Response to nitrogen of three annual grasses

1974 ◽  
Vol 14 (67) ◽  
pp. 167 ◽  
Author(s):  
PS Cocks
Keyword(s):  
Nitrogen Uptake ◽  
Dry Weight ◽  
Low Density ◽  
Lolium Rigidum ◽  
Nitrogen Response ◽  
Harvest Dates ◽  
Wide Range ◽  
Annual Grasses ◽  
Hordeum Leporinum ◽  
Better Than

The responses of three annual grasses (Lolium rigidum, Vulpia myuros, and Hordeum leporinum) to nitrogen fertilizer were studied at three densities. Total herbage and nitrogen uptake were measured at four harvest dates. The response of the three grasses to nitrogen depended on their density. At low density both Lolium and Hordeum had greater dry weight increase than Vulpia, but at high density Vulpia responded as well as Lolium and better than Hordeum. By comparing the nitrogen responses at similar amounts of available herbage it was seen that, over a wide range of availability, both Lolium and Vulpia had greater absolute response than Hordeum. It was concluded that nitrogen response would probably be greatest on swards of Lolium or Vulpia that have a particular amount of available herbage.

The comparative response of tropical and temperate grasses to varying levels of nitrogen and phosphorus nutrition

1971 ◽  
Vol 22 (4) ◽  
pp. 573 ◽  
Author(s):  
JR Wilson ◽  
KP Haydock
Keyword(s):  
Phosphorus Nutrition ◽  
Nitrogen And Phosphorus ◽  
Nitrogen Response ◽  
Tropical Grasses ◽  
Nitrogen Levels ◽  
Species Response ◽  
Wide Range ◽  
Comparative Response ◽  
Low Nitrogen ◽  
Better Than

Ten temperate and nine tropical grasses were compared in glasshouse trials in their response to a wide range of nitrogen and phosphorus nutrition. For all attributes there was a gradation in species response within the temperate and tropical groups; the means for the two groups were different although the spread of values showed some degree of overlap between the groups. In general, the temperate grasses had more tillers per plant and a lower top/root ratio than the tropical grasses. The tropical grasses grew better than the temperate grasses at low nutrient combinations but the reverse was true for the high nutrient combinations. The linear response to nitrogen of the tropical group of species was lower than that of the temperate group but was probably a consequence of the ability of the tropical grasses to grow at low nitrogen levels since the curvature in nitrogen response was similar for all species. Within both groups of grasses, the proportional response to nitrogen increased with increase in the species potential for yield. The temperate grasses accumulated nitrogen and phosphorus to higher concentrations in the plant tops, and were higher in digestibility, than the tropical grasses. Nevertheless, the tropical grasses would appear to have the potential for higher quality forage than is generally produced in field situations.

The germination and establishment of two annual pasture grasses (Hordeum leporinum Link and Lolium rigidum Gaud.)

1973 ◽  
Vol 24 (1) ◽  
pp. 1 ◽  
Author(s):  
PS Cocks ◽  
CM Donald
Keyword(s):  
High Temperatures ◽  
Mediterranean Region ◽  
Soil Surface ◽  
Lolium Rigidum ◽  
High Moisture ◽  
Pasture Grasses ◽  
Annual Grasses ◽  
Similar Range ◽  
Hordeum Leporinum ◽  
Pasture Plants

The germination and establishment of Hordeum lepovinum Link and Lolium rigidum Gaud., two Mediterranean annual grasses, were studied under controlled conditions. Results were related to the ecology of these species as pasture plants in southern Australia. Seeds of the two species germinated over a similar range of constant temperatures (8-30�C); Hordeum germinated much more rapidly than Lolium at all temperatures. Lolium has a marked requirement for alternating temperatures for maximum germination, while Hovdeum has a weak or nil requirement. Both species withstood prolonged wetting at high temperatures without germinating or losing all viability. Prior soaking and redrying before germination increased the rate of germination of both species. Light rains which fall before the first germinating autumn rains usually wet the seed only for short periods and this further increases the advantage of Hordeum over Lolium in rate of germination. Hordeum germinated and established much more readily on the soil surface than did Lolium, even though Lolium absorbed water more rapidly. The success of Houdeum was due both to its rapidity of germination, which allowed it to establish before the soil surface dried out, and to its ability to germinate at high moisture tensions. Because of these features Hordeum leporinum has the potential to germinate earlier, more rapidly, and more freely than Lolium rigidum in the autumn of the Mediterranean region of southern Australia.

Interralations in the growth and development of Lolium. II. Tiller number and dry weight at low density

1966 ◽  
Vol 17 (6) ◽  
pp. 841 ◽  
Author(s):  
JH Silsbury
Keyword(s):  
Developmental Stages ◽  
Dry Weight ◽  
Tiller Number ◽  
Vegetative Stage ◽  
Low Density ◽  
Lolium Rigidum ◽  
Different Seasons ◽  
Allometric Relation ◽  
Controlled Environments ◽  
The Relationship

Relations between plant dry weight and tiller number have been examined in Lolium rigidum and Lolium perenne grown in the field at low density, and in controlled environments. Between plants within a cultivar, dry weight of tops and tiller number were positively related at all developmental stages throughout the growing season. Between four cultivars of L. perenne and L. rigidum, the relationship was positive in the vegetative stage but became negative when plants were reproductive. It is shown that an allometric relation exists between plant dry weight and tiller number during the vegetative stage. This relation did not differ markedly between cultivars, and for L. rigidum and for L. perenne cv. S.24 was not altered when plants were grown in different seasons or in controlled environments.

Comparative germination patterns of annual grasses in north-eastern Victoria

1970 ◽  
Vol 10 (45) ◽  
pp. 401 ◽  
Author(s):  
AA McGowan
Keyword(s):  
Seasonal Distribution ◽  
Cereal Crops ◽  
Late Winter ◽  
Annual Grass ◽  
Lolium Rigidum ◽  
Winter Cereal ◽  
North Eastern ◽  
Annual Grasses ◽  
Hordeum Leporinum ◽  
Bromus Mollis

The seasonal distribution of germination of Lolium rigidum, Vulpa bromoides, Hordeum leporinum and Bromus mollis was measured under field conditions. The study was conducted in north-eastern Victoria from February to August in 1966 and 1967. Although 49-97 per cent of seed of all species had germinated by the end of April, the proportions of Lolium and Volpia that emerged after April (36 and 45 per cent respectively) were greater than the analogous proportions of Hordeum and Bromus (18 and 13 per cent respectively). These differences in germination pattern are considered to be of potential importance in explaining the incidence of annual grass weeds in winter cereal crops, but of little significance explaining the persistence of these grasses in grazed pastures. Less th-an one per cent of the original seeds remained viable on or in the soil by late winter.

Cereal Consumption, Production, and Prices in West Pakistan (Notes & Comments)

1968 ◽  
Vol 8 (2) ◽  
pp. 288-306 ◽  
Author(s):  
G. C. Hufbauer
Keyword(s):  
Food Consumption ◽  
Ad Hoc ◽  
Dry Weight ◽  
Small Sample ◽  
Tax Rates ◽  
Active Population ◽  
Early Settlement ◽  
Consumption Rates ◽  
Late Nineteenth ◽  
Better Than

In the late nineteenth and early twentieth centuries, several Punjab Settlement Officers attempted to estimate food consumption rates. These estimates, based on direct observation and ad hoc guesses, were made partly out of academic curiosity, but more urgently, as an aid in establishing the land revenue (i.e., tax) rates. The pre-1926 estimates are summarized in Table I, expressed in pounds of wheat and other foodgrain consumption per person per year1. Broadly speaking, the later, more systemtic observers (e.g., Sir Ganga Ram and C. B. Barry), found lower consumption levels than the earlier observers. It was generally accepted that the rural populace ate better than urban dwellers. Despite the ingenuity of the early Settlement Officers, their compiled estimates suffer from all the difficulties of haphazard small sample observation. Given the revenue purpose of the estimates, they may be biased towards the able-bodied, economically active, population. Further, the very early estimates may have confused dry weight with cooked weight, including water.

Research of the activity and viability of spermatozoa at different concentrations and proportions of diluents after incubation

2020 ◽  
pp. 88-95
Author(s):  
Svitlana Lobchenko ◽  
Tetiana Husar ◽  
Viktor Lobchenko
Keyword(s):  
Plasma Concentration ◽  
Incubation Time ◽  
Coefficient Of Variation ◽  
Incubation Medium ◽  
Wide Range ◽  
Series Of Experiments ◽  
The Subject ◽  
Boar Spermatozoa ◽  
Native Plasma ◽  
Better Than

The results of studies of the viability of spermatozoa with different incubation time at different concentrations and using different diluents are highlighted in the article. (Un) concentrated spermatozoa were diluented: 1) with their native plasma; 2) medium 199; 3) a mixture of equal volumes of plasma and medium 199. The experiment was designed to generate experimental samples with spermatozoa concentrations prepared according to the method, namely: 0.2; 0.1; 0.05; 0.025 billion / ml. The sperm was evaluated after 2, 4, 6 and 8 hours. The perspective of such a study is significant and makes it possible to research various aspects of the subject in a wide range. In this regard, a series of experiments were conducted in this area. The data obtained are statistically processed and allow us to highlight the results that relate to each stage of the study. In particular, in this article it was found out some regularities between the viability of sperm, the type of diluent and the rate of rarefaction, as evidenced by the data presented in the tables. As a result of sperm incubation, the viability of spermatozoa remains at least the highest trend when sperm are diluted to a concentration of 0.1 billion / ml, regardless of the type of diluent used. To maintain the viability of sperm using this concentration of medium 199 is not better than its native plasma, and its mixture with an equal volume of plasma through any length of time incubation of such sperm. Most often it is at this concentration of sperm that their viability is characterized by the lowest coefficient of variation, regardless of the type of diluent used, which may indicate the greatest stability of the result under these conditions. The viability of spermatozoa with a concentration of 0.1 billion / ml is statistically significantly reduced only after 6 or even 8 hours of incubation. If the sperm are incubated for only 2 hours, regardless of the type of diluent used, the sperm concentrations tested do not affect the viability of the sperm. Key words: boar, spermatozoa, sperm plasma, concentration, incubation, medium 199, activity, viability, rarefaction.

Effect of Contact Ratio on Spur Gear Dynamic Load With No Tooth Profile Modifications

1996 ◽  
Vol 118 (3) ◽  
pp. 439-443 ◽  
Author(s):  
Chuen-Huei Liou ◽  
Hsiang Hsi Lin ◽  
F. B. Oswald ◽  
D. P. Townsend
Keyword(s):  
Dynamic Load ◽  
Spur Gear ◽  
Tooth Size ◽  
Contact Ratio ◽  
Gear Dynamics ◽  
Wide Range ◽  
Gear Contact ◽  
Center Distance ◽  
Selection Of ◽  
Better Than

This paper presents a computer simulation showing how the gear contact ratio affects the dynamic load on a spur gear transmission. The contact ratio can be affected by the tooth addendum, the pressure angle, the tooth size (diametral pitch), and the center distance. The analysis presented in this paper was performed by using the NASA gear dynamics code DANST. In the analysis, the contact ratio was varied over the range 1.20 to 2.40 by changing the length of the tooth addendum. In order to simplify the analysis, other parameters related to contact ratio were held constant. The contact ratio was found to have a significant influence on gear dynamics. Over a wide range of operating speeds, a contact ratio close to 2.0 minimized dynamic load. For low-contact-ratio gears (contact ratio less than two), increasing the contact ratio reduced gear dynamic load. For high-contact-ratio gears (contact ratio equal to or greater than 2.0), the selection of contact ratio should take into consideration the intended operating speeds. In general, high-contact-ratio gears minimized dynamic load better than low-contact-ratio gears.

scholarly journals Cache-efficient sweeping-based interval joins for extended Allen relation predicates

2021 ◽  
Author(s):  
Danila Piatov ◽  
Sven Helmer ◽  
Anton Dignös ◽  
Fabio Persia
Keyword(s):  
Data Structure ◽  
Experimental Evaluation ◽  
State Of The Art ◽  
Temporal Databases ◽  
Access Method ◽  
Wide Range ◽  
Interval Relation ◽  
Cache Efficient ◽  
Join Algorithms ◽  
Better Than

AbstractWe develop a family of efficient plane-sweeping interval join algorithms for evaluating a wide range of interval predicates such as Allen’s relationships and parameterized relationships. Our technique is based on a framework, components of which can be flexibly combined in different manners to support the required interval relation. In temporal databases, our algorithms can exploit a well-known and flexible access method, the Timeline Index, thus expanding the set of operations it supports even further. Additionally, employing a compact data structure, the gapless hash map, we utilize the CPU cache efficiently. In an experimental evaluation, we show that our approach is several times faster and scales better than state-of-the-art techniques, while being much better suited for real-time event processing.

scholarly journals Soil Nitrogen Dynamics in a Managed Temperate Grassland Under Changed Climatic Conditions

Water ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 931
Author(s):  
Mona Giraud ◽  
Jannis Groh ◽  
Horst H. Gerke ◽  
Nicolas Brüggemann ◽  
Harry Vereecken ◽  
...  
Keyword(s):  
Nitrogen Uptake ◽  
Inorganic Nitrogen ◽  
Nitrogen Concentration ◽  
Nitrogen Dynamics ◽  
Climatic Conditions ◽  
Undisturbed Soil ◽  
Nitrogen Emissions ◽  
Growing Period ◽  
Grassland Type ◽  
Wide Range

Grasslands are one of the most common biomes in the world with a wide range of ecosystem services. Nevertheless, quantitative data on the change in nitrogen dynamics in extensively managed temperate grasslands caused by a shift from energy- to water-limited climatic conditions have not yet been reported. In this study, we experimentally studied this shift by translocating undisturbed soil monoliths from an energy-limited site (Rollesbroich) to a water-limited site (Selhausen). The soil monoliths were contained in weighable lysimeters and monitored for their water and nitrogen balance in the period between 2012 and 2018. At the water-limited site (Selhausen), annual plant nitrogen uptake decreased due to water stress compared to the energy-limited site (Rollesbroich), while nitrogen uptake was higher at the beginning of the growing period. Possibly because of this lower plant uptake, the lysimeters at the water-limited site showed an increased inorganic nitrogen concentration in the soil solution, indicating a higher net mineralization rate. The N2O gas emissions and nitrogen leaching remained low at both sites. Our findings suggest that in the short term, fertilizer should consequently be applied early in the growing period to increase nitrogen uptake and decrease nitrogen losses. Moreover, a shift from energy-limited to water-limited conditions will have a limited effect on gaseous nitrogen emissions and nitrate concentrations in the groundwater in the grassland type of this study because higher nitrogen concentrations are (over-) compensated by lower leaching rates.

Triazole, Benzotriazole, and Naphthotriazole as Corrosion Inhibitors for Brass

CORROSION ◽  
1976 ◽  
Vol 32 (10) ◽  
pp. 414-417 ◽  
Author(s):  
R. WALKER
Keyword(s):  
Corrosion Inhibitors ◽  
Lower Cost ◽  
Solution Ph ◽  
Inhibitor Efficiency ◽  
Wide Range ◽  
Better Than

Abstract The use of triazole, benzotriazole, and naphthotriazole as corrosion inhibitors for brass is briefly reviewed. The corrosion of 70/30 brass immersed in a wide range of solutions is reported both with and without the inhibitors. The inhibitor efficiency of benzotriazole is given as a function of the solution pH and the concentration used. Triazole was only effective in mildly corrosive solutions and benzotriazole and naphthotriazole were much better. Generally naphthotriazole was better than benzotriazole but is much more expensive and a higher concentration of benzotriazole can give the same protection as naphthotriazole at a much lower cost.

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