Two field experiments were conducted during a winter growing season of
2007 on two soil types of newly reclaimed and ancient agricultural areas,
however, their soils having different origins and characteristics (i.e., desert sandy
soil calcareous in nature at Noubaria area and the Nile alluvial clayey one at
Gemaiza Agric. Exp. Station) to evaluate the effect of organic compost (as a
source of N-organic) on availability and uptake of essential nutrients and their
positively effects on plant growth and nutritional status at different physiological
stages of wheat (Triticum aestivum, Sakha 69 c.v.) as well as yield and its
components. However, a partial 20 % of N-mineral was substituted by N-organic
manure derived from composted corn stalks and broad bean straw as compared to
applying 100 % N-mineral fertilizer in form of ammonium sulphate (20.6 % N).
The obtained data show that the applied composted plant residues
increased dry matter yield of wheat plants at all physiological stages under study
in both the studied soil types. Also, the application of composted plant materials
was achieved as a superiority effect on nitrogen, phosphorus and potassium
uptake by wheat plants. The grain quality as a function of total protein and
carbohydrates was also superior affected by the applied composted plant
residues, particularly in case of composted broad bean straw under the conditions
of the studied two soil types. That was discursive, since a partial N-mineral
mineral substitution by N-organic manure plays an important role for maximizing
the biological yield of wheat (straw and grain yields) as well as grain quality.
This is mainly due to such agro-management practice is not only partially
capable to retain nutrients in soil for a long-term use, but also leads to improve
soil properties which encouraging the availability, mobility and uptake of
nutrients by growing plants. Consequently, the field experiments under study
emphasized the importance of organic fertilization for either sandy or clayey
soils, due to assess N, P and K availability in soils as well as their mobility and
easily uptake by plant roots as affected by the applied composted plant materials.
Taking into consideration the nutrients enrichment of clayey soil, the rate of
availability and uptake of nutrients in sandy soil was more clearly obvious,
probably due to the soil media have no restrictive agents.
An economical evaluation was performed for the partial N-mineral mineral
substitution by N-organic manure (20 % of N-mineral), by using the composted
plant residues as related to the full dose of N-mineral fertilizer, which showed
that those of low C/N ratio such as composted broad bean had a relatively
superior profitability. Actual net profit of applied fertilizers appeared to be no
pronounced differences in both soil types. This may be due to the easily losses of
N-mineral fertilizer by either volatilization or leaching from a soil calcareous in
nature and relatively coarse in texture, and in turn this reason may be attributed
with external conditions.