Phosphorus balance and critical value in loessial soil of Loess Plateau under long\|term fertilization |
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DOI:10.7606/j.issn81000-7601.2020.03.20 |
Key Words: phosphate apparent balance critical value of soil Olsen-P loessial soil long\|term fertilization dryland of Loess Platean |
Author Name | Affiliation | WANG Shuying | Dryland Agricultural Institute of Gansu Academy of Agricultural Sciences/Key Laboratory of High Water Utilization on Dryland of Gansu Province, Lanzhou, Gansu 730070, China | FAN Tinglu | Dryland Agricultural Institute of Gansu Academy of Agricultural Sciences/Key Laboratory of High Water Utilization on Dryland of Gansu Province, Lanzhou, Gansu 730070, China | LI Lili | Pingliang Academy of Agricultural Sciences, Pingliang, Gansu 744500, China | ZHAO Gang | Dryland Agricultural Institute of Gansu Academy of Agricultural Sciences/Key Laboratory of High Water Utilization on Dryland of Gansu Province, Lanzhou, Gansu 730070, China | ZHANG Jianjun | Dryland Agricultural Institute of Gansu Academy of Agricultural Sciences/Key Laboratory of High Water Utilization on Dryland of Gansu Province, Lanzhou, Gansu 730070, China | LI Shangzhong | Dryland Agricultural Institute of Gansu Academy of Agricultural Sciences/Key Laboratory of High Water Utilization on Dryland of Gansu Province, Lanzhou, Gansu 730070, China | WANG Lei | Dryland Agricultural Institute of Gansu Academy of Agricultural Sciences/Key Laboratory of High Water Utilization on Dryland of Gansu Province, Lanzhou, Gansu 730070, China | DANG Yi | Dryland Agricultural Institute of Gansu Academy of Agricultural Sciences/Key Laboratory of High Water Utilization on Dryland of Gansu Province, Lanzhou, Gansu 730070, China | CHENG Wanli | Dryland Agricultural Institute of Gansu Academy of Agricultural Sciences/Key Laboratory of High Water Utilization on Dryland of Gansu Province, Lanzhou, Gansu 730070, China | TANG Xiaoming | Dryland Agricultural Institute of Gansu Academy of Agricultural Sciences/Key Laboratory of High Water Utilization on Dryland of Gansu Province, Lanzhou, Gansu 730070, China |
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Abstract: |
This study examined the relation of soil phosphorus (P) with P balance under long\|term fertilization, the critical Olsen-P value for crop yield, and the reasonable P fertilizer application rate, and thus provided theoretical basis for the scientific application of P fertilizer and the maintenance of sustainable high production efficiency in loessial soil of Loess Plateau. Based on the long\|term fertilization experiment of loessial soil in Pingling, Gansu (1979-), six fertilizer treatments including no fertilizer (CK), chemical nitrogen (N), chemical N and P (NP), straw plus chemical NP (SNP), farmyard manure (M), and farmyard manure plus chemical NP (MNP) were used in the cropping system of 4-year continues winter wheat followed by 2-year spring corn. A total of 36 years (1979-2016) data of loessial soil in Loess Plateau were analyzed for content of soil Olsen-P and the P uptake by plants. Soil accumulated apparent P balance, P residue in soil, and the relationship between soil accumulated apparent P balance and soil Olsen-P were studied. The response of crop yield to soil Olsen-P was examined by the Mitscherlich equation to determine the critical Olsen-P value for crop yield. The soil P content was depleted each year in the no-P treatments, while in the treatments with P fertilization the P surplus was 4.3~207.9 kg·hm-2. The accumulative P amount was in the range of 154.9~7 483.6 kg·hm-2. The P surplus in the MNP treatment was the highest among the treatments. The P balance was significantly (P<0.05) correlated with soil Olsen-P. The Olsen-P decreased by 1.05 mg·kg-1 in the N treatments for each 100 mg·kg-1 P deficiency. For each surplus of 100 mg·kg-1 in soil, the Olsen-P in the SNP, NP, M, and MNP treatments increased by 7.55, 2.47, 0.28, and 0.46 mg·kg-1, respectively. The agronomic thresholds of wheat and maize were 22.05 and 13.96 mg·kg-1, respectively. It took 21, 24 years for the treatments of NP, SNP, and M to reach the critical Olsen-P value for wheat, respectively, and it took 2 and 8 years for the treatments of NP and SNP to reach the critical Olsen-P value for maize, respectively .When the average P application amount was up to 22.9 kg·hm-2 per year, the P balance does not change, again,was to 33 kg·hm-2 the crop yield and the P utilization rate were both high and the soil P residue was low and the phosphorus accumulation in the soil was less, however to 233 kg·hm-2 yearly, the crop yield did not respond to the P input, and the soil P residue exceeded 90%, which implied much P accumulated in soil and increased high risk of soil P loss. Agronomic critical value of soil Olsen-P was 13.96 mg·kg-1 (maize) and 22.05 mg·kg-1 (wheat.) for dryland cropping system of winter wheat rotated with spring corn yearly in dryland of Loess Plateau. The treatment of SNP can effectively increase soil Olsen-P accumulation. |
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