Economic and environmental concerns require more precise management of irrigation and nutrition of citrus produced on the well-drained sandy Entisols of the central Florida ridge. Fertilizers are readily leached from these soils, and nitrate
Kelly T. Morgan, T. Adair Wheaton, William S. Castle and Laurence R. Parsons
Kelly T. Morgan, T. Adair Wheaton, Larry R. Parsons and William S. Castle
predominant soil order in this area is Entisol, with Candler fine sand (hyperthermic, uncoated, Typic Quartzipsamment) being the dominant soil series ( Obreza and Collins, 2003 ). The Candler series consists of excessively drained, very rapidly permeable soils
Kelly T. Morgan, T.A. Obreza and J.M.S. Scholberg
Understanding the growth pattern of fibrous, orange tree [Citrus sinensis (L.) Osbeck] roots enables proper fertilizer placement to improve nutrient uptake efficiency and to reduce nutrient leaching below the root zone. The objective of this study was to develop relationships defining citrus fibrous root length density (FRLD) as a function of soil depth, distance from the tree trunk, and tree size. Root systems of 18 trees with tree canopy volumes (TCV) ranging from 2.4 to 34.3 m3 on two different rootstocks and growing in well-drained sandy soils were sampled in a systematic pattern extending 2 m away from the trunk and 0.9 m deep. Trees grown on Swingle citrumelo [Citrus paradisi Macf. × Poncirus trjfoliata (L.) Raf.] rootstock had significantly greater FRLD in the top 0.15 m than trees on Carrizo citrange (C. sinensis × P. trifoliata). Conversely, Carrizo citrange had greater FRLD from 0.15 to 0.75 m below the soil surface. FRLD was significantly greater for ‘Hamlin’ orange trees grown on Swingle citrumelo rootstock at distances less than 0.75 m from the tree trunk compared with those on Carrizo citrange. Fibrous roots of young citrus trees developed a dense root mat above soil depths of 0.3 m that expanded both radially and with depth with time as trees grow and TCV increased. Functional relationships developed in this study accounted for changes in FRLD with increase in tree size.
Davie M. Kadyampakeni, Kelly T. Morgan, Arnold W. Schumann and Peter Nkedi-Kizza
(hyperthermic, coated Typic Quartzipsamments) an Entisol excessively drained throughout the profile (ES) ( Obreza and Collins, 2008 ). ‘Hamlin’ orange ( Citrus sinensis ) trees on ‘Swingle’ ( Citrus paradisi × Poncirus trifoliata ) rootstock were planted in Apr
Mack A. Wilson and Michael Aide
Four types of row covers were evaluated on 'Norchip' and 'Atlantis' potatoes at Charleston, Missouri on a Lilbourn sandy loam entisol. Row covers used were spun-bonded polyester, insolar slitted, clear slitted and VisPore. The row covers increased the mean afternoon soil temperature above the ambient afternoon air temperature from 3 to 25°F when potato plants were covered. The number of plants which emerged were significantly different among treatment for the cultivar 'Norchip'. Data for plant height was significantly different between the bare soil control and the row cover treatments. Yield (Kg/HA) were higher with the spunbonded polyester and insolar slitted row covers for both number and weight of grade A (47.6-82.6 mm) potatoes, and results were significantly different.
Mack A. Wilson and Michael T. Aide
`Norchip' and `Atlantic' potatoes grown at Blodgett and Dielstadt, Missouri on 2 sandy, well drained entisols were evaluated using four row covers. The row covers were spunbonded polyester, insolar slitted, clear slitted polyethylene and VisPore. Row covers increased the mean afternoon soil temperature from 62° to 108°. The mean plant heights were significantly different among treatments for the cultivar `Norchip' but were not different for `Atlantic'. Data for average and total plant heights were significantly different between the bare soil control and all row covers. The grade a marketable weights and numbers in Kg and nos/Ha of `Norchip' and `Atlantic' potatoes had a significant contrast at the 0.01 level of probability with cultivars.
Mack A. Wilson, Victor A. Khan and Clauzell Stevens
Four types of row covers were evaluated on two cultivars of potatoes (`Atlantic' and Frito-Lay 795') at Charleston, Missouri on sandv loam entisol. Row covers used were spunbonded polyester, clear and white slitted and VisPore. Significant interactions occurred in the sub-plot (row cover × varieties) and sub-subplots (varieties × flower treatments) for numbers of grade A potatoes. The total numbers of potatoes for 'Atlantic' and 'Frito-Lay 795' cultivars as influenced by flower removal and row cover treatments showed significant interactions of row covers × varieties and varieties × flower treatments. Yield of grade A potatoes for both cultivars as influenced by flower removal and row cover treatments showed a significant interaction between row covers × varieties. Genetic differences occurred among potato cultivars in response to flower removal. cultivar response to row covers were also different based on genetic makeup. Clear and spunbonded polyester were superior to other types of row covers for grade A numbers and yield of potatoes.
Mack A. Wilson and Michael Aide
Potatoes (Solantum tuberosum) were grown on a Lilbourn sandy loam entisol in Charleston, Missouri, with varying rates of potassium fertilizer. Four rates of murate of potash (KCl) were used; 0, 196, 392 and 582 Kg-K/HA. Potassium was measured in tuber and soil by atomic absorption spectrophotometry. The amount of soil potassium was apparently high. Although potassium content in the two cultivars of potatoes, `Norchip' and `Atlantis' was slightly higher (2.3-3.7) as compared to another researcher's data (2%). Obviously, the need for potassium fertilizer for vegetable crops is related to the supplying ability of the soil. Tuber yields (Kg/HA) were higher with added rates of potassium fertilizer than the control, and the results were significant. Yields (Kg/HA) of `Atlantis' were significantly higher than `Norchip.'
Seiichi Miyamoto and Monte Nesbitt
Soil salinity management is a factor for successful production of pecan (Carya illinoinensis) in arid southwestern United States. An exploratory study was performed to evaluate the effect of various soil management practices on salt leaching in basin-irrigated orchards developed on alluvial soils (Torrifluvents, Entisols) of the middle Rio Grande Basin. The practices evaluated were ripping, minimum-till chiseling, and soil profile modification. For ripping, parabolic shanks were passed through the center section (4 to 8 ft wide) between each tree row to a depth ranging from 18 to 36 inches. Minimum-till chisels included 7- and 30-inch shanks, equipped with coulters to reduce break up of the ground surface. Soil profile modification consisted of trenching with a backhoe and profile mixing with a large excavator. The effectiveness of these methods was evaluated by measuring soil salinity and moisture in treated and untreated zones at 17 test sites. Both ripping and minimum-till deep chiseling helped improve salt leaching, and the effectiveness of salt leaching increased as working depths approach the thickness of the clayey layer. However, annual ripping of the center section of each tree row space may not provide wide enough zones to alleviate salt stress to the trees. Straight shanks prune but do not lift tree roots, thus appearing to be better suited for chiseling closer to tree rows. Soil profile modification was highly effective in leaching salts. From the view of minimizing soil aggregate destruction and of maintaining a leveled floor, minimum-till deep chiseling, followed by the use of sand-topdressing and minimum-till shallow chisels for maintenance may prove to be more desirable than conventional ripping, especially in soil types consisting of silty clay loam.
Thomas A. Obreza and Arnold Schumann
a sandy Entisol of Florida under citrus Commun. Soil Sci. Plant Anal. 34 1803 1824 Mattos D. Jr Graetz, D.A. Alva, A.K. 2003c Biomass distribution and nitrogen-15 partitioning in citrus trees on a sandy Entisol Soil Sci. Soc. Amer. J. 67 555 563