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Application of water and nutrients for horticultural production in Florida can be accomplished through many different methods. Often, the irrigation system that is used determines the potential use efficiency for both water and nutrients. Producers face many constraints, real and perceived, that affect management decisions. This article provides an overview of many of the constraints that are encountered and identifies those management practices that are most effective for overcoming these constraints with respect to commonly used irrigation systems. These constraints include those related to irrigation system design and capabilities, soil factors, cultural practices, management intensity, and economic and regulatory conditions. Ultimately, the goal of this discussion is to determine where future research efforts should be focused and what critical issues may be on the horizon that may affect the Florida horticultural industry.
Experiments were conducted in two seasons in Dover, Fla. (central Florida), with bare-root and containerized (plug) strawberry (Fragaria ×ananassa) transplants to evaluate transplant establishment-period water use, plant growth, and flowering responses in the 3-week transplant establishment period. Strawberry plug plants were established with 290 gal/acre water applied only with the transplant at planting time, while 200,000 gal/acre from microjet or 1 million gal/acre of water from sprinkler irrigation were used to establish bare-root transplants. Root, shoot, and crown dry matter of plug plants rapidly increased during the establishment period, while there was a decline in leaf area and root and crown mass of bare-root plants, even with sprinkler or microjet irrigation. Water applied with the bare-root transplant only at planting was not enough to keep the plant alive during the establishment period. Large plug plants, but not irrigated bare-root plants, began flowering at 3 weeks after planting. Plug plants were used to successfully establish strawberry crops with low water inputs.
Strawberry (Fragaria ×ananassa) crops were transplanted in two seasons in central Florida with bare-root and containerized (plug) plants under three transplant establishment-period irrigation methods to evaluate crop fruiting responses and production economics associated with the various establishment systems. Irrigation was not required to establish plug transplants in the field. Early (first 2 months) fruit yield with nonirrigated plug plants was greater than early yield with sprinkler-irrigated bare-root plants (the current commercial system) in one of two seasons and equal in a second season. Total-season yields were similar in each season between the two establishment systems. Large or medium plug plants led to greatest early fruit yields in one season while large plug plants resulted in greatest early yield in a second season. Total yield was greatest with medium plants in one season and large plants in another season. The extra cost for the plug plant system was $1853/acre. In one out of two seasons there was increased net income amounting to $1142/acre due to greater early yield associated with the plug plant cultural system. Strawberry plug transplants showed promise for earlier and more profitable crops in addition to substantial savings in water used for plant establishment in the field. The ability to establish strawberry crops without irrigation will be important in areas where growers are required to reduce farm water consumption.
Recent concerns over the environmental impact of peat harvesting have led to restrictions on the production of peat in Florida and other areas. The objectives of this study were to evaluate the use of composted dairy manure solids as a substitute for sphagnum or reed-sedge peat in container substrates on the growth of Solenostemon scutellarioides L. Codd ‘Wizard Velvet’, Tagetes patula L. ‘Safari Queen’, and Begonia ×hybrida ‘Dragon Wing Red’ and to examine the nutrient content in leachate from pots. Plants were grown for 5 weeks in a greenhouse in 15-cm plastic pots with seven substrates containing various proportions of sphagnum peat (S) or reed-sedge peat (R) and composted dairy manure solids (C), each with 20% vermiculite and 20% perlite. Substrate composition had no effect on plant quality ratings, number of flowers, or root dry mass for any of the plant species evaluated. Substrate composition did not affect the growth index (GI) or shoot dry mass of S. scutellarioides ‘Wizard Velvet’ or the GI of T. patula ‘Safari Queen’. However, growth of B. ×hybrida ‘Dragon Wing Red’ (GI and shoot dry mass) and T. patula ‘Safari Queen’ (shoot dry mass only) was highest in the 3S:0R:0C substrate. The substrates containing sphagnum peat and/or composted dairy manure solids (3S:0R:0C, 2S:0R:1C and 1S:0R:2C) had the highest NH4-N losses through the first 7 d of production. The 0S:3R:0C substrate had the highest initial leachate NO3+NO2-N losses and this trend persisted throughout most of the production cycle. Significantly more dissolved reactive phosphorus was leached from substrate mixes containing composted dairy manure solids than mixes containing only sphagnum or reed-sedge peat materials through 19 d after planting. All substrates tested as part of this study appeared to be commercially acceptable for production of container-grown bedding plant species based on plant growth and quality. However, nutrient losses from the containers differed depending on the peat or peat substitute used to formulate the substrates.
The urban soil environment is usually not conducive to healthy root growth and function, leading to problems with plant establishment, growth, and aesthetic quality. The objective of this study was to determine if the addition of compost with or without the application of shallow tillage or aeration will improve soil physical and chemical properties and plant growth compared with an unamended control in simulated new residential landscapes. Twenty-four mixed landscape plots were established in a randomized complete block design to simulate new residential landscapes. Each plot was constructed using 10 cm of subsoil fill material over a compacted field soil and planted with Stenotaphrum secundatum and mixed ornamental plant species. Composted dairy manure solids were applied as an organic soil amendment at a depth of 5 cm (≈256 Mg·ha−1) in combination with two mechanical soil treatments (tillage to 15 cm and plug aeration) for a total of five soil management treatments plus an untreated control. Soil physical and chemical properties, plant growth, and quality and plant tissue nutrient concentrations were assessed periodically to determine the effect of soil treatment on soil and plant quality. Applications of compost to soils significantly reduced soil bulk density and pH and increased soil organic matter, electrical conductivity, and Mehlich-1 phosphorus and potassium concentrations. All ornamental plant species, with the exception of Raphiolepis indica (L.) Lindl. ex Ker Gawl., exhibited more growth when grown in soils amended with composted dairy manure solids. In most instances, plant tissue nitrogen and phosphorus concentrations were higher for plants grown in soils receiving compost. Results of our study suggested that the addition of composted dairy manure solids to soils can improve soil properties and enhance plant growth in residential landscapes when sandy fill soils are used. In contrast, shallow tillage and aeration had little effect on soil properties or plant growth.