Performance of Medicago sativa Grown in Clay Soil Favored by Compost or Farmyard Manure to Mitigate Salt Stress

Abstract

The use of saline water for the irrigation of forage crops to alleviate water scarcity has become necessary in semi-arid and arid regions and researchers have been seeking ways to offset the harmful results of soil salinity. Soil amendments with compost, manure and other organic material provide a valuable source of plant nutrients and appear to speed up soil recovery. The aim of this study was to compare the benefits of farmyard manure and a municipal solid waste (MSW) compost (40 mg ha−1) for raising alfalfa (Medicago sativa, cv. Gabès) under salt-water irrigation. Both compost and manure improved plant mineral uptake and growth of alfalfa cultivated in clay soil. Using compost in clay soil increased the content of copper (Cu), cadmium (Cd), and zinc (Zn) in plant tissues compared to manure, while the bio-accumulation factor (BAF) of Cu, Pb and Zn was higher in plants grown with manure compared to MSW compost with salt stress. Compost addition could enhance alfalfa growth under salt stress, which depends on salt doses and can greatly improve the recovery effects in a cost-effective way, although additional amendment type should receive special attention in order to be used as a tool for sustainable agriculture.

Efficacy of Woodchip Biochar and Brown Coal Waste as Stable Sorbents for Abatement of Bioavailable Cadmium, Lead and Zinc in Soil

“…The use of organic sorbents as remediative agents in soil has been questioned due to claims that they could be sources of contaminants including HMs. However, unlike other studies (Hamid et al 2018;Mbarki et al 2020) which found high HM concentrations in some organic sorbents (up to 5.7 mg kg −1 Cd, 12.9 mg kg −1 Pb and 116 mg kg −1 Zn), their contents in the sorbents used in this study were much lower and within acceptable range for use in soil systems (Barth et al 2008). Figures 1, 2 and 3 show the EDTA-extractable fractions of Cd, Pb and Zn, respectively, from soils contaminated with a mixture of HMs spiked into soil at three doses.…”

Potential of Native Arbuscular Mycorrhizal Fungi, Rhizobia, and/or Green Compost as Alfalfa (Medicago sativa) Enhancers under Salinity

“…So far, Ca 2+ is supposed to be the hub of secondary messengers via Ca 2+ spiking in the nuclear region of root hairs [57]. Compost is rich in several mineral elements including N, P, K + , and Ca 2+ , and it maintains the soil pH [7]. Compost amendment increased the biomass and yield by increasing the uptake of essential mineral elements in crops [58].…”

“…Due to its high biomass production, high nutritional quality, high protein content, and its perennial growth, alfalfa is becoming more reliable and a great potential species as feedstock for animal and as a sustainable crop for second-generation bioethanol production [5,6]. Alfalfa is widely cultivated in arid and semi-arid areas where salinity is one of the main factors limiting the growth of this crop [7,8], and it strongly contributes to the socio-economic development of the local community [4]. Alfalfa is considered as moderately tolerant to salt and shows a clear stunting and evident yield reduction when the salinity value approaches 20 mM NaCl [9].…”

“…Compost could enhance soil quality (water-holding capacity and enrichment of humus and nutrients) and microbial activities [17]. Furthermore, it plays a pivotal role in inducing salinity tolerance via supplying plants with ample nutrients for their cellular and structural needs [7] and stimulation of antioxidant system [20]. It is likely that in organic agricultural production systems, there was a positive interaction of the root-associated microorganisms, which may benefit the cultivation of the crops under normal and environmental stress conditions.…”

“…However, how the composts exert positive effects on plant growth is still to be elucidated, and there remain knowledge gaps to determine if the application of compost influences rhizobia and AMF functions. Most of the studies have focused on AMF and/or rhizobia inoculation [8,9] or the application of compost [7] to alleviate the adverse impact of salt stress on alfalfa plants. However, to our knowledge, no data are available about the effect of their combined applications and the underlying salinity tolerance mechanisms in alfalfa.…”