Mass balances of nitrogen and phosphorus in an integrated culture of shrimp (Litopenaeus vannamei) and tomato (Lycopersicon esculentum Mill) with low salinity groundwater: A short communication

• Most of N (43.6%) and P (98.8%) entered to the shrimp-tomato system as shrimp food.
• 8.9% and 4.3% of the input P were converted to biomass shrimp and tomato plants.
• 15.2% and 2.5% of total input N were converted to biomass shrimp and tomato plants.
• This shrimp-tomato system reduces the environmental losses of N and P.

This study re-examines the performance of an integrated shrimp-tomato system using the nutrients mass balance approach. A budget was calculated based on nutrients analysis, water management, feeding, fertilization, stocking, harvest and sludge removal. Nitrogen and P content in the input water (groundwater) were low, contributing 33.5% and 0.5%, of the total inputs, respectively. Most of the N (43.6%) and P (98.8%) entered to the system as shrimp food. Likewise, 15.2% and 2.5% of the input N, and 8.9% and 4.3% of the input P, were converted to harvested shrimp and tomato plants, respectively; 4.1% N and 24.6% P remained in the organic sludge, while the environmental losses expressed per unit of production were relatively low, 57 kg N ton−1 and 7.1 kg P ton−1 of product harvested. About 13.4% of input N was unaccounted for, and was assumed to be lost to the atmosphere via denitrification and volatilization. Comparison between these results and previous studies indicate that the shrimp-tomato system produces a relatively low recovery of N and P as harvested products, however, the main progress reached with this system is the reduction of the environmental losses of N and P in terms of kg of each nutrient per ton of the product harvested.