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  • Author or Editor: L. B. Fenn x
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Abstract

Water was translocated from pecan [Carya illinoinensis (Wangenh.) K. Koch ‘Burkett’], grape (Vitis vinifera L. ‘Thompson Seedless’) and tomato (Lycopersicon esculentum Mell. ‘Ace’) roots growing in a moist soil medium, across stem or crown tissue into roots growing in a dry soil medium, and was exuded during periods of high transpiration. Those portions of pecan and grape roots in a dry soil medium (wilting point) were maintained in an absorptive condition for 30 days, whereas tomato roots were injured.

Open Access

Abstract

Turfgrass quality usually is related to fertilization management practices. Nitrogen fertilizer formulations are undergoing change in order to produce acceptable turfgrass response and reduce management costs. Field experiments conducted during 1979–81 evaluated the influence of Ca on urea and nitrate N sources on bermudagrass (Cynodon dactylon L.) turfgrass color, quality, verdure, and root-rhizome dry matter production. Color, quality, and verdure were significantly improved and persisted longer with the addition of Ca to urea N sources. Early season root and rhizome production also was increased with the urea + calcium application. Verdure was not significantly affected among the N sources. There was not a significant increase in tissue N content. Addition of Ca to the fertilizer formulation apparently enhanced N utilization.

Open Access

Abstract

Several different split-root techniques, both horizontal zonation (1, 3, 6) and vertical zonation (2, 4, 7, 8), have been employed to study plant growth and water and nutrient uptake from differentially salinized root zones. High salinity level in one portion of the root zone may not affect overall plant performance if other portions of the root zone are relatively salt free (1, 3, 8). With uniform salinization, sodium chloride concentrations up to −0.8 MPa did not affect the 15N absorption rate in cotton, but osmotic pressures of −1.2 MPa substantially reduced it. However, water uptake and plant growth were affected to a greater extent than was 15N absorption (5).

Open Access

Acidification of < 1% of the effective root zone of a mature pecan tree (Carya illinoensis (Wanghenh.) C. Koch) significantly increased uptake of Zn into the tree and maintained elevated Zn in leaves for 9 years. Sulfuric acid and ZnSO4, applied in a shallow trench, lowered soil pH to a depth of 60 cm and increased volubility of Zn in the acid band. Large concentrations of CaSO4 were formed. Laboratory tests confirmed the movement and volubility of Zn in soils under conditions similar to those in the field. Tree roots did not grow into the acidified band, presumably due to high salinity, but proliferated extensively at the interface of the acidified band and calcareous soil.

Free access