Converting invasive aster (Ageratina adenophora L.) into organic fertilizer source.
Ageratina adenophora originated from Central America and is now flooding in tropical and subtropical countries where tobacco is the primary cash crop. A. adenophora is a noxious invasive plant affecting agriculture, forestry, and livestock production. After converting A. adenophora into an organic fertilizer source, the contents of nitrogen (N), phosphorus (P), and potassium (K) in A. adenophora and soil samples (rhizosphere and non-rhizosphere soil) collected from 42 typical A. adenophora communities were determined. In-situ composting (using cellulolytic decomposing bacteria Clostridium thermocellum and detoxifying bacteria Pseudomonas putida) and field experiment were conducted to compare the fertilizing effects with commercial organic fertilizer. The results showed that firstly, the nutrient contents of N, P, and K varied greatly with growth conditions (N 4.59?15.09 g/kg, P 0.71?5.46 g/kg, and K 7.44?17.65 g/kg). Secondly, NPK nutrients were mainly allocated in the shoots, and the NPK concentrations were comparable to those in shoot parts of rice, maize, and wheat. Depending on growth environments and soil properties, the more fertile soils, the more NPK nutrient contents accumulated. Lastly, applying decomposed A. adenophora gained high-medium tobacco proportion of 89.1% relative to that applied with commercial organic fertilizer (88.6%) (p > 0.05). Applying the decomposed A. adenophora on the experimental field could generate a slightly higher income than using commercial organic fertilizer. Therefore, A. adenophora is supposed to be NPK-rich organic fertilizer source, and the fertilizing effects were comparable to commercial organic fertilizer for promoting flue-cured tobacco yield and quality.