The objectives of this were to investigate the response of Lupinus albus sp. to
phosphate rock (PR) as a source of phosphorus (P) nutrition, and to study the role organic
acid (Citric and Malic) in phosphorus dissolution from PR. Tow experiments we
re
conducted: 1) A greenhouse pot experiment, in order to study the response of white lupin
to the application of PR and Triple super phosphate TSP at three application rates (100-
450-800 ppm). 2)- A laboratory experiment in order to study the role of Citric and Malic
acids concentration and initial pH in P- release from PR. The results showed that Lupinus
albus sp. was able to use PR for P-nutrition, and has a relative agronomic effectiveness of
61% when compared to TSP. The possible Exuded organic acids such as Citric and Malic
were responsible for PR dissolution due to tow mechanisms: 64% of PR dissolution was
due to pH decrease in the rhizosphere area, and 34% due to chelating of calcium cations.
PR dissolution was increased by the increase organic acid concentration, but decreased
when the initial pH value increased. Dissolution was always more pronounced with citric
than malic acid.
The effect of green manure and biofertilizer by using (Lupinus albus and
Lupinus albu s + Rhizobium) on some soil properties and potato growth and
production during two successive seasons of 2007/2008 and 2008/2009 was
studied. The results showed
that green manure provided the soil with 3.75
kg/m2 green organic matter including (398 g dry matter and 14 g nitrogen),
while lupinus albus + Rhizobium provided the soil with 4.55 kg/m2 green
organic matter including (581 g dry matter and 22.3 g nitrogen) and improved
soil chemical properties. The results showed as well that biofertilizer significant
improved potato growth parameters: plant and tuber dry matter, foliage
surface, foliage index, plant length, plant elements content (N,P,K,Ca and Mg),
tuber number and their content of nitrate and protein .The results showed as
well that biofertilizer significant improved marketing potato yield.
دور الترمس الأبيض Lupinus albus sp في تحسين استجابة غراس الزفير Citrus aurantium للصخر الفوسفاتي كرديف للتغذية الفوسفورية في الزراعة العضوية
