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The restoration of polluted soils is crucial for ecosystem recovery services. Evidently, phytoremediation is a biological and sustainable technique that includes the use of plants to remediate heavy-metal-contaminated land; the plants should be tolerant to the contamination and capable of uptake or immobilization of the heavy metals in the soil. Moreover, defining an economically efficient approach to the remediation of a contaminated area, with the possibility of further utilization of phytoremediation biomass, renders energy crops a great option for this technique. Energy crops, in fact, are known for their ability to grow with low agricultural input, and later, the biomass product can be used to produce biofuels, bioenergy, and bioproducts in a sustainable and renewable way, creating economic potential, especially when these crops are cultivated in marginal lands. The aim of this work is to test two monoecious industrial hemp varieties in different levels of Cd, Pb, and Ni in soil. Both varieties were tolerant to levels of Cd and Pb contamination that were higher than the limit for commercial and industrial use, while Ni showed a significant effect at all the tested concentrations. The variety Futura 75 performed better than Kc Dora in terms of productivity and tolerance. [ABSTRACT FROM AUTHOR]

Sweet sorghum is a C4 plant with great biomass potential yield in semi-arid environments. Under growing conditions affected by water shortage and nutrient deficiency, the optimal combination of irrigation and nitrogen (N) fertilization rate is a central issue for sustainable farming systems. In this paper, a N balance study was applied to sweet sorghum cv. Keller, managed under three irrigation levels (I0, I50, I100: 0, 50, and 100% crop evapotranspiration—ETc restoration) and four N-fertilization rates (N0, N60, N120, N180: 0, 60, 120, and 180 kg ha−1). The 15N-labelled fertilization technique was used to assess the fate of N fertilizer within the agroecosystem. Dry biomass yield was significantly affected by the irrigation, while N rates had no effect. Across N and irrigation levels, the isotopic composition showed that approximately 34% of N applied by fertilization was used by the crop, 56% remained in the soil at the end of the cropping season, 1.83% was leached as nitrate, and 1.72% was volatilized as ammonia. N-fertilizer uptake was the lowest in I0, while in N0, the soil was strongly N-impoverished since sorghum showed a great aptitude to benefit from the soil N reserve. An even N input/output system (i.e., N-output corresponded to N-input) was observed in the N120 treatment, and the soil N reserve remained unchanged, while the system was N-enriched (positive input/output) in N180. However, although beneficial for crop nutrition and soil N reserve for subsequent crops in rotation, the N180 treatment is unsustainable due to many environmental side effects in the agroecosystem. [ABSTRACT FROM AUTHOR]