Abstract The main destination of manure is the application to croplands near livestock farms as nutrient source to enhance crop production. The aim of this study was to define the dairy liquid manure (DLM) dose, complementary to the mineral fertilizer, for higher crops yield, in rotation black oat-maize-wheat-soybean, and to identify the soil chemical variables improved by the manure that most affect the yield, in long-term. The experiment was conducted from 2006 to 2015, in no-tillage system, at Paraná State, Brazil. The soil was a Latossolo Bruno Distrófico típico, clayey texture. The treatments consisted by doses of DLM (0, 60, 120 and 180 m3 ha-1 year-1), complementary to the mineral fertilizer (applied in the same amount for all DLM doses). Crops yield and soil chemical variables were evaluated at six depths (0-10; 10-20; 20-30; 30-40; 40-50 and 50-60 cm). The DLM application increased the yield of all crops, but not in all harvests. The DLM even applied at soil surface improved the soil chemical variables in deep layers, resulting in high positive correlation between yield and exchange bases, P, Zn and Mn contents, and high negative correlation with Ca/Mg ratio and potential acidity at depth 0-10 cm. The DLM dose, complementary to the mineral fertilization, that provided higher soybean and wheat yield was about 130 m3 ha-1 year-1, while for maize this dose was equal to or greater than 180 m3 ha-1 year-1. This effect was not attributed to a single chemical variable but the improvement of all chemical variables evaluated.

Resumo O objetivo foi verificar a influência da aplicação de biofertilizante resultante da produção de energia a partir de biomassa de milho na absorção de nutrientes por plantas de pera durante o ciclo de cultivo, e na qualidade dos frutos. O experimento foi realizado em Ferrara (Itália), num pomar da cv. Abate Fétel, sobre Calcisolo Síltico Háplico. Os tratamentos consistiram em controle (sem aplicação) e biofertilizante (aplicação de 30 m3 ha-1 de biofertilizante, localizada na fila), com quatro repetições. Foram avaliados: N mineral, biomassa e respiração microbiana no solo; teor de nutrientes em folhas; e parâmetros de qualidade dos frutos. A aplicação de biofertilizante aumentou a disponibilidade de N mineral, a biomassa e respiração microbianas, e mesmo assim o teor deste nutriente não aumentou nas folhas. Os teores dos nutrientes foliares variaram durante a estação de crescimento e a aplicação de biofertilizante aumentou os teores de potássio, fósforo e zinco nas folhas maduras; enquanto reduziu o teor de magnésio e manganês foliar. A aplicação de biofertilizante reduziu o teor de massa seca, de sólidos totais e de boro dos frutos, sem efeito na firmeza e na acidez titulável. O biofertilizante teve efeito positivo sobre a dinâmica do N mineral no solo e a microbiota edáfica, alterando o teor de nutrientes nas folhas, favorecendo a produção de frutos.

Abstract The aim of this study was to verify the influence of biofertilizer application resulting from energy production from corn biomass on nutrient uptake by pear plants during the growing cycle, and on fruit quality. The experiment was carried out on a Siltic Haplic Calcisol in the Italian province of Ferrara, in a medium-density Abbé Fétel commercial orchard. Treatments consisted of control (no application) and biofertilizer (30 m3 ha-1 biofertilizer application on the row), with four replicates. The following variables were evaluated: mineral N, microbial biomass and respiration in soil; nutrient content in leaves; and fruit quality. Biofertilizer application increased soil mineral N availability; soil microbial biomass and respiration, but the content of this nutrient did not increase in leaves. Leaf nutrient concentration varied during growth season and biofertilizer application increased potassium, phosphorus and zinc concentration in mature leaves and reduced leaf magnesium and manganese concentration. Biofertilizer application reduced fruit dry matter content, total soluble solids and boron concentration, with no effect on fruit firmness and titratable acidity. Biofertilizer application has positive effect on soil mineral N dynamics and soil microflora, altering the content of nutrients in leaves, favoring fruit production.