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Soybean is a legume widely cultivated globally for its seeds, which are rich in oil and protein suitable for animal and human nutrition, and as a biofuel source. One of the main factors that limits production is soil salinity; currently there are an estimated 800 million hectares of agricultural land affected by salt stress worldwide. The aim of this research was to determine whether anatomical, morphological, nutritional, physiological, and biochemical parameters are negatively affected in soybean plants cultivated under different levels of salt stress. The experiment was randomized into five treatments (0, 50, 100, 150, and 200 mM Na+). Plants subjected to concentrations of 50 to 200 mM Na+ exhibited reductions in K (range 21% to 57%), Ca (range 38% to 63%), and Mg (range 20% to 41%) compared to controls (without Na+). Na+ stress progressively produced negative effects on photosynthetic machinery, gas exchange, and photosynthetic pigments, results clearly related to oxidative stress generated by the saline growth conditions. Interestingly, our study revealed that at concentrations up to 100 mM Na+ deposition of epicuticular wax occurred, the quantity and shape of the stomata changed, and the thickness of the leaf epidermis increased. Our broad-based, multidisciplinary, and comparative study proved that soybean plants suffer significant deleterious effects modulated by Na+ stress, mainly at concentrations above 100 mM Na+.

Abstract Economic analysis assists the administration of forest projects (mainly long-term ones) in providing solidity to the investment. This study aimed to analyze the economic viability of an eucalyptus plantation used for pulp production in the mesoregion of Southern Pará, Brazil. Financial analysis was performed using the following methods: net present value (NPV), equivalent annual value (EAV), soil expectation value (SEV), internal rate of return (IRR), and benefit-cost ratio (BCR). Additionally, sensitivity analysis was conducted to identify the cost and revenue values that would represent the interface regarding the viability of the project. To this end, a cash flow was created for different scenarios of cost and revenue. The economic indicators demonstrated that the investment, as proposed in the marketing of standing timber, proved to be economically viable. Sensitivity based on the updated net revenue, despite fluctuations, made the project profitable.