Effects of brewer’s spent grain biochar on the growth and quality of leaf lettuce (Lactuca sativa L. var. crispa.)

Abstract

The need for organic soil amendments is increasing in the Republic of Korea against the backdrop of increased soil acidification and nutrient losses. The pyrolysis of biomass produces biochar which not only increases soil productivity but also provides environmental benefits through carbon sequestration. The portion of the brewer’s spent grain (BSG) recycled is by far less than the amount generated, but pyrolysis can help to reverse this trend by turning BSG waste into a valuable soil amendment. The current study, therefore, evaluated the effects of brewer’s spent grain biochar (BBXXX) produced at three different temperatures of 300 °C, 500 °C and 700 °C on the yield and quality characteristics of the leaf lettuce as well as the effects on soil chemical properties through a pot experiment. Each of the BBXXX and BSG were added to the soil at two rates of 2% and 5% by weight. The pH and carbon content of the BBxxx increased with increasing pyrolysis temperatures and the trend was replicated in the soil upon biochar application i.e. the soil pH and carbon content increased alongside temperatures at which biochar was pyrolyzed. On the other hand, however, the soil electrical conductivity (EC) diminished with the increasing pyrolysis temperatures of the biochar applied. With regards to crop growth, the BB500 5% amendment produced the highest marketable yield of the leaf lettuce and while the lettuce grown on the control produced leaf lettuce with the lowest content of nitrate nitrogen, BB500 5% amendment generally produced the highest quality lettuce. The results indicate that BB500 performed agronomically better than the rest of the amendments and is thus recommended as an effective BSG recycling measure.

Effects of Varying Rates of Nitrogen and Biochar pH on NH3 Emissions and Agronomic Performance of Chinese Cabbage (Brassica rapa ssp. pekinensis)

“…Additionally, apart from the alkaline biochar + 160 kg/ha N rate and acidic biochar + 320 kg/ha N rate amendments, which produced higher statistically significant EC than the control, the ureaonly amendment led to either higher statistically significant EC than the rest of the biochar amendments or no significant statistically different EC values as compared with the rest of the biochar amendments. These observations contravene those made by several previous studies including those of Lee et al [22], Luyima et al [23,24], Yoo et al [25] and others which indicate that biochar amendments generally increased both the soil pH and EC. The increases in soil pH and EC following biochar application to the soil can been generally attributed to the build-up of ash residues during pyrolysis [26].…”

“…On the other hand, biochar amendments caused no statistically significant differences in the contents of soil cations in comparison with the control experiment. These observations contravene those of Nigussie et al [26], Yoo et al [25] and others who found that biochar amendments increased the concentrations of soil cations. However, a study by Hailegnaw et al [30] assessed the effects of different rates of biochar applied to soils with a wide range of soil physicochemical properties on the contents of soil cations and observed both increments and decrements in the cationic contents.…”

Mixing Sodium-Chloride-Rich Food Waste Compost with Livestock Manure Composts Enhanced the Agronomic Performance of Leaf Lettuce

“…Root length and leaf length and width were measured with a metre rule. The chlorophyll content was determined using a chlorophyll meter (SPAD-502, Konica Minolta, Tokyo, Japan) as outlined in Yoo et al [27]. Sweetness and NO 3 − N were measured with a digital saccharimeter (HI 96801, Hanna Instruments Inc, Woonsocket, RI, USA) and a NO 3 − N meter (S040, HORIBA Ltd., Kyoto, Japan), respectively, after extraction of the juice out of the leaves.…”

Biochar Production from Wastewater Sludge for Application in Sustainable Lettuce Plant Cultivation and Climate Change Mitigation

“…Biochar is a solid, carbon-rich product derived from the thermochemical conversion of biomass (e.g., animal manures, agricultural wastes, wastewater sludge, and other waste products) under oxygen-limited conditions via pyrolysis [4]. Biochar contributes to carbon sequestration, reducing greenhouse gas (GHG) emissions, improving soil properties, and adsorbing organic and heavy metal pollutants [5].…”