摘要:

Captan [N‐(trichloromethylthio)‐4‐cyclo‐hexene‐l, 2‐dicarboximide] and benomy1[methyl 1‐(butylcarbamoyl)‐2‐benzimidazolecarbamate] were evaluated as nitrification inhibitors and compared with nitrapyrin [2‐chloro‐6‐(trichloromethyl)pyridine]. Nitrapyrin, captan, and benorayl were applied at 0, 20, 40, and 60 mg/kg with three nitrogen sources, KNO3, (NH4)2SO4, and urea, at 300 mg N/kg to ‘Cherry Belle’ radish (Raphanus sativusL). Nitrapyrin and captan inhibited nitrification effectively, but benomyl was not an effective inhibitor. Growth of radish roots and shoots was restricted with application of nitrapyrin and captan combined with (NH4)2SO4or urea relative to the comparable KNO3treatments. The concentrations of Ca, Mg, and NO3‐N in plants, especially in shoots, fell, and the percentage of ? was increased with the addition of nitrapyrin and captan. Benomyl did not affect plant growth or composition

ISSN:0010-3624    

DOI:10.1080/00103628909368105

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Flax (Linum usitatissiumL.) was grown in field experiments over a five year period on a calcareous and a non‐calcareous Orthic chernozemic soil that were both low in NaHCO3extractable P. Six rates of P‐fertilizer as mono‐ammonium phosphate (MAP) were applied at seeding using four placement methods: 1. broadcast and cultivated 10 cm into the soil (BC); 2. banded in the seed row with the seed (PWS); 3. banded 2.5 cm below and 2.5 cm to the side of the seed (PSS); 4. banded 2.5 cm directly below the seed (PBS).

ISSN:0010-3624    

DOI:10.1080/00103628909368106

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Preliminary DRIS norms were developed and verified for accuracy in diagnosing ? and ? deficiencies and sufficiencies, and in predicting yield responses to applied ? and ? by dallisgrass (Paspalum dilatatumPoir.). Dry matter yield and dry matter accumulation rate, both alone and combined, were used to delineate high‐yield populations. Data were obtained from five‐year soil fertility field experiments on Olivier silt loam, an Aquic Fragiudalf. Data from the first year were used for norm development and subsequent data for norm verification. In the ? study nearly all samples diagnosed were ? deficient, while very few samples in the ? studies were ? deficient. Yield increases due to ? applications frequently occurred where the ? index was negative but not necessarily the most negative index, indicating that all negative ? indices should be indicators of a true ? deficiency in dallisgrass. The most accurate DRIS norms resulted in 82% overall accuracy in diagnosing ? deficiencies and sufficiencies during four years. These same norms identified 100% of the actual yield responses to ? that occurred during the four year period. At both the low and medium soil test ? levels, the number of incorrect diagnoses of ? deficiencies was minimized when only the most negative ? indices were considered true indicators of a P deficiency. At low and medium soil test ? levels, the most accurate DRIS norms resulted in 75% and 83% overall accuracy, respectively, in diagnosing ? deficiencies and sufficiences during four years. There were not enough yield responses to ? for an evaluation of ? response prediction accuracy. Use of the dry matter index as a basis of discriminating between deficiency and sufficiency did not improve overall diagnostic accuracy in evaluating the ? status of dallisgrass but slightly improved overall diagnostic accuracy in evaluating the ? status. Rate of dry matter accumulation as a criterion for selecting the high‐yield population resulted in more young plants in those populations and appeared to improve DRIS norm accuracy in diagnosing the ? and ? requirements of forage with variable age among harvest dates

ISSN:0010-3624    

DOI:10.1080/00103628909368107

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The Diagnosis and Recommendation Integrated System (DRIS) appears to be a more sensitive tool in the early detection of mineral deficiency in soybeans (Glvcine max. L.) than the sufficiency range approach. A small data bank based on information collected in a survey over a two‐year period on early maturing soybeans grown in Quebec was used to calculate new modified DRIS norms. Remedial measures predicted by DRIS gave greater yield increases than those with the sufficiency range approach. Regional deviation in norms were identified and were more important with ? related ratios

ISSN:0010-3624    

DOI:10.1080/00103628909368108

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The relationships between reversibly adsorbed ? (Pi) and other soil properties were studied in 39 cultivated mineral soils of Finland. Piwas desorbed by a method, analogous to resin extraction, in which a soil sample is shaken with strips of Fe‐hydroxide impregnated filter paper in a 0.01 M CaCl2solution. The high affinity of Fe hydroxide for ? maintains a low ? concentration in the solution and enhances ? desorption from the soil. At the solution: soil ratio of 40: 1, Piranged from 7.9 mg dm‐3to 64.2 mg dm‐3with a mean of 31.2 mg dm‐3. Soil ? was also extracted with water (Pw) and 0.5 M Acetic acid‐0.5 M Ammonium Acetate at pH 4.65 (PAC). Piwas 1.2 to 8.9 times greater, with a mean of 3.1, than Pw. The ratio of Pito PAcranged from 1.1 to 6.2 with a mean of 2.6 mg dm‐3. In soils of low ? levels the relative difference between Piand Pwand between Piand PAcwas greater than soils rich in P. The molar ratio of ? extracted with NH4F solution ("Al‐P") to oxalate‐extractable Al, together with soil pH, explained 70%, 73% and 74 % of the variation of Pw, PAcand Pi, respectively. The same fractions of ? are extracted by all three methods but the depletion of these reserves is more effective in the Pimethod. The method for determining reversibly adsorbed ? can be a useful tool in assessing the potential of soil to contribute ? to surface waters upon erosion, as well as in studies on the residual effect of. ? fertilization

ISSN:0010-3624    

DOI:10.1080/00103628909368109

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

ISSN:0010-3624    

DOI:10.1080/00103628909368110

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

ISSN:0010-3624    

DOI:10.1080/00103628909368094

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor