Evaluation of Various Sources of Bacteria on Biofloc Productivity

Biofloc technology is a new alternative in addressing water quality problems in aquaculture which is adapted from conventional domestic waste processing techniques. The main principle applied in this technology is water quality management which is based on the ability of heterotrophic bacteria to utilize organic and inorganic N in water. In a balanced C and N condition in water, heterotrophic bacteria which will utilize N, both in organic and inorganic form, are present in water for the formation of biomass so that the concentration of N in water is reduced. Several types of bacteria that are often used in biofloc are Bacillus sp., Bacillus subtilis, Pseudomonas sp., Bacillus lichenoformis, Bacillus pumilus; Lactobacillus sp.; Bacillus megaterium . Microbes play key role in the biofloc systems. Microbes associated with floc after consumption help to improve digestion, reduces FCR reduces dietary protein level and heterotrophic bacteria, which together probiotic bacteria, inhibit the development of potential pathogen bacteria. With biofloc there are some improves in different aspects during culture like higher growth rates, increased survival, improved water quality, reduced amount of water used and decrease in diseases. Thus, role of microorganisms is important in biofloc system; therefore, it is necessary to carry out more studies related to identification of microbes that can be present in biofloc systems.

EFFECT OF ORGANIC-INORGANIC N SOURCES ON GROWTH, NPK NUTRIENTS AND SECONDARY METABOLITES OF PANAX NOTOGINSENG (BURK.) F. H. CHEN

The effects of organic and inorganic N combined application on P.notoginseng cultivation are poorly known. For this reason, we have carried out a pot culture experiment in 2010. The treatments respectively were (1) control (no N input, CK), (2) organic N (ON), (3) half organic N and half inorganic N (1/2ON+ 1/2IN), (4) inorganic N (IN). Plant growth, NPK and secondary metabolites concentration were assayed. Results showed that compared to CK, ON increased plant height, N, P concentration and accumulation and total saponins concentration, but reduce total flavonoids concentration. IN increased shoot and root biomass, N concentration and accumulation, K accumulation, but reduce total flavonoids and saponins concentration. 1/2ON+ 1/2IN had the highest hair root length, root diameter, biomass, N concentration and accumulation, K concentration in roots, total saponins concentration, but had the lowest K concentration in shoots, total flavonoids concentration in shoots and roots. Correlation analysis showed total flavonoids concentration was negative correlated with N concentration and accumulation, K concentration in shoots, but was positive correlated K concentration in roots. Total saponins concentration was negative correlated with K concentration in shoots whereas positive in roots, and was negative correlated with total flavonoids concentration. Totally, organic and inorganic N combined application with the ratio of 50/50 is the best way for growth and saponins of P.notoginseng.

398 Three Years of Tomato Gas Exchange Response to Nitrogen Sources at Fruiting

The purpose of this 3-year study was to compare organic and inorganic N sources for promoting gas exchange (GE) in tomato at fruiting. Measurements of transpiration (E), photosynthesis (Pn) and internal leaf CO2 concentration (Ci) are reported. The following winter–spring fertility treatments were applied using randomized complete block design with four replications: 1) 0 N winter–0 N spring, 2) 0 N winter–90 kg N/ha spring, 3) 0 N winter–180 kg N/ha spring, 4) 0 N winter+abruzi rye–0 N spring, 5) 0 N winter+hairy vetch–0 N spring, and 6) 0 N winter+crimson clover–0 N spring. In spring of 1996, 1997, and 1999, `Mountain Pride' tomatoes were transplanted in all plots. Maximum E (14.3 μmol·m–2·s–1), Pn (22.8 μmol CO2/m2 per s), and Ci (352.2 μL·L–1) occurred in 1997, 1996, and 1999, respectively. In general, E was affected mostly by treatments 2, 3, 5, and 6 and Pn by treatments 2 and 5, while treatments 1 and 4 affected Ci the most. Results indicate that N from both legumes and synthetic fertilizer enhanced GE of tomato similarly.