Department of Natural Resources and Environmental Design, North Carolina A&T State University, Greensboro, NC, United States of America.
Analytical Services Laboratory, College of Agriculture and Environmental Sciences, North Carolina A&T State University, Greensboro, NC, United States of America.
PLoS One. 2022 Feb 28;17(2):e0264620. doi: 10.1371/journal.pone.0264620. eCollection 2022.
Application of crop residues and biochar have been demonstrated to improve soil biological and chemical properties in agroecosystems. However, the integrated effect of organic amendments and hydrological cycles on soil health indicators are not well understood. In this study, we quantified the impact of hemp residue (HR), hemp biochar (HB), and hardwood biochar (HA) on five hydrolytic enzymes, soil microbial phospholipid (PLFA) community structure, pH, permanganate oxidizable carbon (POXC) soil organic carbon (SOC), and total nitrogen (TN). We compared two soil types, Piedmont and Coastal Plain soils of North Carolina, under (i) a 30-d moisture cycle maintained at 60% water-filled pore space (WFPS) (D-W1), followed by (ii) a 7-day alternate dry-wet cycle for 42 days (D-W2), or (iii) maintained at 60% WFPS for 42 days (D-W3) during an aerobic laboratory incubation. Results showed that HR and HB significantly increased the geometric mean enzyme activity by 1-2-fold in the Piedmont soil under the three moisture cycles and about 1.5-fold under D-W in the Coastal soil. In the presence of HA, the measured soil enzyme activities were significantly lower than control under the moisture cycles in both soil types. The shift in microbial community structure was distinct in the Coastal soil but not in the Piedmont soil. Under D-W2, HR and HB significantly increased POXC (600-700 mg POXC kg-1 soil) in the Coastal soil but not in the Piedmont soil while HA increased nitrate (8 mg kg-1) retention in the Coastal soil. The differences in amendment effect on pH SOC, TN, POXC, and nitrate were less distinct in the fine-textured Piedmont soil than the coarse-textured Coastal soil. Overall, the results indicate that, unlike HA, HR and HB will have beneficial effects on soil health and productivity, therefore potentially improving soil's resilience to changing climate.
应用作物残体和生物炭已被证明可以改善农业生态系统中的土壤生物和化学特性。然而，有机改良剂和水文循环对土壤健康指标的综合影响还不太清楚。在本研究中，我们量化了汉麻残体（HR）、汉麻生物炭（HB）和硬木生物炭（HA）对五种水解酶、土壤微生物磷脂（PLFA）群落结构、pH 值、高锰酸盐可氧化碳（POXC）土壤有机碳（SOC）和总氮（TN）的影响。我们比较了两种土壤类型，北卡罗来纳州皮埃蒙特和沿海平原土壤，在（i）30 天的水分循环中保持在 60%的水填充孔隙空间（WFPS）（D-W1），随后（ii）7 天的干湿交替循环 42 天（D-W2），或（iii）在有氧实验室培养过程中保持在 60%WFPS 42 天（D-W3）。结果表明，在三种水分循环下，HR 和 HB 显著提高了皮埃蒙特土壤中酶活性的几何平均值 1-2 倍，在沿海土壤中 D-W 下提高了约 1.5 倍。在存在 HA 的情况下，在两种土壤类型的水分循环下，测量的土壤酶活性明显低于对照。在沿海土壤中，微生物群落结构的变化很明显，但在皮埃蒙特土壤中则不然。在 D-W2 下，HR 和 HB 显著增加了沿海土壤中的 POXC（600-700mgPOXCkg-1 土壤），但皮埃蒙特土壤中则没有，而 HA 增加了沿海土壤中硝酸盐（8mgkg-1）的保留。在细质地的皮埃蒙特土壤中，与粗质地的沿海土壤相比，改良剂对 pH 值、SOC、TN、POXC 和硝酸盐的影响不太明显。总的来说，结果表明，与 HA 不同，HR 和 HB 将对土壤健康和生产力产生有益影响，因此可能提高土壤对气候变化的适应能力。
