Phosphorus Budget and Soil Extractable Dynamics in Field Crop Rotations in Mollisols.

CIAMPITTI, IA, LE PICCONE, FO GARCIA. RUBIO G.

SOIL SCIENCE SOCIETY OF AMERICA JOURNAL

SOIL SCI SOC AMER

Lugar: Wisconsin; Año: 2011 vol. 75 p. 131 - 142

0361-5995

ABSTRACT A better understanding of phosphorus (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) P balance, ii) extractable P (Pe) dynamics and iii) the relationship between these variables. Two crop rotations were analyzed in a 6 years on-farm experiment: corn-double cropped wheat/soybean (C-W/S) in three sites, and corn- soybean-double cropped wheat/soybeans (C-S-W/S) in four experimental sites. In the C-W/S rotation, the average accumulated P balance was -155.9 kg P ha-1 in the control treatment and 9.5 kg P ha-1 in the fertilized treatment; while in the C-S-W/S rotation, net P balances were -148.2 kg P ha-1 and 44.8 kg P ha-1, respectively. Pe declined over time in the non-fertilized plots in both rotations; whereas in fertilized P plots presented a higher increase in the C-W/S rotation, because P removed was lower than in the C-S-W/S cropping system. Although initial P (Pi) values exerted a large influence on Pe evolution, the data fitted into statistically significant linear functions when Pe evolution was adjusted by Pi. After this standardization, we observed that the rotation effect was almost negligible in both non-fertilized and fertilized treatments. Our study provides functions to estimate Pe evolution for various Pi levels and two contrasting fertilization treatments. This information may be useful for improving P management plans.