Two field experiments were conducted on a sandy soil cultivated
with two summer crops, i.e., peanut (Giza 5) and maize (Giza 2) under
sprinkler irrigation system during growing season of 2004 at Ismailia
Agric. Res. Station. The current work aimed to evaluate impact of
micronutrients in two forms, i.e., mineral (Fe, Mn & Zn sulphates) and
chelating compounds (Fe, Mn & Zn-amino acids, -citrate, -EDTA and -
legnosulphate), added as foliar and soil application, on yield and its
components for each of the studied crops as well as peanut seed and maize
grain contents of some nutrients (N, P, K, Fe, Mn and Zn). Also, this study
takes in consideration the residual effect of the two application methods on
available micronutrients status in soil.
The result obtained reveal that peanut and maize yields and their
components showed, in general, a markedly response to all applied
treatments, with a superior effect for foliar spray but insignificant
differences with soil application, as shown in a descending order
according to their effective roles: amino acids > citrate > sulphates >
EDTA > legnosulphate. The chelating compounds of amino acids and
citrate recorded the superior increases in both peanut and maize for
protein content and 100 peanut seed or maize grain weights, while an
inferiority effect was observed with legnosulphate. Both forms of
EDTA and sulphates were lying in between. The superior effect of
amino acids may be due to their more adhesion for chelating
micronutrients, and enhancing their absorption and transportation inside
the plant in easier status. Moreover, amino acids as micronutrient
compounds are found in smaller molecules that are more suitable for
cell membrane permeability.
There were positive effects for the tested treatments, with exception
of legnosulphonate, on micronutrient contents in peanut seed and foliage or
maize grain and stover, with superiority for amino acids and citrate as
micronutrient compounds. For the residual effect of the applied treatments
on soil available micronutrient contents, data show a markedly increase in
the case of soil application as compared to foliar spray, in spite of an
insignificant differences between micronutrients uptake by the grown
plants in both tested methods.
From aforementioned results, it can be concluded that, the
application of micronutrients either in mineral sulphates or chelating
compounds under both foliar spray and soil application increased crop < br />yields and their components as well as improved the nutritional status of
both peanut and maize plants grown on a sandy soil under sprinkler
irrigation system, with relatively higher ability for increasing available
micronutrients in soil under soil application than foliar one.