Physical Sciences and Mathematics Commons^™

Can Kangaroos Survive In The Wheatbelt?, Graham Arnold

Journal of the Department of Agriculture, Western Australia, Series 4

One of the costs of agricultural development in Western Australia over the past 100 years has been the loss of most of the native vegetation and, consequently, massive reductions in the numbers of most of our native fauna. Thirteen mammal species are extinct and many bird and mammal species are extinct in some areas. These losses will increase as remnant native vegetation degrades under the impact of nutrients washed and blown from farmland, from the invasion by weeds and from grazing sheep.

Even kangaroos are affected. Unless the community manages remnant vegetation to minimise degradation and enhance the regeneration of …

Phosphorus Retention Of Sandy Horticultural Soils On The Swan Coastal Plain, Ian Mcpharlin, Neil Delroy, Bob Jeffery, Greg Dellar, Maurice Eales

Journal of the Department of Agriculture, Western Australia, Series 4

Soils can be ranked according to their phosphorus retention capacity by the phosphorus retention index (PRI). This is the ratio of phosphorus adsorbed by soil to that remaining in solution under a set of standard conditions. Although it is a laboratory measurement, the PRI seems to be a good indication of what happens in practice.

Shallow Drains For Reducing Waterlogging And Salinity On Clay Flats, Don Mcfarlane, Tim Negus, Arjen Ryder

Journal of the Department of Agriculture, Western Australia, Series 4

Flooding, waterlogging and salinity are problems which commonly occur together on the broad valleys of the wheatbelt. Drainage lines often become poorly defined once they reach the valleys and flood waters spread out, causing inundation and waterlogging. This excess water needs to be controlled because it contributes to salinity

Waterlogging Limits Growth On Duplex Soils, Bob Belford, Miles Dracup, David Tennant

Journal of the Department of Agriculture, Western Australia, Series 4

Duplex soils - soils with a sandy topsoil overlying a clayey subsoil -are ividespread in Western Australia's agricultural areas (see map). These soils are potentially highly productive, but crop growth is variable and the soils can become waterlogged. Work on a duplex soil site near Beverley has shoivn that the soil ivaterlogs where the permeability of the clay is low, and that this permeability varies ividely over the site. Waterlogging accounts for an average of half of the variation in wheat yields on this site; surprisingly, lupins have so far appeared less sensitive to waterlogging- The Department of Agriculture and …

Seepage Interceptor Drains For Reducing Waterlogging And Salinity, Don Mcfarlane, Jim Cox

Journal of the Department of Agriculture, Western Australia, Series 4

Shallow interceptor drains can reduce waterlogging on sloping sites. Such drains will more than pay for themselves from the increased crop yield. Recent work has shown that these drains also decrease salinity so that they are cost-effective in the long as well as the short term.

The 1989 Saltland Survey, Richard George

Journal of the Department of Agriculture, Western Australia, Series 4

In March 1989, the Australian Bureau of Statistics (ABS) surveyed farmers in Western Australia to determine the area of previously arable land that was now too saline for conventional agriculture. Farmers reported that 443,441 ha, or 2.83 per cent, of the 15.7 million hectares of cleared farm land in south-western Australia, was saline. This was an increase of about 180,000 ha on the 1979 survey figure.

The worst affected areas were in the 350 mm to 600 mm rainfall zone and included the Shires of Tammin (9.26 per cent arable area saline), Katanning (7.96 per cent), Goomalling (7.93 per cent), …

Waterlogging : One Reason Why Our Crops And Pastures Are Not Achieving Maximum Yields, Department Of Agriculture And Food, Western Australia

Journal of the Department of Agriculture, Western Australia, Series 4

Water, either its lack"or excess, is the main factor affecting the yield of crops and pastures in Western Australia.

The Extent And Cost Of Waterlogging, Don Mcfarlane, Buddy Wheaton

Journal of the Department of Agriculture, Western Australia, Series 4

Waterlogging is an underrated and not widely recognized problem in our cropping areas. Before we can tackle the problem through drainage and alternative cropping systems, we need to know its extent and how much crop yield is lost. The effect of waterlogging on pasture growth is also poorly known.

Mapping The Extent Of Waterlogged Crop Using Satellite Imagery, Jeremy Wallace, Buddy Wheaton

Journal of the Department of Agriculture, Western Australia, Series 4

No abstract provided.

Level Banks Used To Decrease Waterlogging Can Increase Salinity, Don Mcfarlane, Richard Engel, Arjen Ryder, Maurice Eales

Journal of the Department of Agriculture, Western Australia, Series 4

Some farmers have used level W1SALTS banks to control surface zvaters above areas affected by ivaterlogging and salinity. Because the amount of waterlogging has been reduced, crop yields have increased downslope of some banks. However, the banks divert fresh surface water into deeper salty groundwater and, in the long term, worsen salinity. This article details an investigation of the effect of level WIS ALTS banks on saline groundwaters and discusses alternative methods of preventing the waterlogging of saline areas.

Economics Of Interceptor Drains : A Case Study, Andrew Bathgate, Ian Evans

Journal of the Department of Agriculture, Western Australia, Series 4

This case study determines the most likely rate of return to capital invested in constructing seepage interceptor drains to reduce the effect of waterlogging on crop and pasture yields. The analysis of a farm in the Denbarker region, west of Albany, determined what increases were needed in pasture growth to justify the cost of constructing drains across four adjacent paddocks. The benefits of changing rotations to include lupins were also determined, as growing lupins was unprofitable before the construction of drains.

Integrated Control Of Soil Insect Pests Of Potatoes, Stewart Learmonth, John Matthiesson

Journal of the Department of Agriculture, Western Australia, Series 4

One of the more difficult aspects of growing potatoes in Western Australia is controlling soil insect pests. These pests have become more troublesome because the highly effective and persistent organochlorine insecticides previously used to control the main soil pests, African black beetle and whitefringed weevil, were deregistered for agricultural use in 1987. Entomologists from the Department of Agriculture and CSIRO in Western Australia are collaborating to develop new management strategies for these pests that rely less on the use of chemical insecticides