摘要:

Several factors affect phosphate sorption by soils. This study was conducted to evaluate the effects of the chemical and physical properties of surface and subsurface soils of a temperate region on P sorption from solutions containing various concentrations of P. Results showed that Na2S2O4‐extractable Fe and Al of surface soils were significantly correlated with P sorption from a solution containing 10, 15, or 20 ppm P. The relationships between the amounts of P sorbed and the other properties of the surface and subsurface soils studied (e.g., pH, organic C, soluble P, CEC) were influenced by use of 0.01MCaCl2as an equilibrating solution.

ISSN:0010-3624    

DOI:10.1080/00103627709366704

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

The interference of various concentrations of soluble protein and organic acids with chloride (Cl‐) determinations using a specific ion electrode was evaluated. The organic acids, malic and citric, provided 4 to 5 times the Cl‐interference as did soluble protein at equivalent concentrations. A definite interaction of the two interfering substances existed which also led to erroneous estimations of the actual Cl‐concentration.

ISSN:0010-3624    

DOI:10.1080/00103627709366705

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

Leaf and root samples from 120 citrus trees, representing four species from each of six different locations in Egypt, were assayed for mineral elements with an emission spectrograph. The areas represented newly reclaimed lands as well as established orchards in the Nile River Delta. There were symptoms of Zn, Mn, and Fe deficiencies at some, but not all, of the locations. There was a negative correlation between root and leaf concentrations for Mg and positive correlations for B, Fe, P, and K. There were strong positive and negative correlations between plant concentrations of some nutrients and certain soil characteristics (percent soil organic matter, pH in paste, electrical conductivity on a saturation extract, and percent CaCO3). Stepwise regression analyses were therefore made among the soil and plant variables. This test indicated that the soil CaCO3level was responsible for most of the variation in Fe, Mn, and Al in leaves. Soil organic matter or electrical conductivity of the saturation extract was responsible for most of the variability in major cation levels in leaves. Most of the variability in leaf P was due to soil pH rather than percent CaCO3. The stepwise regression suggested that the concentration of leaf Al accounted for some of the variability in leaf Mn; otherwise, no other element in leaves appeared in the stepwise regressions indicating that they were related to the soil variables and were not the result of nutrient interactions.

ISSN:0010-3624    

DOI:10.1080/00103627709366706

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

In a group of 24 related calcareous soils, derived from Jurassic oolitic limestone, there was marked variability (13‐fold) in phosphate buffering when expressed as the maximum buffer capacity. This variability was most closely related to the iron content and pH of the soils, and these together accounted for 72% of the variance. This percentage was not increased by including CaC03content or organic matter, which were also correlated with the maximum buffer capacity. A high correlation with specific surface area of CaCO3was probably an indirect effect due to the high correlation between this variable and the Fe and pH of the soils.

ISSN:0010-3624    

DOI:10.1080/00103627709366707

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

Modulus of Rupture measurements on 8 soils treated and untreated with soil conditioner showed that conventional MOR measurements are not appropriate for measuring the strength of rain‐induced soil crusts, because the formation of the crust imposes certain modifications in the method.

ISSN:0010-3624    

DOI:10.1080/00103627709366708

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

Foliar diagnostic norms for NPK in wheat leaves derived using Beaufils’ Diagnosis and Recommendation Integrated System (DRIS) are presented. These norms were calculated from published and unpublished data of various workers who presented leaf composition with corresponding yields. The preliminary norms appear to be applicable to wheat irrespective of variety and age at which the leaf sample is taken. These norms are able to correctly diagnose the requirements of the crop more often than those based on the critical or sufficiency level approach.

ISSN:0010-3624    

DOI:10.1080/00103627709366709

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

An organosilicone surfactant (L‐77) and Na alginate were evaluated as adjuvants in urea sprays foliar‐applied in spring to prune treesPrunus domesticaL. cv. d'Agen which had received a maintenance soil application in winter of 300 g N/tree. L‐77 (0.03% v/v) enhanced leaf wetting and reduced spray surface tensions to levels at which sprays could infiltrate stomata spontaneously, but 75 g N/tree foliar‐applied as 4 × 0.5% urea/ L‐77 sprays failed to increase leaf N concn or fruit yield. This was attributed to the low N application rate as 450 g soil‐applied N/tree increased both parameters and as 400 g N/tree foliar‐applied post‐harvest with L‐77 increased leaf N concn by 15%. Na alginate (0.02% w/v) did not alter the physical properties of the sprays and failed to enhance spray effectiveness.

ISSN:0010-3624    

DOI:10.1080/00103627709366710

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

ISSN:0010-3624    

DOI:10.1080/00103627709366703

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor