Abstract The concentration of aluminum (Al), manganese (Mn), iron (Fe), zinc (Zn), and copper (Cu) in leaves, shoots, trunks, and roots, and the content of plant‐available Mn and Al in soil was examined after 13‐year treatments of soil pH and nitrogen (N) source in a peach orchard of North Carolina. Raising soil pH by liming tended to reduce soil Al content, but had no effect on soil Mn. Tissue Al and Mn level was decreased in high pH treatment. Poultry manure application resulted in the highest soil Mn content but the lowest soil Al. In comparison with calcium nitrate [Ca(NO3)2], ammonium sulfate [(NH4)2SO4] increased Al availability in soil while had little effect on soil Mn. Acid‐forming N, especially (NH4)2SO4, increased the concentration of tissue Al, Mn, Zn, and Fe. The plants treated with various basic N materials similarly contained lower levels of Al or Mn. Manure treatment resulted in high tissue Cu and Zn but low tissue Fe levels. Tissue Zn was low when mineral N sources containing calcium (Ca) or sodium (Na) were applied.
Summary The influence of water stress on the absorption and translocation of 14 C‐labelled fenoxapropethyl and imazamthabenz‐methyl in Avena fatua L. (wild oat) was studied. The phytoioxicity to A. fatua of both herbicides with a droplet application was also examined under water stress conditions. The absorption of both fenoxaproethyl and imazamethabenz‐methyl was reduced by waler stress when the plants were harvested within 24 h after herbicide application. Up to 48 h after the application, the translocation out of the treated lamina of both herbicides, based on percentage of applied 14 C. was reduced under water stress conditions. When havested 96 h after herbicide application, however, water stress no longer significantly affeaed the absorption and translocation of either herbicide. When the herbicides were applied as individual droplets, water stress reduced the phytotoxicity of fenoxaprop‐ethyl but not that of imazamethabenz‐methyl. It is concluded that the changes in herbieide absorption and translocation may not be the major physiological processes associated with differential whole‐plant response oi A faiua to fenoxaprop‐ethyl and imazamefhabenz‐methyl under water stress.
Abstract Abstract Following 13‐year treatments of soil pH and nitrogen (N) source in a peach orchard of North Carolina, the concentration of calcium (Ca), magnesium (Mg), N, phosphorus (P), and potassium (K) in leaves, shoots, trunks and roots, as well as soil pH, soil exchangeable Ca, Mg, and K content, were determined. Through liming, higher soil pH treatment enhanced soil Ca and tissue Ca level. Among six N sources examined, the highest values of soil pH and soil Ca, Mg, and K were detected following poultry manure application. Compared to ammonium sulfate [(NH4)2SO4], calcium nitrate [Ca(NO3)2] increased soil pH and soil Ca and K content, but reduced soil Mg. For most of macronutrients examined in peach tissues, the highest levels were found in manure treatment. Mineral N sources containing Ca(NO3)2 resulted in high tissue Ca and low tissue N. In the above‐ground tissues, Mg concentration was relatively low following application of mineral N materials containing Ca, K, or sodium (Na). Acid‐ forming N, especially (NH4)2SO4, reduced tissue Ca and P. The magnitude of impact of liming and N source on macronutrients was tissue‐type dependent, with leaves and other new growth the most sensitive ones while trunks seldom responded to the treatments.
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