nutrient to be applied. Predicting such amount is not simple. The performance of leaf analysis annually may reflect the response to fertilizer application ( Fernández-Escobar et al., 2009b ) and provide a good approach to determine the amount of nutrient to
Ricardo Fernández-Escobar, Miguel A. Sánchez-Zamora, Jorge M. García-Novelo, and Concepción Molina-Soria
The nuts of 10 pecan cultivars were used to produce rootstock trees for the propagation of two scion cultivars—Posey and Pawnee. Seed sources included: `Chickasaw', `Colby', `Dooley', `Giles', `Greenriver', `Major', `Mohawk', `Peruque', `Posey', and `Shoshoni'. Leaf analysis performed in 1994 and 1996 revealed that rootstock influenced K and Zn concentrations. Scions propagated on `Posey' seedlings contained the greatest amount of K, while scions propagated on `Greenriver' seedlings contained the least. Zn levels were highest in trees with `Chickasaw' seedling rootstocks and the least in `Major' seedlings. Yield and nut quality was influenced by a major drought during the late summer and fall of 1995. Nuts produced by trees with `Chickasaw' and `Colby' rootstocks had the highest kernel percentage, while trees grown on `Major' and `Posey' had the lowest. The greatest yields, during the drought year, were produced from scion cultivars grafted on `Giles' and `Chickasaw' seedling rootstocks. `Major' and `Greenriver' seedlings produced trees with the smallest yields.
Ray E. Worley, D. A. Hegwood, and S. A. Harmon
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.
Ray E. Worley
Mature ‘Stuart’ pecan trees in good condition on Tifton loamy sand did not respond to fertilizer [10-4.4-8.3 (N-P-K)] at rates from 0-1344 kg/ha annually over a 10-year period, but color and vigor of trees receiving no fertilizer were reduced near the end of the study. Highest yields were obtained with 448 kg/ha. Fertilizer effects on shoot growth and nut quality were inconsistent, but quality tended to be poorer for heavily fertilized than lightly fertilized trees near the end of the study. Fertilizer and limestone effects on yield and shoot growth were also inconsistent for mature ‘Stuart’ trees on Leefield sand at Way cross, Ga. over a 10-year period. Leaf analysis responded very slowly to nutrient application with leaf N and K being first increased by fertilizer application in the 6th and 9th years, respectively. Fertilizer P had little effect on leaf P. Liming to pH 60 with calcite increased leaf Ca and decreased leaf Mg and Al.
Yield and shoot growth of young ‘Desirable’ trees increased with the first 56 kg/ha increment of N, but further increases due to the second increment were seldom significant. Phosphorus and K additions had little effect on yield and shoot growth, but increasing K reduced nut size. Increasing N rates to 112 kg/ha improved vigor and color of trees. Leaf N and K for young trees increased from increasing application levels the first year, and leaf K was maintained in the desired range when soil test plus applied K equaled 112 kg/ha annually. Increasing N and K applications reduced leaf Mg, and increasing K applications increased leaf Mn, Fe, Al, and Na in young trees.
Ray E. Worley
Ray E. Worley and Benjamin G. Mullinix
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.
Shirin Shahkoomahally, Jose X. Chaparro, Thomas G. Beckman, and Ali Sarkhosh
concentrations, and to interpret the leaf analysis, orchard nutritional status, and the amount of soil nutrient removal ( Nachtigall and Dechen, 2006 ) as it relates to the physiological status of the tree. The results are essential for the accurate application
M. Lenny Wells
is of value to recognize the status of pecan tree and orchard soil nutrition typical of a region. Leaf analysis is widely regarded as a reliable index for many of the nutrient elements of pecan trees. Critical ranges for leaf nutrients have been
M. Leonard Wells and Bruce W. Wood
fruit and canopy characteristics HortScience 38 361 366 10.21273/HORTSCI.38.3.361 Worley, R.E. 1974 Effect of N, P, K, and lime on yield, nut quality, tree growth, and leaf analysis of pecan J. Amer. Soc. Hort. Sci. 99 49 57 Worley, R.E. 1990 Pecan leaf
Kwok H. Fong and Albert Ulrich
“White Rose” potato plants were grown in modified Hoagland’s solution at concentrations of 0 to 16 meq/1 of K. After 32 days of growth, 16 plant parts were taken for analysis. The K status of the potato plant was reflected best by the second leaf below the flat top (Fig. 1). This leaf was the recently matured leaf of the plant, was relatively easy to sample, and did not differ greatly in K concentration from the first, third, and fourth leaves. The critical K value at a 10% reduction of growth was 2.3% for the petiole tissues and 1.1% for the blade tissues.