Effects of long-term phosphorus fertilizer applications on plant growth, yield, soil carbon budget and carbon flux

Long-term agricultural researches with annual and perennial cropping systems provide significant insight into the carbon sequestration potential of agriculture in the South-East Anatolia region. This study was exploring an effect of different phosphorous (P) fertilizer application rates on the storage and quality of soil organic carbon (SOC), permanganate oxidizable C (PoxC), plant biomass and carbon uptake, plant CO2 assimilation rate to assess the relationship between Carbon Sequestration and P fertilizers application. Different cropping sequences of corn (Zea mays L.) - wheat (Triticum aestivum L.) (CW system) and application of 4 fertilizer dozes (0, 50,100, 200 kg ha-1) were repeated annually during last 20 years. The study was based on the hypothesis that long-term P-fertilization can affect Carbon Sequestration is soil and plant biomass and impacts on soil CO2 flux. The objectives of the present study were to: (i) analyze the effect of long-term inorganic chemical P fertilization on the plant biomass carbon uptake and SOC amount for wider environmental protection, (ii) estimate effect of long-term P fertilization on CO2 flux related with SOC accumulation. The results demonstrated that P fertilization has positive impact on plant biomass, higher carbon fixation and more carbon residue left in soil, that in a long perspective has an positive impact on soil carbon sequestration. The P fertilizer did not have direct impact on SOC of summer-maize growing season, and had positive impact on SOC while winter-wheat growing season. The fertilization also did not demonstrated direct impact on soil CO2 flux.