Effects of duration of grazed lucerne on long-term yields and nitrogen uptake of subsequent wheat

1980 ◽  
Vol 31 (2) ◽  
pp. 239 ◽  
Author(s):  
ICR Holford

The long-term effects of varying durations of lucerne Icy, extended fallowing, and continuous wheat growing on the growth, yield, and nitrogen uptake of subsequent wheat crops were determined on two contrasting soils in northern New South Wales. Durations of lucerne ley were 3+, 2+ and 1+ years on a black earth and 5+, 3+ and 1+ years on a red-brown earth. With the exception of the first wheat crop, wheat production for several years following lucerne exceeded that following extended fallow or continuous wheat growing, whether measured as vegetative yield at anthesis, grain yield, nitrogen uptake, or grain protein. The beneficial effects of lucerne on vegetative yield, nitrogen uptake, and grain protein reached a maximum in the second crop after lucerne, and the effects of 2+ or more years of lucerne remained significant for the next five crops on the black earth and the next two crops on the red-brown earth. Grain yields fluctuated widely with season, the magnitude of the lucerne effect being much more dependent on rainfall, but the duration of the effect was similar for grain and vegetative parameters. The shorter duration of the lucerne effect on the red-brown earth appeared to be associated with its more freely draining nature and consequent loss of accumulated nitrogen. The optimum duration of lucerne for maintaining nitrogen-dependent wheat yields was 3+ years on both soil types. It eliminated the need for nitrogen fertilizer for the following five wheat crops on the black earth and three wheat crops on the red-brown earth. Extended fallowing also had a beneficial effect on all parameters, particularly in the first and second crops after the fallow ended. Its effect was generally significantly smaller than the lucerne effect except in the first crop after fallow.

1993 ◽  
Vol 33 (4) ◽  
pp. 451 ◽  
Author(s):  
LW Burgess ◽  
D Backhouse ◽  
BA Summerell ◽  
AB Pattison ◽  
TA Klein ◽  
...  

The effect of 3 stubble management regimes (burning after harvest, incorporation with a disc plough, retention on the surface) on the incidence of infection of wheat with Fusarium graminearum Schw. Group 1 was studied for 5 seasons at 2 sites at Moree, New South Wales. One site had high initial incidence (site A) and the other low initial incidence (site B). There were no differences in incidence of infection between retained and incorporated treatments. Stubble burning reduced the increase in incidence of infection in 2 of 5 years at site A and 3 of 4 years at site B. Failure of control in other years was attributed to susceptible weed hosts and poor burns. When stubble was retained on the plots at site B that had been burnt, incidence of infection in the next season increased to a level not significantly different from the retained or incorporated treatments. Incidence of infection at the fourth consecutive wheat crop at both sites was close to the maximum recorded, which was 92% at site A and 65% at site B. There was no evidence of a decline in incidence by the time of the most recent season assessed (eighth year of continuous wheat cultivation at site A, and sixth year at site B). In most years, the differences in yield between treatments were not significant.


1989 ◽  
Vol 40 (2) ◽  
pp. 255 ◽  
Author(s):  
ICR Holford

Long-term yields, nitrogen uptake and responsiveness of grain sorghum following three lucerne rotations, an annual legume rotation, long fallowing, and continuous wheat growing were measured on a black earth and red clay in northern New South Wales. The three lucerne rotations compared two methods of lucerne establishment (with or without a cover crop) and two methods of grazing management (short or extended grazing).There were large beneficial effects of lucerne leys on the first grain sorghum crop, whether they were measured as grain yield, nitrogen content of the foliage and grain, or nitrogen uptake. The effect was much smaller in the second year but it increased in the third and fourth years, in direct relation to the rainfall during the sorghum flowering period. The effect was larger on the black earth than on the red clay, reflecting the much higher lucerne yields on the former soil. Evidence indicated that the nitrogen contribution from lucerne after the first year was no greater than the nitrogen accumulated by long fallowing, and this was attributed to very low rainfall and lucerne yields during the four year ley period.The annual legume rotation suffered from drought and insect damage in most years, and following sorghum yields tended to be lower than those achieved by long fallowing.Differences in the effects of establishment method and grazing management on total lucerne yields were reflected in the differences in subsequent grain sorghum yields. Largest differences were on the black earth where extended grazing lowered the total yields of lucerne and subsequent grain sorghum. Sowing lucerne under wheat had little effect on total yields of lucerne or sorghum.


1962 ◽  
Vol 2 (6) ◽  
pp. 185 ◽  
Author(s):  
RR Storrier

In a red-brown earth soil from Wagga Wagga the fluctuations in the level of mineral nitrogen (ammonia plus nitrate-nitrogen) and its availability to wheat under growing period rainfalls of 6 inches and 16 inches were studied. Ammonia-nitrogen did not exceed 8 lb nitrogen per acre 6 inches but showed statistically significant short term fluctuations. Mineral nitrogen decreased steadily from the 4-5 leaf stage of plant growth, reaching minimum values in the ear-emergence period when a temporary nitrogen deficiency occurred. Following rainfalls of about one inch or more, conditions favoured biological activity and nitrogen was mineralized, absorbed by the crop and/or leached down the profile. In one season a release of mineral nitrogen about two weeks before flowering contributed an estimated 20-30 per cent of the total nitrogen uptake of the crop. Nitrogen uptake by the wheat crop ceased after flowering and subsequent changes in mineral nitrogen level reflect the net result of mineralization and demineralization processes, and nitrogen uptake by weeds, particularly skeleton weed. Absorption of nitrogen from the profile depended upon seasonal conditions, with the surface 18 inches suppling the greater part of the nitrogen absorbed by the crop. This indicates the need to sample regularly to at least a depth of 18 inches, particularly during the period from 4-5 leaf to flowering, when studying the relation between mineral nitrogen and crop growth. The data suggest that the response of wheat, as measured by grain yield and protein content, to the higher levels of mineral nitrogen in the improved soils of southern New South Wales is determined by soil moisture levels, particularly in the post-flowering period.


2006 ◽  
Vol 83 (3) ◽  
pp. 219-222 ◽  
Author(s):  
L. Yap ◽  
T. Butler ◽  
J. Richters ◽  
K. Kirkwood ◽  
L. Grant ◽  
...  

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.


1965 ◽  
Vol 5 (19) ◽  
pp. 487 ◽  
Author(s):  
AC Taylor

Three surveys in southern New South Wales assessed the importance of a number of agronomic factors on grain protein content. Grain from clover ley areas had an average of 1.3 per cent more protein than grain from crops without a clover ley background. Multiple regression analyses of the 1961 and 1963 data from clover ley crops showed that each year of ley was associated with an average increase of 0.14 per cent protein. Each week's delay of sowing beyond April 1, was associated with an average increase of 0.17 per cent grain protein. Amount of superphosphate applied to ley, intensity of cropping, and length of fallow had no effect or inconsistent effects on grain protein. With crops after natural leys only sowing time had a consistent effect on grain protein. The regression was the same as for crops with a clover ley background.


1988 ◽  
Vol 28 (2) ◽  
pp. 215
Author(s):  
AC Taylor ◽  
WJ Lill ◽  
AA McNeill

Dry matter and nitrogen uptake of wheat tops at flowering, dry matter and nitrogen of wheat grain at maturity, and soil mineral nitrogen (0-90 cm) at sowing and flowering, were measured at 68 sites (1 experiment per site in 5 Shires) in southern New South Wales to test the hypotheses that: (i) mineral nitrogen below 30 cm would improve the prediction of wheat yields, (ii) soil mineral nitrogen would be better indicated by wheat yields at flowering than those at maturity, and (iii) soil mineral nitrogen would be better indicated by nitrogen uptake by wheat than by dry matter yields. Mineral nitrogen concentrations in soil at depths greater than 30 cm did not improve the prediction of wheat attributes, but hypotheses (ii) and (iii) were validated. Curvilinear regressions, significant (P< 0.05) on 2 occasions, were not important in this study. The best regression of wheat dry matter at flowering against soil mineral nitrogen at sowing was a single straight line, but the best models for the other 3 wheat variables were all bilinear. The best of the latter related the uptake of nitrogen by wheat at flowering to mineral nitrogen in the soil at sowing as follows: FNUH = (31.6 � 5.9) + (0.892 � 0.110) TMNS30 and FNUL = (9.7 � 7.3) + (0.892 � 0.110) TMNS30 where FNUH is nitrogen uptake by wheat at flowering (kg/ha) in 1960, 1964 and 1966 (when Shire wheat yields were above the Shire's long term average), FNUL is nitrogen uptake by wheat at flowering (kg/ha) in 1961, 1965 and 1974 (when Shire wheat yields were below the Shire's long term average), and TMNS30 is total mineral nitrogen (0-30 cm) (kg/ha) at sowing.


1987 ◽  
Vol 27 (4) ◽  
pp. 533 ◽  
Author(s):  
SM Bromfield ◽  
RW Cumming ◽  
DJ David ◽  
CH Williams

Soil profiles from limed and unlimed commercial pastures and from lime trials on pastures in the Crookwell district of the Southern Tablelands of New South Wales were sampled and pH measured at 2- or 5-cm intervals to depths ranging from 10 to 60 cm. A single application of lime (3.6-5.6 t/ha depending on the soil) incorporated into the surface 10 cm had a long-term effect and maintained pH above 5.5 in the top 30 cm for at least 12 years. Lime applied as a topdressing to soils on granite raised the pH by at least 0.2 pH units to a depth of 15 cm after 6 years. The depth affected was less on the heavier-textured basaltic soils and on the initially more acid sedimentary soils. There appears to be a role for top-dressing with lime to prevent subsurface acidity from developing under pastures and to correct it in the upper layers of light textured soils. The pH profiles from a given treatment were variable and highlighted the problem of obtaining a field measurement for soil pH that is representative of the plant's environment.


1995 ◽  
Vol 35 (7) ◽  
pp. 915 ◽  
Author(s):  
WL Felton ◽  
H Marcellos ◽  
RJ Martin

Four experiments were commenced after a 1980 wheat crop, and a fifth after the 1981 crop, at different sites representing the major soil types of northern New South Wales in the 550-700 mm rainfall zone, to examine the influence of 3 fallow management practices [no tillage (NT); stubble retention after harvest, cultivation (SM); stubble burning after harvest, cultivation (SB)] on wheat production. Data considered in this paper cover the continuous wheat subtreatments of the 5 experiments (1981-90). Nitrogen applied at 50 kg Nlha in addition to the basal treatment was included as a treatment from 1986 to 1988. Across all sites and seasons, grain yields were in the order SB>SM = NT, stubble retention having a greater effect than tillage. In some years at some sites, differences in grain yield and grain N yield were not significant. In others, when significant yield differences occurred, variations in grain yield and grain N yield were highly correlated with differences in soil N available for the crop. The data show that the influence of fallow management interacted with season and crop nutrition, and required long-term study for proper assessment.


Sign in / Sign up

Export Citation Format

Share Document