摘要:

The method described here is useful for the quick determination of soil moisture, especially when many determinations are to be made at a time. The only pieces of apparatus required are some wide‐mouthed conical flasks, a few pieces of glass rod and a balance. The principle involves recording the weight of the flask filled with water and soil sample of known weight (A). This flask weight (H), and the predetermined soil particle density (Dp) and weight of the water‐filled flask (G) are then used to calculate moisture percentage (MP) in the soil sample from the formula:

ISSN:0010-3624    

DOI:10.1080/00103627909366938

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

The objective of this work was to appraise the double acid (0.05N HCl+0.025N H2SO4) extraction agent for assessing the availability of Ca, Mg, and K in organic soils. The evaluation was done by determining the relation and interactions between the concentrations of Ca, Mg and K extracted from soils and those found in onion and alfalfa tissues.

ISSN:0010-3624    

DOI:10.1080/00103627909366939

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

Studies were conducted to determine (1) differences in foliar Mn among field‐grown cultivars and (2) the interactions among cultivars and locations.

ISSN:0010-3624    

DOI:10.1080/00103627909366940

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

The A and B horizons of 28 Delaware soils were incubated with 0, 200, 1000 and 2000 ug K/g of soil for one week, one, two and six months. Potassium soil test values were determined using the double acid extractant. The amount of K necessary to raise the soil test value one unit varied between five and 12 ug K/g of soil and was influenced by time of incubation, soil type, amount of K added and soil horizon. Correlation coefficients between the units of K necessary to raise the soil test values one unit and sand, silt and clay and cation exchange capacity are presented. Increasing soil test values to some predetermined point does not appear agronomically or economically sound for the Coastal plain soils of Delaware. Using this procedure to determine fertilizer K recommendations results in recommendations several fold higher than those recommendations which result from using field crop response to determine the amount of K fertilizer to be applied.

ISSN:0010-3624    

DOI:10.1080/00103627909366941

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

The indirect procedure for sulfate determination by Ba absorption spectroscopy was modified so that low concentrations of SO4in small volumes of solutions could be determined rapidly and precisely. Major modifications consisted of seeding the sample with BaSO4, precipitating in ethanol solutions to lower BaSO4solubility, and determining Ba in a N2O‐acetylene flame using the absorption mode.

ISSN:0010-3624    

DOI:10.1080/00103627909366942

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

Setaria and paspalum were found to be very tolerant of excess Mn. Green panic and sorghum were somewhat less tolerant with foliar symptoms due to excess Mn being exhibited in plants containing 1000 ppm Mn and yield reductions occurring in plants containing Mn concentrations of the order of 2000 ppm. Excess Mn did not effect the early seedling growth of sabi grass but regrowth was severely depressed. Rhodes grass and buffel grass were severely effected by excess manganese. Regrowth of these two species was more adversely effected than initial seedling growth indicating that these species probably would not survive to maintain a stable pasture in Mn toxic situations.

ISSN:0010-3624    

DOI:10.1080/00103627909366943

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

The effects of 3 N sources, ammonium sulfate (AS), ammonium nitrate (AN), and sodium nitrate (SN) in combination with P, K, Ca, and Mg on vine weight, leaf Mg and Mn concentrations in Bush Blue Lake 274 snap beans were studied in 3 greenhouse experiments using a Hagerstown silt loam soil. In NP treatments, regardless of N source, plants were more vigorous, by 29% or more when compared to those of Check or N treatment. SN resulted in slightly less vigorous plants with higher Mg and lower Mn concentrations compared to those of AS. AN treatments had intermediate effects. Addition of K resulted in increased vine weight and decreased leaf Mg concentrations. Adding both K and Mg to the NP treatment did not affect the leaf Mg concentration.

ISSN:0010-3624    

DOI:10.1080/00103627909366944

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

ISSN:0010-3624    

DOI:10.1080/00103627909366937

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor