摘要:

A comprehensive review on the chemistry and mineralogy of nonexchangeable potassium is presented. Forms of soil K, the effect of mineralogy on release of nonexchangeable K, methods of determining nonexchangeable K, and the kinetics of non‐exchangeable ? release are fully discussed.

ISSN:0010-3624    

DOI:10.1080/00103628509367593

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Plant species vary in their ability to absorb many major and minor nutrients and thus continually change ionic equilibria in soils. Experiments were conducted under controlled conditions to investigate the influence of corn, onion and wheat growth on the ionic equilibria, selectivity coefficient and diffusion coefficient of K, Ca and Mg in soil.

ISSN:0010-3624    

DOI:10.1080/00103628509367594

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The root growth of an Al sensitive barley (Hordeum vulgareL.) was used to evaluate the influence of surface applied amendments on the properties of an acid subsoil. Soil columns were packed with 10 cm of A horizon over 45 cm of an acidic Bt horizon from a Gilpin silt loam. Prior to planting of the barley the columns received surface treatments of dolomitic lime (8.4 Mg.ha‐1), hog manure (44.8 Mg.ha‐1) with and without lime, cow manure (44.8 Mg.ha‐1) with and without lime, gypsum (14.6 Mg.ha‐1), and EDTA (5.1 Mg.ha‐1) with lime. The columns were leached twice weekly over a 6 week period with 5 cm additions of water.

ISSN:0010-3624    

DOI:10.1080/00103628509367595

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The rate and temporal pattern of ? mineralization from decomposing residues of hairy vetch (Vicia villosaRoth) and rye (Secale cerealeL.) were compared with the pattern of ? uptake by corn (Zea maysL.) planted under no‐tillage into these cover crops in the field. In a second field study where no corn crop was grown, the pattern of ? mineralization from killed fescue sod was compared with the pattern from killed hairy vetch plus sod. Hairy vetch was far more effective than rye in supplying corn ? requirements. In both experiments, the majority of ? mineralized during the corn growing season became available only after a period corresponding to corn silking. The results suggest poor synchronization between ? release via cover crop mineralization and corn ? uptake in the no‐till system.

ISSN:0010-3624    

DOI:10.1080/00103628509367596

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Soils of an association may vary in productivity and fertility response because of differences in landscape positions, hydrologic properties, and capacity to retain and release nutrients. These differences may in turn affect the validity of fertilizer recommendations based on soil testing programs. The yield pattern of alfalfa was studied over three years in Gilpin, Ernest, Brinkerton soils of an association developed in residium and colluvium from sandstone and shale parent material (from Brookville, Jefferson County, Pennsylvania), and in the Cambridge ‐ Venango — Frenchtown soils of an association developed in sandstone and shale glacial till (from Meadville, Crawford county, Pennsylvania). Soil test recommendations for F and ? were compared with yield response of alfalfa to increasing application of the respective nutrients (0, 45 and 90 kg P.ha‐1, and 0, 175, 350 and 525 kg K.ha‐1) in each of the six soils.

ISSN:0010-3624    

DOI:10.1080/00103628509367597

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Phytophthora root rot (PRR) is an important disease of alfalfa (Medicago sativaL.) in wet soils. Excess soil water (ESW) stress is required for the successful infection and development of PRR. The effects of P at 0, 40, and 80 μg.g‐1soil and K at 0, 120, and 240 μg.g‐1soil (in factorial combinations) on the severity of PRR or ESW stress was investigated on a PRR‐susceptible (Iroquois) and a resistant (Oneida) alfalfa cultivar in a greenhouse trial. P and K applications significantly increased the dry weight of tops prior to imposition of PRR or ESW stress. However, plants subjected to PRR or ESW stress did not respond significantly to P or K and there was no significant effect of P or K on the severity of PRR or ESW injury. The plants subjected to PRR or ESW stress had lower tissue P concentration than those under stress‐free conditions. Increasing P additions resulted in a significant increase in P concentration of Iroquois plants, while in Oneida the response was non‐significant. The response of K concentration in the plant to increasing K additions was dependant on P levels.

ISSN:0010-3624    

DOI:10.1080/00103628509367598

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

ISSN:0010-3624    

DOI:10.1080/00103628509367592

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor