Development of organic vegetable production systems in Indiana

Tristand Ernest Ferguson Tucker, Purdue University

Abstract

In recent years organic production has increased as new producers are attracted to price premiums, and the perception that organic production practices are more environmentally friendly, sustainable, and that organic food is more nutritious and safer then conventionally produced food. The National Organic Program establishes production standards that promote crop diversity, the use of crop rotations, cover crops, and the use of on farm inputs. Cover crops provide many benefits that include nutrient capturing, repositioning of nutrients in the soil profile and providing nutrients to following crops. Three experiments were conducted in 2007 and 2008 at the Meigs Horticulture Research Farm to study the use of cover crops, their potential to capture and release nutrients and a comparison of organic and conventional tomato production. The first experiment measured nutrient capture and subsequent nutrient release of spring planted red clover, alfalfa, hairy vetch, cereal rye, annual ryegrass and buckwheat cover crops. Soil samples were collected from plots after cover crop incorporation to measure nitrogen mineralization rates. Mineralization rates for nitrogen peaked between 2 and 4 weeks after cover crop incorporation for all cover crops tested. When soil conditions were dry during decomposition, peak mineralization rate occurred later than under moist soil conditions. Biomass and nutrient accumulation varied among cover crop species but, hairy vetch accumulated the most N of all legumes and non-legumes. The second experiment examined the productivity and profitability of a vegetable crop rotation following 2 years of red clover where no external nitrogen was added. The rotation followed two years of red clover and in 2007 included a spring crop of radishes followed by sweet corn. Sweet corn was followed by buckwheat and then either a winter crop of hairy vetch, cereal rye, or wheat. In 2008, the rotation was pumpkins following harvest of winter crops. Radish and sweet corn yields in 2007 were comparable to state average yields. In 2008, wheat and rye yields were similar to those obtained under conventional culture in the US. Pumpkin yields were less than those obtained in variety trials the previous year. Profitability of these crop rotations after 2 years were $239 ha-1 in the rye system, $1,365 ha -1 in the wheat system, and $1,376 ha-1 in the hairy vetch system. The third experiment compared organic and conventional production of fresh market tomatoes comparing hybrid and heirloom varsities. Tomato yields were not influenced by either production system or variety classification, however, fruit size and quality differed. Heirloom fruit tended to be larger with higher soluble solids content, while hybrid fruit had higher marketability, higher lycopene content and a higher grade than heirloom fruits. Fruit from organic plots regardless of classification, were larger but of a lower quality than from conventional plots.

Degree

M.S.

Advisors

Weller, Purdue University.

Subject Area

Agronomy|Horticulture

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