Determining Mehlich‐3 and DTPA extractable soil zinc optimum economic threshold for maize

2020 ◽  
Author(s):  
Nicolás Martínez Cuesta ◽  
Nicolás Wyngaard ◽  
Hernán Saínz Rozas ◽  
Nahuel Reussi Calvo ◽  
Walter Carciochi ◽  
...  
Keyword(s):  
Economic Threshold ◽  
Extractable Soil ◽  
Soil Zinc

Contamination of soil with zinc, copper, lead, and cadmium in the Wollongong city area

Soil Research ◽  
1973 ◽  
Vol 11 (1) ◽  
pp. 27 ◽  
Author(s):  
F Beavington
Keyword(s):  
Industrial Area ◽  
Sampling Procedure ◽  
Control Area ◽  
Industrial Land ◽  
Mean Values ◽  
Grid Sampling ◽  
City Area ◽  
Lead And Cadmium ◽  
Extractable Soil ◽  
Soil Zinc

From a grid sampling procedure over 56 km2 of the Wollongong city area, levels of acetic acid-extractable soil zinc, lead, and cadmium, and EDTA-extractable soil copper, have been investigated. Mean levels of these metals in four groups of urban grassland, namely, farm land, recreational land, industrial land, and roadsides, are up to 10 times greater than those in a rural control area. Highest levels of all four metals are found in the Port Kembla industrial area, where 21 samples within 1 km of the main heavy metals smelting complex have mean values of 82 p.p.m. zinc, 343 p.p.m. copper, 21 p.p.m. lead (15 samples), and 2.8 p.p.m. cadmium (11 samples); mean levels in the rural area are 2.7 p.p.m. zinc, 5.3 p.p.m. copper, <1 p.p.m. lead, < 1 p.p.m, cadmium. Profile samples show that all four contaminants were very largely concentrated in the top 15 cm soil, confirming an airborne origin.

ASSESSMENT OF AVAILABLE SOIL SULPHUR IN AN 35S GROWTH CHAMBER EXPERIMENT

1974 ◽  
Vol 54 (3) ◽  
pp. 309-315 ◽  
Author(s):  
J. R. BETTANY ◽  
J. W. B. STEWART ◽  
E. H. HALSTEAD
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Growth Chamber ◽  
Yield Response ◽  
Laboratory Studies ◽  
Organic S ◽  
Chamber Experiment ◽  
Extractable Soil

Growth chamber and laboratory studies of four selected soils differing in C:N:S ratios and the percentage of total S present as HI-reducible S in the soil organic matter showed that: (1) the yield response of alfalfa to applied S occurred when the 0.01 M CaCl2-extractable soil SO4—S was less than 3.3 μg/g, (2) mineralization of soil organic S was unaffected by the addition of 25 μg S/g to the soils, and (3) the amount of S mineralized was not directly related to the quantity of total S, HI-S or the percentage of total S present as Hi-reducible S. It was noted that the largest amount of S mineralized occurred from the soil with the lowest C:N:S ratios.

Soil Zinc Transformations as Affected by Applied Zinc and Organic Materials

2011 ◽  
Vol 42 (9) ◽  
pp. 1038-1049 ◽  
Author(s):  
S. Kamali ◽  
A. Ronaghi ◽  
N. Karimian
Keyword(s):  
Organic Materials ◽  
Soil Zinc

Impact and Economic Threshold of Thrips tabaci on Onions

1995 ◽  
pp. 71-76 ◽  
Author(s):  
François Fournier ◽  
Guy Boivin ◽  
Robin K. Stewart
Keyword(s):  
Thrips Tabaci ◽  
Economic Threshold

Tillage, crop residue and crop sequence effects on nitrogen availability in a legume-based cropping system

2004 ◽  
Vol 84 (4) ◽  
pp. 421-430 ◽  
Author(s):  
Y. K. Soon ◽  
M. A. Arshad
Keyword(s):  
Crop Yield ◽  
Crop Residue ◽  
N Uptake ◽  
Microbial Biomass N ◽  
Fertilizer N ◽  
Inorganic N ◽  
Soil Inorganic N ◽  
Crop Sequence ◽  
Extractable Soil ◽  
Soil Inorganic

A field study was conducted to determine the effects and interactions of crop sequence, tillage and residue management on labile N pools and their availability because such information is sparse. Experimental treatments were no-till (NT) vs. conventional tillage (CT), and removal vs. retention of straw, imposed on a barley (Hordeum vulgare L.)-canola (Brassica rapa L.)-field pea (Pisum sativum L.) rotation. 15N-labelling was used to quantify N uptake from straw, below-ground N (BGN), and fertilizer N. Straw retention increased soil microbial biomass N (MBN) in 2 of 3 yr at the four-leaf growth stage of barley, consistent with observed decreases in extractable soil inorganic N at seeding. However, crop yield and N uptake at maturity were not different between straw treatments. No tillage increased soil MBN, crop yield and N uptake compared to CT, but had no effect on extractable soil inorganic N. The greater availability of N under NT was probably related to soil moisture conservation. Tillage effects on soil and plant N were mostly independent of straw treatment. Straw and tillage treatments did not influence the uptake of N from its various sources. However, barley following pea (legume/non-legume sequence) derived a greater proportion of its N from BGN (13 to 23% or 9 to 23 kg N ha-1) than canola following barley (nonlegumes) (6 to 16% or 3 to 9 kg N ha-1). Fertilizer N constituted 8 to 11% of barley N uptake and 23 to 32% of canola N uptake. Straw N contributed only 1 to 3% of plant N uptake. This study showed the dominant influence of tillage on N availability, and of the preceding crop or cropping sequence on N uptake partitioning among available N sources. Key words: Crop residue, crop sequence, labile nitrogen, nitrogen uptake, pea, tillage

Dynamics of nitrogen and dry-matter partitioning and accumulation in broccoli (Brassica oleracea var. italica) in relation to extractable soil inorganic nitrogen

1999 ◽  
Vol 79 (2) ◽  
pp. 277-286 ◽  
Author(s):  
P. A. Bowen ◽  
B. J. Zebarth ◽  
P. M. A. Toivonen
Keyword(s):  
Dry Matter ◽  
N Fertilization ◽  
N Fertilizer ◽  
Organic N ◽  
Soil N ◽  
Inorganic N ◽  
N Accumulation ◽  
Spring Planting ◽  
Extractable Soil ◽  
Soil Inorganic

The effects of six rates of N fertilization (0, 125, 250, 375, 500 and 625 kg N ha−1) on the dynamics of N utilization relative to extractable inorganic N in the soil profile were determined for broccoli in three growing seasons. The amount of pre-existing extractable inorganic N in the soil was lowest for the spring planting, followed by the early-summer then late-summer plantings. During the first 2 wk after transplanting, plant dry-matter (DM) and N accumulation rates were low, and because of the mineralization of soil organic N the extractable soil inorganic N increased over that added as fertilizer, especially in the top 30 cm. From 4 wk after transplanting until harvest, DM and N accumulation in the plants was rapid and corresponded to a rapid depletion of extractable inorganic N from the soil. At high N-fertilization rates, leaf and stem DM and N accumulations at harvest were similar among the three plantings. However, the rates of accumulation in the two summer plantings were higher before and lower after inflorescence initiation than those in the spring planting. Under N treatments of 0 and 125 kg ha−1, total N in leaf tissue and the rate of leaf DM accumulation decreased while inflorescences developed. There was little extractable inorganic soil-N during inflorescence development in plots receiving no N fertilizer, yet inflorescence dry weights and N contents were ≥50 and ≥30%, respectively, of the maxima achieved with N fertilization. These results indicate that substantial N is translocated from leaves to support broccoli inflorescence growth under conditions of low soil-N availability. Key words: N translocation, N fertilizer

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