摘要:

The 1: 1.5 water, Spurway and saturated media extract procedures were evaluated for cyclamen and 1: 1.5 water extract for poinsettia growing in bark, peat and peat + soil using nutrient uptake as the criterion. In addition, the N, P, and K desirable values (DV) to give maxi Timm dry wt in two harvests and to give maximum growth rate for various growing periods, in samples taken at the start of the trial and midway through the trial, were determined using a quadratic function for both crops. The relationships between N, P and K uptake and the soil test values were generally very good, although the methods overestimated N uptake and underestimated P uptake in bark‐relative to peat. Underestimation of P uptake in peat + soil was even greater. The initial desirable N soil test value in relation to midterm harvest (IDVM) for cyclamen in peat varied from 100–104 ppm for water, 303–312 ppm for saturated media and 44–46 for Spurway extraction. The midterm soil test value in relation to final harvest (MDVF) values varied from 125–136 ppm for water, 471–502 for saturated media and 44–53 ppm for Spurway extraction. Corresponding values in bark were generally higher. The IDVM and MDVF values using the water extract for poinsettia were 180–225 ppm and 155–215 ppm in peat and bark respectively. It was not possible to determine phosphorus IDVM values for cyclamen due to the poor fit of the response curve. The phosphorus MDVF values in peat for cyclamen were 8.1–8.8 ppm for water, 24.5–26.7 ppm for saturated media and 3.2–3.5 ppm for Spurway extraction. The corresponding values in bark were about half of those values and even lower in peat + soil. The phosphorus MDVF values in peat for poinsettia were 14–19 ppm and in bark 4–4.5 ppm for the water extraction. It was not possible to determine K desirable values for cyclamen because of lack of adequate plant response from K application. Potassium IDVF and MDVF values for poinsettia in peat were 100–136 and 80–126 ppm respectively. The DV obtained using growth data were broadly similar to those using plant dry wt. The desirable plant nutrient levels for maximum dry wt of cyclamen at final harvest varied from 1.9–2.4% for N, 0.10–0.17% for P and 1.0–1.7% for K. The DV values for poinsettia at mid harvest were 3.6–4.6% N, and at final harvest 2.7–3.6% N and 0.18–0.37% P.

ISSN:0010-3624    

DOI:10.1080/00103628309367389

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

Regression analyses were used to survey the effects of extractable NO3‐N, P, K, Ca, Mg, and soil pH on electrical conductivity (EC) in a 1: 1: 1 (v/v/v) peat‐sand‐perlite azalea (Rhododendron sp.) growing medium amended with soluble 21–3–6 (N‐P‐K) or slow‐release 18–3–6 fertilizer sources. Simple linear correlations indicated a high degree of relationship between NO3‐N, P, and K versus EC (r=0.95**, 0.79**, and 0.79**, respectively). Partial regression coefficients suggested that NO.‐N was the primary ionic species affecting EC. The correlations between EC versus P and K were apparently related to their intercorrelation with NO3‐N, associated with the use of N‐P‐K fertilizers. These relationships were constant across fertilizer sources. The results demonstrate a potential for the use of soil EC in the estimation of NO3‐N in soilless rooting media.

ISSN:0010-3624    

DOI:10.1080/00103628309367390

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

Early spring application of N to Iowa sandy, leachable soils results in reduced sweet corn yields and kernel protein content. Normally, split N applications are used to coincide with crop N demand. Our objectives were to determine if nitrapyrin, a nitrification inhibitor, applied with urea would provide high yields and kernel protein levels when applied at planting.

ISSN:0010-3624    

DOI:10.1080/00103628309367391

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

A corn fertility study was conducted at two locations in northern West Virginia to determine the response of corn(Zea maysL.) to applied Mg and Zn on two soils testing low in Mg by the ammonium acetate and Baker tests and low in Zn by the Baker test. The study consisted of three rates of Mg (0, 112, and 224 kg/ha) and three rates of Zn (0, 3.36, and 6.72 kg/ha) applied in a factorial design. The soil at the Morgantown location was medium textured with a CEC of 22.4, and the soil at the Reedsville location was coarse textured with a CEC of 15.8. Yield responses to applied Mg were obtained only on the coarse textured soil at the Reedsville location where exchangeable Mg was less than 5% of the CEC and equilibrium Mg was less than 9.0 10‐4M. No yield response to Zn was obtained at either location.

ISSN:0010-3624    

DOI:10.1080/00103628309367392

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

Principal component analysis has elucidated relationships between the concentrations of N, P, K, Mg, Ca, S, Na, Cu, Zn, Se, Mn and Fe in perennial ryegrass from pasture. Elemental concentration data from two independent collections of samples were used for the analyses; one collection consisted of plant tops, the other consisted of leaf material and inflorescences. The analysis has revealed that elements act in groups. Two sets of elements, one including N, K, S, Cu, and Zn (group 1) and another including Mg, Mn and Se (group 2) were major contributors towards the variance in the elemental concentrations in leaf tissue. Changes in N concentration were counterbalanced by changes in concentrations of the elements of group 2. Mn showed antagonism towards the elements of group 1. No definite grouping of elements was apparent in the principal components for inflorescence tissue.

ISSN:0010-3624    

DOI:10.1080/00103628309367393

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

Four standard soils prepared by the Canadian Certified Reference Materials Project and one standard NBS plant tissue sample were analysed by Inductively Coupled Plasma‐Atomic Emission Spectroscopy (ICP‐AES) to evaluate the spectral interferences and subsequent correction required for the bulk elemental analysis of the soil and plant digests. Elemental interferences were identified and resolved through use of groups of liquid standards coupled with application of correction factors using the system's software. Accurate results for the standard soils were obtained for 16 elements while content of 19 elements determined in standard orchard leaves were within certified limits. Acceptable results for As, Cd and B in soil could not be obtained, in part due to interferences by Ti.

ISSN:0010-3624    

DOI:10.1080/00103628309367394

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

A solid state Ion Specific Electrode was evaluated for direct determination of chloride in extracts of oven dried, ground plant material. When samples were extracted with water, the electrode response was slow and there was a tendency to overestimate tissue chloride concentrations. When extracted with 0.5 M HNO3the response time was fast and the recovery of added chloride close to 100 percent. The method developed is simple, rapid, and accurate.

ISSN:0010-3624    

DOI:10.1080/00103628309367395

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

ISSN:0010-3624    

DOI:10.1080/00103628309367388

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor