Efficiency of utilization of nitrogen fertilizers on representative soils from southern New South Wales

1976 ◽  
Vol 16 (83) ◽  
pp. 875 ◽  
Author(s):  
GJ Osborne ◽  
RR Storrier

The effects were examined in a glasshouse study of three forms of nitrogen fertilizer (urea, ammonium sulphate and sodium nitrate) on the yield, and nitrogen and phosphorus uptake of ryegrass (Lolium perenne) in six representative farming soils from the southern slopes and plains of New South Wales. The results indicated an average recovery of 82 per cent of applied nitrogen across the three forms of fertilizer and the six soils. Ammonium sulphate led to decreases in soil reaction of the order of 0.8-1.5 pH units and lower recoveries; sodium nitrate increased pH. Ammonium sulphate as a source of nitrogen is considered undesirable as it gave lower dry matter yields and nitrogen recovery values compared with the other fertilizer forms. In addition, because of its effect on soil reaction, it could lead to the loss of nutrients by leaching or fixation processes.

Soil Research ◽  
1976 ◽  
Vol 14 (3) ◽  
pp. 381 ◽  
Author(s):  
GJ Osborne

Six surface and subsoils known to contain native intercalary ammonium were examined to assess the importance of ammonium fixation when nitrogen fertilizers were applied, the availability of native and recently fixed intercalary ammonium to plants, and the effect of potassium on fixation. Only one soil, a grey soil of heavy texture (Ug 5.4), fixed significant amounts of added ammonium sulphate, the level of intercalary ammonium being increased by 55 % in the surface and 100% in the subsoil. The native level of intercalary ammonium was reduced by 8 and 17% by the growth of plants in the red-brown earth (Dr 2.23) and the grey soil of heavy texture, respectively, but was unchanged in the other soils. The addition of small amounts of potassium prior to the ammonium did not affect fixation; however, additions of 500 ppm reduced the fixation of a 200 ppm solution of ammonium by 80 %. Intercalary ammonium is not considered to be important in the nitrogen economy of five of the six major farming soils of the slopes and plains area of southern New South Wales. The sixth, the grey soil of heavy texture, is an alluvium associated with the Murrumbidgee River and its tributaries, and as such is used extensively for irrigated agriculture. Because this soil can fix large amounts of ammonium, the use of ammonium or ammonium forming fertilizers is not recommended.


1986 ◽  
Vol 26 (6) ◽  
pp. 709 ◽  
Author(s):  
AC Taylor ◽  
WJ Lill

Regular hand-weeding was undertaken in experiments located in 167 wheat crops in southern New South Wales from 1967 to 1970 to quantify the effect of weeds on 10 wheat attributes at flowering or maturity. Short annual grasses, skeleton weed, wild oats and annual legumes were the most widespread weeds, all of which tended to occur in mixed stands. At wheat flowering, over all sites, wheat DM, nitrogen concentration, nitrogen uptake, phosphorus uptake and number of ears were increased (P< 0.05) by 11.2, 3.3, 14.4, 13.6 and 7.8%, respectively by weeding; wheat phosphorus concentrations did not respond to weeding. At maturity, grain yield and nitrogen yield increased after weeding (P< 0.05) by 17.3 and 1 7.0%, respectively, but grain protein and kernel weight did not respond to weeding. Regression procedures were used to relate wheat responses to total weed DM and the DM of 8 weed classes. At flowering, for every 100 g of DM removed, wheat DM, nitrogen uptake, phosphorus uptake and ear number increased by 52.3 g m-2, 958 mg m-2, 92.6 mg m-2and 18.7 m-2, respectively. At maturity, grain yield and grain nitrogen yield increased by 31.9 g m-2 and 665 mg m-2, respectively, for every 100g m-2 of weed DM present at flowering. The regressions also showed that, at both flowering and maturity, fumitory, annual grasses and sundry weeds (a group made up of weeds not sufficiently widespread to consider separately) appeared to be the most aggressive weeds. Consideration of standardised responses of the wheat attributes increased by weeding showed that they all responded similarly when corrected for scale of measurement.


1973 ◽  
Vol 13 (65) ◽  
pp. 705 ◽  
Author(s):  
BJ Scott

The dry matter production of a pasture of barrel medic (Medicago truncatula cv. Jemalong) under different rates and methods of application of superphosphate was examined, during 1971 and 1972, on a phosphorus deficient soil at Condobolin, New South Wales. The treatments were factorial combinations of four rates of superphosphate (0, 126, 376, and 753 kg ha-1) and four methods of application of superphosphate (surface spread i.e. topdressed, surface applied in bands, placed at 5 cm depth, and placed at 1 0 cm depth). The dry matter production and phosphorus uptake results demonstrated the effectiveness of subsurface placement of superphosphate, but relative ineffectiveness of surface application during the dry winters experienced. The results also showed that root development in the dry 0-2 cm zone was restricted compared with that in the deeper moist soil layers. Soil phosphorus tests showed that one year after topdressing phosphorus had not moved below the 2-4 cm depth layer, even at 753 kg ha-1 of superphosphate.


1976 ◽  
Vol 16 (79) ◽  
pp. 234 ◽  
Author(s):  
ICR Holford ◽  
AC Gleeson

Responses in herbage yield, nitrogen uptake and phosphorus uptake by white clover pasture to phosphorus and sulphur application were measured on very phosphorus-deficient granitic soils in the Northern Tablelands of New South Wales. The factorial experiment with six rates of P and three of S was repeated over three years (1966, 1967 and 1968) and at three sites. Coefficients of variation of up to 48 per cent indicated considerable within-site variability in herbage yields. Variation among years was caused mainly by variations in incident rainfall. Very large and highly significant responses in all variables to phosphorus occurred at every harvest regardless of the amount of incident rainfall or applied sulphur. However phosphorus responses were greater with increasing rainfall and in the presence of sulphur. To achieve at least 85 per cent of the maximum recorded yield in any one year, 48 to 73 kg P ha-1, were required. Responses to phosphorus were 1000-2000 kg ha-1 with 150 mm rainfall and up to 3000-4500 kg ha-1 with 450 mm rainfall during the growing season. Responses to sulphur were much smaller and less consistent, and occurred only in the presence of applied phosphorus. They also increased with increasing rainfall. The intermediate rate of 28 kg S ha-1 gave the maximum yield of herbage. Sulphur had a larger effect on nitrogen and phosphorus uptake than on herbage yield.


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