Variable impact of compost on phosphorus dynamics in organic dryland soils following a one‐time application

Abstract

Prolonged benefits following a single application of compost in organic dryland wheat (Triticum aestivum L.) in the western United States have been documented, including the long-term bioavailability of phosphorus (P). Information on the bioavailability and forms of P following a one-time compost application in marginal organic agroecosystems with low and infrequent use of fertilizers is required to promote sustainability. The goal of this study was to evaluate changes in Hedley P pools following a one-time application of manure compost and its potential influence on short-term (3-yr) P bioavailability. Steer manure compost at 0, 25, and 50 Mg dry weight ha -1 was applied to two organic dryland sites, Snowville and Blue Creek, with contrasting soil characteristics in northern Utah in a randomized complete block design. Potential phosphatase assays, a laboratory aerobic incubation study, and soil P fractionations were carried out to assess the transformation of P 1 and 3 yr after a one-time compost application. At 0-10 cm, compost application resulted in increased acid phosphatase at Snowville (67.3 vs. 42.7 μg p-nitrophenol g -1 soil, p = .003), while alkaline phosphatase increased at Blue Creek (124 vs. 49 μg p-nitrophenol g -1 soil, p = .0185). The path coefficient between compost P and Hedley labile inorganic P was significant at Snowville, but not at Blue Creek, suggesting that the pathways of P differed between the sites. The Hedley stable P pool was a sink of compost P at Snowville but a source at Blue Creek. In conclusion, our work shows that a one-time compost application had a differential effect on the variation in P dynamics in organic dryland winter wheat-fallow soils. The potential long-term benefits may be greater in semiarid soils with lower available P levels, higher carbonate levels and pH, and drier conditions.

Mineral Components, Organic Matter Quality and Soil Enzymatic Activity under the Influence of Differentiated Farmyard Manure and Nitrogen Fertilisation

“…However, the inhibition of oxidation enzymes (phenol oxidase and peroxidase) was noted. The authors suggest that adding N to soil stimulates microorganisms that produce a greater amount of enzymes that are associated with the hydrolytic acquisition of C. As reported by Li et al [100], statistical analysis showed that NT and C were the main predictors of AlP activity.…”

“…This means that the rate of enzymatic release of phosphates from organic compounds is determined by the end product of several chemical reactions. Also, research by Li et al [100] showed that the activity of AlP, unlike AcP, explained the amount and dynamics of the content of available P in the soil. This suggests a different role of AlP in regulating P availability in soil long-term fertilised with FYM and N.…”

“…Usually, the activity of phosphatases is influenced by the P content, which depends on the macroelement bioavailability to plants [93]. This probably indicates a close relationship with the development phase of plants, the climate and soil properties [100]. Soils with low and medium mineral P contents usually have a higher production of phosphatases.…”

Relationship among Soil Biophysicochemical Properties, Agricultural Practices and Climate Factors Influencing Soil Phosphatase Activity in Agricultural Land

“…This trend is confirmed by Sun et al [41], which showed a negative correlation between both APases and Olsen P and soil solution P. In this case, the negative association has been attributed to the hydrolysis of P compounds by other APase enzymes in the NaHCO 3 -extractable fraction, leading to an increase in dissolved inorganic P in the soil solution. However, other studies showed a positive association between APase activity (both ACP and ALP) and Olsen P, soil solution P, and organic P (Figure 3), which means that the dynamics of P fractions, particularly Olsen P, are closely related to plant development and can be influenced by climate and intrinsic soil characteristics [118,119]. Additionally, the addition of organic P sources, which increase the soluble P content, can negatively impact APase activity, as they contribute to the pool of available inorganic P in the soil [120].…”