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.

Waterlogging : How It Reduces Plant Growth And How Plants Can Overcome Its Effects, Tim Setter, Bob Belford

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

Lack of oxygen is the major cause of limited plant growth in waterlogged soils. When soils become waterlogged less gas diffuses to and from the roots through the soil pores; there are changes in concentrations of mineral elements in soil solutions; and toxic products of roots and soil microorganisms begin to accumulate. These changes adversely affect germination, growth and development of plants.

Plant Growth And Survival In Saline, Waterlogged Soils, Ed Barrett-Lennard, Neil Davidson, Richard Galloway

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

Waterlogged soils in Western Australia are often salt-affected. Recent research has shown that the interaction between waterlogging and salinity has a far greater adverse effect on plant groivth and survival than either of these two factors individually. The consequences of the combined effects of salt and waterlogging for most plant species are increased salt uptake, reduced growth, chlorosis (yellowing of leaves), defoliation, and death. Salt sensitive agricultural species (nonhalophytes) are more severely affected by this interaction than salt tolerant species (halophytes).

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

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.

Causes Of Waterlogging, Jim Cox, Don Mcfarlane

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

Waterlogging is highly variable, both between years and within paddocks. This residts in uncertainty as to whether a paddock should be cropped in a particular year, and whether different management should be used on waterlogged areas within a paddock

A study has determined what are the most important causes of waterlogged soils.