Resting pastures to improve land condition in northern Australia: guidelines based on the literature and simulation modelling

2014 ◽  
Vol 36 (5) ◽  
pp. 429 ◽  
Author(s):  
Joe C. Scanlan ◽  
John G. McIvor ◽  
Steven G. Bray ◽  
Robyn A. Cowley ◽  
Leigh P. Hunt ◽  
...  
Keyword(s):  
Field Experiments ◽  
Growing Season ◽  
Simulation Modelling ◽  
Experimental Information ◽  
Perennial Grasses ◽  
Northern Australia ◽  
Land Condition ◽  
Growing Conditions ◽  
Grazing Lands ◽  
Stocking Rates

Pasture rest is a possible strategy for improving land condition in the extensive grazing lands of northern Australia. If pastures currently in poor condition could be improved, then overall animal productivity and the sustainability of grazing could be increased. The scientific literature is examined to assess the strength of the experimental information to support and guide the use of pasture rest, and simulation modelling is undertaken to extend this information to a broader range of resting practices, growing conditions and initial pasture condition. From this, guidelines are developed that can be applied in the management of northern Australia’s grazing lands and also serve as hypotheses for further field experiments. The literature on pasture rest is diverse but there is a paucity of data from much of northern Australia as most experiments have been conducted in southern and central parts of Queensland. Despite this, the limited experimental information and the results from modelling were used to formulate the following guidelines. Rest during the growing season gives the most rapid improvement in the proportion of perennial grasses in pastures; rest during the dormant winter period is ineffective in increasing perennial grasses in a pasture but may have other benefits. Appropriate stocking rates are essential to gain the greatest benefit from rest: if stocking rates are too high, then pasture rest will not lead to improvement; if stocking rates are low, pastures will tend to improve without rest. The lower the initial percentage of perennial grasses, the more frequent the rests should be to give a major improvement within a reasonable management timeframe. Conditions during the growing season also have an impact on responses with the greatest improvement likely to be in years of good growing conditions. The duration and frequency of rest periods can be combined into a single value expressed as the proportion of time during which resting occurs; when this is done the modelling suggests the greater the proportion of time that a pasture is rested, the greater is the improvement but this needs to be tested experimentally. These guidelines should assist land managers to use pasture resting but the challenge remains to integrate pasture rest with other pasture and animal management practices at the whole-property scale.

Is land condition a useful indicator of soil organic carbon stock in Australia’s northern grazing land?

2016 ◽  
Vol 38 (3) ◽  
pp. 229 ◽  
Author(s):  
S. G. Bray ◽  
D. E. Allen ◽  
B. P. Harms ◽  
D. J. Reid ◽  
G. W. Fraser ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Soil Type ◽  
Northern Australia ◽  
Grazing Land ◽  
Condition Indicators ◽  
Land Condition ◽  
Soc Stock ◽  
Grazing Lands ◽  
Soc Stocks

The grazing lands of northern Australia contain a substantial soil organic carbon (SOC) stock due to the large land area. Manipulating SOC stocks through grazing management has been presented as an option to offset national greenhouse gas emissions from agriculture and other industries. However, research into the response of SOC stocks to a range of management activities has variously shown positive, negative or negligible change. This uncertainty in predicting change in SOC stocks represents high project risk for government and industry in relation to SOC sequestration programs. In this paper, we seek to address the uncertainty in SOC stock prediction by assessing relationships between SOC stocks and grazing land condition indicators. We reviewed the literature to identify land condition indicators for analysis and tested relationships between identified land condition indicators and SOC stock using data from a paired-site sampling experiment (10 sites). We subsequently collated SOC stock datasets at two scales (quadrat and paddock) from across northern Australia (329 sites) to compare with the findings of the paired-site sampling experiment with the aim of identifying the land condition indicators that had the strongest relationship with SOC stock. The land condition indicators most closely correlated with SOC stocks across datasets and analysis scales were tree basal area, tree canopy cover, ground cover, pasture biomass and the density of perennial grass tussocks. In combination with soil type, these indicators accounted for up to 42% of the variation in the residuals after climate effects were removed. However, we found that responses often interacted with soil type, adding complexity and increasing the uncertainty associated with predicting SOC stock change at any particular location. We recommend that caution be exercised when considering SOC offset projects in northern Australian grazing lands due to the risk of incorrectly predicting changes in SOC stocks with change in land condition indicators and management activities for a particular paddock or property. Despite the uncertainty for generating SOC sequestration income, undertaking management activities to improve land condition is likely to have desirable complementary benefits such as improving productivity and profitability as well as reducing adverse environmental impact.

SGS Pasture Theme: effect of climate, soil factors and management onpasture production and stability across the high rainfall zone of southern Australia

2003 ◽  
Vol 43 (8) ◽  
pp. 945 ◽  
Author(s):  
P. Sanford ◽  
B. R. Cullen ◽  
P. M. Dowling ◽  
D. F. Chapman ◽  
D. L. Garden ◽  
...  
Keyword(s):  
Soil Ph ◽  
Perennial Grass ◽  
Growing Season ◽  
Perennial Grasses ◽  
Annual Rainfall ◽  
Stocking Rate ◽  
Rotational Grazing ◽  
Soil P ◽  
High Rainfall ◽  
Stocking Rates

The Sustainable Grazing Systems (SGS) National Experiment (NE) Pasture Theme explored factors that influenced annual herbage accumulation and perennial grass and legume content across the NE sites, in the high rainfall zone (HRZ, >600 mm/year annual rainfall) of southern Australia using multi-variate analysis and the SGS Pasture Model. Annual rainfall was a poor predictor of annual herbage accumulation. The length of growing season accounted for 30% of the variation in annual herbage accumulation. Much of the remaining 70% of variation in annual herbage accumulation was explained by soil Olsen P, the proportion of native species in the pasture and stocking rate, together with interactions among other factors including legume content. Simulated effects of set stocking and rotational grazing on herbage accumulation using the SGS Pasture Model, predicted that rotational grazing was unlikely to result in large increases in herbage accumulation. In contrast, it was predicted that the adoption of deep-rooted C3 and C4 perennial grasses could provide useful increases in herbage accumulation. Perennial grass content and basal cover were both significantly influenced by growing season length (P<0.001), grazing method (P<0.001) and an interaction between stocking rate and soil pH (P = 0.002). These analyses suggested that to maintain or improve the perennial grass component of a pasture at medium–high stocking rates, it was crucial to adopt grazing strategies that included rotation or resting. Perennial grass percent also significantly (P<0.001) increased in response to ameliorating the soil pH. Legume content of pastures significantly (P<0.001) increased in response to set stocking and increased stocking rate.To be botanically stable and productive, sown pastures based on perennial grasses in the HRZ of southern Australia will need to be grazed at high stocking rates (15–23 DSE/ha) in combination with rotational grazing or resting, and with adequate soil P. Additional gains in production and stability could be obtained by ensuring an adequate legume component, including a C4 perennial grass and ameliorating soil acidity. Pastures based on native perennial grasses may require lower soil P and more conservative stocking rates, depending on species.

Emergence, seedling development and survival of native and exotic grasses on a sandy red earth in South-Western Queensland.

1976 ◽  
Vol 1 (1) ◽  
pp. 31 ◽  
Author(s):  
RG Silcock ◽  
LM Williams
Keyword(s):  
Exotic Species ◽  
Native Species ◽  
Dry Matter ◽  
Growing Season ◽  
Perennial Grasses ◽  
Exotic Grasses ◽  
Stage Of Development ◽  
Average Survival ◽  
Red Earth ◽  
Growing Conditions

The growth and development of eight perennial grasses, from sowing until flowering, was studied in the field on a sandy red earth near Charleville, south-western Queensland. They included four species native to this soil, Thyridolepis mitchelliuna, Aristida armata, Digitaria ammophila and Monachather paradoxa, and four exotic species Cenchrus ciliuris cv. Biloela, Anthephora pubescens, Eragrostis curvula and Schmidtia bulbosa. Cenchrus ciliaris, A. pubescens and S. bulbosa emerged much more promptly than the other species and much less viable seed was left in the soil after the fist germination event. The native species tillered and flowered earlier than the exotic grasses and survived better under adverse growing conditions. Average survival at the end of the first growing season, during which good seasonal conditions pre- vailed, was 30% of the emergent seedlings. Schmidtia bulbosa performed best within the exotic group and this was associated with early tillering and earlier flowering. The exotic species needed at least a four month growing season before they flowered under field conditions compared with two months or less for the native grasses. However this disadvantage was offset somewhat by their greater dry matter yield at this stage of development.

scholarly journals Features of the vegetation of winter wheat agrophytocenoses after the predecessors of leguminous perennial grasses

2021 ◽  
Vol 1 (98) ◽  
pp. 150-162
Author(s):  
О. P. Tkachuk ◽  
Keyword(s):  
Winter Wheat ◽  
Grain Yield ◽  
Plant Height ◽  
Plant Density ◽  
Growing Season ◽  
Close Correlation ◽  
Perennial Grasses ◽  
Mineral Fertilizers ◽  
Growing Conditions ◽  
Perennial Legumes

The article is devoted to solving the problem of increasing the yield of winter wheat crops when it is grown after the predecessors of six types of perennial legumes. The features of the passage of the growth and development phases of winter wheat plants in the spring are shown, depending on the predecessors. The dynamics of plant height in the spring-summer period is analyzed. The change in the density of winter wheat plants during the spring renewal of the growing season and at the end of the growing season was studied. The spring thinning of winter wheat plants, the coefficient of total and productive tillering are calculated. The total number of stems of winter wheat plants and productive stems is shown. The level of grain yield of winter wheat, depending on its predecessors, was investigated, and correlation-regression relationships between it and the factors of spring-summer vegetation of crops were revealed. A close correlation has been proved between the grain yield and the number of all stems, as well as productive stems of winter wheat plants on an area of one square meter, as well as between the grain yield and the height of winter wheat plants at the beginning of spring regrowth. It is shown that the most favorable growing conditions and the level of grain yield of winter wheat when growing it after various types of perennial legumes is observed after the predecessor of meadow clover, where the highest plant density at the end of the growing season was observed – 145 million pcs/ha, the number of total – 878 pcs./m2 and productive stems – 799 pcs./m2, as well as the highest plant height at the beginning of spring regrowth – 6 cm. This allows you to get a winter wheat grain yield of 5.8 t/ha without the use of mineral fertilizers. After white melilot, the yield of winter wheat was 10.2 % less and amounted to 5.21 t/ha; after sandy sainfoin – 14.% less – 4.99 t/ha; after the eastern goat's rue – by 21.6 % less – 4.55 t/ha; after sowing alfalfa – by 24.5 % less – 4.38 t/ha and after horned grass – the lowest yield – 4.03 t/ha, which is 30.6 % less than after meadow clover

scholarly journals How Long Before a Second Defoliation of Actively Growing Grass Plants in the Desert Grassland?

2020 ◽  
Vol 7 ◽  
Author(s):  
Sarah Noelle ◽  
Timothy Lyons ◽  
Alessandra Gorlier ◽  
Mitchel P. McClaran ◽  
Mary Nichols ◽  
...  
Keyword(s):  
Plant Height ◽  
Perennial Grass ◽  
Growing Season ◽  
Perennial Grasses ◽  
Desert Grassland ◽  
Winter Grazing ◽  
Grazing Period ◽  
Animal Diet ◽  
Stocking Rates ◽  
Reduced Time

In the Desert Grassland, second and subsequent defoliations on perennial grasses during the active growing season can have substantial impacts on grass recovery and reproduction following herbivory. Land managers implement tactics to avoid multiple defoliations on plants by way of rotational grazing, reduced stocking rates, and/or reduced time spent within a given pasture. We explored frequency and rate of defoliation by cattle on perennial bunchgrasses within an 11-day grazing period in three pastures including distance to water (300 and 600 m) and plant height to determine their influence on animal diet selection. Results indicate that 32% of all marked plants were defoliated by cattle and only 5% of defoliated plants were defoliated a second time by day 10 of the grazing period. Defoliation patterns in the studied pastures did not differ between two distances from water, or in relation to plant height. However, at the second defoliation cattle grazed plants that were shorter than at the first defoliation suggesting a selection for high quality re-growth over larger forage on offer. The results of this study show that a 10-day grazing period during the growing season of the Desert Grassland is an effective strategy to avoid second defoliations on individual perennial grass plants while maintaining sufficient forage for use during the dormant winter grazing season.

Safe pasture utilisation rates as a grazing management tool in extensively grazed tropical savannas of northern Australia

2008 ◽  
Vol 30 (3) ◽  
pp. 305 ◽  
Author(s):  
L. P. Hunt
Keyword(s):  
Perennial Grass ◽  
Grazing Intensity ◽  
Growing Season ◽  
Perennial Grasses ◽  
Management Tool ◽  
Management Approach ◽  
Tropical Savannas ◽  
Forage Production ◽  
Stocking Rates

The concept of safe pasture utilisation rates is frequently promoted as a tool for use in setting livestock numbers in perennial grass pastures in northern Australia’s tropical savannas to achieve a grazing intensity that is ecologically and economically sustainable. However, recommended pasture utilisation rates have been defined and applied in several ways, and this has led to some confusion among managers, researchers and advisers about their appropriate use. In order to reduce this confusion, this paper reviews the ecological basis and use of safe pasture utilisation rates as a management tool, concentrating on two common ways (i.e. strategic and tactical) in which they are applied. The main objective of both approaches is to limit the intensity of grazing of perennial grasses during the growing season when they are most sensitive to defoliation. When used in a strategic way, safe pasture utilisation rates provide an indication of long-term safe stocking rates that will avoid pasture deterioration in most years. Alternatively, they are used in a tactical sense to adjust stocking rates to track forage production, usually on an annual basis. Using the tactical approach, stocking rates are set at the end of the growing season in order to use a ‘safe’ proportion of the standing forage available at that time during the subsequent 12 months. Thus, stocking rates for one growing season are based on the quantity of forage available at the end of the previous growing season. In areas with high year-to-year variability in pasture growth this may lead to overgrazing during the growing season. This paper concludes by suggesting several strategies to better manage pasture utilisation levels under a tactical management approach to ensure that palatable perennial grass populations persist in the long term. A call is also made for researchers and land management advisers to be clear in the way recommended safe pasture utilisation rates are defined and intended to be used.

scholarly journals Estimating the Leaf Nitrogen Content with a New Feature Extracted from the Ultra-High Spectral and Spatial Resolution Images in Wheat

2021 ◽  
Vol 13 (4) ◽  
pp. 739
Author(s):  
Jiale Jiang ◽  
Jie Zhu ◽  
Xue Wang ◽  
Tao Cheng ◽  
Yongchao Tian ◽  
...  
Keyword(s):  
Nitrogen Content ◽  
Precision Agriculture ◽  
Field Experiments ◽  
Mean Squared Error ◽  
Growing Season ◽  
Leaf Nitrogen ◽  
Textural Analysis ◽  
Hyperspectral Images ◽  
Leaf Nitrogen Content ◽  
New Feature

Real-time and accurate monitoring of nitrogen content in crops is crucial for precision agriculture. Proximal sensing is the most common technique for monitoring crop traits, but it is often influenced by soil background and shadow effects. However, few studies have investigated the classification of different components of crop canopy, and the performance of spectral and textural indices from different components on estimating leaf nitrogen content (LNC) of wheat remains unexplored. This study aims to investigate a new feature extracted from near-ground hyperspectral imaging data to estimate precisely the LNC of wheat. In field experiments conducted over two years, we collected hyperspectral images at different rates of nitrogen and planting densities for several varieties of wheat throughout the growing season. We used traditional methods of classification (one unsupervised and one supervised method), spectral analysis (SA), textural analysis (TA), and integrated spectral and textural analysis (S-TA) to classify the images obtained as those of soil, panicles, sunlit leaves (SL), and shadowed leaves (SHL). The results show that the S-TA can provide a reasonable compromise between accuracy and efficiency (overall accuracy = 97.8%, Kappa coefficient = 0.971, and run time = 14 min), so the comparative results from S-TA were used to generate four target objects: the whole image (WI), all leaves (AL), SL, and SHL. Then, those objects were used to determine the relationships between the LNC and three types of indices: spectral indices (SIs), textural indices (TIs), and spectral and textural indices (STIs). All AL-derived indices achieved more stable relationships with the LNC than the WI-, SL-, and SHL-derived indices, and the AL-derived STI was the best index for estimating the LNC in terms of both calibration (Rc2 = 0.78, relative root mean-squared error (RRMSEc) = 13.5%) and validation (Rv2 = 0.83, RRMSEv = 10.9%). It suggests that extracting the spectral and textural features of all leaves from near-ground hyperspectral images can precisely estimate the LNC of wheat throughout the growing season. The workflow is promising for the LNC estimation of other crops and could be helpful for precision agriculture.

scholarly journals Rattail fescue (Vulpia myuros) interference and seed production as affected by sowing time and crop density in winter wheat

Weed Science ◽  
2020 ◽  
pp. 1-10
Author(s):  
Muhammad Javaid Akhter ◽  
Per Kudsk ◽  
Solvejg Kopp Mathiassen ◽  
Bo Melander
Keyword(s):  
Winter Wheat ◽  
Grain Yield ◽  
Seed Production ◽  
Yield Components ◽  
Field Experiments ◽  
Growing Season ◽  
Sowing Time ◽  
Growing Seasons ◽  
Crop Density ◽  
Wide Range

Abstract Field experiments were conducted in the growing seasons of 2017 to 2018 and 2018 to 2019 to evaluate the competitive effects of rattail fescue [Vulpia myuros (L.) C.C. Gmel.] in winter wheat (Triticum aestivum L.) and to assess whether delayed crop sowing and increased crop density influence the emergence, competitiveness, and fecundity of V. myuros. Cumulative emergence showed the potential of V. myuros to emerge rapidly and under a wide range of climatic conditions with no effect of crop density and variable effects of sowing time between the two experiments. Grain yield and yield components were negatively affected by increasing V. myuros density. The relationship between grain yield and V. myuros density was not influenced by sowing time or by crop density, but crop–weed competition was strongly influenced by growing conditions. Due to very different weather conditions, grain yield reductions were lower in the growing season of 2017 to 2018 than in 2018 to 2019, with maximum grain yield losses of 22% and 50% in the two growing seasons, respectively. The yield components, number of crop ears per square meter, and 1,000-kernel weight were affected almost equally, reflecting that V. myuros’s competition with winter wheat occurred both early and late in the growing season. Seed production of V. myuros was suppressed by delaying sowing and increasing crop density. The impacts of delayed sowing and increasing crop density on seed production of V. myuros highlight the potential of these cultural weed control tactics in the long-term management programs of this species.

Red Rice (Oryza sativa) Control in Drill-Seeded Rice (O. sativa)

Weed Science ◽  
1985 ◽  
Vol 33 (5) ◽  
pp. 703-707 ◽  
Author(s):  
Amadou Diarra ◽  
Roy J. Smith ◽  
Ronald E. Talbert
Keyword(s):  
Oryza Sativa ◽  
Grain Yield ◽  
Field Experiments ◽  
Growing Season ◽  
Rice Cultivar ◽  
Rice Grain ◽  
Rice Seed ◽  
Red Rice ◽  
Culm Density ◽  
High Yields

Field experiments were conducted to investigate methods of controlling red rice (Oryza sativaL. ♯ ORYSA) in drill-seeded rice (O. sativa). Treatments included the rice cultivar ‘Mars', coated with calcium peroxide (CaO2) at 40% (w/w) and a crop protectant, R-33865 (O,O-diethyl-O-phenyl phosphorothioate) at 0.5 and 1% (v/w). Molinate (S-ethyl hexahydro-1H-azepine-1-carbothioate) at 6.7 kg ai/ha was applied preplant incorporated (ppi). The land was flooded (2.5 to 5 cm deep) after seeding with rice (100 kg/ha, 2.5 cm deep), and the water was maintained throughout the growing season. CaO2, with or without molinate, increased rice grain yield 50% and increased rice culm density fivefold above untreated rice. Molinate applied ppi controlled 96% of the red rice. Rice seed coated with only CaO2or with CaO2plus R-33865 at 0.5%, each combined with ppi molinate, produced 5690 and 6030 kg/ha of grain, respectively. These high yields were associated with red rice control by molinate and good stands of rice provided by O2supplied by CaO2. R-33865 applied to rice seed at 1% (v/w) injured rice by reducing rice culm densities 41%, compared with rice without protectant.

Critical time for weed removal in glyphosate-resistant soybean as influenced by preemergence herbicides

2019 ◽  
Vol 33 (03) ◽  
pp. 393-399 ◽  
Author(s):  
Stevan Z. Knezevic ◽  
Pavle Pavlovic ◽  
O. Adewale Osipitan ◽  
Ethann R. Barnes ◽  
Clint Beiermann ◽  
...  
Keyword(s):  
Field Experiments ◽  
Critical Time ◽  
Growing Season ◽  
Control Programs ◽  
Main Plot ◽  
Repeated Use ◽  
Sites Of Action ◽  
Alternative Sites ◽  
Preemergence Herbicides ◽  
Weed Removal

AbstractWidespread and repeated use of glyphosate resulted in an increase in glyphosate-resistant (GR) weeds. This led to an urgent need for diversification of weed control programs and use of PRE herbicides with alternative sites of action. Field experiments were conducted over a 4-yr period (2015 to 2018) across three locations in Nebraska to evaluate the effects of PRE-applied herbicides on critical time for weed removal (CTWR) in GR soybean. The studies were laid out in a split-plot arrangement with herbicide regime as the main plot and weed removal timing as the subplot. The herbicide regimes used were either no PRE or premix of either sulfentrazone plus imazethapyr (350 + 70 g ai ha−1) or saflufenacil plus imazethapyr plus pyroxasulfone (26 + 70 + 120 g ai ha−1). The weed removal timings were at V1, V3, V6, R2, and R5 soybean stages, with weed-free and weedy season-long checks. Weeds were removed by application of glyphosate (1,400 g ae ha−1) or by hoeing. The results across all years and locations suggested that the use of PRE herbicides delayed CTWR in soybean. In particular, the CTWR without PRE herbicides was determined to be around the V1 to V2 (14 to 21 d after emergence [DAE]) growth stage, depending on the location and weed pressure. The use of PRE-applied herbicides delayed CTWR from about the V4 (28 DAE) stage up to the R5 (66 DAE) stage. These results suggest that the use of PRE herbicides in GR soybean could delay the need for POST application of glyphosate by 2 to 5 wk, thereby reducing the need for multiple applications of glyphosate during the growing season. Additionally, the use of PRE herbicides could provide additional modes of action needed to manage GR weeds in GR soybean.

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