Submitted to: Chemosphere
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/10/2015
Publication Date: 6/22/2015
Publication URL: http://www.elsevier.com/locate/chemosphere
Citation: Sigua, G.C., Novak, J.M., Watts, D.W. 2015. Ameliorating soil chemical properties of a hard setting subsoil layer in coastal plain USA with different designer biochars. Chemosphere. 142:168-175.
Interpretive Summary: Biochar application to agricultural soils is a rapidly emerging innovative management option to increase soil fertility and improve soil physical and chemical properties. Biochars could be designed to improve chemical properties of soils with a hard setting subsoil layer. However, biochar quality and effect can be inconsistent because different biochars react differently in soils. We hypothesized that addition of different 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 designer biochars on soil chemical properties in Norfolk’s soil series with a hard setting subsoil layer grown with winter wheat (Triticum aestivum, L). All designer biochars were added at the rate of 40 megagrams per hectare. 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 and favorable soil quality were found after additions of designer biochars to a hard setting subsoil layer especially additions of 100% PL and 50:50 blends of PC and PL. On the average, applications of 100% PL and 50:50 blends of PC:PL had the greatest amount of soil total nitrogen (TN) with means of 1.94±0.3% and 1.44±0.3%, respectively. When compared with the control and other designer biochars, 50:50 blends of PC:PL additions resulted in increase of 669% for P, 830% for K, 307% for Ca, 687% for Mg and 2,315% for Na while application of 100% PL increased the concentration of Mehlich extractable phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and sodium (Na) by 363%, 1349%, 152%, 363%, and 3,152%, respectively over the control treatment. Overall, our results showed promising significance since designer biochars did improve chemical properties of a Norfolk’s hard setting subsoil layer.
Technical Abstract: Norfolk soils in the southeastern United States of America (USA) Coastal Plain region have meager soil fertility characteristics because of their sandy textures, acidic pH values, kaolinitic clays and with depleted organic carbon contents. Extensive clay mineral weathering and clay eluviation along with intensive leaching of bases and high levels of exchangeable aluminum has promoted the formation of a hard setting subsoil layers. These soil characteristics severely limit fertility and crop productivity, which leaves few management options for improvements. Application of mulches, composts and manures have frequently been shown to increase soil fertility but because of hot and humid conditions, organic matter is usually mineralized rapidly. As an alternate, designer biochar has been described as a possible means to improve soil fertility and sequester carbon. We hypothesized that the addition of different designer biochars to a hard setting subsoil layer will have variable effects on improving the chemical conditions of this soil layer. The objective of this study was to investigate the contrasting effects of multiple designer biochars on ameliorating chemical properties in hard setting subsoil layer grown with winter wheat in the Coastal Plain regions of the southeastern USA. Our results supported our hypothesis that addition of different designer biochars will have variable results in ameliorating soil chemical properties of a hard setting subsoil layer in Coastal Plain USA. Our study has demonstrated the favorable and beneficial effects of different designer biochars on improving soil chemical properties of Norfolk soils with hard setting subsoil layer. Application of 50:50 blends of pine chips (PC) and poultry litter (PL) and 100% PL were found to be superior compared to other designer biochars because of their favorable effects on soil fertility. When compared with the control and other designer biochars, 50:50 blends of PC:PL additions resulted in increase of 669% for P, 830% for K, 307% for Ca, 687% for Mg and 2,315% for Na while application of 100% PL increased the concentration of Mehlich extractable P, K, Ca, Mg, and Na by 363%, 1349%, 152%, 363%, and 3,152%, respectively over the control treatment. Overall, our results showed promising significance of designer biochars for improving soil fertility of an Ultisol’s soil with hard setting subsoil layer in Coastal Plain, USA.