TY - JOUR

T1 - Droughts Legacy Effects on Phosphorus Transformation from Residues and Mineral Fertilizers in Calcareous and Carbonate-Free Soils

T2 - A 33P Labeling Study

AU - Farooq, Naila

AU - Koirala, Manisha

AU - Loftus, Sara

AU - Zhang, Xi

AU - Zamanian, Kazem

AU - Banfield, Callum C.

AU - Dippold, Michaela A.

N1 - Publisher Copyright: © The Author(s) under exclusive licence to Sociedad Chilena de la Ciencia del Suelo 2024.

PY - 2024/11/15

Y1 - 2024/11/15

N2 - Background: While well-described for soil properties, we barely know how microbial traits determine the availability of various phosphorus (P) forms to crops. Aims: We traced the dynamics of mineral- versus residue-derived P applied to two contrasting soil types during wheat cultivation. Methods: The legacy effect of three pre-sowing moisture conditions was investigated: drought (30% water holding capacity, WHC), alternating cycles of drying (30% WHC) and wetting (70% WHC), and well-watered conditions (70% WHC). 33P-labelled cowpea residues (Vigna unguiculate) and KH233PO4 were applied as fertilizers to calcareous and carbonate-free soils. Results: Under pre-sowing drought conditions, microbial incorporation of 33P from residue P into polar lipids was four times higher than from mineral P. Calcareous soils showed double the microbial biomass than carbonate-free soils. However, when fertilized with residue P, carbonate-free soils exhibited twice the acid phosphatase activity and a 3- to 6-fold greater 33P uptake into phospholipids normalized per unit microbial biomass C. Conclusion: Residue P enhances microbial growth, leading to increased P immobilization, especially in carbonate-free soils. Drought-triggered microorganisms efficiently acquire P from organic sources like residues. This increased microbial P immobilization under pre-sowing drought does not negatively affect plant growth, when a mineralizable organic P pool is consistently available. Regardless of the pre-sowing moisture conditions, residue P fertilization promotes a rapidly cycling microbial biomass-necromass pool, specifically in calcareous soils. This implies that residue P fertilization could be a sustainable, long-term strategy for continuous P supply in P-immobilizing calcareous soils, even under increasing drought conditions due to climate change.

AB - Background: While well-described for soil properties, we barely know how microbial traits determine the availability of various phosphorus (P) forms to crops. Aims: We traced the dynamics of mineral- versus residue-derived P applied to two contrasting soil types during wheat cultivation. Methods: The legacy effect of three pre-sowing moisture conditions was investigated: drought (30% water holding capacity, WHC), alternating cycles of drying (30% WHC) and wetting (70% WHC), and well-watered conditions (70% WHC). 33P-labelled cowpea residues (Vigna unguiculate) and KH233PO4 were applied as fertilizers to calcareous and carbonate-free soils. Results: Under pre-sowing drought conditions, microbial incorporation of 33P from residue P into polar lipids was four times higher than from mineral P. Calcareous soils showed double the microbial biomass than carbonate-free soils. However, when fertilized with residue P, carbonate-free soils exhibited twice the acid phosphatase activity and a 3- to 6-fold greater 33P uptake into phospholipids normalized per unit microbial biomass C. Conclusion: Residue P enhances microbial growth, leading to increased P immobilization, especially in carbonate-free soils. Drought-triggered microorganisms efficiently acquire P from organic sources like residues. This increased microbial P immobilization under pre-sowing drought does not negatively affect plant growth, when a mineralizable organic P pool is consistently available. Regardless of the pre-sowing moisture conditions, residue P fertilization promotes a rapidly cycling microbial biomass-necromass pool, specifically in calcareous soils. This implies that residue P fertilization could be a sustainable, long-term strategy for continuous P supply in P-immobilizing calcareous soils, even under increasing drought conditions due to climate change.

KW - Alternate drying/wetting cycles

KW - Climate change

KW - Legacy effects on microbial traits

KW - Phosphorus

KW - Pre-sowing moisture regime

KW - Sustainable agriculture

UR - http://www.scopus.com/inward/record.url?scp=85209139446&partnerID=8YFLogxK

U2 - 10.1007/s42729-024-02120-1

DO - 10.1007/s42729-024-02120-1

M3 - Article

AN - SCOPUS:85209139446

JO - Journal of Soil Science and Plant Nutrition

JF - Journal of Soil Science and Plant Nutrition

SN - 0718-9508

ER -