Premium
Chemical Restrictions of Roots in Ultisol Subsoils Lessened by Long‐Term Management
Author(s) -
Hardy David H.,
Raper C. David,
Miner Gordon S.
Publication year - 1990
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1990.03615995005400060025x
Subject(s) - ultisol , environmental science , topsoil , lime , agronomy , nutrient , sorghum , cation exchange capacity , fertilizer , soil water , chemistry , soil science , biology , paleontology , organic chemistry
Exchangeable Al in subsoils of Ultisols in the southeastern USA can restrict rooting depth. Downward movement of basic cations (Ca, Mg, and K), applied as lime and fertilizer, may diminish that restriction over time. Materials from the argillic horizon were collected from three paired sites, having managed (long‐term cropping) and nonmanaged topsoils (Typic Paleudults and Hapludults). One managed site was cropped continuously for 15 yr while the others were cultivated for more than 30 yr. Concentrations of extractable cations and other nutrients from the paired sites were compared to determine the magnitude of change due to management. The ability of the subsoils to support plant growth was evaluated in a missing‐nutrient greenhouse experiment with sorghum [ Sorghum bicolor (L.) Moench]. Subsoils of managed sites had greater effective cation‐exchange capacity (CEC) and base saturation than those of nonmanaged sites. While availabilities of Ca, Mg, and K in subsoils of nonmanaged sites were inadequate to support maximal plant growth, they were adequate in subsoils of managed sites. Compared with nonmanaged sites, KCl‐exchangeable Al in subsoils of managed sites was 23% lower at the 15‐yr location and 65 and 100% lower at the two other locations. In the absence of lime, sorghum growth was almost totally inhibited on nonmanaged subsoils amended with optimum nutrients. On the managed subsoils, where 100, 65, and 23% of the nonmanaged exchangeable Al had been neutralized by topsoil fertilization and liming, growth reductions under the same conditions were 0, 50, and 100%, respectively. Thus, relatively long‐term management had improved these Ultisol subsoils for root growth and development.