Lipoic acid (LA) and melatonin (MT) are pleiotropic molecules participating in plant stress resistance by modulating cellular biochemical changes, ion homeostasis, and antioxidant enzyme activities. However, the combined role of these two molecules in counteracting the detrimental impacts of salinity stress is still unknown. In the present study, we determined the effects of exogenous LA (0.5 µM), MT (1 µM) and their combination (LA + MT) on growth performance and biomass accumulation, photosynthetic pigments, enzymatic and non-enzymatic antioxidant activities, and ions homeostatic in canola (Brassica napus L.) seedlings under salinity stress (0, 100 mM) for 40 days. The results indicate that exogenous application of LA + MT improved the phenotypic growth (by 25 to 45%), root thickness (by 68%), number of later lateral roots (by 52%), root viability (by 44%), and root length (by 50%) under salinity stress. Moreover, total soluble protein, chlorophyll pigments, the concentration of superoxide dismutase (SOD), catalase peroxidase (CAT), and ascorbic peroxidase (ASA) increased with the presence of salt concentration into the growth media and then decreased with the addition of LA + MT to saline solution. Leaf protein contents and the degradation of photosynthetic pigments were lower when LA + MT treatments were added into NaCl media. The proline and phenol contents decreased in the exogenous application of LA + MT treatments more than individual LA or MT treatments under the salinity stress. The incorporation of LA or MT or a combination of LA + MT to saline solution decreased salinity-induced malondialdehyde and electrolyte leakage. In conclusion, the alteration of metabolic pathways, redox modulation, and ions homeostasis in plant tissues by the combined LA and MT application are helpful towards the adaptation of Brassica napus L. seedlings in a saline environment. The results of this study provide, for the first time, conclusive evidence about the protective role of exogenous LA + MT in canola seedlings under salinity stress.

The present investigation was conducted to understand the role of enriched biochar on soil nitrogen and carbon dynamics, leaching losses of nutrients, and growth attributes of wheat. Buffalo slurry (BS) was used to enrich the biochar for 24 h and 2% biochar (SB) or enriched biochar (SEB) was used. Enrichment of biochar with BS as SEB improved the C and N contents of biochar by 33–310% and 41–286% respectively. The application of biochar (SB) and enriched biochar (SEB) reduced the net nitrification by 81% and 94%, ammonification by 48% and 74%, and carbon dioxide by 50% and 92% respectively as compared to control. The leaching losses minerals i.e., C (by 30%), N (by 125%), P (by 50%), K (by 82%), Na (by 9%), Ca (by 24%), and Mg (by 12%) was decreased in SEB treatments compared to control. The soil enzyme activities, microbial biomass (MBC and MBN), wheat agronomy, soil bulk density and soil pore density, mineral uptake from the soil, and mineral contents in the plant body were improved in the SEB as compared to SB and control treatments. Our results revealed that the biochar enrichment process could improve the C and N storage in the soil reservoir and lower the environmental risks to soil and water.

Freshwater alternatives to irrigate crops are in dire need of time because of changing climate and scarcity of freshwater. Therefore, seawater can be the best feasible option as it is abundantly available on Earth. Sole application of seawater for agricultural crops is impossible, but the blend with freshwater may not be aggravating the salinization problems in soils. The present investigation was conducted to evaluate the possibility of growing the short period summer vegetables i.e., eggplants, tomato, and pepper with fresh and seawater blends viz. 5%, 10% and 20%, termed as A, B and C treatments, respectively. During the experiment, we considered: (i) crop growth, biomass yield, water consumption, water use efficiency (WUE) and water productivity (WP); (ii) photosynthetic pigments and gas exchange parameters; (iii) concentration of mineral contents and quality traits; (iv) lipid peroxidation, proline contents and ascorbic acid. Tomato productivity was markedly decreased by application of B and C treatments, whereas the growth of eggplant and pepper were not much influenced at the same concentrations. Water consumption dropped, whereas WUE significantly increased in all tested crops upon increasing seawater concentrations. Leaf Na⁺ concentration and other mineral elements increased. These results assumed that certain concentrations of seawater–freshwater blends revealed that there were no significant effects on the quality characteristics, mineral elements concentration and productivity of eggplant and pepper plants; however, tomato plants indicated sensitivity at the three seawater concentrations (A, B and C SFW treatments). Moreover, low concentrations of salinity stress (5% and 10% SFW) seemed to be necessary to attain better crop nutrition and organoleptic values. Accordingly, the results of present will be helpful to coastline farmers in cultivating vegetables and produce nutritive food for their family.

Nitrogen (N) is the prime essential nutrient for agricultural productivity, and its deficiency is overcome through the application of fertilizers. However, the rate of N mineralization from organic N sources is an important process to be monitored for efficient N use and sustainable agricultural management. Laboratory incubation studies were conducted for a period of 150 days to measure N mineralization (N_min) from different organic amendments (OA) in texturally contrasting soils collected at three locations: SL1 (Bahawalpur, sandy loam), SL2 (Bahawalnagar, sandy loam), and SL3 (Rahim Yar Khan, sandy clay loam). A second study was also carried out for 25 days to monitor pH dynamics and ammonia volatilization from the same three OA-treated soils. The results showed that there was no significant difference in net N_min between the soils for poultry manure (PMO) and feather meal (FMO), even if there was a substantial N_min observed for PMC + FMO followed by poultry manure compost (PMC) at SL2 and SL3 soils. This might have happened due to higher microbial biomass carbon (257), nitrogen (61), fungal colonization (88 cfu g⁻¹ soil) and enzyme activity (79) in SL3 soil receiving PMC + FMO after 150 days of incubation. However, the first-order kinetic model (R² = 0.86–0.95) better explained the N_min in all three soils amended with OA (PMC + FMO). The soil pH had more pronounced effects on N_min in all three soils. A non-significant amount of ammonia volatilization was recorded regardless of the initial pH, buffering capacity, and texture variability of the soils. Further study on the particle size of OA and soil pH is warranted to determine the actual effect of OA on N_min.