The main cause of decreased soil fertility and soil organic matter content is intensive crop farming with inadequate management. This study aimed to evaluate soil chemical properties, total organic carbon content, physical granulometric fractions (particulate organic carbon and mineral-associated organic carbon), carbon stocks, and carbon management indices of oxisols in different integrated agricultural production systems (IAPSs) with reference to values in a haymaking area and native forest. The experiments were performed using completely randomized design, considering nine differently managed areas, including seven IAPSs and two reference areas (haymaking area and native forest); four soil samples from the 0.00-0.05, 0.05-0.10, and 0.10-0.20 m layers were randomly collected from each area and the abovementioned variables were evaluated. The results showed no differences in variables between the managed and reference areas, indicating the maintenance of fertility and carbon fractions. Therefore, the tested management strategies promote beneficial modifications of soil properties. Producers should adopt different IAPS management strategies for soil preservation.

Os sistemas integrados de produção lavoura-pecuária (SIPAs) em associação ao sistema de semeadura direta, sofrem ação do pisoteio animal ou do tráfego intenso de máquinas agrícolas, podendo resultar em alterações nas propriedades físicas do solo. O objetivo deste trabalho foi avaliar o efeito da adubação nitrogenada e manejos das forrageiras tropicais nas propriedades físicas do solo. O experimento foi realizado entre outubro de 2017 e janeiro de 2020, em Marechal Cândido Rondon – PR, em blocos ao acaso, com parcelas sub-subdivididas com uma testemunha adicional e quatro repetições. As parcelas foram constituídas por duas espécies forrageiras consorciadas com o milho: Urochloa brizantha e Magathyrsus maximum, mais a testemunha adicional (milho solteiro). As subparcelas consistiram nos manejos das forrageiras: fenação e pastejo; e nas sub-subparcelas, a presença ou ausência de adubação nitrogenada. Foram determinadas: densidade do solo (Ds), porosidade total (Pt), macro (Ma) e microporosidade (Mi), além da resistência do solo à penetração (Rp). A utilização de nitrogênio (N) em cobertura nas forrageiras após os manejos, aumentou a quantidade de Ma na camada de 0-0,05 m para o primeiro ano. Os valores de Ds estão acima do limite considerado crítico para o desenvolvimento das plantas, porém, com tendência à redução. A adoção do SIPA, independente da espécie forrageira utilizada e manejo adotado, seja fenação ou pastejo, não comprometeu a qualidade física do solo, sendo assim, uma ótima alternativa para a diversificação da produção na propriedade.

A soja é uma cultura de destaque e tem grande potencial, mas que pode ser afetada pela toxidez por alumínio presente na maioria dos solos brasileiro. Diante disso, o objetivo do trabalho foi avaliar o efeito de doses elevadas de calcário calcítico sob as características agronômicas da cultura, bem como a influência na absorção dos nutrientes Ca, Mg e K em plantas de soja em duas safras agrícolas no município de Marechal Cândido Rondon. O estudo foi desenvolvido na área experimental da UNIOESTE, campus Marechal Candido Rondon, em um Latossolo Vermelho eutroférrico empregando doses de calcário calcítico (0, 3, 6 e 9 t ha-1) distribuído a lanço sem incorporação. Observou-se efeitos das doses em dois anos agrícolas 2017/2018 e 2018/2019 quando foram avaliados caracteres agronômicos altura de plantas, número de plantas por hectare, diâmetro do caule, número de vagens por planta, número de grãos por planta, massa de mil grãos, produtividade e os teores de nutrientes foliares. Não houve influência das doses de calcário calcítico nas características agronômicas da cultura da soja. Pode ser observado influência das doses de calcário calcítico no acúmulo nutricional de Ca no tecido foliar na dose de 6 t ha-¹. As doses de calcário calcítico proporcionaram redução nos teores de K. O Mg foi influenciado apenas pelo ano agrícola, apresentando maior acúmulo em plantas no segundo ano agrícola.

This work aimed to evaluate the oxidizable and chemical fractions of organic matter and the carbon management index in different integrated agricultural production systems, hay production and native forest areas in an Oxisol. Nine areas with different management systems were evaluated being six managements of the combination between different oat density (40 and 60 kg ha-1) and grazing frequencies (0, 1 and 2) in autumn-winter and soybean succession in spring-summer, one with natural reseeding ryegrass and forage turnip in autumn-winter and soybean succession in spring-summer and two reference areas. In each soil management systems were collected soil samples composite in the 0-5, 5-10 and 10-20 cm layers and determined the Total Organic Carbon (TOC), humic substances (Fulvic Acids - FA, Humic Acids - HA and humin - HUM), the carbon in the oxidizable fractions (F1, F2, F3 and F4) and Carbon Management Index (CMI). Were observed that chemical, oxidizable fractions and CMI, do not have significant differences between with the various managements each other. For TOC, HA, HUM, F1, F3, F4 and CMI, the managements did not differ from the reference areas indicating maintenance of soil carbon.

This study aimed to evaluate the decomposition and release of nutrients from the remaining straw of two annual forage species conducted in an integrated crop-livestock system (ICLS). The experimental design used was randomized blocks, in split plots, with three replicates. The managements were allocated in the plots (52 m²): without grazing, one grazing, and two grazings. Subplots were defined by material collection times after the forage’s desiccation (0, 30, 60, 90, and 120 days after desiccation). Dry matter yield, amounts of carbon, nitrogen, phosphorus, and potassium, and half-life time were evaluated. Oat cultivar IPR Esmeralda had the highest initial dry matter yield (6,099 kg ha^-1) when not grazed, while triticale cultivar IPR 111 showed the highest average values when subjected to grazing (8,088 kg ha^-1). The amounts of N, P, and K released from the remaining dry matter, regardless of the management adopted, decreased over time. Potassium was the nutrient that presented the most accelerated release, with an average half-life of 14 days. When subjected to grazing, triticale is more efficient in nutrient cycling, providing 197, 38, and 231 kg ha^-1 of N, P, and K, respectively, with a half-life time of 10, 37, and 25 days, respectively. Forage species can improve the cycling of nutrients and make them available to crops in succession in the ICLS.

The present work was aimed in order to evaluate the decomposition process of remaining straw from oat cultivars submitted to different handling during the cultivation of corn for silage intercropped with Urochloa brizantha cv. MG13 Braúna. We considered nine oat cultivars named as follows: "IAPAR 61 IBIPORÃ" oat hay (61F), "IAPAR 61 IBIPORÃ" pasture (61P), "IAPAR 61 IBIPORÃ" cover crop (61SM), "Embrapa 139 (Fog)" oat hay (139F),"Embrapa 139 (Fog)" pasture (139P)," Embrapa 139 (Fog)" cover crop (139SM), "Emerald IPR 126" oat hay (EF), "Emerald IPR 126" grazed (EP) and "Emerald IPR 126" cover crop (ESM) from which we evaluated the decomposition of the remaining straw using the method of litter bags. The evaluations were carried out at 0, 15, 30, 60, 90 and 108 days after sowing corn for silage intercropped with Brizantha brachiaria cv. MG13 Braúna (Urochloa brizantha). Every oat cultivar had three repetitions arranged in a split-plot design. We took into account the quantity of straw, organic matter, carbon, nitrogen, carbon / nitrogen ratio, phosphorus and potassium. The results we got clarify that oat decomposition rate varied with the meteorological factors and initial mass, so that the greater the initial mass is, the longer the straw permanency and mulch effectiveness on the soil. The time the residual oat straw took to be decomposed depended on meteorological factors both during the cover crop developmental stage and the decomposition period itself. The higher the initial mass, the greater the time and effectiveness of mulching.