摘要
A red soil derived from Quaternary red clay was employed to study nutrient leaching with soil columns repacked in laboratory. The objective was to identify the effects of fertilization practices on leaching patterns and magnitudes of Ca2+, Mg2+, K+, NH+, and NO-. The treatments were CK (as a control), CaCO3,CaSO4, MgCO3, Ca(H2PO4)2, urea, KCI, and multiple (a mixture of the above-mentioned fertilizers). The fertilizers were added to the bare surface of the soil columns, and then the columns were leached with 120 mL deionized water daily through peristaltic pumps over a period of 92 days. Leaching processes of NH+, and NO- were only measured in CK, urea, and multiple treatments which were directly related to N leaching.Results showed that sole application of CaSO4, and Ca(H2PO4)2 scarcely had any effect on the leaching losses of Ca2+, Mg2+, and K+; the application of MgCO3 stimulated the leaching of Mg2+; the application of CaCOs promoted the leaching of Ca2+, Mg2+ and K+; urea treatment also promoted the leaching of K+ and NH+, and NO- leaching mainly occurred at late stage of leaching process in particular; under KCI treatment, leaching of Ca2+, Mg2+, and K+ was promoted to a large extent; under multiple treatment,leaching of Ca2+, Mg2+, K+, NH+, and NO- was all increased and NO- was mainly leached at the end of leaching process and still had a trend of increase.
A red soil derived from Quaternary red clay was employed to study nutrient leaching with soil columns repacked in laboratory. The objective was to identify the effects of fertilization practices on leaching patterns and magnitudes of Ca2+, Mg2+, K+, NH+, and NO-. The treatments were CK (as a control), CaCO3,CaSO4, MgCO3, Ca(H2PO4)2, urea, KCI, and multiple (a mixture of the above-mentioned fertilizers). The fertilizers were added to the bare surface of the soil columns, and then the columns were leached with 120 mL deionized water daily through peristaltic pumps over a period of 92 days. Leaching processes of NH+, and NO- were only measured in CK, urea, and multiple treatments which were directly related to N leaching.Results showed that sole application of CaSO4, and Ca(H2PO4)2 scarcely had any effect on the leaching losses of Ca2+, Mg2+, and K+; the application of MgCO3 stimulated the leaching of Mg2+; the application of CaCOs promoted the leaching of Ca2+, Mg2+ and K+; urea treatment also promoted the leaching of K+ and NH+, and NO- leaching mainly occurred at late stage of leaching process in particular; under KCI treatment, leaching of Ca2+, Mg2+, and K+ was promoted to a large extent; under multiple treatment,leaching of Ca2+, Mg2+, K+, NH+, and NO- was all increased and NO- was mainly leached at the end of leaching process and still had a trend of increase.
