Optimum Fertilization for Production of Containerized Seabeach Amaranth (Amananthus pumilus)

摘要

Seeds of seabeach amaranth (Amaranthus pumilus Raf.) in dry storage at 4 deg C since Nov. 2003, were removed from storage in Feb. 2005 and graded. Half the graded seeds were stratified (moist-prechilled) for 90 days at 4 deg C. The remaining seeds were returned to dry storage at 4 deg C. After 89 days these seeds were removed from storage and placed in a solution of K-GA_3 at 1000 mg-L~(-1) for 24 h. After treatment, both groups of seeds were sown in containers of two differing volumes, 139 or 635cm~3, with a substrate of peat and pine bark (1:1, v/v) amended with one of two rates of pulverized dolomitic limestone (2.24 or 4.48 kg-rrr~(-3)). The containers were maintained in a greenhouse and after seedling emergence, seedlings were fertilized with a 20N-4.4P-8.2K (20N-10P_2O_5-20K_2O) acidic, water soluble fertilizer or a 15N-2.2P-12.3K (15N-5P_20_5-15K_20) basic, water soluble fertilizer. Each fertilizer was applied thrice weekly at N application rates (NARs) of 75,150,225, or 300 mg-L~(-1). In June 2005,8 weeks after sowing of seeds the study was terminated and data recorded. Regardless of fertilizer, acidic or basic, top dry weight and leaf area of seabeach amaranth increased linearly with increasing NAR, and maximum top dry weight and leafarea occurred with N at 300 mg-L~(-1). In contrast, root dry weight was unaffected by NAR. Seabeach amaranth can be produced successfully in containerized production with maximum top growth occurring with N at 300 mg-L~(-1) provided by an acidic or basic fertilizer having a 4.5N-1 P-1.9K or 6.8N-1 P-5.6K ratio, respectively.