Normal Rainfall Conditions Research Articles

Superphosphate requirements of clover-ley farming. I. The effects of topdressing on productivity in the ley phase

Experiments were undertaken on four farms in southern New South Wales to assess the requirements for superphosphate of clover-ley farming soils. The sites were selected to provide contrasts in initial soil phosphate status (medium v. high) in both low and high average annual rainfall conditions. At each site a sheep-grazing experiment with factorial arrangement of three annual topdressing rates (nil, 125, and 250 kg superphosphate ha-1) and two sheep stocking rates (district average, twice district average) was imposed for the duration of a normal ley phase (4 years). The response to topdressing depended on the initial soil phosphate status and was modified by seasonal rainfall conditions. At the high phosphate sites topdressing had little effect on pasture production, but at the medium phosphate sites topdressing increased pasture availability, and caused rapid and profound changes in botanical conlposition; topdressing induced grass dominance while omission of topdressing led to clover dominance. The changes in botanical composition had important effects on forage quality. With normal seasonal conditions there was no overall response to topdressing in sheep performance, but in poor years the pasture changes conferred by topdressing were reflected in a general increase in the level of sheep productivity.

Physical Microclimates of Erosion-Control Structures in a Salt Desert Area

in the United States since the 1930s when the 'Great Drought' destroyed vegetation to the point where soil erosion impaired human endeavours. The rangelands of the arid West had sparse vegetation and erodible soils even under average rainfall conditions. Treatments with gully plugs, contour furrows and water spreaders were tried as conservation measures to increase vegetation cover and so decrease the erosion hazard. The increasing concern for sustaining yields of forage and water from rangelands has brought extension of these land treatments to areas of marginal response. A more detailed understanding of the ecological and hydrological effects of erosion-control structures is necessary if they are to be of net benefit in harsher environments. Most of the published studies to date report the success or failure of treatments as measured by forage produced. The few papers which examine the causes of success or failure of the erosion-control structures omit consideration of the physical microclimates of gully plugs and furrows in arid, non-irrigated regions. The present paper deals with the application of the energy budget approach to help explain the plant response to these erosion-control structures in a salt desert area.

Supplementary Supply for Wichita, Kan.

This article discusses Kansas' Cheney Reservoir multipurpose project located on the Ninnescah River, Wichita's second water supply, that was conceived and carried out cooperatively by the city of Wichita and the Bureau of Reclamation. The municipal water supply pool has a volume of 149,500 acre‐ft and is calculated to produce a yield of 35 mgd during a drought period such as that of 1952‐56. Under normal rainfall conditions, the pool can be expected to provide 60 mgd. Major works constructed by the city include the Cheney Reservoir pumping station, pretreatment works and appurtenances, the raw‐water transmission line, and a communication and control cable. For convenience, the pumping facilities and the pretreatment works are discussed separately, although they are housed in the same structure.

Rainfall in Italy

THE Italian Meteorological Department has issued an important work on the rainfall of Italy. The tabular matter contains the total precipitation and the number of rain-days for each month of the twenty-six years 1880 to 1905 for 215 of the 700 rainfall stations in connection with the Italian office. The records are not complete in all cases, but fifteen years is the shortest period dealt with. The largest annual total is 90 inches, at Gemona, near the Austrian frontier, the smallest 18.6 inches, at Foggia. On looking through the tables we are struck by the fact that no attempt seems to be made to secure uniformity of exposure for the gauges. The heights above the ground vary between 60 metres and half a metre. A set of excellent coloured plates shows the average rainfall conditions for each month, each season, and for the whole year.