عنوان

Phosphorus soil test calibration for wheat on Moroccan soils

Number

TLpq303892140

.Language of Text, Soundtrack etc

انگلیسی

Title Proper

Phosphorus soil test calibration for wheat on Moroccan soils

General Material Designation

[Thesis]

First Statement of Responsibility

L. Moughli

Name of Publisher, Distributor, etc.

Colorado State University

Date of Publication, Distribution, etc.

1991

Specific Material Designation and Extent of Item

133

Dissertation or thesis details and type of degree

Ph.D.

Body granting the degree

Colorado State University

Text preceding or following the note

1991

Text of Note

Phosphorus fertilizer recommendations for wheat in Morocco are based on the climatic regions disregarding soil P fertility. An improved fertilizer program must be based upon the soil test level. This research was conducted in order to select the best P soil test and calibrate it for wheat. Greenhouse and field experiments were conducted to calibrate P soil tests for wheat (Triticum aestivum L.). Wheat was grown in a greenhouse, up to heading, on 11 soils from different regions of Morocco. The P rates were 7.7, 15.4, 30.8, and 61.6 mg P kg as monocalcium phosphate. Two and three field experiments, with increasing P rates, were conducted in the Tadla and the Gharb regions, respectively. A P adsorption study was conducted on 21 soils including the 11 soils used in the greenhouse experiment. Dry matter production and P uptake were highly correlated with the NaHCO3-P soil level on a wide range of soils while the NH4OAc-P test only correlated well on soils low in lime content. The CaCl2-P and the H2SO4-P soil tests were not effective. The NaHCO3-P soil test was also correlated with wheat P requirement. Phosphorus adsorption was correlated with clay content, CEC/clay ratio, lime content, and organic matter content. Among the different soil P buffering capacity indices tested, the Salmon index was the most effective in predicting wheat P requirement when used concurrently with NaHCO3-P or Joret-Hebert soil tests. This index is easy to determine or can be predicted from the soil clay content. Three of the five locations responded to applied P. The NaHCO3-P test of the responsive sites was lower than the critical level, 12 mg kg, as determined by Cate-Nelson graphical and analysis of variance methods. Square root and straight lines equations described well the yield data. The net return method was more accurate in determining the optimum P fertilizer requirement of wheat. The optimum P requirement was negatively related to the NaHCO3-P soil test level. The use of the NaHCO3-P test will improve P fertilizer recommendations in Morocco. However, the fertilizer P recommendation accuracy can be improved by using, concurrently, the NaHCO3-P test with the soil P buffering capacity.

Agricultural chemicals

Agronomy

Biological sciences

Pure sciences

soil test

Triticum aestivum

L. Moughli

Electronic name

p

[Thesis]

276903

a

Y