Effects of in-row and interrow subsoiling and time of nitrogen application on growth, stomatal conductance and yield of strip-tilled corn

The use of in-row subsoilers in conservation tillage systems in soils underlaid by tillage pans increases rooting depth, root proliferation and water infiltration. Interrow subsoiling 5 weeks after planting, to coincide with sidedress nitrogen applications, might be a practical method for further increasing infiltration of water from irrigation and high-intensity showers. Corn (Zea mays L.) was strip-till planted and grown under irrigation for 2 years at one location and 1 year at another to study the effects of subsoiling, placement and timing of nitrogen application (157 kg ha⁻¹) on plant growth, stomatal conductance and yield. Treatments included (1) not subsoiled, N applied at planting; (2) subsoiled in-row at planting, N applied at planting; (3) not subsoiled, N applied 5 weeks after planting; (4) subsoiled in-row at planting, N applied 5 weeks after planting; (5) subsoiled interrow, and N applied 5 weeks after planting; and (6) subsoiled in-row at planting and interrow 5 weeks after planting, N applied 5 weeks after planting. Nitrogen applied 5 weeks after planting resulted in higher yields than when applied at planting. In-row subsoiling at planting, interrow subsoiling 5 weeks after planting and subsoiling in-row at planting plus interrow 5 weeks later resulted in increased stomatal conductance between irrigations. Delaying N application resulted in decreased stomatal conductance in treatments that were in-row subsoiled at planting. Grain yields were lower without than with subsoiling, especially when N was applied at planting. When water was not limiting, subsoiling interrow 5 weeks after planting was as effective in increasing grain yield as in-row subsoiling at planting. In one test, the highest grain yield (9.96 t ha⁻¹) resulted from the cumulative effect of subsoiling in-row at planting plus interrow 5 weeks later.     

Measurement of basal serum insulin concentration in the diagnosis of Cushing's disease in ponies.

A high basal plasma or serum insulin concentration is commonly accepted as an indicator of Cushing's disease in horses. The results of the combined dexamethasone suppression test and thyrotropin-releasing hormone stimulation test were compared with the basal insulin concentrations and insulin response tests of eight hyperinsulinaemic and insulin-resistant ponies with clinical histories of chronic or recurrent laminitis that were suspected of having Cushing's disease. Seven of the eight ponies had normal responses to the combined test indicating that basal insulin concentrations are not a specific indicator of the disease.     

Reciprocal apparatus dysfunction as a cause of severe hind limb lameness in a horse.

A 2-year-old Appaloosa mare was admitted because of acute, severe hind limb lameness (grade 4 of 5). The hock could be flexed or extended without influencing the position of the stifle joint, and the fetlock and proximal interphalangeal joints could be extended while the hock was maintained in flexion. The diagnosis was functional loss of the reciprocal apparatus. The differential diagnoses for functional loss of the reciprocal apparatus include disruption of the common calcaneal tendon, the gastrocnemius muscle, the peroneus tertius, or the superficial digital flexor muscle. In this horse, the diagnosis was disruption of the superficial digital flexor muscle. The horse made an excellent recovery following 5 months of stall confinement.     

Irrigation water conservation by using wide-spaced furrows

Studies of wide-spaced furrow irrigation were conducted at Goodwell, OK. Wide-spaced furrow irrigation applies water to the root zone while maintaining a relatively dry soil surface. This condition reduced evapotranspiration losses and can reduce water requirements by 20 to 50%. Probability of a yield reduction with this water conservation method is lessened by either: (a) abandoning the wide-spaced furrow irrigation method on 1 August of a high water-stress season; or (b) alternating the dry furrows in an alternate-furrow scheme. A high stress season is defined as one in which the August wind velocity averages greater than 1.8 m/s and less than 7.5 cm of rain falls between 15 July and 1 September (in the temperate northern hemisphere). The test for high stress conditions consists of measuring rain and wind velocity beginning on 15 July. The averages are examined on 1 August. If rainfall average is less than 1.6 mm/day and wind average is more than 1.8 m/s then normal irrigation is practiced on subsequent irrigations. Studies were conducted in 60 m plots and in field scale research with 0.8 km rows.     

Postpartum interval in beef cows shortened by enclomiphene

This study was designed to determine whether an anti-estrogen can block the negative effect of estrogens on luteinizing hormone (LH) release and therefore decrease the postpartum interval in suckled beef cows. In Exp. I, eight suckled postpartum beef cows were randomly assigned to treatment and control groups. Treatment cows received 1 g/d clomiphene citrate (im) from d 21 to 28 postpartum, while control cows were injected with saline. On d 28 postpartum, there was no difference (P greater than .05) in mean total and basal LH concentrations or LH pulse frequency between treatment and control cows. All control cows exhibited estrus on d 52 +/- 3; treatment cows exhibited estrus on d 134 +/- 12 (P less than .05). In Exp. II, 17 suckled cows were randomly assigned to three treatment groups: 1) control group (n = 6) receiving one empty implant, 2) 10-cm enclomiphene implant group (n = 5) and 3) 30-cm enclomiphene implant group (n = 6). The silastic implants were placed sc on d 20 and removed on d 29 postpartum. Mean total LH concentrations during d 24 to 29 postpartum in the 30-cm enclomiphene implant group were higher than the 10-cm implant (P less than .05) and control group (P less than .05). The postpartum period in the 30-cm enclomiphene group (45 +/- 6 d) was shorter than the 10-cm implant (94 +/- 24 d) and control (96 +/- 20 d) groups (P less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)     

The North American Animal Disease Spread Model: a simulation model to assist decision making in evaluating animal disease incursions

The North American Animal Disease Spread Model is a stochastic, spatial, state-transition simulation model for the spread of highly contagious diseases of animals. It was developed with broad international support to assist policy development and decision making involving disease incursions. User-established parameters define model behavior in terms of disease progression; disease spread by animal-to-animal contact, contact with contaminated personnel or equipment, and airborne dissemination; and the implementation of control measures such as destruction and vaccination. Resources available to implement disease control strategies, as well as the direct costs associated with these strategies, are taken into consideration. The model records a wide variety of measures of the extent of simulated outbreaks and other characteristics. The graphical interface and output visualization features also make it a useful tool for training and preparedness exercises. This model is now being used to evaluate outbreak scenarios and potential control strategies for several economically important exotic animal diseases in the United States, Canada, and elsewhere. NAADSM is freely available via the Internet at http://www.naadsm.org.     

Sebertia acuminata: A Hyperaccumulator of Nickel from New Caledonia

Sebertia acuminata (Sapotaceae) from New Caledonia has been shown to be a hyperaccumulator of nickel. The nickel content of the latex (25.74 percent on a dry weight basis) is easily the highest nickel concentration ever found in living material. The nickel is in the form of a low-molecular-weight, water-soluble organic complex.     

Islander: A golden nematode resistant potato variety for fresh market and chipping

The Islander potato variety is a medium maturing variety with oblong, shallow-eyed, white-skinned tubers. High dry matter and good chip color characterize this variety which is better adapted to Long Island, New York and New Jersey than to other northeastern areas. It is resistant to golden nematode and net necrosis; moderately resistant to common scab and early blight; and less susceptible than most varieties to acid scab and Rhizoctonia. The Islander is a product of the cross Chipbelle × Norchip.     

Campbell 14: A verticillium resistant round white potato variety

The Campbell 14 potato variety is a medium-late maturing variety with round to oblong, smooth, shallow-eyed, white tubers. This variety is intended primarily for fresh market; however, under some conditions chip color will be acceptable. Campbell 14 is resistant to verticillium wilt and to the net necrosis caused by the potato leafroll virus.