Speaker
Description
1.Introduction
Phosphorus (P) is an essential element for plant nutrition. The current fertilization strategies rely on mineral fertilizers, obtained from non-renewable and finite resources, whose production will peak in the coming decades. In a scenario of world population growth, reducing dependence on mineral fertilizers while maintaining/increasing agricultural productivity is essential. To this end, fertilizers strategies should involve P recycling by using agricultural residues. The aim of the work is to evaluate the efficiency of different agricultural residues as P fertilizers in a rainfed crop rotation cycle representative of Mediterranean regions: wheat-sunflower-pea.
2.Materials, methods
Two experiments under field conditions were carried out in south Spain for 3 years involving as treatments: composted olive oil mill, horse manure vermicompost, and mineral P fertilizer which were applied at 30 kg P ha-1, and a control without fertilizer. The same rates of potassium and nitrogen were applied to all the treatments. Phosphorus fertilizer was applied before sowing only to the first crop (wheat).
3.Results and discussion
Fertilization with composted agricultural residues was effective as P source for crops. In the first experiment, the highest grain yield of wheat was obtained with olive oil mill compost However, in the second crop of the rotation (sunflower), the horse manure vermicompost showed a significant increase (41%) relative to mineral fertilizer and non-fertilized control. In the second experiment, vegetable waste vermicompost led the highest grain yield of wheat. Phosphorus uptake by pea in the first experiment was increased significantly with olive oil mill and vegetable waste vermicompost (mean value of 11.1 kg ha-1) compared to mineral fertilization and non-fertilized control. Olsen P in soil amended with organic P sources maintain their value of 7.2 mg kg-1, slightly higher than control without fertilization at the end of both crop rotations. However, mineral fertilization led to the highest Olsen P values in soil, which however decreased over time more quickly than organic fertilizers. It can be concluded that the composted agricultural residues studied can be used as effective P sources for crops, and thus may contribute to decrease the dependence on mineral P in agriculture and consequently to the sustainability of agricultural systems.
Funding: Spanish Ministry of Science and Innovation and the European Regional Development Fund of the European Union through the National Research, Development and Innovation Program (Plan Nacional I+D+i). Projects AGL2017-87074-C2-1-R and PID2020-118503RB-C21
| Keywords | phosphorus, crop rotation, organic fertilizers |
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