Physical Sciences and Mathematics Commons^™

Laser Levelling Land For Flood Irrigation, M D. Green, J. P. Middlemas

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

Since the introduction of laser levelling to Western Australia's South-West irrigation area five years ago, many farmers have benefited from this new and precise method of land-forming.

The use of lasser controlled earthmoving equipment to redevelop irrigated paddocks has led to improved irrigation efficiency and drainage. Less water is used for each irrigation, water is applied more evenly and less labour is needed. many older, grass-dominated paddocks have been reseeded to improve pasture species.

Eradicating Fruit Fly From Carnarvon, Kingsley Thomas Fisher

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

Late last year the Mediteranean fruit fly (Ceratitis capitata Weidemann) was eradicated from Canarvon, Western Australia by using an intergrated programme of sterile insect releases and bait spraying.

The eradication marked the end of a four-year study on the use and effectiveness of the Sterile Insect Technique, a biological control technique which uses an insect pest against itself. such a study can be used as a basis for treating other threatening insect pests, such as the serious cattle pest screw-worm fly, should they be found in Asustralia.

Being a biological control method, the Sterile Insect Technique is an exellent …

Water Quality For Irrigation, P R. George

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

Although irrigation and salinity problems are frequently inseperable, there is a range of management methods that can be used to handle marginal quality water. Freuently these methods are simple, but require careful planning.

The wide range in tolerance of crops to salinity can be exploiter to ensure that appropriate crops are selected for the water available.

Because crops vary in their sensitivity to salt uptake in the leaves or the roots, watering methods can be changed to avoid problems. For profitable production enough water should be applied to ensure adequate water is available for plant growth as well as to …

Residual Values Of Australian Rock Phosphates, Michael D A Bolland

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

For years superphosphate has been the cheapest, convenient and most effective way of supplying phosphorus to newly cleared soils in Western Australia's South-West that are acutely deficient in phosphorus. However its effectiveness as a phosphorus source falls markedly after application. Regular applications are needed to maintaine profitable pastures and crops on these soils.

After a big jump in supperphosphate prices in the mid 970s, researchers tested the use of Australian rock phosphates as potentially cheaper alternative phosphorus fertilisers to superphosphate. On the none-leaching sands, as this article shows, none of the rock phosphates was as effective for plant growth as …

Changes In Forest Soils Following Clearcutting Of Pine Forests In The Ouachita Mountains Of Arkansas, Harlan R. Stoin, Bajuri Bin Kadmin, Lyell F. Thompson

Journal of the Arkansas Academy of Science

Soil characteristics of the mineral surface soil (0-6 cm) on three small watersheds in the Ouachita Mountains of Arkansas from which the pine forests have been clearcut, crushed, and burned for site preparation were studied for the first two years following clearcutting and compared to soils from adjacent uncut pine forest watersheds. Following clearcutting and burning, soil pH was generally higher than in uncut forest soils. The greatest pH differences occurred within several months of burning and generally decreased through the end of the second year. Soil organic matter content was lower immediately following clearcutting and burning and increased to …

Interceptor Drains And Waterlogging Control, J W. Cox, T R. Negus

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

Department of Agriculture trials of seepage interceptor drains from 1972 to 1983 primarily assessed the effects of such drains on salt encroachment. Although these trials showed that the drains had little influence on salt storage within the topsoil, they did reduce waterlogging downslope.

To investigate this drainage effect further, the Department's Narrogin office surveyed 35 drains on 14 properties in the winter of 1981, followed by detailed crop measurements in December that year. Provided the drains were properly designed, surveyed and constructed, and well maintained, they could be expected to increase crop yields during a waterlogging year by about 1 …