Acid soils has become an agro-economic issue because they are expensive and difficult to ameliorate. Acid soil is a worldwide problem which occupy 30 to 40% of the world arable land area mainly located in Africa and South America affecting about 56% and 31 % of their arable land respectively. In Australia and New Zealand, 239 million ha of agricultural land is acidic. Production in these soils is limited because of lack of essential nutrients, mainly phosphorus. Aluminium and iron phytotoxicity is another major problem in these soils. Approches such as liming and applying excessive amount of phosphorus soluble fertilizers can ameliorate the production in these soils, however these are non economic practices. Sparingly soluble phosphorus fertilizers, such as phosphate rock,  could be a good alternative to water soluble phosphorus fertilizers because it is considered as a slow release fertilizer, in other words it can provide plant with phosphorus and calcium during plant growth cycle. Moreover, it has the ability to increase soil pH in long term of use by the fact of releasing calcium in these soils. Finally, it has a low cost of phosphorus compared to water soluble phosphorus. the reactivity of PR is determined by a combination of factors including the degree of substition of carbonate with phosphorus in the rock, and the particle size of the material at application. The subsequent dissolution of PR in soil environment is also determined by a combination of factors including soil acidity (as indicated by soil pH), precipitation, relative soil P and Ca retention/adsorption/fixation and plant species. In this project, we aim to invesitgate the effect of soil pH, soil water content and soil type on the dissolution and agronomic performance of four moroccan phosphate rock with different reactivity. phosphate rock dissolution and its agronomic performance can be enhanced by some practices such as cover cropping and mixing green manure with phosphate rock. Coformulation of phosphate rock with other minerals can enhance the dissolution, the agronomic performance and P use efficiency of phosphate rock. The use of phosphorus solubilizing bacteria can also enhance of use of moroccan PR. In this project, laboratory, glasshouse studies will be conducted and results will be confirmed in field conditions. The specific objectives of this project are:

- Determine and quantify the effect of soil pH, soil water content and soil type on the dissolution of four moroccan phosphate rock with different reactivity in the laboratory (incubation study). -            Determine and quantify the effect of soil pH and soil water content on the agronomic performance and P use efficiency of moroccan phosphate rock using different plant species. - Investigate rhizosphere mechanisms affecting the dissolution and the agronomic and P use efficiency of moroccan phosphate rock by different plant species. - Evaluate the aptitude of a range of cover crops on enhancing the agronomic performance and P use efficiency of moroccan phosphate rock in the subsequent crop (main crop). - Investigate the effect of co-granulation of moroccan phosphate rock with other water soluble P fertilizer on the dissolution and the agronomic and P use efficiency of phosphate rock. -  Evalute  plant available phosphorus by four soil tests in three different acid soils amended with four Moroccan phosphate rock and three rates of lime (glasshouse study).  - Evaluate agroeconomic effect of the direct use of moroccan phosphate rock in different agro-ecosystems. 

Criteria of the candidate:  
* PhD in the subject discipline

* Proven ability to perform multidisciplinary research and contribute to funded research programs.
* Demonstrated understanding of operational requirements for a successful research project and managing time and resources.
* Proven ability to identify and fulfil the academic writing requirements for development of proposal, reports and scientific publications.
* Good English communication skills, both verbal and writing are important.
* Ability to work both as part of a team and to work independently.