ترجمه مقاله نقش ضروری ارتباطات 6G با چشم انداز صنعت 4.0
- مبلغ: ۸۶,۰۰۰ تومان
ترجمه مقاله پایداری توسعه شهری، تعدیل ساختار صنعتی و کارایی کاربری زمین
- مبلغ: ۹۱,۰۰۰ تومان
We evaluated fertilizer effects on phytoplankton and zooplankton concentrations in channel catfish Ictalurus punctatus nursery ponds. In 2001, three ponds were not fertilized and three ponds were fertilized with inorganic (8.4 kg/ha N, 2.0 kg/ha P followed by twice a week applications at half the initial rate) and organic fertilizer (224 kg/ha cottonseed meal followed by once a week applications of 28 kg/ha) for 4 weeks. Total P and soluble reactive P (SRP) were significantly higher in fertilized ponds ( P < 0.05), however no differences in algal populations resulted. Of the zooplankton, only copepod nauplii were higher in fertilized ponds. In 2002, 26 ponds were used. Sixteen ponds were newly constructed; 10 ponds were old (>10 years). Within each age group, treatments of no fertilizer (controls), organic fertilizer only, inorganic fertilizer only, or both organic and inorganic fertilizers were used for 3 weeks.