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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]

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]