عنوان

Long-term nitrogen fertilization effects on nitrogen mineralization potential in soils under different cropping systems and different environments

Number

TLpq304142900

.Language of Text, Soundtrack etc

انگلیسی

Title Proper

Long-term nitrogen fertilization effects on nitrogen mineralization potential in soils under different cropping systems and different environments

General Material Designation

[Thesis]

First Statement of Responsibility

M. El Gharous

Subsequent Statement of Responsibility

R. L. Westerman

Name of Publisher, Distributor, etc.

Oklahoma State University

Date of Publication, Distribution, etc.

1994

Specific Material Designation and Extent of Item

136

Dissertation or thesis details and type of degree

Ph.D.

Body granting the degree

Oklahoma State University

Text preceding or following the note

1994

Text of Note

Scope of study. Nitrogen mineralization of soil organic matter has long been recognized to be very important in meeting plant N needs. Recommendations for N fertilizer requirements for cereals are presently based on the level of nitrate in the top 15 cm of the soil before planting, deep sampling (60 cm) is considered when unusual cropping conditions arise. In order to improve N fertilizer recommendations, mineralization during the season needs to be accounted for. It is also hypothesized that long term N fertilization increases the magnitude of the easily mineralized N pool in soils. Different soil types from Oklahoma and Morocco were used to estimate the mineralization potential usd\rm (N\sb0)usd and the decomposition rate constant (k). The effect of fertilizer N and the relationship with plant N uptake and soil initial mineral N were investigated. Findings and conclusions. Soil N mineralization potential usd\rm (N\sb0)usd varied with soil type and cropping systems. The application of fertilizer N increased the soil's capacity to mineralize organic N in all cropping systems and environments. Also, it was found that usd\rm N\sb0usd decrease linearly with soil depth. The contribution of lower depth (20-60 cm) to total usd\rm N\sb0usd in the soil profile was found to be about 60%. Initial soil mineral N was highly correlated to plant N uptake, soil usd\rm N\sb0usd and usd\rm N\sb0k.usd The product of usd\rm N\sb0kusd and soil mineral N at start were found to be a reliable N availability index.

Agronomy

Biological sciences

fertilization

nitrogen

M. El Gharous

R. L. Westerman

Electronic name

p

[Thesis]

276903

a

Y