Subtropical recent alluvial soils are low in organic carbon(C).Thus,increasing organic C is a major challenge to sustain soil fertility.Biochar amendment could be an option as biochar is a C-rich pyrolyzed material,wh...Subtropical recent alluvial soils are low in organic carbon(C).Thus,increasing organic C is a major challenge to sustain soil fertility.Biochar amendment could be an option as biochar is a C-rich pyrolyzed material,which is slowly decomposed in soil.We investigated C mineralization(CO_(2)-C evolution)in two types of soils(recent and old alluvial soils)amended with two feedstocks(sugarcane bagasse and rice husk)(1%,weight/weight),as well as their biochars and aged biochars under a controlled environment(25±2℃)over 85 d.For the recent alluvial soil(charland soil),the highest absolute cumulative CO_(2)-C evolution was observed in the sugarcane bagasse treatment(1140 mg CO_(2)-C kg^(-1)soil)followed by the rice husk treatment(1090 mg CO_(2)-C kg^(-1)soil);the lowest amount(150 mg CO_(2)-C kg^(-1)soil)was observed in the aged rice husk biochar treatment.Similarly,for the old alluvial soil(farmland soil),the highest absolute cumulative CO_(2)-C evolution(1290 mg CO_(2)-C kg^(-1)soil)was observed in the sugarcane bagasse treatment and then in the rice husk treatment(1270 mg CO_(2)-C kg^(-1)soil);the lowest amount(200 mg CO_(2)-C kg^(-1)soil)was in the aged rice husk biochar treatment.Aged sugarcane bagasse and rice husk biochar treatments reduced absolute cumulative CO_(2)-C evolution by 10%and 36%,respectively,compared with unamended recent alluvial soil,and by 10%and 18%,respectively,compared with unamended old alluvial soil.Both absolute and normalized C mineralization were similar between the sugarcane bagasse and rice husk treatments,between the biochar treatments,and between the aged biochar treatments.In both soils,the feedstock treatments resulted in the highest cumulative CO_(2)-C evolution,followed by the biochar treatments and then the aged biochar treatments.The absolute and normalized CO_(2)-C evolution and the mineralization rate constant of the stable C pool(K_(s))were lower in the recent alluvial soil compared with those in the old alluvial soil.The biochars and aged biochars had a negative priming effect in both soils,but the effect was more prominent in the recent alluvial soil.These results would have good implications for improving organic matter content in organic C-poor alluvial soils.展开更多
There are many remediation techniques for organic contaminated soils,but relatively few of them are applicable to trace elementcontaminated soils.A field experiment was carried out to investigate assisted natural reme...There are many remediation techniques for organic contaminated soils,but relatively few of them are applicable to trace elementcontaminated soils.A field experiment was carried out to investigate assisted natural remediation(ANR) of an acid soil contaminated by As,Cd,Cu,Zn and Pb using one inorganic amendment,sugar beet lime(SL),and two organic amendments,biosolid compost(BC)and leonardeite(LE).The experiment was arranged in a completely randomized block design with four treatments in three replicates:1) a non-amended control(NA);2) SL amended at 30 Mg ha^(-1) year^(-1);3) BC amended at 30 Mg ha^(-1) year^(-1) and 4) LE amended at 20 Mg ha^(-1) year^(-1) plus SL amended at 10 Mg ha^(-1) year^(-1)(LESL).The amended plots received two doses of each amendment(DO2):one in October 2002 and another in October 2003.The plots were then divided in half into two subpolts and one subplot received another two doses of the same amendments(DO4) in October 2005 and October 2006.In 2011,the pH values of the amended soils were greater than that of the NA soil,with the SL-amended soil showing the highest pH.Total organic carbon(TOC) was also greater in the amended soil,and greater with DO4 than with DO2.Amendments reduced the concentrations of 0.01 mol L^(-1) CaCl_2-extractable Cd,Cu and Zn,especially in the SL-amended soil.Plant cover of colonizing vegetation was enhanced by amendments,but was independent of amendment doses.Changes in soil properties from 2003 to 2011 showed that the first amendment application of DO2 caused a high differentiation between all the amendment treatments and the NA treatment.After the second application of DO2,soil pH and TOC continued increasing slowly.Further two applications of amendments(DO4) caused differences only in the organic treatments.Plant cover increased over time in all the treatments including NA.It could be concluded that the slow and steady natural remediation of this soil could be enhanced by amendment application(ANR).展开更多
基金the BARC(Bangladesh Agricultural Research Council)for awarding a postgraduate scholarship with research support to the first author through the NATP(National Agricultural Technology Program)Phase-ⅡProject。
文摘Subtropical recent alluvial soils are low in organic carbon(C).Thus,increasing organic C is a major challenge to sustain soil fertility.Biochar amendment could be an option as biochar is a C-rich pyrolyzed material,which is slowly decomposed in soil.We investigated C mineralization(CO_(2)-C evolution)in two types of soils(recent and old alluvial soils)amended with two feedstocks(sugarcane bagasse and rice husk)(1%,weight/weight),as well as their biochars and aged biochars under a controlled environment(25±2℃)over 85 d.For the recent alluvial soil(charland soil),the highest absolute cumulative CO_(2)-C evolution was observed in the sugarcane bagasse treatment(1140 mg CO_(2)-C kg^(-1)soil)followed by the rice husk treatment(1090 mg CO_(2)-C kg^(-1)soil);the lowest amount(150 mg CO_(2)-C kg^(-1)soil)was observed in the aged rice husk biochar treatment.Similarly,for the old alluvial soil(farmland soil),the highest absolute cumulative CO_(2)-C evolution(1290 mg CO_(2)-C kg^(-1)soil)was observed in the sugarcane bagasse treatment and then in the rice husk treatment(1270 mg CO_(2)-C kg^(-1)soil);the lowest amount(200 mg CO_(2)-C kg^(-1)soil)was in the aged rice husk biochar treatment.Aged sugarcane bagasse and rice husk biochar treatments reduced absolute cumulative CO_(2)-C evolution by 10%and 36%,respectively,compared with unamended recent alluvial soil,and by 10%and 18%,respectively,compared with unamended old alluvial soil.Both absolute and normalized C mineralization were similar between the sugarcane bagasse and rice husk treatments,between the biochar treatments,and between the aged biochar treatments.In both soils,the feedstock treatments resulted in the highest cumulative CO_(2)-C evolution,followed by the biochar treatments and then the aged biochar treatments.The absolute and normalized CO_(2)-C evolution and the mineralization rate constant of the stable C pool(K_(s))were lower in the recent alluvial soil compared with those in the old alluvial soil.The biochars and aged biochars had a negative priming effect in both soils,but the effect was more prominent in the recent alluvial soil.These results would have good implications for improving organic matter content in organic C-poor alluvial soils.
基金supported by the Programa Operativo Feder de Andalucia 2007-2013 of Sapin (No.PAIDI AGR108)the Project of the Plan Nacional de Investigacion of Spain(No.AGL201123617)
文摘There are many remediation techniques for organic contaminated soils,but relatively few of them are applicable to trace elementcontaminated soils.A field experiment was carried out to investigate assisted natural remediation(ANR) of an acid soil contaminated by As,Cd,Cu,Zn and Pb using one inorganic amendment,sugar beet lime(SL),and two organic amendments,biosolid compost(BC)and leonardeite(LE).The experiment was arranged in a completely randomized block design with four treatments in three replicates:1) a non-amended control(NA);2) SL amended at 30 Mg ha^(-1) year^(-1);3) BC amended at 30 Mg ha^(-1) year^(-1) and 4) LE amended at 20 Mg ha^(-1) year^(-1) plus SL amended at 10 Mg ha^(-1) year^(-1)(LESL).The amended plots received two doses of each amendment(DO2):one in October 2002 and another in October 2003.The plots were then divided in half into two subpolts and one subplot received another two doses of the same amendments(DO4) in October 2005 and October 2006.In 2011,the pH values of the amended soils were greater than that of the NA soil,with the SL-amended soil showing the highest pH.Total organic carbon(TOC) was also greater in the amended soil,and greater with DO4 than with DO2.Amendments reduced the concentrations of 0.01 mol L^(-1) CaCl_2-extractable Cd,Cu and Zn,especially in the SL-amended soil.Plant cover of colonizing vegetation was enhanced by amendments,but was independent of amendment doses.Changes in soil properties from 2003 to 2011 showed that the first amendment application of DO2 caused a high differentiation between all the amendment treatments and the NA treatment.After the second application of DO2,soil pH and TOC continued increasing slowly.Further two applications of amendments(DO4) caused differences only in the organic treatments.Plant cover increased over time in all the treatments including NA.It could be concluded that the slow and steady natural remediation of this soil could be enhanced by amendment application(ANR).
