Wolf plant effects on water relations, growth and productivity in crested wheatgrass

1994 ◽  
Vol 74 (4) ◽  
pp. 767-771 ◽  
Author(s):  
J. T. Romo

When improperly managed in pastures, crested wheatgrass (Agropyron desertorum (Fischer ex Link) Schultes) develops wolf plants because of the long-term persistence of inflorescences. The objective of this study was to test the hypothesis that the wolf plants have no effect on the growth and water relations of grazed or subordinate plants in crested wheatgrass. Treatments applied to wolf plants included killing with glyphosate, mowing to a 10-cm stubble, killing with glyphosate + mowing to a 10-cm stubble, and a control. Rates of vegetative and reproductive development, tiller and whole plant weights, tiller replacement and xylem water potentials of leaves were determined for subordinate plants for 2–3 yr following treatment. The presence of wolf plants had no consistent effect on the water relations or on growth of subordinate plants of crested wheatgrass. Because they play no apparent beneficial role in the water status and productivity of crested wheatgrass, management techniques should be implemented to exploit the forage produced by wolf plants. Accessing this forage can substantially increase the grazing capacity of crested wheatgrass pastures. Key words:Agropyron desertorum (Fischer ex Link) Schultes, grazing management, pasture improvement, plant water relations

1986 ◽  
Vol 13 (1) ◽  
pp. 143 ◽  
Author(s):  
R Munns ◽  
A Termaat

This paper discusses whole-plant responses to salinity in order to answer the question of what process limits growth of non-halophytes in saline soils. Leaf growth is more sensitive to salinity than root growth, so we focus on the process or processes that might limit leaf expansion. Effects of short-term exposure (days) are considered separately from long-term exposure (weeks to years). The answer in the short term is probably the water status of the root and we suggest that a message from the root is regulating leaf expansion. The answer to what limits growth in the long term may be the maximum salt concentration tolerated by the fully expanded leaves of the shoot; if the rate of leaf death approaches the rate of new leaf expansion, the photosynthetic area will eventually become too low to support continued growth.


1996 ◽  
Vol 47 (2) ◽  
pp. 277
Author(s):  
RA Dynes

Managing voluntary feed intake of grazing animals is essential to maximise returns and to meet market specifications. Restricting nutrient intake is successfully achieved by controlled grazing management techniques and with feed additive use in intensive feeding systems. Increasing feed intake in the long-term will be a greater challenge to research. There is considerable potential with existing genotypes of sheep to increase intake, because intake appears to be limited by a lack of hunger drive rather than by limitations due to tissue energy transactions or gut load. Increasing voluntary feed intake will be successful if we can increase the hunger drive within the brain. Increasing the hunger drive may be achieved by decreasing the metabolic satiety signal arising from tissue transactions, by reducing the magnitude of the satiety signals arising from the gastrointestinal tract or by modifying neurotransmitters within the brain to enhance the hunger drive.


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.


1986 ◽  
Vol 107 (1) ◽  
pp. 179-186 ◽  
Author(s):  
A. M. Abd El-Moneim ◽  
P. S. Cocks

SUMMARYThe ley-farming system (integrated cereal and livestock production in which cerealsrotate with self-regenerating pastures) is considered to be of great potential benefit to north Africa and west Asia. In the colder parts of this region (of which north Syria is typical) its application is limited by poor adaptation of commercial medic cultivars (mainly Medicago truncatula and M. littoralis). An extended selection programme hag identified M. rigidula as adapted to the soils and climate of the region but nothing is known of its adaptation to the ley-farming system itself.An experiment which included 23 selections of M. rigidula and one each of M. rotata and M. noeana was conducted over 3 years during which herbage production, seed yield, and the fate of seeds were observed during the 1st year when pastures were established, the 2nd year when wheat was sown, and the 3rd year when the pasture regenerated. Of the 400–800 kg seed/ha produced in the 1st year an average of 87% remained in the soil in spring of the 3rd year. The weight of seed regenerating in the 3rd year varied from 30 to nearly 170 kg/ha, and herbage production, especially in winter, depended heavily on the number of regenerating seedlings. The most productive regenerating pastures produced nearly 2 t/ha of dried herbage by 1 January, and more than 6 t/ha for the whole growing season.The results showed that there was sufficient residual and newly produced seed at the end of the 3rd year to be sure that subsequent regeneration would result in similar herbage yields in the 5th year, and that the pasture was assured of long-term persistence. The significance of this for livestock production is discussed, and it is concluded that the results should encourage further investigation of grazing management and socioeconomic factors seen as constraints to introducing the ley-farming system to north Syria.


1994 ◽  
Vol 74 (2) ◽  
pp. 341-345 ◽  
Author(s):  
Leonard J. Eaton

Effects of herbicide and herbicide-fertilizer combinations on vegetative and reproductive growth of the lowbush blueberry (Vaccinium angustifolium Ait.) were assessed over a 12-yr period (six production cycles). All treatments stimulated stem lengths, fruit buds per stem and fresh fruit yields compared with untreated controls, but only after 3–6 yr. After the second cycle, stem lengths and fruit bud numbers were greater in herbicide + NPK-treated plants than in all others. Fresh fruit yields were variable throughout the study but were higher in herbicide and herbicide + fertilizer plots than in untreated controls after 1982, except in 1988. Nitrogen levels were greater in leaves and rhizomes of plants in all herbicide and herbicide + fertilizer plots than in control plots after 10 yr, whereas phosphorus was higher only in plants fertilized with NPK. These results suggest the lowbush blueberry responds slowly to herbicide and fertilizer applications. Increased vegetative and reproductive development, as well as denser plant stands, resulted from repeated herbicide and fertilizer applications. Fertilizers applied in conjunction with herbicides stimulate vegetative growth (and fruit buds if an NPK fertilizer), but appear to have no consistent effect on fresh fruit yields. Key words:Vaccinium angustifolium, fertilizer, herbicide, fruit buds, yield


Author(s):  
Thomas Klammer ◽  
Neil Wilner ◽  
Jan Smolarski

Capital expenditures can be crucial to firms long-term success, especially in a complex global environment. As companies increasingly compete in the global market place, it is important to study project evaluation processes from an international perspective. Capital investments involve substantial monetary commitments and risks that affect long-term firm profitability and influence capital allocation decisions in the future. Survey research in the area of capital expenditure analysis has been extensively done in both the United States [US] and the United Kingdom [UK]. This research is the first comparative survey of practices in both countries that we are aware of. A direct comparison of the use of project evaluation, management science, and risk management techniques in the two countries is made. The survey instrument used is an adaptation of the Klammer [1970] instrument that has been used repeatedly in surveys of American firms. This is the first time that it has been applied to British firms. The use of a common instrument allows for more meaningful comparisons. The samples consisted of 127 American and 59 British firms with sales of at least $100 million and capital expenditures of at least $10 million. Preliminary results indicate a continued extensive use of discounted cash flow techniques by US firms. Techniques such as payback or urgency continue to be used, but to a lesser degree than discounting. Firms in the UK also make extensive use of discounting but do so to a lesser degree than their American counterparts. Payback is widely used in the UK. Risk management techniques are widely used in both countries, with sensitivity analysis being the most popular technique in both countries. Extensive use of technical and administrative procedures, such as detailed budgets, standardized forms and post-audits, are evidenced in both countries. The paper offers reasons that have to do with organizational structure and form, as well as market differences, to explain our results.


Author(s):  
Connie Zheng

This chapter reviews the legacy of several ancient Chinese sages (i.e. Guanzi, Hanfeizi, Shangyang, Xunzi, and Yanzi) and explores their thinking of ruling the state and managing the people. The thoughts of the old are compared with those known in the mainstream Western management texts. Striking similarities in thoughts and key organization and management issues of old and new are identified. For contemporary organizations to be successful, essential people-management principles must be espoused to sustain organizations for a long term as to preserve ancient states. Nonetheless, the world is in ceaseless change, dynasties and nations rise and fall as organizations acquire, merge, die, or emerge as new. Despite perpetual principles, management techniques require constant adaptation to meet modern challenges.


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