| Safe management practices on the soil phosphorus (P) has been highly concerned by the public due to the consecutive accumulation, decling yield response and increasing environmental risk caused by the excessive application of P fertilizers in the agriculture in China. In this study, the input, balance and spatio-tempeoral variation of phosphorus in the continuum of fertilizer-plant-soil during the last 30 years were investigated from literature at macro scale, and the transformation and availability of the accumulated P in soil were monitored in situ during long-term experiment. The results obtained at macro and plot level were combined to indicate the changes of total P application in Hebei province as well as the P balance, yield response to the application rate and forms of P fertilizers, transformation and movement in the soil profile for the grain, vegetable and orchard production system in Hebei. The main results are as following:1. It was found that the fast increase periods of P fertilization rate in Hebei province during 1980-1985 and 1990-1995 were observed, where the average annual increase rate was 14%; meanwhile, the total consumption of compound P fertilizers reached up to 894*103 tones and the respective contribution to the total P consumption increased from 10%2. Analysis of P balance based on the input-output indicated that the soil P status of winter wheat-summer maize rotation systems were characterized with depletion period (1949-1972), surplus (1972-1995) and high surplus (1996-), and the current P surplus is estimated to be 109.4-134.9 kg·hm-2. In vegetable soils, the estimated annual P surplus ranged from 314.9 kg·hm-2 to 367.2 kg·hm-2 durng the periods of 1980-1997 and 1998-now, higher P surplus up to 626.1 kg·hm-2 were found in greenhouse vegetable production. While in orchard production (e.g. apple), the P surpluses during 1980-2000 and 2000-now were 339.6% and 435.7%, respectively. Thus an increasing P surplus in agricultural soils in Hebei province was recognized.3. In comparison with the P status obtained in second state survey, the average soil Olsen-P in Hebei increased with 18.5 mg·kg-1 and the annual increase rate was 0.6 mg·kg-1 by 2008. This has been confirmed by the decline arable lands with Olsen-P <5 mg·kg-1 and increase of arable land with Olsen-P 20-40 mg·kg-1. However, the increase rate differed among different regions. For example, Shijiazhuang, Tangshan and Langfang were with greater annual increase rate varied from 15.0% to 19.7% with an annual accumulating rate of 0.7 mg·kg-1; and lower increase rates ranging from 7.7% to 9.1% with an annual accumulating rate of 0.3-0.4 mg·kg-1in Cangzhou, Xingtai and Handan were found. Such difference might be driven by the local economy situation.4. The accumulative level of soil P was highly different among winter wheat-summer maize rotation (WMR), vegetable production and orchards. For example, Olsen-P in the 0-20cm layer of WMR soil ranged from 9.5 mg·kg-1 to 47.7 mg·kg-1 with an average of 21.3 mg·kg-1 and average increase rate of 0.6 mg·kg-1; where 43.3% of the sampling sites were associated with an Olsen-P over 20. While the Olsen-P in 0-20cm layer of vegetable soils ranged from 74.9 to 582.6 mg·kg-1 with an average of 271.9 mg·kg-1, and the estimated annual increase of Olsen-P were 23.1-33.7 mg·kg-1; Similarly, high accumulation of soil P were found in orchards, where Olsen–P in 0-20cm layer were 159.1-211.3 mg·kg-1 or 7.6-10.1 times greater than in WMR.5. It was obtained through a long-term experiment of 8 years on vegetables that P fertilization significantly increased the yields of four vegetables by 21.5%-71.6% when 180360 kg P2O5/ha (P1P2) were applied, but no significant impact of applying organic P on the basis of mineral P application were obtained. Such yield response to P application can be fitted with Quadratic function and the maximal P fertilization rate for Chinese cabbage was 357-596 kg·hm-2 with an average of 443.0 kg·hm-2, 250-350 kg·hm-2 for summer cabbage, pepper and kidney bean. The analysis of accumulated P and Olsen-P level showed that the soil Olsen-P level might be increased by 1.06 mg·kg-1 when 100 kg·hm-2 of fertilizer P accumulated in soil during the 8-year experiment.6. P in vegetable soils were significantly increased after continuous 8-year P fertilization, where the annual increase of Olsen-P were 2.7-10.5 mg·kg-1 with the P fertilization of 180-720 kg hm-2, and 2.1 mg·kg-1 and 5.9 mg·kg-1 for M1 and M2 treatments. Mineral P mainly accumulated in the form of inorganic P, but the P in organic fertilizer accumulated in both inorganic and organic forms. It also indicated that the ratios of Olsen-P to total P increased under both organic and inorganic P fertilizations, indicating a favored enrichment of soil P in the form of Olsen-P.7. Significant increases of soil Ca2-P, Ca8-P, Al-P and Fe-P were observed after 8-year P fertilization but such increases were not found in O-P and Ca10-P. It was also indicated that the proportion of Ca2-P and Ca8-P in the total inorganic P increased with P fertilization rate, and the annual increase rate of Ca2-P, Ca8-P, Al-P and Fe-P were 0.3-6.6 mg·kg-1, 10.5-42.7 mg·kg-1, 3.0-13.1 mg·kg-1 and 1.6-4.7 mg·kg-1, respectively.8. In the long-term experiment, P accumulation occurred in 0-60 cm in the first three years, and the increase of Olsen-P in 60-80cm were observed after 5 years, especially in high P fertilization treatments, P accumulation in 80-100 cm were also observed. 9. In situ measurements of Olsen-P in the vegetable soil profiles in Gaocheng, Xushui and Tangshan showed that major accumulation of P occurred in the top layer but the P downward movements were also observed, where accumulated P in 60-80 cm accounted for 6.7%-11.9% of the total accumulation and Olsen-P in this layer increased by 1.8-4.3 mg·kg-1 annually. While in orchard, the accumulated P in 60-80cm layer reached 3.2 kg/hm-2 after 21-year fertilization, accounting for 7.4% of the total accumulation.
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