الفهرس 
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Abstract
The current work was carried out at the Soil Science partment, Faculty of Agriculture, mnia Uni versi ty during Jperiod 1979-1980. The field work was conducted at the :ate Farm in the newly reclaimed sandy calcareous soils in st Sarnalout, Minia Governorate. The experiments aimed at lUdying the effect of macro and micronutrients on the yield ~chemical composition of potatoes. The nutrients studied .re the macronutrient s N, P and K and the micronutrient s, .,Mn and Zn. In order to study the possible interactions :tween these nutrients, three separate experiments were arried out each with two nutrients, i.e. N-N ; P-Zn and
;·Mn. The three experiments were carried out at the same
.:ne for two successive seasons.
The main findings obtained could be summarized in the llawing :
.trogen-Potassium Experiment :
. Soil application of nitrogen of 150 Kg per feddan increased progressively the tuber yield of potatoes. The yield inncreased due to the first increament of 100 Kg H was higher than the yield increase due to the additional increament
of 150 Kg N.
·Foliar application of urea in the spring season reduced the yield slightly, while in the autumn season, urea caused significant yield increases when applied either at a concentration of 0.50 % or 1.0 %.
·Potassium application resulted in a higher significant yield increases at different rates of nitrogen •
. The response to either N or K fertilizers was higher in the autwnn crop than in the spring crop.
·A possitive but insignificant N-K interaction was found ·The efficiency of N fertilizer applied to the soil as MWonium nitrate was very law and ranged from 5 to 11 % in the spring season and from 19 to 24 % in the autumn
·Efficiency of urea applied as a foliar spray was very higher in the autumn season.
·Efficiency of potassium was very low and ranged from 0.6 to 2.9 % in the spring season and from 1.2 to 8.4 % in the autumn season.
·The effect of N and K fertilizers on the chemical composiition of potatoes revealed that both Nand K application resul ted in significant increases of either IT and K in
both potato leaves and tubers, whereas it tended to deccreased the N content of tubers but did not affect the N content of potato leaves. The N-K interaction was not significant.
Both iT and K has no significant effect on P content of otato leaves and tubers. Iron content of tubers and leaves s not affected by N application, but K application caused :ome significant increase in the Fe content of leaves but .ot that of tubers.
Both N and K application resulted in some increases in lncontent of both leaves and tubers but did not consistently ~fect the content of Mn_in either leaves or tubers.
Ihosphorus-Zinc Experiment :
. Considerable yield increases due to either P or Z appliication were obtained in both seasons.
1· The maximum yield of potatoes was obtained at 500 Kg/feddan superphosphate. The yield of this treatment was almost
J times the yilled of 0 Buperphosphate.
J. Zinc application gave a highly significant yield increases at different rates of phosphorus.
·Slight and insignificant yield increazes were obtained from foliar spray of phosphoric acid at a concentration 0.25 or 0.50 %.
·Effects of P-Zn interaction on potato yield was insigniificant.
-The efficiency of P fertilizer applied to th~ soil as superphosphate was fairly high and ranged from 8-10 % in the spring season and from 12 to 23 % in the autumn season,
·Phosphoric acid application showed much higher efficiency than soil application of superphosphate.
-Soil application of phosphorus sienificantly increased
lr,P and Ie concentrations in both potato leaves and tubers, whereas it tended to decrease the concentrations of microonutrients Fe, Un and Zn in both leaves and tubers. These decreases, however, were insignificant in most cases.
-Application of Zn tended to increase the concentr2tions of N, K , Mil and Zn but to decrease those of P and Fe in both leaves and tubers of potato.
:ron-Uanganese Experiment:
,-Potato tuber yield significantly increased with either
Fe or Mil application with an obvious indicates that levels
of either elements significantly enchanced the responses to the other element.
·The yields in the autumn crop, as well as their responces of both Fe and Mn fertilization, were much higher than those of the spring crop.
·Yield increases due to 1~ treatments were significant when these treatments were combined with the Fe 304 spray while it vres insignificant when combined vdth Fe chelate
did not significantly affect the concentrations of either 1, P and K in potato leaves or tubers, although slight increases were obtained.
-Foliar spray of Fe 804 significantly increased the conncentrations of Fe, Mil and Zn in potato leaves but did not effect those elements in the tubers.
Foliar spray of Fe-chelate, although slightly increased the concentrations of all the studied nutrients in both leaves and tUbers, its effect was nither consistent nor significant.
’~ganese application resulted in significunt increases in the concentrations of N, P, ~m and Zn but did not significantly affect the content of either K or Fe in pot~to leaves and tubers.
from the results obtained in this work several concluu:ons could be made :
·It was obvious that major improvements in the yield of potatoes could be achieved by proper man gement methods especially in the field of fertilization.
-Due to the low fertility of the newly reclaimed sandy callcareous soils, the yield of potatoes showed remarkable to the application of all the studied nutrients, i.e. N,P,
K, Fe, I~ln and Zn.
·It could be recomoended to use the following fertilizer rates of 150, 200, 600 Kg/feddan of a~onium nitrate and potassium sulphate and superphosphate to obtained higher yields than previously in the area.
·fuliar application of macronutrients such as Nand P proved to be less effective.
-The relatively very low efficiencies of both N and K fertilizers give an indication of the low capacity of the e~erimental sandy soils to retain either water or nutriients. This problem should be studied in detail in order
to find \vays to menimize the losses of the applied fertiilizers. This ~ be achieved through menimizing the amount of irrigation water or applying less soluble forms of the fertilizers or split application of the fertilizers.