Improvement of Rice Husk Residue Silicon Availability for Replenishing Available Silicon in Paddy Soil

Increasing agricultural land area has proven beyond every reasonable doubt that it is not the solution to low yield in agricultural produce. Soil management strategies could improve the productivity and also enhance sustainability. Today’s soil management strategies depend solely on inorganic chemical-based fertilizer which is inaccessible to many small-scale farmers, due to its high cost. The use of rice husk biochar (RHB) from rice husk residue (RH), produced through the process of pyrolysis, could be one of the possible cost-effective soil management strategies in rice-based farming system. In this study, a pot experiment was conducted in the Experimental Glasshouse, Shimane University, Japan (35°29´14.30N and 133°04´07.92E) during the summer season (June to September 2017) to investigate how changes in nutrient compositions of RH pyrolyzed at different temperatures (300°C, 400°C, 500°C, 600°C and 700°C) influence rice plant agronomic parameters, soil available silica and plant silica uptake. The experimental units were replicated three times and arranged in a completely randomized design. The RH and RHB used were slightly acidic to alkaline (6.8 – 10.7). They contained elevated nutrients in comparison to the soil. The RHB treatments were found not to have much influence on the plant agronomic parameters this time. The soil available silicon after harvest could be improved or at least maintained with RHB treatments. For instance, RHB at 400°C increased the soil available Si by 61% compared to the original content (93.8 mg SiO2 pot-1). This implies that RHB could create a potential biogenic silicon pool in a paddy field. The RHBs increased soil Si availability for rice growth through an increment of plant Si uptake and soil available Si against the control. The highest increment against the control during the cropping season was found in RHB at 500°C (455.9 mg SiO2 pot-1).  Finally, charring of RH by controlling the heating temperatures is an effective way of improving RH as Si amendment

The Potential of Biochar to Enhance the Water Retention Properties of Sandy Agricultural Soils

The impact of climate change has become increasingly severe in drylands, resulting in heat stress and water deficiency and, consequently, reducing agricultural production. Biochar plays an important role in improving soil fertility. The properties of sandy soils where water deficiency occurs with a greater frequency need to be enhanced by biochar amendments to increase the water retention capacity (WRC). Few studies have reported the effects of biochar on the readily available water (RAW) of these soils or an evaluation of the optimal application rate of the biochar. In this study, we aimed to assess the effect of different biochar types and application rates on the soil properties related to water retention. Under laboratory conditions, we amended sandy soil with four different types of biochar (woodchip (WBC), waterweed of Ludwigia grandiflora (WWBC), poultry litter (PLBC) and bagasse (BBC)) at rates of 0%, 5%, 10%, 15%, 25%, 50%, 75% and 100%. Soils treated with zeolite and perlite, both conventional materials, were arranged for a comparative study. The water content in the amended soils was recorded at saturation, field capacity, wilting point and oven-dry. Our results show a reduction in the bulk density by increasing the amendment rate across all biochar types. Although the WRC increased with the application rate, the RAW reduced and peaked at a 5% (v/v) biochar content for almost all the biochar types. WBC and WWBC showed the highest RAW increments of 165% and 191%, respectively, at a 10% (v/v) rate. In most cases, higher rates (such as 75% (v/v) of PLBC) caused negative effects on the RAW. Following these results, it is clear that both the biochar type and the application rate significantly influence the hydrological properties and the RAW capacity of sandy soils. A 5% (v/v) biochar amendment could significantly improve the readily available water to mitigate drought in sandy agricultural soils

Effect of the Interaction between Wood Vinegar and Biochar Feedstock on Tomato Plants

Abstract: This study investigated the effect of the interaction between wood vinegar and biochar feedstock on total biomass, fruit weight (yield), and sugar content of tomato plants (Solanum lycopersicum L.). An experiment was conducted in two locations with six different biochar types produced from either plant or animal feedstock. Each biochar was incorporated into soil (1:2500 g/g) along with chemical fertilizer. Wood vinegar was diluted with water (1:200 mL) and applied once weekly for the vinegar treatment. Biochar application resulted in a higher yield and biomass of the chicken manure biochar owing to its high ammonium-nitrogen content. Vinegar application increased the yields of the plant feedstock, which was particularly evident for most of the yield parameters with the bamboo biochar. Regardless of treatment, yield and biomass were not significantly different between the animal and plant feedstock. The sugar content was higher for the chicken manure and animal litter biochar, which was attributed to better pH conditions. The combination of plant feedstock biochar and vinegar application for improving the yield of tomatoes is promising. In contrast, vinegar application could potentially limit the yield and fruit sugar content of tomato plants treated with animal feedstock biochar. Highlights: • The soil was amended with biochar, with or without vinegar application. • The chicken manure biochar plants had the highest yield and biomass. • Vinegar application increased the yield of the plant feedstock. • Plant and animal feedstock plants had similar yield and biomass. • The pH of the animal feedstock was better because of higher CO2 and MgO contents. • Fruit sugar content for animal feedstock plants was better due to higher phosphorus

Change in nutrient composition of biochar from rice husk and sugarcane bagasse at varying pyrolytic temperatures

Abstract Purpose Waste management is one of the significant challenges facing Nigeria’s agricultural sector. To manage this problem, the conversion of agricultural wastes to biochar is a practical solution. Methods In this work, the chemical composition of biochar from rice husk and sugarcane bagasse, two predominant agricultural wastes, commonly generated in Nigeria was studied. These wastes were pyrolyzed at 300–700 and 350–700 °C for rice husk biochar (RHB) and sugarcane bagasse biochar (SBB), respectively. Results It was found that biochar yield and total nitrogen decreased with increasing pyrolysis temperature while ash content, pH, EC, total carbon, extractable Ca, Mg, Na, available phosphorus and silica were increased. In RHB, extractable K increased with increasing pyrolysis temperature, while in SBB it decreased with its maximum observed in RHB. Conclusions Rice husk pyrolyzed at high temperature may produce nutrient-rich biochar with high nutrient contents and these could ameliorate acidic soils. Finally, SBB could give high available silicon with acid pre-treatment

Sustainable Plant Growth Promotion and Chemical Composition of Pyroligneous Acid When Applied with Biochar as a Soil Amendment

The pyrolysis of biomass material results in pyroligneous acid (PA) and biochar, among other by-products. In agriculture, PA is recognized as an antimicrobial agent, bio-insecticide, and bio-herbicide due to antioxidant activity provided by a variety of constituent materials. Application of PA to crop plants and soil can result in growth promotion, improved soil health, and reduced reliance on polluting chemical crop inputs. More detailed information regarding chemical compound content within PA and identification of optimal chemical profiles for growth promotion in different crop species is essential for application to yield effective results. Additionally, biochar and PA are often applied in tandem for increased agricultural benefits, but little is known regarding the optimal proportion of each crop input. This work reports on the effect of combined applications of different proportions of PA (200-and 800-fold dilutions) and chemical fertilizer rates (100%, 75%, 50%, and 0%) in the presence or absence of biochar on Komatsuna (Brassica rapa var. perviridis, Japanese mustard spinach) plant growth. To elucidate the chemical composition of the applied PA, four different spectroscopic measurements of fluorescence excitation were utilized for analysis—excitation-emission matrix, ion chromatography, high-performance liquid chromatography, and gas chromatography-mass spectrometry. It was determined that PA originating from pyrolysis of Japanese pine wood contained different classes of biostimulants (e.g., tryptophan, humic acid, and fulvic acid), and application to Komatsuna plants resulted in increased growth when applied alone, and in different combinations with the other two inputs. Additionally, application of biochar and PA at the higher dilution rate increased leaf accumulation of nutrients, calcium, and phosphorus. These effects reveal that PA and biochar are promising materials for sustainable crop production