (P5) and CAMBISSOLO HÁPLICO Tb Eutrófico típico ­ Inceptisol (Terra Boa Velha Chica) (P6 and P7). Os agricultores denominaram no levantamento emicista como terras férteis e melhores para o desempenho das atividades agrícolas, nas seguintes áreas: Terra Boa ou Malhada do Boi (P1) e as áreas denominadas de Velha Chica ou Terra Boa (P6 e P7), corroborando com a classificação eticista, em função do material de origem, sendo classificadas como CAMBISSOLOS, com maior fertilidade natural.