Horseradish (Armoracia rusticana) is a hardy perennial that is grown for its white, fleshy, and pungent roots. Illinois leads the United States in production of horseradish, with ≈1500 acres and an annual farm-gate value of about $10 million, with most processed and added as an ingredient to various commercially produced condiments. Horseradish in Illinois is primarily grown in the Mississippi River Valley region adjacent to St. Louis due to the well-drained, deep friable, high organic matter, moist loam soils that are present in this area. Most of the production is located in Madison and St. Claire counties. This region of southwestern Illinois has been producing horseradish commercially for over 150 years. This review provides an overview of the basics of horseradish production in Illinois, including propagation, cultivars, planting, cultivation, fertilization, pest management, harvest, grading, storage, and marketing. Horseradish is one of the most important specialty crops grown in Illinois, and current and future production concerns are also discussed.

Greenhouse hydroponics and field experiments were conducted to determine how nitrogen (N) fertilizer treatments affect tomato (Lycopersicon esculentum Mill.) growth, yield, and partitioning of N in an effort to develop more sustainable fertilization strategies. In a hydroponics study, after 4 weeks in nitrate treatments, shoot dry weight was five times greater at 10.0 than at 0.2 mm nitrate. An exponential growth model was strongly correlated with tomato root growth at all but 0.2 mm nitrate and shoot growth in 10 mm nitrate. Root dry weight was only 15% of shoot biomass. In field studies with different population densities and N rates, height in the 4.2 plants/m2 was similar, but shoot weight was less than in the 3.2 plants/m2. At 12 weeks after planting, shoot fresh weight averaged 3.59 and 2.67 kg/plant in treatments with 3.2 and 4.2 plants/m2, respectively. In 1998, final tomato yield did not respond to N rate. In 1999, there was a substantial increase in fruit yield when plants were fertilized with 168 kg·ha-1 N but little change in yield with additional N. Nitrogen content of the leaves and the portion of N from applied fertilizer decreased as the plants grew, and as N was remobilized for fruit production. Both studies indicate that decreasing N as a way to reduce N loss to the environment would also reduce tomato growth.

A foam mulch system was developed that can be applied as an aqueous mixture of cotton and cellulose fibers, gums, starches, surfactants and saponins and dries to an one inch thick mat. This mulch may overcome the difficulty in applying and lack of persistence with natural mulches. Foam mulch also has the advantage of being able to be incorporated into the soil without requiring disposal like some plastic mulches. The objective of our study was to determine the effect of foam mulch and its color on weed control within the crop row and on yields of basil (Ocimum basilicum) and tomatoes (Lycopersicon esculentum). The foam mulch maintained its integrity for the entire growing season and provided weed control within the crop row comparable to black plastic mulch. The only weeds that emerged in the crop row were through holes in either the black or foam mulch. Foam mulch color did not affect weed control because regardless of color it did not allow light penetration andserved as a physical barrier impeding weed emergence. Basil shoot biomass was not affected by mulch treatment. Mulch color affected early, ripe fruit, and total yield of tomato. Tomato yields in the blue foam were greater than other treatments. Yields in the black foam mulch were similar to those in black plastic mulch. Further research is needed to characterize the effects of foam mulch on crop microenvironment. Currently foam mulch is being commercialized for use in the home landscape and other highvalue situations.

Greenhouse hydroponic and field experiments were conducted to determine the effect of nitrogen (N) fertilizer on eastern black nightshade growth and N content. After 4 wk in hydroponics, the greatest shoot dry mass occurred in the 5 or 10 mM nitrate treatments. An exponential model was strongly correlated with eastern black nightshade root and shoot growth in the 5 or 10 mM nitrate treatments. Eastern black nightshade reached the exponential stage of growth approximately 21 d after transfer to the nitrate treatments. Root dry mass was only 10% of shoot biomass. There was a substantial increase in height and growth rate when plants were fertilized with 168 kg N ha−1. Eastern black nightshade was at its maximum growth 12 wk after planting, and fresh mass increased with N up to 336 kg N ha−1, the greatest N concentration in the study. The greatest N content was in the upper leaves and the least in the lower stem. These results indicate that eastern black nightshade growth is favored by high rates of N.