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The application of high-quality seeds ensures successful crop establishment, healthy growth, and improved production in both quantity and quality. Recently, biochar-based seed coating has been recognized as a new, effective, and environmentally friendly method to enhance seed quality, seedling uniformity, and nutrient availability. To study the impact of biochar coating on the surface mechanical properties of coated seeds, rice emergence and growth, and related physical and physiological metabolic events, laboratory experiments were performed on two water-saving and drought-resistance rice (WDR) varieties (Huhan1512 and Hanyou73) using biochar formulations with varying contents (20%–60%). The results showed that the appropriate concentration of biochar significantly improved emergence traits and seedling performance of the two rice varieties, compared to the uncoated treatment, and that the optimal percentage of biochar coating was 30% (BC30). On average, across both varieties, BC30 enhanced emergence rate (9.5%), emergence index (42.9%), shoot length (19.5%), root length (23.7%), shoot dry weight (25.1%), and root dry weight (49.8%). The improved germination characteristics and vigorous seedling growth induced by biochar coating were strongly associated with higher water uptake by seeds, increased α-amylase activity and respiration rate, and enhanced accumulation of soluble sugar and soluble protein. Moreover, the evaluation results of mechanical properties related to seed coating quality found that increasing the proportion of biochar in the coating blend decreased the integrity and compressive strength of the coated seeds and reduced the time required for coating disintegration. In conclusion, biochar coating is a cost-effective strategy for enhancing crop seed quality and seedling establishment. [ABSTRACT FROM AUTHOR]

Seed germination and stand establishment are the first steps of crop growth and development. However, low seed vigor, improper seedbed preparation, unfavorable climate, and the occurrence of pests and diseases reduces the germination rate and seedling quality, resulting in insufficient crop populations and undesirable plant growth. Seed coating is an effective method that is being developed and applied in modern agriculture. It has many functions, such as improving seed vigor, promoting seedling growth, and reducing the occurrence of pests and diseases. Yet, during seed coating procedures, several factors, such as difficulty in biodegradation of coating materials and hindrance in the application of chemical ingredients to seeds, force us to explore reliable and efficient coating formulations. Biochar, as a novel material, may be expected to enhance seed germination and seedling establishment, simultaneously ensuring agricultural sustainability, environment, and food safety. Recently, biochar-based seed coating has gained much interest due to biochar possessing high porosity and water holding capacity, as well as wealthy nutrients, and has been proven to be a beneficial agent in seed coating formulations. This review presents an extensive overview on the history, methods, and coating agents of seed coating. Additionally, biochar, as a promising seed coating agent, is also synthesized on its physico-chemical properties. Combining seed coating with biochar, we discussed in detail the agricultural applications of biochar-based seed coating, such as the promotion of seed germination and stand establishment, the improvement of plant growth and nutrition, suitable carriers for microbial inoculants, and increase in herbicide selectivity. Therefore, this paper could be a good source of information on the current advance and future perspectives of biochar-based seed coating for modern agriculture. [ABSTRACT FROM AUTHOR]

Low temperature seriously affects the growth of crops and poses a huge threat to food production. The application of wood vinegar can be used as a cost-effective and environmentally friendly strategy to promote crop growth and enhance stress resistance, and the physiological resistance to low-temperature stress of rapeseed still needs further research. The present study investigated the effects of spraying wood vinegar on the growth, photosynthesis, osmotic adjustment, and antioxidant enzymes of rapeseed seedlings under low-temperature stress. The results showed that spraying wood vinegar at normal temperature reduced the stomatal conductance but increased the leaf area and total biomass of rapeseed and enhanced stomatal density and water use efficiency. The leaf area and total biomass of rapeseed sprayed with wood vinegar at low temperature improved by 22% and 31%, respectively, and stomatal density and water use efficiency increased by 14% and 83%, respectively, and intercellular CO2 concentration and stomatal conductance were reduced by 9% and 41%, compared to the low-temperature, respectively. Besides, the application of wood vinegar liquid improved the proline, soluble protein, and soluble sugar content of leaves by 208%, 38%, and 115%, respectively, and the activity of superoxide dismutase increased by 27%, the content of malondialdehyde decreased by 46%, compared to the low-temperature. Spraying wood vinegar could alleviate low-temperature stress by improving the anti-oxidant enzyme content and osmoprotectants, reducing the stomatal conductance, and enhancing water use efficiency. These results provide new insights for wood vinegar to relieve the low-temperature stress of rapeseed, and this strategy can be used for low-temperature rapeseed cultivation and management, and benefit farmers' plant profit. [ABSTRACT FROM AUTHOR]

Rapeseed has formed three ecological types, namely winter, semi-winter, and spring during the long domestication process. Different ecotypes have different low-temperature requirements for floral initiation. Rapeseed growth has a large demand for nitrogen, and the amount of nitrogen application significantly impacts the number of flowering. Meanwhile, the time of floral imitation determined the quantity of floral bud, the final number of pods, and yield of rapeseed. Therefore, it is of great significance to understand the regulation of temperature and nitrogen on floral initiation. This experiment selected representative semi-winter and spring rapeseed varieties to study the leaf's soluble sugar and protein concentration under different nitrogen supplies and the transcriptome reactions to vernalization for spring and semi-winter varieties rapeseed in transition to floral initiation. The results showed that the soluble sugar content and carbon-to-nitrogen ratio changed due to the different growth processes and nitrogen application rates. The increase of the sugar content to a peak could be regarded as the signal to start floral initiation. Reducing the nitrogen application rate increased the peak of sugar content, but the effect on the appearance time of the peak was not obvious. Under normal (20–25 °C) and low temperatures (10–15 °C), the floral initiation time of spring variety "1358" showed no difference, nor did expression of hub gene SOC1, which is involved in the flowering regulation network. The semi-winter variety "Zhongshuang No. 11" did not commence floral initiation under normal temperature because of the lacking of vernalization requirement. Low temperature promoted the floral initiation of semi-winter variety mainly through the FLC, SOC1, and LFY signaling pathways, and the gibberellin also played a positive factor in this process. In essence, the present study provides valuable information on the gene expression differences of vernalization-driven floral transition for spring and semi-winter ecotypes of rapeseed when the photoperiod is not an unlimited factor. [ABSTRACT FROM AUTHOR]

Dry direct-seeded rice (dry-DSR) is an efficient, resource-saving and environmentally friendly cropping system. The employment of water-saving and drought-resistant rice (WDR) for dry direct-seeding can better meet the needs of dry-direct seeding systems. However, the decline in seedling emergence rate and poor seedling growth are the main bottlenecks under current direct-seeded rice production. Seed treatment is a sustainable and effective technique to overcome these issues. Therefore, growth chamber and field experiments were conducted to assess the impact of poplar wood vinegar (WV) priming and rice straw biochar (BC) coating on emergence, establishment, growth, physio-biochemical events, and ultimate yield. We treated the seeds of WDR viz., Hanyou 73 with WV, BC, and co-treatment WV + BC. The results showed that seed priming with 1:50 WV concentration and coating with 20% BC content was the optimal ratio for promoting germination and seedling growth. The field evaluation indicated that individual WV and BC markedly promoted the final emergence by 58% and 31%, respectively, while co-treatment WV + BC increased by 67%. Likewise, WV and BC significantly enhanced total seedling biomass by 26% and 10%, respectively, and the respective enhancement of WV + BC was 31%. For ultimate yield, WV and BC produced 12% and 19% higher grain yield, respectively, whereas WV + BC yielded 20%. The above results revealed that WV and WV + BC were the most effective treatment. Our findings may provide new avenues for advancing pre-sowing seed treatments facilitating the stand establishment and grain yield of dry direct-seeded rice. [ABSTRACT FROM AUTHOR]

Wood vinegar is formed by the condensation of smoke produced during the production of biochar. It mainly contains acetic acid, butyric acid, catechol, and phenol. Wood vinegar has a compound effect of promoting crop growth similar to plant growth regulators and is environmentally friendly. Moreover, it can enhance the biological and abiotic resistance of crops. In this study, foliar spraying was carried out systematically in the field with the hybrid variety of Huayouza 9 for two years to study the effects of wood vinegar and its compounds on the growth of rapeseed (Brassica napus L.). We applied four treatments with tap water as a control (CK), namely wood vinegar diluted 400-fold (M), M mixed with gibberellin (T1), M mixed with sodium D-gluconate (T2), and M mixed with melatonin (T3). They were sprayed in the seedling stage and overwintering stage, respectively. The results showed that the seed yield, the leaf area index, and the number of pods per plant of rapeseed treated with M increased by an average of 9.58%, 23.45%, and 23.80% in two years as compared to the CK, respectively. Compared with M, the seed yield of rapeseed treated with T1, T2, and T3 increased by an average of 7.88%, 6.90%, and 1.32% in two years, respectively. The treatments also improved the quality of rapeseed. In particular, the glucosinolate content of rapeseed treated with T2 and T3 decreased by an average of 12.83% and 6.72% in two years compared to the CK, respectively. The four treatments selected in the current study improved the resistance of rapeseed at the low temperature of 2–6 °C by increasing the activity of superoxide dismutase and proline and soluble protein contents, as compared to the CK. Besides, all treatments containing M reduced the incidence of Sclerotinia sclerotiorum and Peronospora parasitica (downy mildew) in rapeseed. More specifically, the T3 treatment significantly decreased the infection rate of these two diseases mentioned above by an average of 17.33% and 12.14% in two years compared to the CK, respectively. Therefore, the study and application of wood vinegar due to its compound effects on crop growth and yield is of great importance to sustainable agriculture, crop ecology, and environmental protection. [ABSTRACT FROM AUTHOR]

Compensating nitrogen input and increasing nitrogen utilization efficiency (NUtE) are necessary for sustainable crop production. Research studies on the co-application of biochar and nitrogen to promote rapeseed growth, soil fertility, and improve nutrient utilization efficiency are found to be limited. This study aims to examine the integral effects of biochar and nitrogen over soil fertility, rapeseed growth and nitrogen utilization efficiency. The experiment was conducted in a completely randomized design to assess various morphological, physiological and biochemical traits of rapeseed and soil chemical properties under the application of four nitrogen levels (0, 75, 225, and 450 kg ha−1 equivalent to 0, 133, 400 and 800 mg nitrogen pot−1) and four biochar levels (0, 5, 10, and 15 MT ha−1 equivalent to 0, 10, 20 and 30 g biochar pot−1 soil by weight basis). The results of this study showed that the integral application of biochar at 30 g pot−1 and nitrogen at 800 mg pot−1 at 45 days after sowing (DAS) and 60 days after sowing (DAS) compensated the amount of nitrogen and increased soil organic carbon (SOC 69%), total nitrogen accumulation (TNA) (93% and 62%), leaf biomass (60% and 33%), stem biomass (20% and 22%) and photosynthesis (20% and 17%) at 45 DAS and 60 DAS, respectively as compared to a single application of nitrogen. However, under the conditions of no nitrogen or 75 kg ha−1 nitrogen application, the application of biochar to promote the growth of rapeseed plants is limited due to the less nitrogen supply. In contrast, the application of nitrogen at 800 mg pot−1 and biochar at 10 or 20 g pot−1 showed that the growth of early seedlings was adversely affected due to high nitrogen concentration in soil. The findings of the present study imply that within the appropriate nitrogen application range, the interaction of biochar and nitrogen might have an economical approach towards better utilization of nitrogen and sustainable crop production. [ABSTRACT FROM AUTHOR]