Converting from Seepage Irrigation to Plasticulture for Vegetable Production: A Case Study

This article is intended to provide information to producers and Extension agents that are interested in using drip irrigation for vegetable production. Cabbage production in Florida is dominated by the use of seepage or sub-irrigation. This system has traditionally been used because it is inexpensive to maintain and simple to use. Seepage irrigation works by damming tail water ditches, pumping water into open furrows, and effectively raising the water table to a depth accessible to the crop root system (For more information see EDIS Publication #HS1217). This type of irrigation practice is almost completely unique to Florida and is possible due to the persistence of a shallow, impermeable layer in the soil profile. This system can require vast quantities of water to be pumped from the aquifer in low-rainfall years. Plasticulture, or the use of drip irrigation and plastic mulch, has been proposed as an alternative production method for cabbage production in Florida. An on-farm demonstration was set up to provide a platform for collaboration between researchers, growers, and Extension professionals. The demonstration was located on Greene’s Farms in Bunnell, FL. The goal of the demonstration was to grow high-density cabbage populations using plasticulture side by side with seepage on a commercial farm. Fertilizer and irrigation management was closely matched between systems. The plasticulture system was designed to provide a small-scale installation of this technology for learning and commercial adaptation purposes. This small-scale system has great potential for encouraging adoption of this type of system with low risk to the grower. This article illustrates an innovative approach for converting from seepage irrigation to plasticulture and points out some options and challenges for growers considering a plasticulture system.

Economic Feasibility of Converting from a Bare Ground System with Seepage Irrigation to Plasticulture for Cabbage Production: Where is the Risk?

Weather has a major influence on cabbage (Brassica oleracea var. capitata L.) production. Variation in yield between years and cropping seasons is common in North America. Cabbage in Florida has historically been cultivated on bare ground with seepage irrigation. The objectives of this study were to compare yield and profit of a bare ground cabbage production system used in Florida with an alternative plasticulture system. Data from various cabbage trials were combined by production system and used to create regression equations that predicted yield based on air temperature and solar radiation that were significantly correlated with yield. The regression equations were then simulated with correlated stochastic air temperature and solar radiation to estimate the yield distributions for both systems. Cabbage price ($/Mg fresh) was stochastically simulated (correlated to yield) to be used in the profit model. The profit model was created by using the product of yield and the price per unit yield minus fixed and variable costs associated with production and marketing. Simulated profit for bare ground and plasticulture was used to estimate their respective distributions to provide a tool for making better management decisions in the presence of risky weather conditions. The plasticulture system was estimated to have a 36% higher cost but a 57% higher profit than the bare ground system. This is, in large part, because the simulated mean yield for the bare ground system was 29.7 Mg·ha−1 compared with 54.4 Mg·ha−1 for plasticulture. These findings confirmed that plasticulture is an economically viable best management practice for cabbage production in Northeast Florida.

Old Melioration Systems: The Influence Onto Functioning Of Geoecosystems Of River Valleys In The Parsęta (NW Poland)

Meliorations and their specific forms – irrigations – are one of the forms of anthropopressure within geoecosystems. The research studies conducted within the Parsęta basin focused on the sub-irrigation (seepage irrigation) systems formed in the 19th century. Query of archive materials and maps, hydrochemical and phytosociological terrain mapping and laboratory testing of water samples collected were used in the studies. In the study area were found the remains of the thirty old irrigation systems, which together occupy 2% of the Parsęta basin area. For many years most of them have not fulfilled their primary economic functions. Still, these systems have an impact on the cycle of waters and have become an important factor in increasing the geo- and biodiversity within the postglacial landscape. By expanding a range of wetland riparian areas, they fulfil relevant functions to protect surface waters against the supply of biogenic components. Some of them could be used to enlarge wetlands and floodplains within river valleys.

Subsurface Drip Irrigation (SDI) for Enhanced Water Distribution: SDI - Seepage Hybrid System

In terms of water use efficiency, the traditional seepage irrigation systems commonly used in areas with high water tables are one of the most inefficient methods of irrigation, though some irrigation management practices can contribute to better soil moisture uniformity. Subsurface drip irrigation systems apply water below the soil surface by microirrigation, improving the water distribution and time required to raise the water table for seepage irrigation. This 6-page fact sheet was written by Lincoln Zotarelli, Libby Rens, Charles Barrett, Daniel J. Cantliffe, Michael D. Dukes, Mark Clark, and Steven Lands, and published by the UF Department of Horticultural Sciences, March 2013. http://edis.ifas.ufl.edu/hs1217

Finite Element Numerical Simulation of Two-Dimensional Unsaturated Soil Water Movement Problems

According to the fundamental theory of soil water dynamics, the mathematical model of 2-D unsaturated soils water movement with variable is established under the condition of furrow irrigation or underground channel seepage irrigation,and is calculated by the finite element numerical simulation method .The numerical simulation shows that the calculated results of numerical simulation is in good agreement with the measured date of experiment.

Effect of El Niño–Southern Oscillation on the Number of Leaching Rain Events in Florida and Implications on Nutrient Management for Tomato

Most of the winter vegetable production in the southeastern United States is located in Florida. High-value vegetable crops are grown under intensive fertilization and irrigation management practices using drip, overhead, or seepage irrigation systems. Rainfall events may raise the water table in fields irrigated by seepage irrigation resulting in leaching of nutrients when the level is lowered to remove excess water. The objective of this study was to assess the effect of El Niño–Southern Oscillation (ENSO) phases on rainfall distribution and leaching rain occurrences during the fall, winter, and spring tomato (Solanum lycopersicum) growing seasons using long-term weather records available for main producing areas. Differences in fall growing season mean precipitation during El Niño, La Niña, and neutral years were found to be nonsignificant. Winter and spring mean precipitations during El Niño, La Niña, and neutral years were found to be significantly different. Winter and spring average rainfall amounts during La Niña and neutral years were lower than during El Niño years. During El Niño years, at least one leaching rainfall event of 1.0 inch or more in 1 day occurred at all locations and all planting seasons and two of these events occurred in more than 9 of 10 years except during the winter and spring planting seasons at the Tamiami Trail station located in Miami–Dade County. During the fall growing season of El Niño years, three to four 1.0 inch or more in 1-day leaching rainfalls may be expected at least 4 of 5 years at all locations. In the case of larger leaching rainfall events (3.0 inches or more recorded in 3 days or 4.0 inches or more recorded in 7 days), the probability of having at least one event was mostly less than 0.80. Based on these results, nitrogen fertilizer supplemental applications of 30 to 120 lb/acre could be applied during the fall growing season of all ENSO phases and during all planting seasons of El Niño years. Using current fertilizer prices, one supplemental fertilizer application of 30 lb/acre nitrogen and 16.6 lb/acre potassium costs $55/acre. Assuming a median wholesale price of $12 per 25-lb box, this additional cost may be offset by a modest yield increase of 4.6 boxes/acre (compared with a typical 2500 25-lb box/acre marketable yield). These results suggest that ENSO phases could be used to predict supplemental fertilizer needs for tomato, but adjustments to local weather conditions may be needed.

Estimation of lateral water flow and bromide transport in a subsurface seepage irrigation system

Subsurface seepage irrigation is a common method used by growers in the Tri-County Agricultural Area (TCAA), Florida, USA, owing to its cost-effectiveness and low maintenance requirements. This study investigated the lateral flow of the perched water and the lateral transport of bromide (Br−) in this irrigation system in the TCAA and estimated the potential discharge of Br− into the drainage canals at the edges of the field, using the Visual MODFLOW/ MT3DMS models in conjunction with field experiments. Simulations showed that the perched water flowed from the northeast to the southwest of the field. Migration of the Br− plume from the source areas toward the canals was very slow and varied depending on the selection of the outer Br− concentration contour levels. However, the lateral transport of Br− from the perched water into the canals occurred after about 61 days. The simulations further revealed that the rate of perched water Br− discharge into the canals averaged 8.6 g day−1 during a 30-day discharge period (from 61 to 91 days). This rate is very important for estimating Br− discharge into the canals and could also provide useful information for evaluating dissolved nutrient discharge into canals from the subsurface seepage irrigation system.