Recovery of Soil Test Phosphorus from an Acidic Soil Amended with Organic and Inorganic Phosphorus
Open Journal of Soil Science
Information on soil test phosphorus (P) in soil treated with organic amendments is important to a sound management of manure additions to agricultural fields. This study compared the recovery of cow manure, chicken manure, city compost P relative to triple super phosphate P (TSP) for an acidic soil with different antecedent soil test P (STP). Phosphorus was added at rates of 0, 100, 200, 400 and 800 mg P·kg −1 soil based on total P. The soil was incubated at field capacity for 1, 4, 8 and 16
... r 1, 4, 8 and 16 weeks (wk) after which they were extracted using NaHCO 3 (Olsen) Mehlich-3, Kelowna and Bray & Kurtz-1 extractants. Regardless of extractants, after 1 wk incubation, the highest STP source was the TSP and the least was the city compost. Soil Test P increased with the addition of amendments from different P sources. Among the amendments, soil test P in TSP amended soil gradually decreased but in the city compost amended soil slightly increased with incubation time, whereas the changes of soil test P with time in the cow and chicken manures amended soil was very negligible. Across the amendments and rates of P additions, the value of extractable P with Olsen was of 55 mg·kg −1 (16%), with Mehlich-3 was of 112 mg·kg −1 (32%), with Kelowna was of 88 mg·kg −1 (24%) and with Bray & Kurtz was of 104 mg kg −1 (29% of total added P). The P extraction efficiency was in the order: NaHCO 3 < Kelowna < Bray & Kurtz-1 < Mehlich-3. This study indicates that P in organic amendments reflects plant available P through the entire incubation period but P in the TSP are likely to under estimate after 8 wk of incubation.