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- Author or Editor: Ray E. Worley x
Abstract
Fungicidal applications in 1966 exerted a profound influence on the number of nutlets set in 1967. Nutlet set ranged from practically none without fungicide sprays to 1.34 per terminal where 5 applications of Du-Ter were made at the rate of 0.12 lb per tree. Du-Ter was the most effective fungicide and dodine was next best in their enhancement of nutlet production. Dodine and Du-Ter were also most effective in controlling scab.
Abstract
A longitudinal splitting of pecan which causes loss of nuts of thin-shelled cultivars during the “water” stage of the kernel is described. A similar splitting was induced by forcing water into the nut with a hypodermic needle. Soaking of nuts in water either on or off the trees did not induce splitting.
Abstract
Field data indicate that part of the K requirement for sweet potatoes (Jpomoea batatas Lam.) may be satisfied by Na without reducing yields or quality, but high rates of substitution reduced yield in some years. Significant reduction in leaf K occurred with increased substitution by Na. Sweet potatoes readily absorbed Na with leaf Na increasing as Na application increased.
Abstract
A quick method of estimating pecan yield is described and compared with mechanically harvested yields. The estimate accounted for 80% of the yield variation.
Alternate bearing is a major economic problem for producers of pecan nuts [Carya illinoinensis (Wangenh.) K. Koch], yet a fundamental understanding of alternate bearing remains elusive. Nut yields (over a period of up to 78 years) from a commercial-like orchard of 66 cultivars was used to calculate alternate bearing intensity (I). Best-fit regression analysis indicates no association between I and fruit ripening date (FRD) or nut volume; although, there was moderate association with post-ripening foliation periods (PRFP) in that I tends to decrease as the length of the PRFP decreases. Multiple regression models indicated that FRD and nut volume were poor predictors of I: however, PRFP possessed significant inverse predictive power. Late-season canopy health, as measured by percentage of leaflet retention, decreased as FRD approached early-season ripening. Late-season photoassimilation rate was high er on foliage of trees with late FRDs than those with mid- or early-season ripening dates. These data provide new insight into the complex nature of alternate bearing in pecan and provide evidence for modifying the existing theories of alternate bearing of pecan.
Abstract
Concentration of pecan roots in the 15-45 cm layer of soil and lower soil pH, P, and K in the 15-30 cm layer than in adjacent layers indicate that pecan trees are feeding primarily in this zone. Fertilization with N-containing complete fertilizers or NH4NO3 reduced soil pH gradually, and continued annual application gradually affected deeper soil layers. Phosphorus and K applications affected soil pH very little.
Continued annual applications of P gradually built up residual soil P (measured one year later) to high levels at all layers sampled for old trees over a 10-year period. When P applications were based on topsoil P levels, subsoil P level was not affected over a 5-year period.
Applications of K usually increased residual soil K, but rate effects were slow to appear in old trees and were often erratic. Rates of K were readily reflected in residual soil K levels at depths to 70 cm when rates were based on topsoil K level.
Abstract
Magnesium sulfate applied as a soil amendment (34 kg Mg/ha annually for 3 years or a single application of 224 kg Mg/ha) increased leaf Mg 5 years after initial application. Dolomite increased soil pH and soil test Mg but not leaf Mg. Sulfate of potash magnesia and MgO increased soil test Mg and slightly, though insignificantly, increased leaf Mg. Single foliar sprays of MgSO4 and Mg(NO3)2 did not affect leaf Mg.
Abstract
Mature pecan, Carya illinoensis (Wang.) Koch., grove management systems of 1) rotational summer grazing, 2) clean cultivation + winter legume, 3) winter or spring intercropping + summer cultivation, and 4) closely mowed sod affected yields differently in different years, but did not affect total yield or tree growth significantly over a 10-year period. Kernel quality, nuts/kg count, nut size, and tree growth were not affected consistently by management systems. Extra fertilization, particularly N, applied to grazed and intercropped plots reduced soil pH and residual soil K; but treatments affected soil P very little. Leaf Zn and Mn were also high for these treatments. Applied N, or N from legumes, was reflected in higher leaf N. Leaf K, Mg, Fe, B, Cu, Al, Mo, and Sr were not affected significantly by management treatment.
Abstract
‘Woodard’ pecan (Carya illinoensis (Wang.) K. Koch) is an exceptionally thin-shelled nut of high percentage kernel for the inshell trade.
Abstract
Although variation between years was large, yield responses were obtained from N in 3 years, P in 2 years, and K in 1 year of the 4 year test. Results indicated that application levels should be 25-50 lb of N/A, 11-22 lb of P/A, and not over 42 lb of K/A. A complete fertilizer supplying 50-22-42 lb of N-P-K/A gave the highest average yield. Fertilizer treatments had little effect on leaf analysis at harvest in 1963, and correlation coefficients were not significant for leaf mineral concentration of N, P, K, Ca, Mg, Na, Mn, Fe, B, Zn, Al, Mo, Ni, Sr, Ba, and Ti with yield. Significant negative correlation coefficients were found for yield with leaf Cu, Zn, Al, and Ti, but they were all -.36 or less.