A long-term （21-year） field experiment was performed to study the responses of soil inorganic P fractions and P availability to annual fertilizer P application in a calcareous soil on the Loess Plateau of China. Soi...A long-term （21-year） field experiment was performed to study the responses of soil inorganic P fractions and P availability to annual fertilizer P application in a calcareous soil on the Loess Plateau of China. Soil Olsen-P contents increased by 3.7, 5.2, 11.2 and 20.6 mg P kg-1 after 21-year annual fertilizer P application at 20, 39, 59, and 79 kg P ha-1, respectively. Long-term fertilizer P addition also increased soil total P and inorganic P （Pi） contents significantly. The contents of inorganic P fractions were in the order of Ca10-P 〉 Cas-P 〉 Fe-P 〉 A1-P 〉 occluded P 〉 Ca2-P in the soil receiving annual fertilizer P application. Fertilizer P application increased Cas-P, A1-P and Ca2-P contents as well as their percentages relative to Pi. Pi application increased Fe-P and occluded P contents but nor their percentages. Soil Ca10- P content remained unchanged after fertilizer P application while its percentage relative to Pi declined with increasing fertilizer P rate. All Pi fractions but Ca10-P were correlated with Olsen-P significantly. 90% of variations in Olsen-P could be explained by Pi fractions, and the direct contribution of Cas-P was predominant. Long-term annual superphosphate application would facilitate the accumulation of soil Cas-P, and thus improve soil P availability.展开更多
Plants have diverse strategies to cope with phosphorus （P） deficiency. To better understand how maize responds to P deficiency, a field experiment with two P levels, 0 and 100 kg P205 ha-1 （P0 and P100, respectivel...Plants have diverse strategies to cope with phosphorus （P） deficiency. To better understand how maize responds to P deficiency, a field experiment with two P levels, 0 and 100 kg P205 ha-1 （P0 and P100, respectively）, was carried out as a part of a long-term Pfertilizer field trial. Plant and soil analyses showed that P-deficient maize reduced its growth rate, increased P use efficiency, and formed more thin roots with the diameter less than 0.6 mm at jointing and silking stages, compared to the plants treated with P100. Further, there were no differences in major inorganic P fractions （Ca2-P, Cas-P, Al-P, Fe-P, occluded P and Ca10-P） between the rhizospheric and bulk soils at each harvest, even when soil Olsen-P was only 1.38 mg kg-1. These results suggested that maize responded to P deficiency by reducing the internal P demand for growth and increasing P acquisition ability by favorable root morphological alteration at low carbon cost.展开更多
基金Supported by the National Basic Research Program (973 Program) of China (No.2005CB121102)the Knowledge Innovation Program of the Chinese Academy of Sciences (No.kzcx2-yw-424)the National Natural Science Foundation of China (No.30500077)
文摘A long-term （21-year） field experiment was performed to study the responses of soil inorganic P fractions and P availability to annual fertilizer P application in a calcareous soil on the Loess Plateau of China. Soil Olsen-P contents increased by 3.7, 5.2, 11.2 and 20.6 mg P kg-1 after 21-year annual fertilizer P application at 20, 39, 59, and 79 kg P ha-1, respectively. Long-term fertilizer P addition also increased soil total P and inorganic P （Pi） contents significantly. The contents of inorganic P fractions were in the order of Ca10-P 〉 Cas-P 〉 Fe-P 〉 A1-P 〉 occluded P 〉 Ca2-P in the soil receiving annual fertilizer P application. Fertilizer P application increased Cas-P, A1-P and Ca2-P contents as well as their percentages relative to Pi. Pi application increased Fe-P and occluded P contents but nor their percentages. Soil Ca10- P content remained unchanged after fertilizer P application while its percentage relative to Pi declined with increasing fertilizer P rate. All Pi fractions but Ca10-P were correlated with Olsen-P significantly. 90% of variations in Olsen-P could be explained by Pi fractions, and the direct contribution of Cas-P was predominant. Long-term annual superphosphate application would facilitate the accumulation of soil Cas-P, and thus improve soil P availability.
基金Supported by the National Basic Research Program (973 Program) of China (No. 2013CB127402)the Fundamental Research Funds for the Central Universities, China (No. 2012YJ054)the Innovative Research Group Grant of the National Natural Science Foundation of China (No. 31121062)
文摘Plants have diverse strategies to cope with phosphorus （P） deficiency. To better understand how maize responds to P deficiency, a field experiment with two P levels, 0 and 100 kg P205 ha-1 （P0 and P100, respectively）, was carried out as a part of a long-term Pfertilizer field trial. Plant and soil analyses showed that P-deficient maize reduced its growth rate, increased P use efficiency, and formed more thin roots with the diameter less than 0.6 mm at jointing and silking stages, compared to the plants treated with P100. Further, there were no differences in major inorganic P fractions （Ca2-P, Cas-P, Al-P, Fe-P, occluded P and Ca10-P） between the rhizospheric and bulk soils at each harvest, even when soil Olsen-P was only 1.38 mg kg-1. These results suggested that maize responded to P deficiency by reducing the internal P demand for growth and increasing P acquisition ability by favorable root morphological alteration at low carbon cost.
