TY - JOUR
T1 - Temporal changes in labile soil phosphorus pools in grassland receiving P recycled from dairy processing sludge
AU - Khomenko, Olha
AU - Fenton, Owen
AU - Leahy, J. J.
AU - Daly, Karen
N1 - Publisher Copyright:
© 2023
PY - 2023/12
Y1 - 2023/12
N2 - Replacing chemical fertilisers with recycled products will require new advice for phosphorus (P) use. Emerging P fertilisers derived from dairy processing sludge (DPS) include products such as struvite and hydrochar. A field study monitored temporal changes in available, exchangeable, and Mehlich3 P pools in a P deficient grassland amended with DPS-derived hydrochar and struvite. Herbage P content and yields were compared with data from plots amended with a mineral P fertiliser. Regardless of fertiliser used, there was no statistical difference in dry matter yield. However, herbage P content varied depending on the fertiliser type. The optimal P content in herbage for cattle feed (0.3–0.4 %) was reached using struvite and mineral fertiliser. Application of struvites increased available, exchangeable, and Mehlich3 P, raising the available P levels to the agronomic optimal value for crop production (>5 mg L-1) within one month. In hydrochar amended plots, the optimal level of P was reached 4 months after fertilisation, at the end of the growing season. During the low growth or dormancy period, soil P levels decreased and remained low regardless of the treatment. In the struvite amended plots, available and exchangeable P pools recovered at the beginning of the second season. This effect was not observed in mineral fertiliser and hydrochar amended plots. A single application of struvite can replace mineral fertilisers supplying crops with P for more than one season. This needs to be reflected in the advice for growers to avoid excessive P application and legacy P deposition.
AB - Replacing chemical fertilisers with recycled products will require new advice for phosphorus (P) use. Emerging P fertilisers derived from dairy processing sludge (DPS) include products such as struvite and hydrochar. A field study monitored temporal changes in available, exchangeable, and Mehlich3 P pools in a P deficient grassland amended with DPS-derived hydrochar and struvite. Herbage P content and yields were compared with data from plots amended with a mineral P fertiliser. Regardless of fertiliser used, there was no statistical difference in dry matter yield. However, herbage P content varied depending on the fertiliser type. The optimal P content in herbage for cattle feed (0.3–0.4 %) was reached using struvite and mineral fertiliser. Application of struvites increased available, exchangeable, and Mehlich3 P, raising the available P levels to the agronomic optimal value for crop production (>5 mg L-1) within one month. In hydrochar amended plots, the optimal level of P was reached 4 months after fertilisation, at the end of the growing season. During the low growth or dormancy period, soil P levels decreased and remained low regardless of the treatment. In the struvite amended plots, available and exchangeable P pools recovered at the beginning of the second season. This effect was not observed in mineral fertiliser and hydrochar amended plots. A single application of struvite can replace mineral fertilisers supplying crops with P for more than one season. This needs to be reflected in the advice for growers to avoid excessive P application and legacy P deposition.
KW - Availability
KW - Dairy processing waste
KW - Exchangeable phosphorus
KW - Hydrochar
KW - Phosphorus use efficiency
KW - Struvite
UR - http://www.scopus.com/inward/record.url?scp=85176202068&partnerID=8YFLogxK
U2 - 10.1016/j.soisec.2023.100110
DO - 10.1016/j.soisec.2023.100110
M3 - Article
AN - SCOPUS:85176202068
SN - 2667-0062
VL - 13
JO - Soil Security
JF - Soil Security
M1 - 100110
ER -