The effect of tillage and gypsum application on the macropore structure of an Australian Vertisol used for irrigated cotton

Desorption rate curves of n-pentane on 5A zeolites at 418 K and 10-0.03 kPa were determined, and the effects of different macropore structure on desorption performance were analyzed. Results show that macropore distribution of 5A-1 concentrates in 0.25-1.25 μm, while that of 5A-2 ranges from mesopore category to 0.3 μm, but 5A-3 contains both pores of 0.01-0.1 μm and 0.2-2 μm inside, reflecting a broadest distribution; 5A-3, 5A-1 and 5A-2 reach desorption equilibrium after 1100 s, 1400 s and 2000 s respectively at 0.03 kPa, indicating that abundant macropores make n-pentane fastest desorbed from 5A-3, but this advantage gradually disappears with the increasing pressure; the effective desorption diffusion coefficients of n-pentane on 5A-1, 5A-2 and 5A-3 are 4.2×10-15-2.2×10-14 m2/s, 2.0×10-15-2.3×10-14 m2/s, 7.4×10-15-2.4×10-14 m2/s respectively, suggesting that plenty macropores make the diffusivity less affected by the changes of pressure, which can guarantee a fast diffusion rate of n-pentane even at low pressure.

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Fallow management, soil water, plant-available soil nitrogen and grain sorghum production in south west Queensland

Australian Journal of Experimental Agriculture ◽

10.1071/ea9920473 ◽

1992 ◽

Vol 32 (4) ◽

pp. 473 ◽

Cited By ~ 19

Author(s):

G Gibson ◽

BJ Radford ◽

RGH Nielsen

Keyword(s):

Soil Water ◽

Nitrate Nitrogen ◽

Soil Nitrate ◽

Zero Tillage ◽

Fallow Management ◽

South West ◽

Primary Tillage ◽

Grain Nitrogen ◽

Texture Contrast ◽

Gypsum Application

The effects of tillage frequency (conventional, reduced and zero), primary tillage implement (disc, blade and chisel plough), stubble management (retention and removal), gypsum application, and paraplowing were examined with respect to soil water storage, soil nitrate accumulation, crop establishment, crop growth, grain yield and grain nitrogen content for 4 successive sorghum crops on a sodic, texture-contrast soil in south west Queensland. Retention of sorghum stubble (v. removal) produced an increase in mean yield of sorghum grain of 393 kg/ha, due to increased soil water extraction and increased water use efficiency by the following crop. The highest mean yield occurred after reduced blade tillage with stubble retained. Zero tillage with stubble removed gave the lowest mean grain yield. Zero tillage always had the lowest quantity of soil nitrate-nitrogen at sowing. In one fallow, increased aggressiveness of primary tillage (disc v. blade plough) increased the quantity of nitrate-nitrogen in the top 60 cm of soil at sowing. These effects on available soil nitrogen did not result in corresponding differences in grain nitrogen content. Results indicate that for optimum fallow management on this texture-contrast soil in south west Queensland, sorghum residues should be retained, tillage frequency should be reduced, but not to zero, blade ploughing should be preferred to discing, and gypsum application should not be practised.

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Image Analysis Procedure to Quantify Soil Macropore Structure

Applied Engineering in Agriculture ◽

10.13031/2013.26282 ◽

1991 ◽

Vol 7 (5) ◽

pp. 636-642 ◽

Cited By ~ 1

Author(s):

Y. J. Han ◽

V. L. Quisenberry

Keyword(s):

Image Analysis ◽

Analysis Procedure ◽

Macropore Structure ◽

Soil Macropore

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Organic residue, limestone, gypsum, and phosphorus adsorption by lowland soils

Scientia Agricola ◽

10.1590/s0103-90162002000200022 ◽

2002 ◽

Vol 59 (2) ◽

pp. 349-355 ◽

Cited By ~ 12

Author(s):

Alex Teixeira Andrade ◽

Luiz Arnaldo Fernandes ◽

Valdemar Faquin

Keyword(s):

Low Cost ◽

Phosphate Adsorption ◽

Organic Residue ◽

Organic Residues ◽

Phosphorus Adsorption ◽

P Adsorption ◽

Randomized Design ◽

Exchangeable Al ◽

Completely Randomized Design ◽

Gypsum Application

Organic residue application is a low cost alternative to reduce the use of inorganic fertilizers and correctives. In order to study the effect of organic residues, limestone and gypsum application on phosphorus adsorption by lowland soils, four experiments were carried out. A Mesic Organosol (OY), a Melanic Gleysol (MG), a Haplic Gleysol (GX), and a Fluvic Neosol (RU) were used in a completely randomized design and factorial scheme (3 x 2), with five replicates: three soil amendment practices (limestone, gypsum and no corrective) and two levels of organic residue (with and without corral manure). Soil samples were incubated for 60 days, with and without organic residue incorporation. After this period, we applied the corrective and incubated the soil for 30 days, then P and basic fertilization (macro and micronutrients) were applied and the soil was incubated for additional 60 days. Equilibrium phosphorus, maximum phosphate adsorption capacity, pH, exchangeable Al and phosphorus-buffering index were measured. Organic residue and limestone application increased soil pH and reduced exchangeable Al, decreasing P adsorption. Gypsum application did not increase the pH but reduced exchangeable Al and P adsorption.

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