Biochar in manure can suppress water stress of sugar beet (Beta vulgaris) and increase sucrose content in tubers

Optimizing biochar application for enhanced cotton and sugar beet production in Xinjiang: a comprehensive study

BACKGROUND

Optimizing biochar application is vital for enhancing crop production and ensuring sustainable agricultural production. A 3-year field experiment was established to explore the effects of varying the biochar application rate (BAR) on crop growth, quality, productivity and yields. BAR was set at 0, 10, 50 and 100 t ha-1 in 2018; 0, 10, 25, 50 and 100 t ha-1 in 2019; and 0, 10, 25 and 30 t ha-1 in 2020. Crop quality and growth status and production were evaluated using the dynamic technique for order preference by similarity to ideal solution with the entropy weighted method (DTOPSIS-EW), principal component analysis (PCA), membership function analysis (MFA), gray relation analysis (GRA) and the fuzzy Borda combination evaluation method.

RESULTS

Low-dose BAR (≤ 25 t ha-1 for cotton; ≤ 50 t ha-1 for sugar beet) effectively increased biomass, plant height, leaf area index (LAI), water and fertility (N, P and K) productivities, and yield. Biochar application increased the salt absorption and sugar content in sugar beet, with the most notable increases being 116.45% and 20.35%, respectively. Conversely, BAR had no significant effect on cotton fiber quality. The GRA method was the most appropriate for assessing crop growth and quality. The most indicative parameters for reflecting cotton and sugarbeet growth and quality status were biomass and LAI. The 10 t ha-1 BAR consistently produced the highest scores and was the most economically viable option, as evaluated by DTOPSIS-EW.

CONCLUSION

The optimal biochar application strategy for improving cotton and sugar beet cultivation in Xinjiang, China, is 10 t ha-1 biochar applied continuously. © 2024 Society of Chemical Industry.

Biochar effects on salt-affected soil properties and plant productivity: A global meta-analysis

Biochar has been recognized as a promising practice for ameliorating degraded soils, yet the consensus on its effects remains largely unknown due to the variability among biochar, soil and plant. This study therefore presents a meta-analysis synthesizing 92 publications containing 987 paired data to scrutinize biochar effects on salt-affected soil properties and plant productivity. Additionally, a random meta-forest approach was employed to identify the key factors of biochar on salt-affected soil and plant productivity. Results showed that biochar led to significant reductions in electrical conductivity (EC), bulk density (BD) and pH by 7.4%, 4.7% and 1.2% compared to the unamended soil, respectively. Soil organic carbon (by 55.1%) and total nitrogen (by 31.3%) increased significantly with biochar addition. Moreover, biochar overall enhanced plant productivity by 31.5%, and more pronounced increases in forage/medicinal with higher salt tolerance than others. The results also identified that the soil salinity and biochar application rate were the most important co-regulators for EC and PP changes. The structural equation model further showed that soil salinity (P < 0.001), biochar pH (P < 0.001) and biochar specific surface area (P < 0.01) had a significant negative effect on soil EC, but it was positively impacted by biochar pyrolysis temperature (P < 0.05). Furthermore, plant productivity was positively affected by biochar pH (P < 0.001) and biochar feedstock (P < 0.01), while negatively influenced by biochar pyrolysis temperature (P < 0.01). This study highlights that woody biochar with 7.6 < pH < 9.0 and pyrolyzed at 400-600 °C under 30-70 t ha-1 application rate in moderately saline coarse soils is a recommendable pattern to enhance forage/medicinal productivity while reducing soil salinity. In conclusion, biochar offers promising avenues for ameliorating degradable soils, but it is imperative to explore largescale applications and field performance across different biochar, soil, and plant types.

The impact of the application of compochar on soil moisture, stress, yield and nutritional properties of legumes under drought stress

Nowadays, when climate change is becoming more and more evident, drought stress plays a very important role, including in agriculture. The increasing number of years with extreme temperatures in the Czech Republic has a negative impact on agricultural production, among other things. Therefore, ways are being sought to reduce these negative impacts. One of them may be the use of compochar (a mixture of compost and biochar) to improve water retention in the soil. The effect of compochar addition on soil properties and crop yield was tested under conditions simulating severe drought stress (greenhouse experiments) compared to normal conditions (field experiments). The aim was to find the most suitable ratio of compochar addition that would reduce the negative effects of drought stress on the yield and quality of peas and beans. Tested soil was only able to retain water between 0.03 and 0.18 cm3/cm3, while the compochar itself retained between 0.12 and 0.32 cm3 cm-3. Three substrate variants were tested by varying the amount of compochar (10, 30 and 50 % v/v) in the soil, and all three substrates showed a similar water content between 0.03 and 0.21 cm3 cm-3 depending on the planted crop and week of cultivation. No apparent stress was observed in crops planted in 100 % compochar. Nevertheless, in general, the trend of chlorophyll a/b ratio increased with increasing amounts of compochar in the soil, indicating stress. Yield increased by approximately 50 % for both test crops when 30 % compochar was used as substrate. The flavonoid content in beans was between 410 and 500 μg CE g-1 DW and in peas was approximately 300 μg CE g-1 DW. The results showed that the utilization of compochar had no effect on either total phenol content, flavonoid content or antioxidant capacity. The combination of compochar with soil (30 %) was found to positively affect the (i) soil moisture, (ii) crop yield, and (iii) nutritional properties of peas and beans and (iv) the ability of plants to withstand drought stress.

Biochar-Mediated Control of Metabolites and Other Physiological Responses in Water-Stressed Leptocohloa fusca

We investigated biochar-induced drought tolerance in Leptocohloa fusca (Kallar grass) by exploring the plant defense system at physiological level. L. fusca plants were exposed to drought stress (100%, 70%, and 30% field capacity), and biochar (BC), as an organic soil amendment was applied in two concentrations (15 and 30 mg kg-1 soil) to induce drought tolerance. Our results demonstrated that drought restricted the growth of L. fusca by inhibiting shoot and root (fresh and dry) weight, total chlorophyll content and photosynthetic rate. Under drought stress, the uptake of essential nutrients was also limited due to lower water supply, which ultimately affected metabolites including amino and organic acids, and soluble sugars. In addition, drought stress induced oxidative stress, which is evidenced by the higher production of reactive oxygen species (ROS) including hydrogen peroxide (H2O2), superoxide ion (O2-), hydroxyl ion (OH-), and malondialdehyde (MDA). The current study revealed that stress-induced oxidative injury is not a linear path, since the excessive production of lipid peroxidation led to the accumulation of methylglyoxal (MG), a member of reactive carbonyl species (RCS), which ultimately caused cell injury. As a consequence of oxidative-stress induction, the ascorbate-glutathione (AsA-GSH) pathway, followed by a series of reactions, was activated by the plants to reduce ROS-induced oxidative damage. Furthermore, biochar considerably improved plant growth and development by mediating metabolites and soil physio-chemical status.