Saturday, 15 July 2006

The Effect of Different Phosphoric Fertilizers: Fluoride and Strontium in a Soddy-Podzolic Soil-Plant System.

Olga V. Shelepova, Potatueva Yalia, Karpova Elena, Sidorenkova Nadezhda, and Ignatov Vitalij. Dolgoprydnaya Agrochemical Experimental Station, Dmitrovskoe sh. 167, Moscow, 127204, Russia

Annual (and over a long period of time) application of some forms of phosphoric fertilizers, derived from Khibiny apatite concentrate, causes an accumulation of such toxic elements as fluoride and strontium in Soddy-podzolic soils and plants. The long-term experiment on testing the forms of phosphoric fertilizers was established at the Dolgoprydnaya Agrochemical Experimental Station on Soddy-podzolic heavy loam soil in 1933. The input of P2O5 over the years of experiment was 3825 kg, with the annual influx of F and Sr being equal to 1,69 kg F/ha and 3,28 kg Sr/ha in the case of simple superphosphate (Ps) application, and 2,02 kg F/ha and 0,1 kg Sr/ha in the case of ammophos (Pam) application. The total influx of F and Sr under regular fertilization during the experiment was equal to 118,6 kg F/ha and 229,5 kg Sr/ha in the Ps variant and 141,7 kg F/ha and 6,71 kg Sr/ha in the Pam variant. Excess of F and Sr inputs above their outputs during many years resulted in an accumulation of F and Sr compounds in the soil of agroecosystem: the total content of F increased by 80 mg F kg-1 under Ps application and by 110 mg F kg-1 under Pam application (variant “control” – total content of F in the soil 340 mg F kg-1, variant “NK+Ps” – 420 mg F kg-1, variant “NK+Pam” – 450 mg F kg-1). The total content of Sr in the soil increased by 20 mg Sr kg-1under Ps application only (variant “control” – 123 mg Sr kg-1, variant “NK+Ps” – 143 mg Sr kg-1, variant “NK+Pam” – 118 mg Sr kg-1). The quantity of exchangeable F and Sr increased in soil also – these forms are the most accessibility from the plants. The amount of F mobile forms (0,01m HClO4 extract in ration of 1 to 5) increased in 2,2 time in the Ps variant and in 1,9 time in the Pam variant (variant “control” – 3.0 mg F kg-1, variant “NK+Ps” – 6.7 mg F kg-1, variant “NK+Pam” – 5.8 mg F kg-1). But the content of water soluble forms of F increased in soil insignificantly - variant “control” – 1.2 mg F kg-1, variant “NK+Ps” – 1.6 mg F kg-1, variant “NK+Pam” – 2.6 mg F kg-1). The amount of Sr mobile forms (1m HCl extract in the ratio of 1 to 10) increased in 4,5 time in the Ps variant, but it didn't differ from the control in the Pam variant (variant “control” – 3.7 mg Sr kg-1, variant “NK+Ps” – 16.5 mg Sr kg-1, variant “NK+Pam” – 3.6 mg Sr kg-1). F and Sr are the elements that have different biological accessibility. F it has low accessibility and Sr it has high accessibility. An increase in the soil amount of F mobile and water soluble forms didn't cause F accumulation in aboveground biomass in most of the crops: the F content in vetch-oats green biomass in the variants Ps and Pam didn't significantly differ from the control (variant “control” – 1.8 mg F kg-1, variant “NK+Ps” – 1.4 mg F kg-1, variant “NK+Pam” – 2.1 mg F kg-1). While the accumulation of Sr mobile forms under regular Ps application resulted in an increase it the Sr content in aboveground and underground parts of the plants – the quantity in vetch-oats green matter t mounted to the maximum value and significantly differed from the control (variant “control” – 6.6 mg Sr kg-1, variant “NK+Ps” – 18.4 mg Sr kg-1, variant “NK+Pam” – 8.9 mg Sr kg-1). The Sr content in tuber of the potatoes increased in 3.5 time also - variant “control” – 1.9 mg Sr kg-1, variant “NK+Ps” – 6.6 mg Sr kg-1, variant “NK+Pam” – 2.0 mg Sr kg-1.

Back to 3.3A Future Challenges in P Fertilization and the Environment - Poster
Back to WCSS

Back to The 18th World Congress of Soil Science (July 9-15, 2006)