Compost Tea Nearly Doubles Phosphorus Availability in High Calcium Soils

Effect of Applying Compost Tea Through Leaves and Soil on Soil P availability and P Uptake of Maize (Zea mays L.) at Alfisol Jatikerto Kab. Malang
January 2023
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       Farmers know that phosphorus promotes fruit and flower development.  Farmers also know that phosphorus can be hard to access in the soil, as it binds up with calcium, iron, or aluminum pretty easily.  To overcome this, excess phosphorus is applied to ensure that there is plenty for the plant and for what is to be "wasted" to soil chemistry.  This practice is inefficient in both materials and labor.   So, what can be done?  
           Well, you guessed it... compost tea!!!   It's well known that bacteria and fungi have the ability to dissolve bound-up phosphorus, making it plant available.  The microbes in compost tea have been shown to help promote this flower-friendly function.  In this current research, a group of scientists in tropical Indonesia wanted to see if applying compost tea to soils high in calcium (Alfisols), would help to improve available phosphorus levels and growth in corn.  The researchers brewed an aerated compost tea at several dosage levels to determine if there is an optimal range, and then applied the tea by way of both foliar sprays and soil drenches.   They then looked at phos levels at 14, 28, and 42 days after planting.    It was found that, yes indeed, the tea helped.
           According to the researchers conclusion "the percentage increase in available P levels in the application of compost tea to the soil (CT3) was 85.78% and to the leaves (CT6) of 29% compared to the control".  This means that applying tea to soil nearly doubled the amount of available phosphorus.  Applying tea to just the leaves also showed an increase in available phos, this could be due to the plants absorbing nutrition from their leaves, which promotes overall growth and would increase the amount of sugars being sent to the roots that then feed the  microbes that help dissolve phos from its bound-up state.   That last sentence is pure conjecture on our part, but makes sense and could be the next step in this ground-dissolving research.   Looking forward to more from these compost-wise scientists!  

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