Comparative ecophysiology of grain sorghum and Abutilon theophrasti in monoculture and in mixture     

S TRAORÉ  J L LINDQUIST  S C MASON  A R MARTIN  & D A MORTENSEN 《Weed Research》2002,42(1):65-75

Selection of crop genotypes that are more competitive with weeds for light interception may improve crop yield stability in the presence of weeds. The effects of interference on ecophysiological characteristics of Abutilon theophrasti Medic. and three morphologically diverse grain sorghum hybrids was evaluated to determine the relative tolerance and suppressive ability of the three hybrids and specific traits that may contribute to those differences. A tall hybrid was more tolerant to A. theophrasti interference than two medium stature hybrids. Early leaf area growth of two medium-stature sorghum hybrids was reduced by A. theophrasti interference, whereas early growth of a tall hybrid was unaffected. The height of A. theophrasti was greater than two moderate-stature hybrids but lower than the tall hybrid. Greatest leaf area density (L_D) of the tall sorghum hybrid was above that of A. theophrasti , whereas greatest L_D of medium-stature hybrids was below that of the weed. In monoculture, the partitioning of new biomass to various plant organs was similar among sorghum hybrids, whereas the tall sorghum hybrid partitioned less biomass to leaves and more to stems than medium hybrids in mixture. The results indicate that the three hybrids differ in their susceptibility to A. theophrasti competition. Crop traits that may contribute to greater crop competitiveness include greater maximum height and its growth rate and greater height of maximum leaf area distribution.  相似文献   

Weed management in conservation crop production systems   总被引：1，自引：0，他引：1  

MARTIN A. LOCKE  KRISHNA N. REDDY  ROBERT M. ZABLOTOWICZ 《Weed Biology and Management》2002,2(3):123-132

Information on weed management in conservation crop production systems is needed as adoption of practices such as reduced tillage and cover crops becomes more widespread. This review summarizes recent research on weed management aspects in these systems. Changes in patterns of tillage, planting systems, and other management strategies can alter the soil environment and lead to shifts in weed populations. Weed patterns and populations are not always consistent and vary with locale, crop, and herbicide use. However, in many long-term conservation management studies, a general increase in perennial weeds and grass species has been observed. The development of low-dose herbicides, selective postemergence herbicides, and transgenic crops has greatly improved the flexibility of producers who use conservation systems where opportunities for tillage are limited. With a higher level of management inputs, producers can successfully implement conservation management practices.  相似文献   

Influence of aldicarb on root lesion nematodes, leaf disease and root rot in wheat and barley   总被引：1，自引：0，他引：1  

J. KIMPINSKI  H. W. JOHNSTON  R. A. MARTIN 《Plant pathology》1987,36(3):333-338

The effects of aldicarb on populations of root lesion nematodes (primarily Pratylenchus penetrans ) and on grain yields of spring barley and wheat were examined in the field over 3 years, 1981*83. The incidence of barley net blotch ( Pyrenophora teres ), wheat leaf blotch ( Leptosphaeria nodorum ), and common root rot ( Cochliobolus sativus ) was also recorded in 1982 and 1983. Aldicarb treatments reduced the size of root lesion nematode populations in soil and roots in all years, except in the mid-season soil sample in 1983. The severity of leaf disease was decreased only in 1982, but the incidence of root rot was not significantly affected by the nematticide. Although aldicarb increased cereal grain yields by approximately 15% there was no significant relationship between numbers of root lesion nematodes in roots and soil and fungal disease symptoms on barley and wheat.  相似文献   

Arthroscopic Surgery for the Treatment of Osteochondritis Dissecans in the Equine Femoropatellar Joint     

C. W. McILWRAITH BVSc  MRCVS  PhD  DiplomateACVS  G. S. MARTIN DVM  MS 《Veterinary surgery : VS》1985,14(2):105-116

Forty limbs with femoropatellar osteochondritis dissecans in 24 horses were treated with arthroscopic surgery. Lesions were bilateral in 16 horses and unilateral in eight horses. Diagnostic examination and surgical treatment were performed through a single arthroscopic portal; five different instrument portal locations and six instrument approaches were used. Lesions were localized to the lateral trochlear ridge of the femur in 31 affected joints, medial trochlear ridge in two joints, lateral and medial trochlear ridges together in two joints, lateral trochlear ridge plus patella in four joints, and patella alone in one joint. The lesions consisted of subchondral defects containing chondral or osteochondral flaps or fragments, or were seen as dimpling, cracking, fibrillation, or erosion of articular cartilage, or intact cartilage over a subchondral defect. Loose bodies were found in three joints. There was a poor correlation between radiologic and arthroscopic findings. Surgical manipulations included removal of flaps, fragments, and undermined articular cartilage, and debridement of the subchondral defect. Three horses were euthanized: one electively to assess the joint grossly, one because of complications following surgery and salmonellosis, and one because of unrelated forelimb abnormalities. Immediate clinical improvement after surgery was seen in the 22 horses permitted to survive. Long-term follow-up on seven of 10 racehorses revealed that two have raced successfully, two are "ready to race," three are training sound, two are sound at pasture (still in convalescence), and one has been reoperated. Of six horses used for show or pleasure, three are being shown sound, one is sound for pleasure, and two are training sound. The remaining horses are convalescing.  相似文献   

Control of bracken (Pteridium esculentum G. Forst (Cockayne)) in pasture with asulam     

R. J. MARTIN 《Weed Research》1977,17(1):49-54

Asulam was tested for the control of bracken in non-arable pasture on the North Coast of New South Wales between 1971 and 1976. Satisfactory results were obtained with applications between April and early July, providing treated fronds were mature. The degree of control varied between years and sites. Rates of 4–8 kg a.i./ha reduced frond numbers from 70 to 100% after 6 months but recovery commenced as early as 9–12 months after application. Whole plants and sections of rhizome were excavated 4, 6 and 9 months after treatment and a sequence of events is described for the effect of asulam on bracken. The effects of frond maturity, frond density and frost are discussed in relation to herbicide effectiveness and ecological implications of the results are discussed in relation to increasing productivity of bracken-infested pasture.  相似文献   

DECREASED RADIOPHARMACEUTICAL UPTAKE (PHOTOPENIA) IN DELAYED PHASE SCINTIGRAPHIC IMAGES IN THREE HORSES     

DAVID G. LEVINE  BETH M. ROSS  MICHAEL W. ROSS  DEAN W. RICHARDSON  BENSON B. MARTIN 《Veterinary radiology & ultrasound》2007,48(5):467-470

Decreased radiopharmaceutical uptake, photopenia, in delayed phase scintigraphic images is recognized in people but has only been reported rarely in horses. We describe three horses with septic osteitis, bone sequestrum formation, or distal limb thrombosis that had photopenia of the affected extremity. Photopenia may indicate the presence of ischemia and can be used to facilitate clinical decision making and prognosis assessment  相似文献   

Bypass Surgery for Intestinal Occluding Abscesses in the Equine: A Report of Two Cases     

T. S. TAYLOR D.V.M.  M.S.    M. T. MARTIN D.V.M  W. C. McMULLAN D.V.M.  M.S. 《Veterinary surgery : VS》1981,10(3):136-138

The medical management of two horses with small intestine occluding abdominal abscesses was supported by surgical bypasses. In the first case the small intestine was transected proximal to the abscess and an end-to-side anastomosis performed distally; in the second case a side-to-side anastomosis was performed without bowel transection. The results suggest bowel transection with an end-to-side anastomosis to be the preferred procedure.  相似文献   

Feline pancreatic Islet cell hyalinosis associated with diabetes mellitus and lowered serum-insulin concentrations     

J. PETER FINN  C. L. MARTIN  J. G. MANNS 《The Journal of small animal practice》1970,11(9):607-619

A case of feline spontaneous diabetes mellitus with an absolute deficiency of insulin is presented. The characteristic hypertrophy of the Islets and hyalinosis is described and compared to the disease in dogs.
Résumé. On présente un cas de diabète sucré spontané chez un chat, avec une insuffisance totale d'insuline. L'hypertrophie caractéristique des îlots et l'hyalinose sont décrites et comparées avec les lésions observées chez le chien.
Zusammenfassung. Ein Fall von spontanem Diabetes mellitus mit absolutem Insulinmangel wird beschrieben. Die charakteristische Hypertrophie der Inseln und Hyalinose werden beschrieben und mit der Krankheit bei Hunden verglichen.  相似文献   

An Empirical Note on Federal Regional Development Programs     

RANDOLPH C. MARTIN 《Growth and change》1979,10(2):46-49

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Effect of posture on the elimination of radon in the breath     

MARTIN EJ  FERGUSON JK 《Science (New York, N.Y.)》1953,118(3056):112-114

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