Maria Karoline de Carvalho Rodrigues de Sousa

This study hypothesized that urea fertilization could optimize animal performance in an agroforestry system. This study evaluated how increasing rates of N fertilization (0, 100, 200, and 400 kg N ha⁻¹ year⁻¹) using urea (CH₄N₂O) affected forage mass, nutritive value, and beef cattle (Bos indicus) performance in an agroforestry system with Massai grass (Megathyrsus maximus Jacq. cv. Massai) and legume tree (Mimosa caesalpiniifolia Benth.), in the humid tropic region of Brazil, over 2‐year period. The experiment was carried out in a randomized complete block design with four treatments (N fertilizer rates) and three replications. Forage mass was positive and linearly affected by N fertilization (p = .0236, R² = 0.92), ranging from 1297 to 1583 kg DM ha⁻¹ under 0 and 400 kg N ha⁻¹ year⁻¹, respectively. There was greater average forage mass during the rainy period (1826 kg ha⁻¹) (p < .05). Crude protein in green forage mass increased linearly (p = .0041, R² = 0.91) in function of the N applied. Cattle average daily gain showed a positive quadratic response to the rates of N applied (p = .0298, R² = 0.97), ranging from 0.46 kg to 0.68 kg animal day⁻¹; and the gain per area increased linearly from 1.84 to 2.68 kg LW ha⁻¹ day⁻¹ (p = .0640, R² = 0.96). The findings indicate that applying 200 kg N ha⁻¹ year⁻¹, split‐applied during the rainy season, would yield acceptable outcomes in terms of forage mass, nutritive value, and animal performance for this type of agroforestry system.

The intensive use of land has accelerated the loss of soil quality, a process that can be avoided by adopting conservationist production systems, such as the Integrated Crop-Livestock-Forest (CLFI system). It is noteworthy that in the Southwest of the State of Maranhão a substantial portion of soils in rural properties are degraded and in distinct stages of erosion, since they have been exploited for decades with non-properly managed pastures. Therefore, the objective of this work was to emphasize the importance of physical and chemical changes in the soil of pastures under crop-livestock-forest integration in general and in the Amazon region of state of Maranhão, Brazil. Therefore, a literature review was conducted through a search for studies in the Google Scholar database, which encompasses multiple other databases, such as Scielo, Elsevier, Scopus, Capes, and others. In face of the conditions of degradation in pastures throughout the state of Maranhão and the broad distribution of native forests such as Babassu forests, the use of technology from CLFI systems could allow for their recovery and sustainable status by means of economically and ecologically feasible productivity. Research on this field is therefore necessary to highlight short- and long-term efficiencies regarding carbon sequestration and quality of organic matter on the soil.