Ameliorating soil chemical properties of a hard setting subsoil layer in Coastal Plain USA with different designer biochars

• Biochar was used to ameliorate chemical properties of Norfolk soils.
• Additions of designer biochars have variable effects on soil chemical properties.
• Designer biochars did improve chemical properties of hard-setting Norfolk subsoil.

Biochar application is an emerging management option to increase soil fertility. Biochars could improve chemical properties of soils with hard setting subsoil layer. However, biochar effect can be inconsistent because different biochars react differently in soils. We hypothesized that addition of designer biochars will have variable effects on improving the chemical properties of hard setting layers. The objective of this study was to investigate the effects of biochars on soil properties in Norfolk’s soil with a hard setting subsoil layer grown with winter wheat (Triticum aestivum L.). All designer biochars were added at the rate of 40 Mg ha−1. Feedstocks used for biochars production were: plant-based (pine chips, 100% PC); animal-based (poultry litter, 100% PL); 50:50 blend (50% PC:50% PL); 80:20 blend (80% PC:20% PL); and hardwood (100% HW). Higher nutrient availability was found after additions of biochars especially additions of 100% PL and 50:50 blend of PC and PL. On the average, applications of 100% PL and 50:50 blend of PC:PL had the greatest amount of soil total nitrogen with means of 1.94 ± 0.3% and 1.44 ± 0.3%, respectively. When compared with the control and other biochars, 50:50 blend of PC:PL additions resulted in increase of 669% for P, 830% for K, 307% for Ca, 687% for Mg and 2315% for Na while application of 100% PL increased the concentration of extractable P, K, Ca, Mg, and Na by 363%, 1349%, 152%, 363%, and 3152%, respectively. Overall, our results showed promising significance since biochars did improve chemical properties of a Norfolk’s soil.