摘要:

Using data from the Purdue University soil characterization laboratory and soil descriptions made by field soil scientists, we have developed a semi‐quantitative relationship between organic matter content and soil color for cultivated, silt loam soils of Indiana. This relationship is correct for about 90% of the samples examined and divides them in three categories: < 3%, 3–5%,, and > 5% organic matter. This is not a replacement for chemical analysis but a tool that could be of use when examining problems in the field.

ISSN:0010-3624    

DOI:10.1080/00103627909366981

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

A corn‐small grain cropping sequence resulted in a greater total grain yield than corn or small grain alone or grain sorghum double cropped with small grain. Drought restricted yield responses to N, P and K in non‐irrigated plots but under irrigation grain yield for each cropping sequence was directly related to fertilizer applied. All fertilizer treatments increased soil acidity. Phosphorus and K applied at 26 and 50 kg/ha, respectively for each crop in the sequence maintained P and K levels in the soil. After three years, the high rate of fertilizer (87 and 166 kg/ha of P and K, respectively) resulted in greater soil P and K values than the low rate of fertilizer.

ISSN:0010-3624    

DOI:10.1080/00103627909366982

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

Alfalfa (Medicago sativaL.) does not grow as well as it used to in areas of Canada and northwestern United States. Affected plants have nitrogen (N)‐deficiency symptoms, few or no nodules, and respond to N fertilizer. For lack of a good explanation, such plants are called “sick”;.

ISSN:0010-3624    

DOI:10.1080/00103627909366983

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

Soybeans were grown in a Savannah sandy loam in the greenhouse to the prebloom stage. The effects of various soil treatments on foliar Mn concentrations were observed through time. There was a linear relationship between applied Mn and foliar Mn. The concentration of Mn in the older trifoliolates was higher than in younger ones. The mobility of Mn varied depending on the level of foliar Mn, Manganese is immobile at low concentrations of foliar Mn but at high levels of foliar Mn some may be translocated out of the leaf. Flooding the soil was quickly reflected in high foliar Mn of the newly developing leaves but not in the older ones. Newly developing leaves accumulated normal concentrations of foliar Mn after drying of the soil but older leaves, those developed during flooding retained the high foliar concentrations they had accumulated when the soil was anaerobic. Thus, the uppermost mature trifaliolate is the part of the plant which should be sampled for chemical analysis if the current status of soil Mn is desired.

ISSN:0010-3624    

DOI:10.1080/00103627909366984

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

The minerai content of enzymatically isolated pear leaf cuticles has been determined using a technique allowing a high sensitivity and a wide elemental coverage : the spark source mass spectrometry. About thirty elements have been detected, classified in different classes according to their content : N, K (major) Ca, Si, Al, Na (≥ 1 000 ppm) Fe, Cl, Mg (≥ 100 ppm) P, Cu, Zn, Ti, Ba, Mn, Ni, Co, Sr (≥ 10 ppm) B, Ag, Rb, Cr, Sn, V, Pb, Cd, U etc... (traces). These results are compared with analysis of entire pear leaves effected simultaneously and with those reported in literature concerning isolated tomato fruit cuticles. The problem of their validity for cuticles in situ, is discussed.

ISSN:0010-3624    

DOI:10.1080/00103627909366985

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

A procedure using matrix‐compensated Mo standards to determine Mo in plant tissue by flameless atomic absorption is described. Concentration ranges of macroelements (N,P,K,Ca,Mg), microelements (Cu,B,Zn,Mn,Al,Fe), and HC1O4. typical of those found in HNO3‐HC1O4plant tissue digests were examined for their effect on the observed analytical value of Mo. The mean of 20 Mo determinations of NBS orchard leaves SRM 1571 was 0.28 ± 0.01 ppm Mo compared to the NBS certified value of 0.3 ± 0.1 ppm Mo. Recovery of Mo added to digests of orchard leaves and alfalfa tops ranged from 95 to 105%.

ISSN:0010-3624    

DOI:10.1080/00103627909366986

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

In order to set up a routine soil testing laboratory for advisory purpose, sample preparation and handling is very important. Potassium is one of the essential nutrients, whose handling’ has not been studied in Nigeria. Laboratory and greenhouse experiments were therefore set up to study the effect of sample preparation and handling on exchangeable K. The results have indicated that air drying at 72°F resulted in a significant increase in extractable K while even drying at 110°C for 24 hours resulted in similar values with those obtained for field moist samples. Correlation coefficients between K uptake by plants and exchangeable K determined from moist and oven dry samples were not significantly different from each other whereas there was significant correlation (r=0.904***) between K uptake and exchangeable K determined from air‐dry samples. Under wetting‐ and drying, there was an increase in soil K. The mechanism for this is not understood. Furthermore no significant difference exists between shaking of soil samples for 5 minutes and 60 minutes and storage for two years has no effects on extractable K.

ISSN:0010-3624    

DOI:10.1080/00103627909366987

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

It was found that sodium tetraphenylboron, NaB(C6H5)4, can be used as a reagent for determination of K in acid sodium acetate extracts of soils. After extraction and filtration, sodium hydroxide and formaldehyde are added prior to the reagent to avoid interference of ammonium. At low concentrations of K in the extracts (<30 mg K/1) the white precipitate of potassium tetraphenylboron, KB(C6H5)4, is colloidal and the concentration of K can be determined turbidimetrically with a simple instrument in the field or on the farm.

ISSN:0010-3624    

DOI:10.1080/00103627909366988

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

ISSN:0010-3624    

DOI:10.1080/00103627909366980

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor