Untreated wastewater used for irrigating crops is the major source of toxic heavy metals and other pollutants in soils. These heavy metals affect plant growth and deteriorate the quality of edible parts of growing plants. Phytohormone (IAA) and exopolysaccharides (EPS) producing plant growth-promoting rhizobacteria can reduce the toxicity of metals by stabilizing them in soil. The present experiment was conducted to evaluate the IAA and EPS-producing rhizobacterial strains for improving growth, physiology, and antioxidant activity of Brassica juncea (L.) under Cd-stress. Results showed that Cd-stress significantly decreased the growth and physiological parameters of mustard plants. Inoculation with Cd-tolerant, IAA and EPS-producing rhizobacterial strains, however, significantly retrieved the inhibitory effects of Cd-stress on mustard growth, and physiology by up regulating antioxidant enzyme activities. Higher Cd accumulation and proline content was observed in the roots and shoot tissues upon Cd-stress in mustard plants while reduced proline and Cd accumulation was recorded upon rhizobacterial strains inoculation. Maximum decrease in proline contents (12.4%) and Cd concentration in root (26.9%) and shoot (29%) in comparison to control plants was observed due to inoculation with Bacillus safensis strain FN13. The activity of antioxidant enzymes was increased due to Cd-stress; however, the inoculation with Cd-tolerant, IAA-producing rhizobacterial strains showed a non-significant impact in the case of the activity of superoxide dismutase (SOD), peroxidase (POX) and catalase (CAT) in Brassica juncea (L.) plants under Cd-stress. Overall, Bacillus safensis strain FN13 was the most effective strain in improving the Brassica juncea (L.) growth and physiology under Cd-stress. It can be concluded, as the strain FN13 is a potential phytostabilizing biofertilizer for heavy metal contaminated soils, that it can be recommended to induce Cd-stress tolerance in crop plants.

Rice production holds a significant position in the Thai economy. Although it is the world’s largest rice exporter, Thailand’s increase in rice production is the result of an expansion in the cultivation area rather than an increase in yield per unit area. The present study was designed to estimate the technical efficiency and its governing factors for certified organic rice-growing farms in Yasothon Province, Thailand. A data envelopment model was employed to assess the technical efficiency of 328 farmer groups. The data revealed that the average technical efficiency was 23% and 28% under constant returns to scale (CRS) and variable returns to scale (VRS) specifications, respectively. Farmers can reduce the use of machinery, fertilizer, seed, and labor as input factors by about 80.1%, 25.62%, 24.72%, and 19.15%, respectively, while still achieving the same level of output. Multiple regression analysis was applied to estimate factors that affect the pure technical efficiency score (PTES) in the test regions. Results show that household size, farm size, water source, market accessibility, health symptoms, income, and labor were highly related to the TES and the amount of organic rice production. The regression coefficients of the predictors show that the income was the best predictor of the PTES at a significance level of p < 0.05. It is concluded that the farmers can potentially increase their yields by up to 72%–77% under current management practices.

Zinc (Zn) is critical for the activity of many enzymes including involved photosynthetic CO₂ fixation and indirectly involved in the production of growth hormones and internode elongation in crop plants. In this regard, a field experiment was conducted to investigate the comparative effectiveness of the Zn blended, Zn coated and bio-activated Zn coated urea on the growth, physiological, yield, and quality of wheat. Three types of urea were prepared including bio-activated Zn coated, Zn coated and Zn blended urea. The bio-activated Zn coated urea was prepared by inoculating the powdered organic material with Zn solubilizing bacterium (Bacillus sp. AZ6) and then this material was mixed with ZnO. This bioactive Zn was coated on urea at the rate to formulate 1.5% bio-activated Zn coated urea. Moreover, Zn blended urea was prepared by mixing powder ZnO with urea while Zn coated urea with 1.5% Zn was prepared by mixing ZnO and urea under proper moisture conditions to ensure proper coating. In results, growth parameters were significantly increased with the application of bio-activated Zn coated urea as compared to other urea formulations and the control. The same treatment caused the maximum increase in quality parameters like oil contents (55%), protein (30%), and N concentration (30%) as compared to the control. In conclusion, the application of 1.5% bio-activated Zn coated urea was highly effective in enhancing the growth, physiological, yield, and quality parameters of wheat.