Phosphorus availability from rock phosphate: Combined effect of green waste composting and sulfur addition
Journal of Environmental Management
Phosphorus is extremely important for plant growth, yet it's use in agriculture is extremely inefficient. A conservative estimate is that 50% of applied phosphorus becomes unavailable as it binds with other elements in the soil. To help alleviate this, we can thank microbes.
To address this problem, a team of scientists from Italy and Spain added rock phosphate to greenwaste-compost piles at several levels, let the compost go through its thermophilic cycle, and then determined soluble phosphate levels.
The scientists found that soluble phosphorus levels increased with the addition of compost. The increase was most drastic in the treatments that had the lowest amount of rock phosphate added. Furthermore, the addition of rock phosphate made for more efficient use of nitrogen in the compost, retaining it so that it was not lost to the environment. Adding elemental sulfur was also shown to help increase phosphorus solubility. Take home message: add a little soft rock phosphate to your compost pile to create a phosphorus rich biofertilizer.
Effects of selected root exudate components on soil bacterial communities
Root exudates are substances that plant roots secrete into the rhizosphere, stimulating microbial activity which in turn helps to support a healthy soil system and productive garden. The exudates are composed of a mixture of compounds each with its own unique properties.
A group of scientists from New Zealand wanted to know which of the exudate-constituents affected microbial growth the most. They did this by selecting six of the most common root exudate components: sugars (a mixture of fructose, glucose, sucrose), lactic acid, maleic acid, and quinic acid. With these ingredients, five artificial exudates were concocted to make treatments: sugars, sugars+all acids, sugars+individual acids). The artificial exudates were then watered into soil over a 14 day period. After the 14 days, microbial activity was measured (microbial activity can be measured in bulk, it gives us a good idea of population size). Also, the numbers of species (or diversity) in each treatment was quantified.
The scientists found that the most effective recipe to promote microbial activity was the combination of sugars and lactic acid. The high level of microbial activity indicates that this treatment had the highest microbial populations. Interestingly, the sugar/lactic acid brew had the lowest diversity. The most diversity was seen in the sugar/maleic acid brew. Even more interestingly...the sugar/maleic acid had the lowest amount of microbial activity. The scientists suppose that the sugar/lactic acid brew enabled the most efficient group of microbes to quickly proliferate, while the sugar/maleic acid caused slower growth which allowed a diversity of bacteria to grow. The combination of sugars and quinic acid, as well as the combination of sugars and all of the acids produced relatively high microbial activity as well as species diversity. Take home message, use a diverse food source for your teas, and you will have a diverse and abundant microbial community. Thanks Kiwis!
The Effects of Rate and Method of Aerated Compost Tea Application on Yield and Yield component of Tomato (Lycopersicon esculentum Mill.) at Burusa, South Western Ethiopia.
International Journal of Multidisciplinary and Current Research
A group of scientists in Ethiopia wanted to see whether or not compost tea would help improve tomato production. Local farmers are trying to avoid using chemical fertilizers due to economic and environmental costs. Compost tea is a low cost alternative worth investigating.
The scientists and farmers worked together, potting up Roma tomatoes into several groups that each received a different amount of compost tea. The first group received none, and the other four were watered or foliar sprayed weekly with 300, 600, 900, and 1200mililiters of tea. The plants received standard care otherwise.
Several parameters were studied during the experiment, including: plant height, number of primary branches, root length, days to flower initiation, days to first harvest, number of fruit per plant, fruit weight, fruit size, and fruit quality.
It was shown that across the board, compost tea was significantly beneficial. Compost tea helped to grow bigger plants that produced more, larger, higher quality fruit, that were able to be harvested sooner. The total marketable yield of tomatoes was 0.6kg per plant for the control group, and 2.4kg/plant in the high application rate group. That is a four-fold increase in tomatoes to market. That kind of increase in production could lead to improving the lives of thousands of people. Thanks compost tea! (the Materials and Methods section in this paper is worth the read, click the Link Here to learn more)