Phosphorus budget and soil extractable dynamics in field crop rotations in mollisols
A better understanding of the P cycle is necessary to provide insights into management strategies that could enhance P bioavailability for crops. Our objectives were to evaluate the effects of continuous P fertilization on [i] the P budget, [ii] soil-extractable P [Pe] dynamics, and [iii] the relationship between these variables. Two crop rotations during a 6-yr period were analyzed in seven on-farm experiments: corn [Zea mays L.]-double cropped wheat [Triticum aestivum]/soybean [Glycine max [L.] Merr.] [C-W/S], and corn-soybean-double croppedwheat/ soybean [C-S-W/S]. Calculations of net P input considered only P removal [output] and fertilization [input]. Initial soil-test P was 13.4 mg P kg-1 [average for the four sites] for the C-W/S rotation and 37.9 mg P kg-1 for the C-S-W/S rotation [average for the three sites]. Treatment combinations were two annual rates: unfertilized and grain P removal estimation +10 percent [average 34 kg P ha-1 yr-1 ]. Not applying P to soils testing 45 to 68 mg kg-1 of initial Pe resulted in a steep Pe decline [slope 0.2 mg kg-1 per unit of negative P budget]. Nevertheless, soils with more than 25 mg kg-1 of initial Pe levels resulted in a very small and gradual decline [slope 0.02 mg kg-1 ]. Use of current P rates applied by local farmers probably results in a small soil-test P buildup with time. The P required to increase Pe by 1 mg P kg-1 was 11 and 8 kg P ha-1 yr-1 for the C-W/S and C-S-W/S rotations, respectively.
| Main Authors: | , , , |
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| Format: | Texto biblioteca |
| Language: | eng |
| Subjects: | ANNUAL RATES, CORN [ZEA MAYS L.], CROP ROTATION, IN-FIELD, MANAGEMENT STRATEGIES, MOLLISOLS, P REMOVAL, P-CYCLES PER UNIT, SOYBEAN [GLYCINE MAX [L.] MERR.], TRITICUM AESTIVUM, AMINO ACIDS, BIOCHEMISTRY, BUDGET CONTROL, CROPS, GRAIN [AGRICULTURAL PRODUCT], NITROGEN FIXATION, PHOSPHORUS, SOIL MECHANICS, SOIL TESTING, SOILS, ROTATION, BIOAVAILABILITY, DOUBLE CROPPING, FARMERS ATTITUDE, FERTILIZER APPLICATION, MAIZE, MANAGEMENT PRACTICE, MOLLISOL, SOIL DYNAMICS, SOIL TEST, SOYBEAN, WHEAT, GLYCINE MAX, ZEA MAYS, |
| Online Access: | http://ceiba.agro.uba.ar/cgi-bin/koha/opac-detail.pl?biblionumber=46579 |
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| Summary: | A better understanding of the P cycle is necessary to provide insights into management strategies that could enhance P bioavailability for crops. Our objectives were to evaluate the effects of continuous P fertilization on [i] the P budget, [ii] soil-extractable P [Pe] dynamics, and [iii] the relationship between these variables. Two crop rotations during a 6-yr period were analyzed in seven on-farm experiments: corn [Zea mays L.]-double cropped wheat [Triticum aestivum]/soybean [Glycine max [L.] Merr.] [C-W/S], and corn-soybean-double croppedwheat/ soybean [C-S-W/S]. Calculations of net P input considered only P removal [output] and fertilization [input]. Initial soil-test P was 13.4 mg P kg-1 [average for the four sites] for the C-W/S rotation and 37.9 mg P kg-1 for the C-S-W/S rotation [average for the three sites]. Treatment combinations were two annual rates: unfertilized and grain P removal estimation +10 percent [average 34 kg P ha-1 yr-1 ]. Not applying P to soils testing 45 to 68 mg kg-1 of initial Pe resulted in a steep Pe decline [slope 0.2 mg kg-1 per unit of negative P budget]. Nevertheless, soils with more than 25 mg kg-1 of initial Pe levels resulted in a very small and gradual decline [slope 0.02 mg kg-1 ]. Use of current P rates applied by local farmers probably results in a small soil-test P buildup with time. The P required to increase Pe by 1 mg P kg-1 was 11 and 8 kg P ha-1 yr-1 for the C-W/S and C-S-W/S rotations, respectively. |
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