The distribution of net nitrogen mineralisation within surface soil. 1. Field studies under a wheat crop

Soil Research ◽  
2000 ◽  
Vol 38 (1) ◽  
pp. 129 ◽  
Author(s):  
Erry Purnomo ◽  
A. S. Black ◽  
C. J. Smith ◽  
M. K. Conyers
Keyword(s):  
Soil Depth ◽  
New South ◽  
Field Studies ◽  
Soil Disturbance ◽  
Wheat Crop ◽  
N Mineralisation ◽  
Total N ◽  
South Wales ◽  
Highly Correlated ◽  
Soil Temperature And Moisture

To test the hypothesis that net nitrogen (N) mineralisation is concentrated in the surface few centimetres following minimal soil disturbance for crop establishment, mineralisation was measured during the growth of wheat. The soil was a Red Kandosol located in southern New South Wales. Mineralisation was estimated usingin situ incubations inside capped PVC tubes, which were sampled every 3 weeks. Soil from the tubes was sampled at depth intervals of 2 cm to a depth of 10 cm and at 5-cm intervals from 10 to 20 cm. The results showed that net N mineralisation decreased with depth to 20 cm. Over the season, an average of 32% of the N mineralised in the top 20 cm of soil originated from the 0–2 cm layer, 72% was from the 0–6 cm layer, and only 13% was from soil below 10 cm. The decrease in N mineralisation with soil depth was highly correlated with decreases in the organic carbon (r2 = 0.84, P < 0.05) and total N (r2 = 0.83, P < 0.05) concentration. The soil's N-supplying ability is concentrated near the surface where it is susceptible to erosional loss. The N supply may also be inhibited by temperature and moisture extremes, which are common in the surface few centimetres of soil where mineralisation was concentrated. The PVC enclosures created artefacts in soil temperature and moisture, although it is argued that the effects on net N mineralisation were small in most sampling periods.

Wheat response after temperate crop legumes in south-eastern Australia

1991 ◽  
Vol 42 (1) ◽  
pp. 31 ◽  
Author(s):  
J Evans ◽  
NA Fettell ◽  
DR Coventry ◽  
GE O'Connor ◽  
DN Walsgott ◽  
...  
Keyword(s):  
New South ◽  
Wheat Yield ◽  
Wheat Crop ◽  
First Year ◽  
Mineral N ◽  
Total N ◽  
Available N ◽  
Relative Contribution ◽  
South Wales ◽  
Eastern Australia

At 15 sites in the cereal belt of New South Wales and Victoria, wheat after lupin or pea produced more biomass and had a greater nitrogen (N) content than wheat after wheat or barley; on average these crops assimilated 36 kg N/ha more. The improved wheat yield after lupin averaged 0 . 9 t/ha and after pea 0.7 t/ha, increases of 44 and 32% respectively. The responses were variable with site, year and legume. Soil available N was increased by both lupin and pea and the levels of surface inorganic N measured at the maturity of first year crops was often related to N in wheat grown in the following year. Of two possible sources of additional N for wheat after legumes, namely mineral N conserved in soil by lupin or pea (up to 60 kg N/ha) and the total N added in the residues of these legumes (up to 152 kg N/ha), both were considered significant to the growth of a following wheat crop. Their relative contribution to explaining variance in wheat N is analysed, and it is suggested wheat may acquire up to 40 kg N/ha from legume stubbles. Non-legume break crops also increased subsequent wheat yield but this effect was not as great as the combined effect of added N and disease break attained with crop legumes.

The availability of mineral nitrogen in a wheat soil from southern New South Wales

1962 ◽  
Vol 2 (6) ◽  
pp. 185 ◽  
Author(s):  
RR Storrier
Keyword(s):  
Nitrogen Uptake ◽  
New South ◽  
New South Wales ◽  
Nitrogen Deficiency ◽  
Ammonia Nitrogen ◽  
Mineral Nitrogen ◽  
Wheat Crop ◽  
Wagga Wagga ◽  
Emergence Period ◽  
South Wales

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.

Characteristics of soil and productivity of Pinus radiata (D Don) in New South Wales .II. Pedogenesis on a range of parent materials

Soil Research ◽  
1986 ◽  
Vol 24 (1) ◽  
pp. 103 ◽  
Author(s):  
PJ Ryan
Keyword(s):  
Pinus Radiata ◽  
Soil Depth ◽  
New South ◽  
New South Wales ◽  
Morphological Properties ◽  
Slope Position ◽  
Site Classification ◽  
Physical Factors ◽  
Parent Materials ◽  
South Wales

Soil profile descriptions were made at a series of 11-year-old unfertilized Pinus radiata stands in the Lithgow district of New South Wales. Catenas within three soil parent materials were selected to compare variation in soil physical and morphological properties with growth of P. radiata. These parent materials were a Silurian siltstone, a Permian conglomerate and a Silurian-Devonian rhyolite. Basal area growth of the P. radiata stands increased down catenas on the Silurian siltstone as soil depth to a root impeding layer increased. Plateau soils on the Permian conglomerate had hardsetting surfaces and high gravel contents, and were associated with very poor pine growth. By way of contrast, lower slope, colluvial gradational earths were deep, fine-textured soils and supported more productive pine stands. The Silurian-Devonian rhyolite parent material produced highly leached soils, commonly with conspicuously bleached A2 horizons and poor sandy textures of surface soil. Both physical and chemical features of the rhyolite interacted with pedological processes to affect adversely soil physical conditions and trace element availability, in particular boron. The poorer P. radiata growth on lower or concave slope in comparison with upper slope position was a result of increased soil leaching and horizon differentiation. This pattern contrasted with improved pine growth on the deeper soils on lower slopes on the two sedimentary parent materials. These case studies emphasize the importance of geology and pedological processes when evaluating the applicability of specific soil physical factors to site classification for P. radiata plantations.

scholarly journals Mathematical Functions to Model the Depth Distribution of Soil Organic Carbon in a Range of Soils from New South Wales, Australia under Different Land Uses

Soil Systems ◽  
2019 ◽  
Vol 3 (3) ◽  
pp. 46 ◽  
Author(s):  
Brian W. Murphy ◽  
Brian R. Wilson ◽  
Terry Koen
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Exponential Function ◽  
Depth Distribution ◽  
Soil Depth ◽  
New South ◽  
Exponential Functions ◽  
Two Phase ◽  
Mathematical Functions ◽  
South Wales

The nature of depth distribution of soil organic carbon (SOC) was examined in 85 soils across New South Wales with the working hypothesis that the depth distribution of SOC is controlled by processes that vary with depth in the profile. Mathematical functions were fitted to 85 profiles of SOC with SOC values at depth intervals typically of 0–5, 5–10, 10–20, 20–30, 30–40, 40–50, 50–60, 60–70, 70–80, 80–90 and 90–100 cm. The functions fitted included exponential functions of the form SOC = A exp (Bz); SOC = A + B exp (Cz) as well as two phase exponential functions of the form SOC = A + B exp (Cz) + D exp (Ez). Other functions fitted included functions where the depth was a power exponent or an inverse term in a function. The universally best-fitting function was the exponential function SOC = A + B exp (Cz). When fitted, the most successful function was the two-phase exponential, but in several cases this function could not be fitted because of the large number of terms in the function. Semi-log plots of log values of the SOC against soil depth were also fitted to detect changes in the mathematical relationships between SOC and soil depth. These were hypothesized to represent changes in dominant soil processes at various depths. The success of the exponential function with an added constant, the two-phase exponential functions, and the demonstration of different phases within the semi-log plots confirmed our hypothesis that different processes were operating at different depths to control the depth distributions of SOC, there being a surface component, and deeper soil component. Several SOC profiles demonstrated specific features that are potentially important for the management of SOC profiles in soils. Woodland and to lesser extent pasture soils had a definite near surface zone within the SOC profile, indicating the addition of surface materials and high rates of fine root turnover. This zone was much less evident under cropping.

CROP UTILIZATION OF PLACED AND BROADCAST 15N-UREA FERTILIZER UNDER ZERO AND CONVENTIONAL TILLAGE

1984 ◽  
Vol 64 (4) ◽  
pp. 563-570 ◽  
Author(s):  
M. R. CARTER ◽  
D. A. RENNIE
Keyword(s):  
N Uptake ◽  
Moisture Stress ◽  
Field Studies ◽  
Conventional Tillage ◽  
Soil Disturbance ◽  
Zero Tillage ◽  
Fertilizer N ◽  
Tillage Systems ◽  
N Application ◽  
Total N

Growth chamber and field studies were conducted to assess the relative utilization of placed and broadcast 15N-urea by spring wheat. The field studies were conducted on zero and conventional (shallow) tillage systems, of 4-yr duration, located on Chernozemic soils at two locations in Saskatchewan. Placement below the seeding depth in comparison to broadcast application, generally reduced fertilizer N immobilization and increased fertilizer N uptake, recovery, and efficiency. Under moisture stress, placed applications were effective in enhancing dry matter yield and total N uptake. It is concluded that fertilizer N placement for these two contrasting tillage systems should be identical, thus some soil disturbance under zero tillage may be necessary to achieve optimum crop use of applied fertilizer N. The dominant N transformation processes and possible tillage induced differences, in regard to methods of N application, are discussed. Key words: Placed and broadcast N application, N efficiency, N utilization, 15N-urea, zero tillage, soil moisture

Impact of legume 'break' crops on the yield and grain quality of wheat and relationship with soil mineral N and crop N content

2003 ◽  
Vol 54 (8) ◽  
pp. 777 ◽  
Author(s):  
J. Evans ◽  
G. Scott ◽  
D. Lemerle ◽  
A. Kaiser ◽  
B. Orchard ◽  
...  
Keyword(s):  
Green Manure ◽  
Soil Depth ◽  
New South ◽  
Wheat Yield ◽  
Grain Legumes ◽  
Grain Protein ◽  
Mineral N ◽  
Yield Increase ◽  
South Wales

The effect of annual 'break' crops on the yield and protein content of wheat was investigated over 3 seasons on a Red Kandasol on the south-western slopes of New South Wales. The 'break' crops included lupin and pea grown for grain, pea and vetch managed for silage, clovers managed for silage or hay, and vetch and clovers managed for green manuring. Wheat was sown for 2 years following the legume year, or canola and wheat followed the legumes. Averaged over 3 experiments the yields of first crop wheat following pea or vetch silage crops were comparable with those after grain pea. Yields following clover forage conservation crops or green manures exceeded those after grain pea by at least 0.41 t/ha; average yield increase after clover green manure was 0.93 t/ha. In one experiment, yields of second crop wheat were greater, by up to 0.37 t/ha, after forage conservation or green manure legume 'breaks' than after grain legumes. In 2 experiments, second crop wheat yields were greater after a first crop of canola than a first crop of wheat. Compared with continuous wheat yield, aggregate mean wheat yield increases were 3.5–4 t/ha following grain legumes, pea, and vetch silage crops, but 5.3–6.3 t/ha following clover forage conservation and green manure crops. However, the relative effects of legume treatments on wheat yield were significantly seasonally dependent. Yield and grain protein variation in wheat after legumes was significantly correlated with variation in mineral N at wheat establishment. However, in one experiment, yield was correlated only with variation in mineral N below the 20-cm soil depth, whereas protein was correlated only with variation in mineral N above the 20 cm soil depth. Yield increases in first crop wheat did not occur at the expense of grain protein.

Effect of timing of pasture grass removal on subsequent take-all incidence and yield in wheat in southern New South Wales

2002 ◽  
Vol 42 (8) ◽  
pp. 1087 ◽  
Author(s):  
C. R. Kidd ◽  
G. M. Murray ◽  
J. E. Pratley ◽  
A. R. Leys
Keyword(s):  
Grain Yield ◽  
New South ◽  
New South Wales ◽  
The Other ◽  
Gaeumannomyces Graminis ◽  
Wheat Crop ◽  
Late Winter ◽  
Pasture Grass ◽  
South Wales ◽  
Take All

Winter cleaning is the removal of grasses from pasture using selective herbicides applied during winter. We compared the effectiveness of an early (June) and late (July) winter cleaning with an early spring herbicide fallow (September), spring (October) herbicide and no disturbance of the pasture on development of the root disease take-all in the subsequent wheat crop. Experiments were done at 5 sites in the eastern Riverina of New South Wales in 1990 and 1991. The winter clean treatments reduced soil inoculum of Gaeumannomyces graminis var. tritici (Ggt) compared with the other treatments at all sites as measured by a bioassay, with reductions from the undisturbed treatments of 52–79% over 5 sites. The winter clean treatments also significantly reduced the amount of take-all that developed in the subsequent wheat crop by between 52 and 83%. The early and late winter clean treatments increased the number of heads/m2 at 3 and 1 sites, respectively. Dry matter at anthesis was increased by the winter clean treatments at 3 sites. Grain yield was increased by the winter cleaning treatments over the other treatments at the 4 sites harvested, with yield increases of the early winter clean over the undisturbed treatment from 13 to 56%. The autumn bioassay of Ggt was positively correlated with spring take-all and negatively correlated with grain yield of the subsequent wheat crop at each site. However, there was a significant site and site × bioassay interaction so that the autumn bioassay could not be used to predict the amount of take-all that would develop.

Influence of moist - dry cycles on pH changes in surface soils

Soil Research ◽  
1999 ◽  
Vol 37 (6) ◽  
pp. 1057 ◽  
Author(s):  
K. I. Paul ◽  
M. K. Conyers ◽  
A. S. Black
Keyword(s):  
Soil Moisture ◽  
New South ◽  
N Mineralisation ◽  
Moist Soil ◽  
Water Acidification ◽  
Acidic Soils ◽  
Surface Soils ◽  
Soil Layers ◽  
South Wales ◽  
Dry Soil

It is well established that in the moderately acidic soils of southern Australia, the 0–2 cm layer commonly has a higher pH than soil layers between 2 and 10 cm depth. The surface 2 cm of soil is also exposed to much greater fluctuations of moisture content than deeper soil layers. There are contradictory or speculative reports in the literature on how soil moisture fluctuation affects pH and processes which influence pH. Therefore, the aim of this study was to determine the effect of moist–dry cycles on pH, and on processes involving H+ transformations, in 3 surface soils (0–2 cm) sampled from southern New South Wales. Following a pre-incubation, the 3 surface soils were incubated for 28 days at 30°C and were: (i) maintained continuously dry, (ii) subjected to short (2 days dry, 5 days moist) or long (7 days dry, 7 days moist) moist–dry cycles, or (iii) maintained continuously moist. During the incubation, the pH of continuously dry soil slightly increased by 0.03–0.10 units, while the pH of continuously moist soil decreased by 0.16–0.39 units. In soils subject to both short and long moist–dry cycles, the pH decreased by 0.06–0.34 units. However, relative to soils maintained moist, exposure to moist–dry cycles suppressed acidification by 0.05–0.26 pH units. In dry soils the pH increased, since some of the NH4+-N produced by net N mineralisation was not subsequently nitrified, and there was a net reduction of Mn. In soils which received water, acidification was predominately attributed to nitrification. Relative to soils maintained moist, acidification was suppressed by 1.6–6.5 mmol H+/kg due to the 11–35% decrease of nitrification on exposure to moist–dry cycles. In acidic surface soils (pH <5.5), acidification rates were further suppressed by 0.1–1.0 mmol H+/kg due to the 1.06–2.06 times greater net Mn reduction in moist–dry soils than in continuously moist soils.

Observations supporting parental care by a viviparous reptile: aggressive behaviour against predators demonstrated by Cunningham’s skinks

2019 ◽  
Vol 67 (3) ◽  
pp. 180
Author(s):  
Gregory S. Watson ◽  
David W. Green ◽  
Jolanta A. Watson
Keyword(s):  
Parental Care ◽  
Thermal Imaging ◽  
Aggressive Behaviour ◽  
New South ◽  
Field Studies ◽  
Alpine Region ◽  
Squamate Reptiles ◽  
South Wales ◽  
Australian Magpie

Most reptiles exhibit no parental care and aggressive behaviour towards heterospecific predators has rarely been recorded in the natural environment. Several species of the subfamily Egerniinae are amongst the most highly social of all squamate reptiles, exhibiting stable social aggregations and high levels of long-term social and genetic monogamy. We have examined Cunningham’s skinks, Egernia cunninghami, over a three-year period during late January and early February (total 32 days) in the alpine region of New South Wales using video and thermal imaging. Four birthing sessions were witnessed during our field studies of social aggregations of skinks. Our observations monitored skink encounters, in the presence of offspring, with an eastern brown snake, Pseudonaja textilis (two separate encounters, one recorded by video/imaging) and 12 encounters with the Australian magpie, Gymnorhina tibicen. All events were associated with aggressive chasing and/or attack by adult skinks. The first snake encounter involved the active targeting of a recently born juvenile with the mother of the juvenile attacking the snake (running towards the snake, biting and remaining attached for several seconds). The second encounter (the following year) comprised two adult skinks attacking and biting a snake, Pseudonaja textilis. All magpie encounters resulted in chases by adult skinks.

Reproductive Seasonality in Female Platypuses, Ornithorhynchus anatinus, in the Upper Barnard River, New South Wales.

1998 ◽  
Vol 20 (2) ◽  
pp. 207
Author(s):  
J.M. Jakubowski ◽  
N.P. New ◽  
G.M. Stone ◽  
R.C. Jones
Keyword(s):  
Blood Plasma ◽  
Seasonal Change ◽  
Coefficient Of Variation ◽  
New South ◽  
Reproductive Seasonality ◽  
South Wales ◽  
Ornithorhynchus Anatinus ◽  
Highly Correlated ◽  
Change In Mean ◽  
Mean Concentration

Progesterone concentrations were determined in samples of blood, urine and faeces collected from female platypuses which were captured in the Upper Barnard River, NSW, from February to November, 1996. Mean concentrations in blood plasma were higher in July, August and September than in other months with the highest concentrations being in August. Progesterone concentrations in dried urine and faeces were highly correlated with values for blood plasma (r = 0.61, P&lt;0.05 and 0.7 1, P&lt;O.OI, respectively), and the coefficient of variation for progesterone determinations was lower for samples of urine and faeces than blood. There was a seasonal change in mean concentration of cortisol in blood (being elevated in May-August), but the concentrations of progesterone and cortisol in blood were not significantly correlated.

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