Wheat yields and indices of available soil nitrogen in Southern NSW - A preliminary evaluation

1971 ◽  
Vol 11 (50) ◽  
pp. 295 ◽  
Author(s):  
RR Storrier ◽  
AT Hanly ◽  
TB Spence ◽  
AN Smith

Linear regression analyses were used to evaluate the usefulness of a number of measures of the available soil nitrogen in accounting for the variability in wheat yields under field conditions in southern New South Wales. Single soil tests, such as total mineral nitrogen in the surface sample (0-10 cm depth), could account for only 38 and 18.5 per cent of the variation in yield at flowering and harvest respectively. However, the Use of bilinear regression involving boiling water soluble nitrogen in the surface horizon and nitrate-nitrogen in the sub-soil (10-30 cm depth) accounted for 64 and 36 per cent of the variation in yield at flowering and harvest respectively. The use of these tests to predict the nitrogen fertilizer requirement of wheat will necessitate the measure ment of climatic, cultural and edaphic factors as well as response to nitrogen fertilizer.

Soil Research ◽  
1977 ◽  
Vol 15 (2) ◽  
pp. 159 ◽  
Author(s):  
GJ Osborne

The nitrogen in six surface soils from southern New South Wales was chemically fractionated into the mineral nitrogen; hydrolysed ammonium + amino sugar; hydrolysed non-distillable acid soluble nitrogen; intercalary ammonium and insoluble humin nitrogen fractions. These fractions were determined before and after a glasshouse study in which ryegrass (Lolium perenne) was grown. There was no significant relationship between any of the fractions and the dry matter producion of ryegrass at three harvest dates. The levels of each fraction varied between the soils ; however, each fraction as a percentage of the total nitrogen showed little variation, either before or after plant growth. In four soils the hydrolysed ammonium + amino sugar fraction was increased during the glasshouse study, while the hydrolysed non-distillable acid soluble fraction was decreased on three soils, increased on two, and was unchanged in the remaining soil. Two methods of hydrolysis were compared and found to give significantly different results for some soils. On the basis of the data presented, the chemical fractionation of soil nitrogen following acid hydrolysis was of no practical value as a predictor of plant yield.


1982 ◽  
Vol 22 (117) ◽  
pp. 317 ◽  
Author(s):  
KS Haddad ◽  
CJ Kaldor

Fifteen acidic soils (0-1 5 cm), three from each of the five main parent materials in the Central Tablelands of New South Wales, were collected for a glasshouse experiment. The hot water soluble boron content of these soils and some other related soil properties were measured. Boron at nil and 1.5 �g/g air-dried soil and lime at nil and 670 �g/g air-dried soil in a factorial combination were applied to the soils. The effects of the treatments on the performance of lucerne (Medicago sativa cv. Hunter River) grown on these soils were studied. Boron application tended to increase the production of lucerne dry matter on sandstone, shale and slate, and granitic soils, but not on basaltic or alluvial soils. Also, it increased the boron concentration in the leaves of lucerne grown in all soils and consequently, reduced the calcium to boron ratio. The boron levels that produced 90% of the maximum yield and below which boron deficiency symptoms were manifested by the plants, were 0.34 �g/g in air-dried soil and 25 �g/g in oven-dried leaves. There was a linear correlation (r = 0.98) between the hot water soluble boron content of the untreated soils and the boron concentration in the leaves. The hot water soluble boron content of the soils derived from sandstone, shale and slate, and granite was much lower than the basaltic or alluvial soils and were nearly equal to or below the determined critical level. Although liming had the tendency to induce the symptoms of boron deficiency, the effect of lime was greater than boron in increasing the yield. The role of lime in eliminating the problems of these acidic soils and hence promoting the yield of lucerne is discussed.


1967 ◽  
Vol 7 (27) ◽  
pp. 380
Author(s):  
JB Sumeghy ◽  
HC Kirton

To test the potential suitability of ten tomato varieties in the Murrumbidgee Irrigation Area of New South Wales to mechanical harvesting, the yields from 'once-over' harvests were compared with the yields from a harvest consisting of four pickings at weekly intervals. In a second experiment the effect of plant spacing, time of harvest, and side-dressing with nitrogen fertilizer were studied for the most promising varieties from the first experiment. The varieties Roma 884, VF145-22-8, and VF145 held their crops for prolonged periods without deterioration and so showed potential for mechanical harvesting. High planting density gave the highest yields from a single picking, and later picking and nitrogen side-dressing also increased yield.


1974 ◽  
Vol 14 (67) ◽  
pp. 231 ◽  
Author(s):  
OR Southwood ◽  
F Mengersen ◽  
PJ Milham

The effect of three rates of nitrogen (22.4, 44.8 and 89.6 kgNha-1 as anhydrous ammonia) and three seeding rates (67.3, 100.9, and 134.5 kg ha-1) on forage and grain production of two oat cultivars and on herbage nitrate-nitrogen concentration, was assessed at three sites in the southern New South Wales wheat belt. When oats were sown after two or three consecutive wheat crops nitrogen at 22.4 kg ha-1 was optimal for both forage and grain production. Herbage growth was best at the highest seeding rate (134.5 kg ha-1) but grain production was not influenced by seeding rate. Herbage growth of the oat cultivars Cooba and Coolabah was similar, but grain yields were higher from the latter. Herbage nitrate nitrogen increased linearly with nitrogen fertilizer application, levels that could be toxic to animals occurring in June. Cautious grazing management may be required during this period.


1982 ◽  
Vol 22 (115) ◽  
pp. 62 ◽  
Author(s):  
DP Heenan ◽  
LG Lewin

Two experiments were done at the Yanco Agricultural Research Centre, New South Wales, in 1978-79 and 1979-80 to measure the response of long grain rice, cv. Inga, to rates of nitrogen applied at two different times. The highest yields were recorded when the nitrogen was applied at panicle initiation. Increasing the rate from 100 to 200 kg N/ha at panicle initiation had no effect on grain yield. When the nitrogen was applied earlier, just before permanent water, yields were highest at 50 kg N/ha and declined at the highest rates (150 and 200 kg N/ha). This negative yield response was mainly due to a drop in the percentage of filled florets, and occurred despite an increase in panicle number.


1978 ◽  
Vol 56 (1) ◽  
pp. 75-79 ◽  
Author(s):  
Gordon Pritchard

Extraction of eggs of Dacus tryoni from fruit was aided by first identifying oviposition sites with a water-soluble dye and then digesting the fruit tissue around the oviposition site with a mixture of enzymes consisting of equal parts of 1% pectinase and 1% cellulase. The numbers of eggs laid per week were estimated by a formula that incorporated the numbers of hatched and unhatched eggs present on one occasion each week, the proportion of fertile eggs in each variety of fruit, and the development time of eggs.Many more eggs were laid in an orchard in New South Wales, Australia, in a wet year (1966–1967) than in a dry year (1965–1966). This was due in part to a larger population of adults that migrated into the orchard in the wet year and to the fact that fruit remained on the trees longer. There was evidence that the rate of oviposition in the wet season fell off as fruit became scarcer towards the end of the season. Aggressive behaviour of females on fruit and movement of gravid females away from the orchard are possible explanations.


1980 ◽  
Vol 20 (103) ◽  
pp. 181 ◽  
Author(s):  
JW Read ◽  
JV Lovett

Two phalaris hybrids (Siro 11 46 and allopolyploid) and the parent lines (Phalaris aquatica and P. arundinacea) were compared in monoculture with nitrogen fertilizer and in a mixed sward with white clover and lucerne. The experiment was flood irrigated and the effects of defoliating the swards at intervals of 21, 42 and 84 days were measured. The hybrid (Siro 11 46) was the most productive genotype at all defoliation intervals. Eighty one % of its annual yield occurred in spring and summer. This production imbalance renders Siro 11 46 unsuitable as the foundation of a pasture for high production throughout the year. The mixed sward produced more than the monoculture sward when defoliated every 21 or 42 days and there was increased production associated with increased defoliation interval. The monoculture sward was more productive than the mixed sward at an 84 day defoliation interval. The yield of Siro 1146 + white clover was 2.25 t ha-1 per 84 days, compared with a mean yield of phalaris + white clover of 1.78 t ha-1 per 84 days for the three other genotypes. The results indicate that Siro 11 46 grown with white clover and defoliated approximately every 42 days would be a suitable alternative pasture to Paspalum dilatatum and white clover in the two-pasture system used in irrigation areas of southern New South Wales. The problems of low acceptability and suspected toxicity of Siro 1146 are discussed.


1969 ◽  
Vol 9 (36) ◽  
pp. 27 ◽  
Author(s):  
EG Cuthbertson

The response of wheat to nitrogen fertilization and to the time and mode of skeleton weed control was determined at three locations in southern New South Wales. Nitrogen fertilization was found to increase grain yield significantly in most situations. But nitrogen reduced total grain yield where adverse seasonal conditions caused severe water stress after flowering. Added nitrogen exaggerated the water stress and reduced grain weight. Temporary removal of skeleton weed, obtained by spraying the fallow with 2,4-D four to six weeks before seeding, increased grain yield by an average of nearly 5 bushels an acre. The magnitude of the response was modified by rainfall incidence, weed cover, and time of spray application relative to seeding. The effects of chemical weed control, followed by crop competition, were apparent in stubble sown crops 12 to 18 months later in the form of reduced weed populations and increased grain yield. Preplanting sprays reduced the response to nitrogen fertilizer but the interaction, generally, was not significant. Spraying the fallow with a contact herbicide, or substituting an additional cultivation for the 2,4-D fallow spray, also increased grain yield. These results emphasize the importance of suppressing skeleton weed, by the most appropriate means available, in the period before sowing.


1991 ◽  
Vol 31 (2) ◽  
pp. 221 ◽  
Author(s):  
GJ Crocker ◽  
ICR Holford

The effects of pasture improvement on soil pH, total nitrogen, organic carbon and extractable phosphorus (P) were determined by analysing adjacent soils from improved and unimproved pastures at 67 sites on the Northern Tablelands of New South Wales. Pasture improved sites contained at least 1 clover species, predominantly white clover, and had received at least 125 kg P/ha over periods of 15-45 years. The majority of pasture improved sites contained more soil nitrogen, carbon and phosphorus and were of lower soil pH than adjacent unimproved sites. However, the decreases in pH were not statistically significant and not usually related to the magnitude of the increases in other soil fertility parameters nor to the amounts of superphosphate applied or duration of fertiliser history. The largest decline in soil pH and largest increase in organic carbon were on granitic soils which had received more than 250 kg P/ha. The relatively small decreases in soil pH and lack of relationship with fertiliser history, compared with soils from southern New South Wales, were attributed to: (i) re-cycling of legume-fixed nitrogen by summer-growing grasses; (ii) the naturally lower pH, higher nitrogen content and higher buffering capacity of many northern soils. Soil acidification therefore seems to be much slower and less frequent in the perennial pasture systems of the Northern Tablelands of New South Wales.


Soil Research ◽  
1981 ◽  
Vol 19 (3) ◽  
pp. 239 ◽  
Author(s):  
ICR Holford

Changes in total and mineral nitrogen and organic carbon were measured over a nine year period in two contrasting soils of northern New South Wales after various durations of grazed lucerne, extended fallowing and continuous wheat growing. At least 2 1/2 years of lucerne ley were required to raise the total soil nitrogen above the original level on both soil types. For each year of lucerne growth the average increase (above the control treatments) in total soil nitrogen (0-15 cm) was equivalent to about 140 kg nitrogen ha-1 in the black earth and about 110 kg nitrogen ha-1 in the red-brown earth. Significantly higher levels of soil nitrogen were maintained after the lucerne treatments throughout the 9 years of measurement on the black earth and for 5 years on the red-brown earth. Lucerne had a much larger effect on nitrogen than on organic carbon, which was significantly increased only in the black earth. There were very large increases in mineral nitrogen (0-15 cm) in the first year of measurement after lucerne. Levels remained greater than they were originally for the first 4 years, and they were greater for 7 years in the black earth and 4 years in the red-brown earth following lucerne than following continuous wheat or extended fallow. The decline in mineral nitrogen during wheat cropping after lucerne was greatly increased by excessive rainfall (574 mm or more) during the fallow. Leaching was greater in the red-brown earth than in the black earth, and this explained occasional differences in nitrogen uptake by wheat between the two soil types. Some evidence suggested that under moderately moist conditions nitrogen mineralization from lucerne-fixed nitrogen was greater in the red-brown earth than in the black earth but under drier conditions it was less.


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