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A field experiment was conducted in 2018 at Marciano della Chiana (Arezzo, AR, Central Italy) with the main aim of investigating the effect of soil amendment with organic fraction municipal solid waste (OFMSW) compost and legume green manuring (Vicia villosa Roth, cv. villana) on a tobacco crop (dark fire-cured Kentucky type, cv. Foiano) grown under both full (100% of ETc) and deficit (70% of crop evapotranspiration, ETc) irrigation. The treatments are hereafter reported as GM (vetch green manuring) and NGM (no vetch green manuring), FI (full irrigation) and DI (deficit irrigation), and C (compost soil amendment) and NC (no compost soil amendment). The following parameters were calculated: (i) yield of the cured product (CLY, Mg ha−1) at a standard moisture content of 19%; (ii) irrigation water use efficiency (IWUE, kg of cured product m−3 seasonal irrigation volume), nitrogen (N) agronomic efficiency (NAE, kg of cured product kg−1 mineral N by synthetic fertilizers). Dry biomass accumulated in the stem and leaves (Mg ha−1) was also measured at 25, 57, 74, and 92 days after transplanting (DAT). The N recovery from the different plant parts (kg ha−1) was determined at 57 and 74 DAT. The C/N ratio, NO3-N (kg ha−1), the soil organic matter (SOM, %), and the soil contents of P2O5 and K2O (mg kg−1) were also analytically determined at 43, 74, and 116 DAT. Water retention measurements were carried out on soil samples at 116 DAT at 0–0.3 and 0.3–0.6 soil depths. Overall, there was a negative effect of both compost amendment and green manuring on yield. Green manuring and compost soil amendment improved soil chemical characteristics (i.e., SOM and C/N), as well as the plant N recovery, the IWUE, and the NAE. They increased the water retention capacity of the soil when the tobacco crop was deficit-irrigated and appeared to be promising practices to support the deficit irrigation strategy, contributing to reaching good agronomic results, although under the conditions of water shortage, and showing synergistic action in those conditions. [ABSTRACT FROM AUTHOR]

Organic amendment and green manuring are two agricultural practices highly recommended to improve sustainability in agriculture since they show numerous beneficial effects on both soils and crops. The main aim of the present study was to evaluate the effect of both, specifically organic fraction municipal solid waste (OFMSW) compost and horse bean (Vicia faba L., cv minor) green manure, combined separately or together with a mineral fertilization using synthetic products and in comparison with a mineral fertilization alone (control), on a top-quality tobacco crop (dark fire-cured Kentucky) grown in the cultivation district of Central Italy (High Tiber Valley, Tuscany region) in 2020 and 2021. The following parameters were measured: (i) leaf emergence rate (LER, leaves day−1); (ii) crop growth rate (CGR, kg dry biomass ha−1 day−1); (iii) root weight density (RWD, mg cm−3); (iv) yield of cured product (CLY, Mg ha−1). Analytical determinations were carried out on soil, sampled at the 0–0.3 m depth (organic matter, %; total N, %; NO3-N, mg kg−1; C/N; P and K, mg kg−1), and on plant biomass (total N, %; NO3-N, kg ha−1). Soil water retention measures were also made. Water productivity (WP, kg cured product m−3 gross crop evapotranspiration, ETc gross), irrigation water use efficiency (IWUE, kg cured product m−3 seasonal irrigation volume) and N agronomic efficiency (NAE, kg cured product kg−1 mineral N applied by synthetic fertilizers) were calculated. Both the applications of OFMSW compost and horse bean green manure increased soil content of organic matter and main nutrients (N, P and K), as well as C/N, when compared with control conditions. There was an increase in soil water content in C conditions over the entire soil matric potential interval (0.04 to 1.2 MPa) with a maximum value at 1.2 MPa in both years. Both practices appeared promising for tobacco cultivation and could help to better address the nitrogen needs of the crop during the season and reduce potential water pollution due to nitrates. Considering the amount of synthetic nitrogen fertilizer saved by using both organic soil amendment and green manuring, there should be fewer potential carbon emissions due to the production, transportation and field application of synthetic nitrogen fertilizers. [ABSTRACT FROM AUTHOR]