Traffic and tillage effects on soil conditions and crop growth on a swelling clay soil

Five soils were cropped with four plant species in pot experiments in the glasshouse, without addition of potassium, until growth virtually ceased, after which the depleted soils were replanted with either the same species, or a different one, to test the reproducibility of the 'exhaustion' conditions imposed. Uptake of potassium by the plants exceeded the changes in exchangeable potassium in four soils; the excess amounts taken up differed markedly between species and these differences were reproducible on replanting. Uptake by setaria (Setaria anceps) and siratro (Macroptilium atropurpureum) exceeded that by Rhodes grass (Chloris gayana) and lucerne (Medicago sativa), except for one swelling clay soil from which uptake by lucerne equalled that by siratro. Most of the differences between species were attributed to the uptake of initially non-exchangeable potassium, which was removed in significant amounts from three of the soils. For these three soils, uptake from non-exchangeable sources was detected only after about 80% of the exchangeable potassium had been removed. It is postulated that the efficiency of plant removal of non-exchangeable potassium from soil is directly related to the degree to which plant roots can lower the concentration of potassium in the soil solution.

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Effects of gypsum-slotting on infiltration rates and moisture storage in a swelling clay soil

Soil Use and Management ◽

10.1111/j.1475-2743.1986.tb00693.x ◽

1986 ◽

Vol 2 (3) ◽

pp. 114-118 ◽

Cited By ~ 11

Author(s):

N.S. Jayawardane ◽

J. Blackwell

Keyword(s):

Clay Soil ◽

Swelling Clay ◽

Infiltration Rates ◽

Moisture Storage

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Three-dimensional analysis of stiffened raft footings on swelling clay soil

International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts ◽

10.1016/0148-9062(92)92698-c ◽

1992 ◽

Vol 29 (5) ◽

pp. 281

Keyword(s):

Dimensional Analysis ◽

Clay Soil ◽

Three Dimensional ◽

Swelling Clay

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Bionic Design of a Potato Digging Shovel with Drag Reduction Based on the Discrete Element Method (DEM) in Clay Soil

Applied Sciences ◽

10.3390/app10207096 ◽

2020 ◽

Vol 10 (20) ◽

pp. 7096

Author(s):

Junwei Li ◽

Xiaohu Jiang ◽

Yunhai Ma ◽

Jin Tong ◽

Bin Hu

Keyword(s):

Discrete Element Method ◽

Drag Reduction ◽

Clay Soil ◽

Clayey Soil ◽

Reduction Rate ◽

Compressive Force ◽

Discrete Element ◽

Soil Conditions ◽

Total Force ◽

Element Method

The resistance of ordinary potato digging shovels can increase dramatically when used in a clay soil because of the adhesion between the soil and shovel. In this paper, a new type of bionic potato digging shovel was designed to decrease adhesion. The bionic structural elements, i.e., scalelike units (S-U) were applied to the potato digging shovel with inspiration from pangolin scales. The discrete element method (DEM) considered cohesion was used to simulate the drag reduction performance in clayey soil conditions. An ordinary plane shovel (O-P-S) was used for comparison. Three indicators (total force, draft force and compressive force) were used to characterize the drag reduction performance. The effect of the design variables of the bionic structures (length [l] and height [h]) and the transversal and longitudinal arrangement spacing (S1 and S2) of the structures on the drag reduction performance were analyzed. The results showed that the drag reduction performance of the bionic shovels with suitable parameters was better than that of the O-P-S. The best bionic sample labeled as a bionic prototype had a 22.26% drag reduction rate during the soil bin test and a 14.19% drag reduction rate during the field test compared to the O-P-S.

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