Effects of management on soil fertility under pasture. 1. Influence of experimental grazing and fertilizer systems on growth, composition and nutrient status of the pasture

1974 ◽  
Vol 14 (69) ◽  
pp. 470 ◽  
Author(s):  
JR Simpson ◽  
SM Bromfield ◽  
GT McKinney
Keyword(s):  
Nitrogen Availability ◽  
Subterranean Clover ◽  
Nutrient Status ◽  
Grazing Pressure ◽  
Grass Species ◽  
Botanical Composition ◽  
Annual Grass ◽  
Growth And Nutrition ◽  
Animal Excreta ◽  
Annual Grasses

Pasture plots containing phalaris, subterranean clover and annual grass species were fertilized annually at suboptimal (P1), adequate (P2) or a 'luxury' rate (P3) of superphosphate. A fourth treatment combined rate P3 with fertilizer nitrogen (P3N). Each pasture was grazed during five years at a high (H) or a low (L) grazing pressure in such a way that there was little feed left on the H plots and a large amount on the L plots at the end of summer. In this way eight pasture situations were created which differed in botanical composition, nutrient availability, herbage production and the amount of nutrients returned as animal excreta. The plots were used to investigate the effects of fertilizer input and grazing pressure on the growth and nutrition of the different pasture components. Protected microplots during the fourth and fifth years showed that the P1 plots remained responsive to phosphate. The yields of annual grasses on the microplots were increased by H treatment but the proportion of phalaris to annual grasses was reduced, particularly at P1. Clover yields and total pasture yields were affected by previous grazing pressure only in the drier fourth year. At high levels of superphosphate and grazing (P3H), the greater grass-clover ratio and higher grass nitrogen uptake indicated greater nitrogen availability in this treatment.

scholarly journals Invasive Grasses Increase Nitrogen Availability in California Grassland Soils

2010 ◽  
Vol 3 (1) ◽  
pp. 40-47 ◽  
Author(s):  
Sophie S. Parker ◽  
Joshua P. Schimel
Keyword(s):  
Nitrogen Availability ◽  
Perennial Grass ◽  
N Cycling ◽  
Rooting Depth ◽  
Grass Species ◽  
Annual Grass ◽  
Annual Grasses ◽  
California Grassland ◽  
Pool Sizes ◽  
Native Perennial Grass

AbstractAs Europeans colonized California, they introduced annual grasses from the Mediterranean Basin. These exotic annual grasses eventually invaded grasslands throughout the state, some of which were once dominated by native perennial grass species. Annual grasses differ from perennials in their phenology, longevity, rooting depth, litter chemistry, and interaction with the microbial community. As these traits may influence plant nitrogen (N) use, it is likely that the invasion by annual species resulted in changes in the availability and cycling of N in California grassland systems. We addressed the question of how invasive annual grasses influence rates of N cycling by measuring N pool sizes and rates of net and gross mineralization and nitrification, gross immobilization, and the denitrification potential of soils from experimentally planted annual and perennial-dominated grasslands. With an increase in annual grass cover, we saw increases in ammonium (NH4+) pool sizes and rates of N mineralization, nitrification, and denitrification in soils. These differences in N status suggest that N cycling in California grasslands was altered at sites where native perennial bunchgrasses were invaded by nonnative annual grasses. One consequence of annual grass invasion may be a legacy of NH4+-enriched soils that hinder the reestablishment of native perennial grass species.

The effects of grazing on the phosphorus requirement of an annual pasture

1971 ◽  
Vol 22 (1) ◽  
pp. 81 ◽  
Author(s):  
PG Ozanne ◽  
KMW Howes
Keyword(s):  
Subterranean Clover ◽  
Growing Season ◽  
Maximum Growth ◽  
Grazing Pressure ◽  
Light Interception ◽  
Botanical Composition ◽  
Stocking Rate ◽  
Phosphorus Requirement ◽  
Root Size

The applied phosphorus requirement of a pasture sown to subterranean clover was measured with and without grazing. Under moderate grazing pressure, in the year of establishment, the pasture required about 50 % more phosphorus than when ungrazed. In the following season, at a higher stocking rate, the grazed areas needed twice as much phosphorus as the ungrazed to make 90% of their maximum growth. In both years this difference in requirement between stocked and unstocked treatments was present throughout the growing season. Increased phosphorus requirement under grazing is associated with the need for greater uptake of phosphorus under conditions where redistribution of absorbed phosphorus within the plant is prevented by defoliation. It does not appear to be due to effects of defoliation on root size. Nor does it depend on differential light interception or on changes in botanical composition.

scholarly journals Changes in yellow bristle grass (Setaria pumila) abundance after drought implications for pasture management

2009 ◽  
Vol 62 ◽  
pp. 211-216 ◽  
Author(s):  
K.N. Tozer ◽  
T.K. James ◽  
C.A. Cameron
Keyword(s):  
Key Management ◽  
Perennial Grass ◽  
Perennial Grasses ◽  
Botanical Composition ◽  
Annual Grass ◽  
Bare Ground ◽  
Pasture Management ◽  
Soil Calcium ◽  
Annual Grasses ◽  
Previous Summer

Yellow bristle grass (YBG) which is a summeractive annual grass reduces pasture quality and becomes unpalatable to stock as panicles mature Farmers are concerned that an extreme drought from November 2007 to March 2008 may have facilitated the spread of YBG and other summeractive annual grass weeds Botanical composition was assessed on 12 Waikato dairy farms in February 2009 and YBG abundance was related to key management factors These findings were compared with data collected from the same farms (February 2008) during the drought Between years ryegrass cover and the proportion of bare ground decreased These components were replaced by two summeractive annual grasses YBG and summer grass and to a lesser extent summeractive perennial grasses clovers and dicots In 2009 YBG cover was negatively associated with summeractive perennial grass cover and pH and positively associated with YBG cover in the previous summer and soil calcium levels

Tactical versus continuous stocking in perennial ryegrass-subterranean clover pastures grazed by sheep in south-western Victoria. 2. Ryegrass persistence and botanical composition

2001 ◽  
Vol 41 (8) ◽  
pp. 1109 ◽  
Author(s):  
R. A. Waller ◽  
P. W. G. Sale ◽  
G. R. Saul ◽  
G. A. Kearney
Keyword(s):  
Perennial Ryegrass ◽  
Dry Matter ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Summer Rainfall ◽  
Grazing Pressure ◽  
Botanical Composition ◽  
Average Mass ◽  
Gravelly Soil ◽  
Western Victoria

A 4-year field experiment was carried out in south-western Victoria to determine whether tactical stocking might improve perennial ryegrass (Lolium perenne L.) persistence and prime lamb production, compared with the more common practice of continuous stocking. Tactical stocking consisted of variable-length summer, autumn and winter rotations and continuous stocking in spring. The 2 grazing strategies were compared on 2 contrasting pastures: an upgraded pasture, sown with newer cultivars of perennial ryegrass and subterranean clover (Trifolium subterraneum L.) with 26 kg phosphorus/ha.year, and a more typical naturalised perennial ryegrass pasture receiving 6 kg phosphorus/ha.year. Paddocks were grazed by Border Leicester x Merino ewes, which were mated to a terminal sire to lamb in September. The effects of the grazing systems and pasture treatments on ryegrass persistence and pasture botanical composition are presented in this paper. The perennial ryegrass component of the sward decreased from an average mass of 1000 kg dry matter/ha on the upgraded pasture and 400 kg dry matter/ha on the typical pasture in spring 1996 to 100 kg dry matter/ha and <50 kg/ha for the 2 pasture types, respectively, in spring 1998. This occurred irrespective of the grazing system imposed. The decline of ryegrass was attributed to several factors including the very dry 3-year period, summer rainfall events that caused ryegrass buds to break dormancy then die when dry conditions resumed, the gravelly soil type where the experiment was located, and the high grazing pressure used. A number of species became more prevalent in the pastures as the ryegrass disappeared. Silver grass (Vulpia spp.) increased 4–5-fold on all treatments. By the fourth year, barley grass (Hordeum leporinum) and Bromus spp. had increased significantly with tactical stocking compared with continuous stocking. Capeweed (Arctotheca calendula L.) and Erodium spp. increased on both the continuously stocked and upgraded pastures. The subterranean clover component was maintained across all treatments over the 4 years, indicating that tactical stocking did not adversely affect clover persistence. Since ryegrass declined irrespective of treatment, the tactical stocking system used in this study cannot be recommended for improving ryegrass persistence.

A comparison of the effects of autumn deferment and continous grazing on the growth of an annual pasture

1973 ◽  
Vol 13 (65) ◽  
pp. 669 ◽  
Author(s):  
JG McIvor ◽  
DF Smith
Keyword(s):  
Shoot Apex ◽  
Plant Density ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Early Winter ◽  
Botanical Composition ◽  
Growing Seasons ◽  
Annual Grasses ◽  
One Year ◽  
Apex Height

The effects of deferred autumn grazing on a pasture comprising nearly equal proportions of subterranean clover (Trifolium subterraneum), capeweed (Arctotheca calendula) and annual grasses were measured over two growing seasons. Autumn deferment increased the survival of capeweed seedlings in both years and of clover in one year but had little effect on the annual grasses. Although there was more herbage present on the deferred plots in early winter, under later set stocking at normal levels by spring the amount of herbage present, plant density, botanical composition and seed numbers were similar on all plots. The accumulation of herbage under deferred grazing caused an elevation of shoot apex height in capeweed, but not in clover. When combined with subsequent intensive grazing, the number of capeweed plants surviving to flowering was sharply reduced. However, this management also resulted in a reduction in herbage production in spring.

Influence of preseason weed management and in-crop treatments in two successive wheat crops 1. Weed seedling numbers and wheat grain yield

1993 ◽  
Vol 33 (2) ◽  
pp. 167 ◽  
Author(s):  
PM Dowling ◽  
PTW Wong
Keyword(s):  
Grain Yield ◽  
Weed Management ◽  
Seed Set ◽  
Seedling Emergence ◽  
Grass Species ◽  
Wheat Crop ◽  
Annual Grass ◽  
Wheat Grain ◽  
Heavy Grazing ◽  
Annual Grasses

The effect of 5 preseason management treatments on seed set reduction of annual weed grasses and their regeneration in the following autumn was evaluated in a 2-year field experiment commencing at Orange in spring 1986. Preseason (spring) treatments were paraquat, glyphosate (2 rates), unsprayed heavy grazing, and unsprayed control. In the first of 2 successive wheat crops (planted 1987), 3 in-crop weed control treatments [control, chlorsulfuron (both sod-seeded), and trifluralin plus cultivation] were imposed. In 1988, the second wheat crop was sown into a cultivated seedbed or direct-drilled. The preseason treatments reduced potential annual grass regeneration by 91-99% compared with the control, with heavy grazing being the best treatment. For each preseason treatment compared with the control, the pattern of actual seedling emergence within the crop during 1987 was similar to that of potential emergence for each grass species (except Lolium rigidum), but numbers were lower and more variable (7-86% of potential numbers). The proportion of Bromus spp. and Vulpia spp. emerging within the crop declined from the first to the second crop, while L. rigidum increased to an average of 93% of the annual grass population in 1988. Trifluralin plus cultivation increased the control of annual grasses in 1987. In 1988, the 1987 in-crop treatments had little carryover effect on annual grass control; however, wheat grain yield was increased by both chlorsulfuron and trifluralin. Preseason management reduced seed set of annual grass weeds, and this control was maintained under cropping for at least 2 years (except for L. rigidum). Wheat grain yield responded to this control. Long-term control of L. rigidum where soil is disturbed appears difficult because of apparent long-lived seed in the soil.

INFLUENCE OF VARIOUS HERBICIDES AND TWEEN 20 ON THE EFFECTIVENESS OF GLYPHOSATE

1980 ◽  
Vol 60 (3) ◽  
pp. 939-945 ◽  
Author(s):  
P. A. O’SULLIVAN ◽  
J. T. O’DONOVAN
Keyword(s):  
Brassica Campestris ◽  
Triticum Aestivum L ◽  
Grass Species ◽  
Tween 20 ◽  
Annual Grass ◽  
Hordeum Vulgare L ◽  
Initial Reduction ◽  
Annual Grasses ◽  
Excellent Control ◽  
High Degree

Glyphosate (N-phosphonomethyl glycine) at 0.21 kg/ha applied at the 4-leaf stage provided excellent control of wheat (Triticum aestivum L.), barley (Hordeum vulgare L.), oats (Avena sativa L.), and rape (Brassica campestris L.). Tank mixtures of 0.21 kg/ha glyphosate with bromoxynil/MCPA, bromoxynil, MCPA, 2,4-D, or dicamba resulted in an initial reduction (antagonism) of glyphosate activity on the grass species at 5 days after treatment. At 34 days after treatment, the early differences had disappeared and grass kill was virtually complete with all treatments containing glyphosate. The early reduction in annual grass control with these mixtures was overcome in most cases by addition of Tween 20. Dicamba at 0.11 kg/ha, applied sequentially at various times in relation to glyphosate at 0.21 kg/ha, provided significantly increased early control of annual grasses over that obtained with glyphosate alone. Glyphosate combinations with bromoxynil/MCPA, bromoxynil, MCPA, 2,4-D, or dicamba were as effective or more effective for rape control than the various broad-leaved herbicides applied alone. Rape showed a high degree of tolerance to dicamba.

Species distribution within improved pastures over central N.S.W. in relation to rainfall and altitude

1991 ◽  
Vol 42 (4) ◽  
pp. 647 ◽  
Author(s):  
DR Kemp ◽  
PM Dowling
Keyword(s):  
Linear Relationship ◽  
Subterranean Clover ◽  
Mean Annual Temperature ◽  
Botanical Composition ◽  
Perennial Species ◽  
Survey Area ◽  
Annual Species ◽  
Wide Range ◽  
Annual Grasses ◽  
Point Quadrat

Botanical composition has a large influence on pasture productivity, but little information is available about the botanical composition of pastures on farms, the interactions of species or reasons for their distribution. A survey was done, during two successive springs and using a point quadrat method, of the botanical composition of improved pastures in central New South Wales and maps prepared of the proportion of species or groups of species in pastures. The survey area covered a wide range in rainfall (600-1000 mm), altitude (300-1400 m) and the boundary where perennial and annual pasture species overlap. Subterranean clover was the most common legume and occurred in all parts of the region. Above 700 mm rainfall, white clover replaced subterranean clover in a linear relationship, though the proportion of the pasture occupied by both species never exceeded 30%. Annual grasses were found throughout the survey area, and they were also replaced by perennial species at higher rainfall, higher altitude sites, in a linear relationship. The total proportion of the pasture from both perennial and annual grasses did not exceed a mean of 55%. The high proportion of annual species was attributed in part to continuous grazing practices. Perennial species were found down to 600 mm rainfall but only exceeded the proportion of annual species when the rainfall exceeded 800 mm for legumes or 900 mm for grasses or where the altitude was above 900 m (<12�C mean annual temperature) for both groups. It was concluded that among perennial or annual groups, legumes and grasses occupied slightly different niches in the pasture, and they would not always replace one another exclusively. The legume content of pastures, especially in the higher rainfall areas, was considered to be less than satisfactory for animal production. Pasture recommendations need to consider the climatic limits where species are able to make a major contribution to production as well as the climatic limits for persistence.

Changes in the Quantitative Floristics in Some Astrebla Spp. (Mitchell Grass) Communities in South-Western Queensland in Relation to Trends in Seasonal Rainfall

1981 ◽  
Vol 29 (5) ◽  
pp. 533 ◽  
Author(s):  
DM Orr
Keyword(s):  
Relative Abundance ◽  
Perennial Grass ◽  
Grazing Pressure ◽  
Perennial Grasses ◽  
Seasonal Rainfall ◽  
Individual Species ◽  
Botanical Composition ◽  
Basal Cover ◽  
Wide Range ◽  
Annual Grasses

Seasonal changes in the quantitative floristics at a wide range of Astrebla grassland sites in south-western Queensland were monitored between 1972 and 1980 with a wheel point apparatus. Changes in the floristics were measured in terms of both relative abundance and basal cover. A large increase in the relative abundance of perennial grasses, particularly Aristida latifolia, Astrebla spp. and Dichanthium sericeum, occurred between 1972 and 1976. This increase was at the expense of annual grasses and forbs which declined in both relative abundance and number of genera present. The relative abundance of perennial grasses declined between 1978 and 1980 and this was associated with a large increase in the forbs such as Daucus glochidiatus and Plantago spp., particularly at southern sites. The contribution of annual grasses to botanical composition remained low throughout the period. Total basal cover differed between years although these differences were not significant. As perennial grass, particularly Astrebla spp., was the major vegetation component of total basal cover, changes in the latter were associated mainly with changes in the basal cover of Astrebla spp. Changes in the contribution of individual species to total basal cover were related to changes in the relative abundance of those species. Changes in botanical composition in Astrebla grassland may be influenced more by trends in seasonal rainfall than by grazing pressure.

Preemergence Herbicides Followed by Trifloxysulfuron Postemergence in Cotton

2007 ◽  
Vol 21 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Robert J. Richardson ◽  
Henry P. Wilson ◽  
Thomas E. Hines
Keyword(s):  
Weed Control ◽  
Field Studies ◽  
Grass Species ◽  
Annual Grass ◽  
Common Ragweed ◽  
Common Lambsquarters ◽  
Pitted Morningglory ◽  
Annual Grasses ◽  
Preemergence Herbicides ◽  
Smooth Pigweed

Field studies were conducted in 1999, 2000, and 2001 to evaluate weed control and cotton response from PRE herbicides followed by (fb) trifloxysulfuron POST. In the first study, trifloxysulfuron at 3.8, 7.5, or 15 gai/ha was applied POST with or without pendimethalin at 690 gai/ha applied PRE in a factorial treatment arrangement. Visible crop injury occurred after all trifloxysulfuron applications, but injury was not affected by application of pendimethalin PRE. Cotton injury was 19 to 22% 7 d after POST treatment (DAT) from trifloxysulfuron at 3.8 to 15 g/ha but was 5 to 12% 28 DAT. Trifloxysulfuron controlled smooth pigweed, common ragweed, and common cocklebur, but spurred anoda, large crabgrass, goosegrass, and stinkgrass were not controlled by trifloxysulfuron. Morningglory species (tall morningglory, ivyleaf morningglory, and pitted morningglory) control with trifloxysulfuron at 7.5 and 15 g/ha was at least 79%, whereas velvetleaf was controlled 66% over all years. In a second study, clomazone, pendimethalin, pendimethalin plus fluometuron, pyrithiobac, or flumioxazin were applied PRE fb 7.5 g/ha trifloxysulfuron POST. Cotton injury from PRE herbicides fb trifloxysulfuron was 13 to 39% 7 DAT. Spurred anoda control exceeded 54% only with treatments that included flumioxazin or pyrithiobac PRE. Common lambsquarters, common cocklebur, and morningglory species were controlled at least 75% with all treatments that included trifloxysulfuron POST, whereas pendimethalin and clomazone usually controlled annual grasses. In both studies, the application of pendimethalin PRE controlled annual grass species and improved control of smooth pigweed and common lambsquarters over that controlled by trifloxysulfuron POST without a PRE herbicide.

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