Integrated culture of white shrimp (Litopenaeus vannamei) and tomato (Lycopersicon esculentum Mill) with low salinity groundwater: Management and production

Abstract

The optimal utilization of water in arid and semi-arid regions is pivotal for resource sustainability. The integration of aquaculture with traditional agriculture may be a solution to achieve more efficient water use, maximizing farm production without increasing water consumption, avoiding disposition of aquaculture effluents and supplementing additional fertilizer to the agricultural crop. The objective of this study was to test the feasibility of an integrated shrimp (Litopenaeus vannamei) -tomato (Lycopersicon esculentum Mill) culture and evaluating the effects of the irrigation with shrimp farm effluent on tomato yield and to describe shrimp production. A field experiment was carried out in a randomized complete block design to evaluate the effects of three different water types on the growth of tomatoes: effluent water from shrimp culture tanks, nutritive solution prepared for tomatoes, and water directly from the well. Groundwater (0.65gL−1 of salinity) supplemented with KCl and MgNO3 was used with a shrimp stocking density of 50 postlarvae shrimp per m2. Evaluations for shrimp (mean weight, growth rate, survival and yield) and for tomato plants (fruit number, mean fruit weight and yield) were performed. Daily monitoring included temperature, conductivity, pH and dissolved oxygen in shrimp tank waters. Chemical analysis in a weekly monitoring included major ions and nutrients. The shrimp yield was 11.1±0.2kg per tank (3.9±2.0tha−1) with a mean survival of 56.3±1.1%, a mean weight of 13.9±0.4g, and a feed conversion rate of 1.60±0.03. The yield of tomatoes irrigated with shrimp effluent (33.3±2.1kg per 45 plants) was comparable to those irrigated with nutritive solution (35.7±1.7kg), and significantly (P<0.05) higher than those irrigated with groundwater (25.5±2.4kg). The budget evidenced that most of the N (43.6%) and P (99.4%) entered to the shrimp–tomato system as shrimp food. Within the system, 13.2% and 2.1% of the input N were converted to harvested shrimp and tomato plants; similarly, 8.9% and 4.3% of the input P, were converted to harvested shrimp and tomato plants. From this work, it is demonstrated that the shrimp–tomato culture system is feasible, with a water consumption rate of 2.1m3 per kg of harvested products. However, more research is needed to adjust the shrimp–tomato culture system in regards to the precise integration of the number of tomato plants per shrimp culture area and to optimize the composition of water used in terms of the major ions (concentration and ratio) and salinity.