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Biochar affects growth and shoot nitrogen in four crops for two soils
Citation:
Olszyk, D., T. Shiroyama, J. Novak, K. Cantrell, G. Sigua, D. Watts, AND M. Johnson. Biochar affects growth and shoot nitrogen in four crops for two soils. Agrosystems, Geosciences & Environment. John Wiley & Sons, Inc., Hoboken, NJ, , e20067, (2020). https://doi.org/10.1002/agg2.20067
Impact/Purpose:
Biochar is the carbon-rich material remaining after pyrolysis of cellulosic and manure feedstocks. It has potential as a soil amendment to sequester carbon and to improve soil water-holding and nutrient properties- thereby enhancing plant growth. However, biochar produced from some feedstocks also could adversely affect crop quality by changing soil pH and reducing nutrients in plant tissues. To evaluate these effects of biochar on the nutrient quality of four crops, we conducted a study with pots in the greenhouse using carrot, corn, lettuce and soybean. Plants were grown in one of two sandy soils from South Carolina, along with biochar (1% by weight) produced from two types of manure, poultry litter and swine solids; two types of cellulose, switchgrass and pine chips; and two blends of pine chips plus poultry litter. Each of the feedstocks and feedstock blends was produced at 350, 500, and 700 ̊ C to determine impact of pyrolysis temperature on the effects of the biochar. The type of crop, soil type, and feedstock source and production temperature all affected concentrations of nutrients in leaf tissue. These results indicate that plant leaf tissue nutrient quality is impacted by the type of biochar and its pyrolysis temperature. Thus, when using biochar as a soil amendment, the potential nutrient changes must be considered during the production of the crops
Description:
To address the need for information on biochar effects on crop growth and nitrogen (N), a greenhouse study was conducted with carrot, lettuce, soybean, and sweet corn using sandy loam (Coxville series) and loamy sand (Norfolk series) soils and a variety of biochars. Biochar was produced from pine chips (PC), poultry litter (PL), swine solids (SS), switchgrass (SG), and two blends of PC plus PL (50/50% [55] and 80/20% [82], wt/wt), with each feedstock pyrolyzed at 350, 500, or 700 ˚C. The results confirmed that biochar can increase crop growth; however, the responses varied with crop, soil, and feedstock and to a lesser extent with pyrolysis temperature. In general, lettuce had large increases in shoot and root dry weights vs. no‐biochar controls with many biochars, primarily the SS and 55 blend and to a lesser extent with 82 followed by PL, and then PC and SG, especially when grown in the Coxville soil. Biochar had more limited effects on carrot, sweet corn, and soybean weights. Some biochars decreased crop growth (e.g., PL at 700 ˚C) for soybean shoot and pod dry weights with the Norfolk soil. Shoot N concentrations decreased with SS, 55, and 82 for carrot, lettuce, and sweet corn with the Norfolk soil but tended to increase for soybean. Shoot N uptake increased or decreased depending on biochar feedstock and temperature, crop, and soil. These results confirm that biochar can increase crop growth and affect shoot N, which is essential for crop growth.Methods Plants were grown using sandy loam (Coxville series) and loamy sand (Norfolk series) soils, with biochar produced from six feedstocks: pine chips (PC), poultry litter (PL), swinesolids (SS), switchgrass (SG), and two blends of PC plus PL (PC/PL, 50/50% and 80/20% w/w). Biochar from each feedstock was produced at 350, 500 and 700˚C. Results Biochar PC/PL mixtures and SS, and to a lesser extent PL followed by PC and SG, increased lettuce shoot and root growth (dry weight) compared with the no biochar control, especially when grown in the Coxville soil. The PL/PC and SS biochars generally decreased lettuce leaf % N, P, Ca and Mg; while K generally increased with PL, but decreased with SS with both soils. The PC and SG biochars caused some reduction in lettuce leaf % N, P, Ca, Mg, and K especially in the Coxville soil. Biochar effects on growth and nutrients for the other crops were more varied. Conclusion This study indicated that while biochar can increase crop growth in these two soils, it can decrease leaf nutrients concentrations important for plant growth, especially N.
