scholarly journals Soil Management Systems to Overcome Multiple Constraints for Dryland Crops on Deep Sands in a Water Limited Environment on the South Coast of Western Australia

Agronomy ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1881
Author(s):  
David J. M. Hall ◽  
Stephen L. Davies ◽  
Richard W. Bell ◽  
Tom J. Edwards
Keyword(s):  
Western Australia ◽  
Plant Tissue ◽  
Soil Strength ◽  
Wetting Agent ◽  
South Coast ◽  
Yield Potential ◽  
The South ◽  
Nutrient Levels ◽  
Soil Constraints ◽  
Water Repellence

Deep sands on the south coast sandplain of Western Australia (WA) have multiple soil constraints including water repellence, high soil strength, low nutrient levels and subsoil acidity. The aim of the study was to test contrasting methods of managing water repellence and to assess their impacts on one or more soil constraints to crop production. These methods included seeding tyne design (knife point, winged points, paired row), soil wetting agent addition, strategic inversion tillage (rotary spading, mouldboard ploughing to 0.35 m) and clay-rich subsoil addition (170 t ha−1 with incorporation by spading to 0.20 or 0.35 m). Limesand (2 t ha−1) was applied as a split plot treatment prior to tillage. Cumulative crop yields were increased by 2.1–2.6 t ha−1 over five years by the strategic deep tillage and clay application treatments compared to the control. Water repellence was reduced by the inversion ploughing and subsoil clay addition treatments only. The effect of water repellence on crop establishment was expressed only in low rainfall years (Decile < 4) and mitigated by the paired row, wetting agent, spader and clay-amended treatments. In all years, plant numbers were adequate to achieve yield potential regardless of treatment. Soil K and plant tissue K and B were increased where clay had been applied. Inversion tillage reduced soil pH, organic carbon (OC) and macro nutrients in the 0–0.1 m layer although in most years there was no significant decline in plant tissue macro nutrient levels. Soil strength was reduced as a result of the inversion tillage to a depth of 0.35 m. However, the alleviation of soil strength and the crop yield responses diminished with time due to re-compaction. No crop response to the applied lime was found over five years at this site since the soil pHCaCl2 exceeded 4.7 within the root zone. In terms of soil constraints, we conclude that compaction was the dominant constraint at this site followed by water repellence and K deficiency.

Claying and deep ripping can increase crop yields and profits on water repellent sands with marginal fertility in southern Western Australia

Soil Research ◽  
2010 ◽  
Vol 48 (2) ◽  
pp. 178 ◽  
Author(s):  
D. J. M. Hall ◽  
H. R. Jones ◽  
W. L. Crabtree ◽  
T. L. Daniels
Keyword(s):  
Organic Carbon ◽  
Western Australia ◽  
Crop Production ◽  
Crop Yields ◽  
Nutrient Retention ◽  
Soil Strength ◽  
Yield Potential ◽  
Control Treatment ◽  
Water Repellent ◽  
Water Repellence

Sandplain soils on the south coast of Western Australia have multiple limitations to crop production that include water repellence, low water and nutrient retention, subsoil acidity, and high soil strength. Crops on sandplain soils achieve, on average, almost 85% of their rainfall-limited yield potential; however, where there are multiple limitations the corresponding value is often <50% in any given year. Previous research has shown the value of applying clay-rich subsoil (‘claying’) to ameliorate water repellent soils and improve nutrient retention. Other studies have shown that deep ripping is effective in reducing compaction in sandplain soils. This paper quantifies the effects of 5 subsoil clay rates (0, 50, 100, 200, and 300 t/ha), with and without deep ripping to 0.5m, on soil properties, crop growth, and profitability in a replicated field experiment. Crop yields were increased by 0.3–0.6 t/ha as result of added clay. The clay content of the surface soil required to alleviate water repellence and achieve the highest yield increases was 3–6% in soils with ~1% organic carbon. Longer term effects of claying included increased soil organic carbon by 0.2%, pH by 0.6 units, potassium by 47 mg/kg, soil strength by 250 kPa, and cation exchange capacity by 1.3 cmolc/kg to a depth of 0.1 m. However, changes in plant-available water (mm/m) were inconsistent between the clay treatments. Deep ripping to 0.5 m increased crop yields by 0.1–0.5 t/ha. These crop yield responses were still evident 3 years after the ripping treatment had been applied. Soil strength measurements indicate that re-compaction of the ripped treatments had occurred to a depth of 0.2 m in the second year following ripping. Crop responses to claying and deep ripping were additive. Claying and deep ripping, while almost doubling yields, achieved only 50–70% of the rainfall-limited yield potential on these marginally fertile soils. The highest clay rates (>3–6%) had cumulative discounted cash returns $AU100–200/ha higher than the unclayed ‘control’ treatment and $300/ha higher than the lowest clay rates. For most of the clay treatments, deep ripping increased discounted returns between 2005 and 2007 by $80–120/ha.

A Precambrian fayalite granite from the south coast of Western Australia

Lithos ◽  
1978 ◽  
Vol 11 (3) ◽  
pp. 209-218 ◽  
Author(s):  
N.C.N. Stephenson ◽  
H.D. Hensel
Keyword(s):  
Western Australia ◽  
South Coast ◽  
The South

An aerial survey for sperm whales off the coast of Western Australia 1963-1965.

1968 ◽  
Vol 19 (1) ◽  
pp. 31 ◽  
Author(s):  
JL Bannister
Keyword(s):  
Continental Slope ◽  
Western Australia ◽  
West Coast ◽  
Aerial Survey ◽  
South Coast ◽  
Sperm Whales ◽  
The South ◽  
The West ◽  
Offshore Area ◽  
Direction Of Movement

Objectives, methods, and results of a two-year aerial survey for sperm whales off the coast of Western Australia, 1963-65, are described. Data from commercial whaling operations have been included where appropriate. Sperm whales were found well off the west coast, but only in a narrow strip along the continental slope off the south coast. On both coasts, the main direction of movement was parallel to the coastline and towards Cape Leeuwin. Unexpectedly, whales off the west coast were heading mainly southwards throughout the year. Densities in the offshore area north of Perth were significantly higher than along the continental slope in the same region but similar to those along the continental slope from Perth to Cape Leeuwin. The situation was reversed on the south coast with whales being found, in high densities, only along the continental slope. Off the west coast, there were marked decreases in abundance in winter, with peaks in spring-early summer and autumn; no change in direction of movement could be related to the peaks. Average numbers calculated as present in the survey area at one time were: west coast, c. 1000 whales; south coast, c. 200 whales. South coast data indicate the passage of about 40 whales in one 24 hr period, very similar to results from whaling company aerial spotter data off Albany. The hypothesis of two separate populations of sperm whales off Western Australia is discussed and thought to be unlikely. A small amount of data on baleen whale sightings is recorded.

Seed set in two sympatric banksias, Banksia attenuata and B. baxteri

2001 ◽  
Vol 49 (5) ◽  
pp. 597 ◽  
Author(s):  
S. J. Wooller ◽  
R. D. Wooller
Keyword(s):  
Small Mammals ◽  
Western Australia ◽  
Seed Set ◽  
South Coast ◽  
The South ◽  
Banksia Attenuata

Two species of banksia, studied on the south coast of Western Australia, flowered simultaneously and had floral characteristics often associated with vertebrate pollination. The pollen of both was carried by honeyeater birds and small mammals (honey possums). Despite this, differential exclusion of vertebrates and invertebrates from inflorescences indicated that Banksia attenuata set substantial quantities of seed when visited only by invertebrates, although seed set increased with the addition of vertebrate visitors. Banksia baxteri set much seed in the absence of any animal visitors and seed set increased with invertebrate, but not vertebrate, visitation. We suggest that these differences in pollination strategies reflect regeneration by B. baxteri solely from canopy seeds released after fire, whereas B. attenuata also regenerates from seeds released between fires, as well as from lignotubers and epicormic buds.

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