The associations among ion uptake, root development and biomass under salt stress have not been fully understood. To study this, a pot experiment was conducted with the objective to determine the concentrations of sodium (Na), potassium (K), calcium (Ca), magnesium (Mg), zinc (Zn) and iron (Fe) and explore their associations with the biomass and root development by using eight wheat cultivars grown on control and salt stress treatments. About 6 folds increase Na⁺/K⁺ ratio in root, while 10 folds in the shoot were detected in salt stress compared to that for control. Ca, Mg, Zn concentrations in both root and shoot, and Fe concentration in the shoot were significantly changed by salt stress, except Fe concentration in the root. Principal component analysis revealed significant associations of these ions with the aboveground biomass and root traits. On salt stress treatment, the Na⁺/K⁺ ratio in shoot showed a significant negative correlation with root weight and aboveground biomass, while aboveground biomass correlated positively with lateral root length and root weight. A strategy towards manipulating the ion homeostasis, particularly Na⁺/K⁺, combined with selecting genotypes with better salt tolerance is of promise to alleviate the effects of salt stress.

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Composting is an effective method of recycling organic solid waste, and it is the key process linking planting with recycling. To explore the reuse of agricultural organic solid waste as a resource in the Yellow River Delta, the effects of microbial inoculant and different additives (calcium superphosphate, biochar, tomato straw, rice husk, and sugar residue) on pile composting of cow dung were studied to obtain the best composting conditions. The results showed that microbial inoculant and additives all played positive roles in the process of aerobic composting, and the experimental groups outperformed the control groups without any additives. For discussion, the microbial inoculant promoted rapid pile body heating more than the recovery materials alone, and the effects on aerobic composting were related to the organic matter of substrates and biochar. After being composted, all the materials were satisfactorily decomposed. Degradation of additives into humic acid might serve as electron shuttles to promote thorough organic matter decomposition. These results provide a scientific basis data for industrial composting of organic solid waste processed by on-site stacking, and provide a reference for researcher and practitioners for studying the applications of microbial inoculant on aerobic composting.

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