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- Author or Editor: Ray E. Worley x
Yield and quality of pecan nuts were as high when 50 pounds N/acre was applied through a dripirrigation system as with 100 pounds/acre (112 kg·ha−1) applied either all broadcast or half broadcast-half fertigated. All N treatments kept leaf N well above the 2.50% (dry weight) lower threshold recommended for pecans. The 50 pounds N/acre-all-fertigated treatment resulted in less soil pH reduction and less loss of K, Ca, and Mg from soil in the nonwetted zone underneath the tree canopy than broadcast treatments. Soil pH, K, and Mg were slightly lowered in the 6- to 12-inch (15 to 30 cm) soil layer when all of the N was fertigated. Higher leaf Ca and Mg from the low rate of N fertigated reflected the higher concentrations of these elements in the soil in the nonwetted zone rather than the lower concentrations in the wetted zone. There was no evidence of a detrimental effect on the tree from lowering the N application to only 50 pounds/acre and applying it in four monthly applications through the drip irrigation system beginning 1 Apr.
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.
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
‘Woodard’ pecan (Carya illinoensis (Wang.) K. Koch) is an exceptionally thin-shelled nut of high percentage kernel for the inshell trade.
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
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.
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
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
Correlations between pecan yield, quality, tree growth, and various nutritional variables were studied over an 8-year period. Yield was negatively correlated with yield the previous year, but yield was positively correlated with yield accumulated over several years. Terminal shoot growth and nuts/lb. varied in a pattern similar to yield. Soil and leaf analysis was not often correlated with yield, nut quality, or tree growth. Degree of leaf retention in a heavy crop year was positively correlated with yield the following season.
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.