Claim · model-written summary
Application of 380 kg K per ha was calculated to maintain initial exchangeable K in the Keith soil.
- Taxon
- alfalfa
Medicago sativae0 - Outcome
- maintain initial NH 4 C 2 H 3 O 2e1
- Value
- 380e1
- Setting
- Keithe2
Not reportedMaterialGeneCompoundOrgan / stageInteractorInteractor roleSecond interactorSecond interactor roleTreatmentComparatorDirectionQualifier
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“alfalfa ( Medicago sativa L.)”
e1“Application of 380 and 5 kg K ha −1 were calculated to maintain initial NH 4 C 2 H 3 O 2”
e2“in the Keith and Ravola soils, respectively”
Title
Six Years of Phosphorus and Potassium Fertilization of Irrigated Alfalfa on Calcareous Soils
J. L. Havlin; D. G. Westfall; H. M. Golus Soil Science Society of America Journal 1984. doi:10.2136/sssaj1984.03615995004800020022x
Other claims from this paper (15)
- Observation Soil test P declined in both soils in the alfalfa experiments.
- Intervention effect Despite declining soil test P, no significant yield response to fertilizer P was observed in alfalfa although one was expected.
- Mechanism Organic P mineralization and/or an extensive mycorrhizal association were suggested as contributing to P availability.
- Intervention effect Application of 50 kg P per ha maintained the initial NaHCO3-extractable P at both locations.
- Intervention effect Soil P declined below the initial level for all P rates other than 50 kg P per ha.
- Intervention effect Phosphorus uptake by alfalfa was significantly increased by P fertilization on the Keith soil.
- Intervention effect Phosphorus uptake by alfalfa was not increased by P fertilization on the Ravola soil.
- Observation Soil test K remained at high levels in both soils.
- Intervention effect No yield responses of alfalfa to fertilizer K were observed.
- Recommendation Application of 5 kg K per ha was calculated to maintain initial exchangeable K in the Ravola soil.
- Mechanism The low K maintenance requirement of the Ravola soil was apparently due to a high nonexchangeable K release rate that buffered exchangeable K near 100 mg per kg.
- Intervention effect Potassium uptake by alfalfa was significantly increased by K fertilization in the Ravola soil.
- Intervention effect Potassium uptake by alfalfa was not increased by K fertilization in the Keith soil.
- Observation Very large P and K reserves exist in both soils.
- Recommendation Unless improved forage quality changes the economic benefit, P and K fertilization of these soils is not recommended.