Effects of phosphorus and molybdenum application on the yield and nitrogen content of azolla (Azolla caroliniana, Wildenow)
1987
Hechanova, S.C. Jr. | Curayag, L.J. (Central Mindanao Univ., Musuan, Bukidnon (Philippines). Dept. of Crop Science)
Three levels of phosphorus (0, 8, 20 ppm P) and three levels of molybdenum (0, 1.5, 3.75 ppm Mo) were studied to evaluate their influence on the yield, performance and nitrogen content of azolla. Results of the study showed that the different levels of phosphorus had significant influence on vigor, yield, and nitrogen content of azolla plant in two croppings. The highest computed yield (2,735.4 kg per hectare) of fresh azolla was obtained from the plots which received 20 ppm phosphorus and zero molybdenum. This treatment gave an equivalent dry matter yield of 238.1 kg per hectare with an estimated 123.84 kg nitrogen produced per hectare per year. The control plots (zero P, zero Mo) and those with 8 ppm phosphorus gave relatively lower yields. The treatments receiving zero molybdenum were found to give generally higher yields than in the plots fertilized with the element. Regardless of the phosphorus treatment the highest fresh yield of azolla obtainable at zero molybdenum was 1,730.76 kg per hectare which is equivalent to 142.23 kg dry matter yield per hectare. Based on this average yield and its corresponding N content, a total of 74.56 kgs N per hectare per year was obtainable assuming that there are 16 croppings on one year. For soil and water media having similar characteristics used in this study, azolla can be successfully grown without molybdenum application but it requires the application of phosphorus at the rate of 20 ppm P.
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