Abstract Diversified crop rotation is an option for expanding producer incomes, and its adoption has presented a series of agronomic advantages compared to less diversified crop rotation systems. In this context, the objective of this study was to verify if higher-diversified crop rotation systems perform economically better than low-diversified ones. To this end, we conducted an experiment in no-tillage crop areas in Londrina, in south of Brazil, for the years 2014/15 to 2016/17. The experiment design was randomized blocks, with six treatments, consisting of crop rotation systems with different levels of diversification, and four replications. We observed that higher-diversified crop rotation systems yield higher revenues and profits. Only these systems, specifically the ones that included canola-corn, crambe-corn, and safflower-soybeans, or wheat-corn+brachiaria, canola-corn, and edible beans-soybeans were economically feasible. Despite higher cost, diversified systems with a greater number of commercial crops in winter presented higher profits. However, diversified systems with a high proportion of cover crops in winter are economically infeasible because their net return is negative.

RESUMO O índice de qualidade participativo do sistema plantio direto tem o intuito de avaliar a qualidade e a eficiência do manejo do solo quanto ao uso do sistema plantio direto, sendo formado pela soma ponderada de oito indicadores: intensidade da rotação de culturas, diversidade da rotação de culturas, persistência de resíduos na superfície do solo, frequência de preparo do solo, uso de terraços agrícolas, avaliação da conservação do solo, fertilidade balanceada do solo e tempo de adoção do sistema plantio direto. O objetivo deste estudo foi verificar com qual intensidade esses indicadores se correlacionam com o índice de qualidade participativa do sistema plantio direto e caracterizar os produtores rurais que participaram da pesquisa. Foram utilizados dados da ITAIPU Binacional, referentes ao índice de qualidade participativo do sistema plantio direto II. Foram realizadas análises descritivas e foi calculado o coeficiente de correlação de Pearson entre o índice e cada indicador. Com o intuito de verificar a relação dos indicadores entre si e dos produtores rurais que participaram da pesquisa com os indicadores, foram realizadas as análises de componentes principais e de agrupamento. Apesar de todas as correlações serem significativas ao nível de p-value ≤ 0.05, algumas correlações foram fracas, indicando a necessidade de mudanças para aperfeiçoar o índice. Com a análise de componentes, foram identificados três componentes principais, que explicam 66% da variabilidade dos dados e com auxílio da análise de agrupamento, os 121 produtores foram separados em cinco grupos. Verificou-se que o índice de qualidade participativo do sistema plantio direto II apresenta algumas limitações e, portanto, deve ser reavaliado para aumentar sua eficiência como indicador de qualidade do sistema plantio direto.

ABSTRACT The no-tillage system participatory quality index aims to evaluate the quality and efficiency of soil management under no-tillage systems and consists of a weighted sum of eight indicators: intensity of crop rotation, diversity of crop rotation, persistence of crop residues in the soil surface, frequency of soil tillage, use of agricultural terraces, evaluation of soil conservation, balance of soil fertilization and time of adoption of the no-tillage system. The aim of this study was to assess the extent to which these indicators correlate with the no-tillage system participatory quality index and to characterize the farmers who participated in the research. The data used were provided by ITAIPU Binacional for the indicators of the no-tillage system participatory quality index II. Descriptive analyses were performed, and the Pearson correlation coefficient between the index and each indicator was calculated. To assess the relationship between the indicators and the farmers’ behavior toward the indicators, principal component analysis and cluster analysis were performed. Although all correlations are significant at p-value ≤ 0.05, some correlations are weak, indicating a need for improvement of the index. The principal component analysis identified three principal components, which explained 66% of the variability of the data, and the cluster analysis separated the 121 farmers into five groups. It was verified that the no-tillage system participatory quality index II has some limitations and should therefore be reevaluated to increase its efficiency as an indicator of the quality of the no-tillage system.

Abstract The aim of this study was to verify the dynamics of milk production in Southern Brazil, analyzing the spatial distribution, evolution and structure of bovine milk production systems in the dairy-specialized microregions. To this end, annual data from 2000 to 2015 are drawn from the Municipal Livestock Survey, reported by the Instituto Brasileiro de Geografia e Estatística, and the Programa Nacional de Fortalecimento da Agricultura Familiar, reported by the Banco Central do Brasil. Location quotient analyses, principal component analyses and clustering analyses are applied. Results of the location quotient analysis indicate that, of the 94 microregions in Southern Brazil, 36 are specialized in milk production. Two principal components were identified (mechanized production and family production) capable of explaining 78.3% of the variation in the data. Among microregions specialized in milk production, cluster analysis identifies four groups that are differentiated by productivity levels and predominance of family versus commercial production. Furthermore, results reveal that there is substantial heterogeneity among microregions specialized in bovine milk production in Southern Brazil.

Abstract: The aim of this study was to determine how often rural farmers in a watershed use no-tillage systems combined with crop rotation, contour farming and agricultural terraces. The study area was Paraná Watershed III (PB3) in the western region of Paraná State, and data from the 2006 Agricultural Census of the Brazilian Institute of Geography and Statistics were used. A frequency distribution analysis of farms as a function of the no-tillage (NT) area was conducted in combination with a cluster analysis of soil and water conservation practices (adoption of crop rotation, contour farming and agricultural terrace practices). The results showed that the farms in PB3 adopt adequate soil and water conservation practices, with 73% adopting NT combined with at least 2 other conservation practices; however, agricultural terracing was found to be the most neglected practice in the region. In addition, based on the soil and water conservation practices in the watershed, 5 groups of farms were identified, the worst of which, those located in the municipalities that mainly neglect conservation practices, live in areas with highly erodible soils.

ABSTRACT Retaining sugarcane straw over the soil after harvesting can improve soil structure and increase soil carbon stabilization, mainly in macroaggregates. We evaluated the carbon content in the aggregate classes in areas under burn and no-burn (adopted for five years) sugarcane management systems, focusing on the superficial layer (0.00-0.20 m). The experiment was carried in an Oxisol and the treatments consisted in burnt sugarcane, manual harvest; burnt sugarcane, mechanized harvest; and no-burn, mechanized harvest. The retention of sugarcane straw on the soil surface is justified by the increase in carbon content and carbon stock in the surface layer (0.00-0.20 m) by restructuring of the soil, even though it cannot match the structure of the soil under native forest. Our results suggest that in no-burn management the carbon not occluded inside aggregates was important to increase carbon stabilization in soil and that more attention should be given to macroaggregates 2.00-8.00 mm present in this management system, that showed higher carbon content and was responsible for increase of the geometric and weight diameter, increasing the erosion resistance in the long term in relation to burn systems.