In the United States, pumpkin crops are produced primarily for wholesale, fresh-market, and ornamental use. Pumpkin production increased 6.4% in the U.S. between 2004 and 2005, totaling 1.1 billion lb in 2005 (U.S. Department Agriculture, 2006). An increase in the demand for pumpkin crops over the past decade has been the result of the growing popularity of events such as fall festivals, grade school farm tours, and u-pick crops. Most farms in New Jersey are surrounded by, or are located near, urban and suburban areas; therefore, many farmers operate roadside markets that sponsor agritourism events featuring the fall harvest of pumpkin crops. In 2007, New Jersey harvested 2500 acres of pumpkin, accounting for 5% of U.S. production (Ingerson-Mahar et al., 2007).
A critical aspect of entertainment agriculture, where agritourism is a main focus of the operation, is maintaining attractive fields that are weed-free and in a condition suitable for consumers to enter. Small farm operators near urban areas could apply autumn leaves collected from municipal shade trees to help 1) maintain an attractive field, 2) maintain suitable soil conditions for customer entry, 3) improve cleanliness of u-pick pumpkin fruit, and 4) improve overall soil health with the addition of organic matter to the soil (Heckman and Kluchinski, 2000a, 2000b). Municipal leaves spread over the soil surface may also help to conserve soil moisture, prevent soil erosion, and build soil fertility (Heckman and Kluchinski, 1996, 2000a, 2000b). Another advantage of leaf mulch is that it may serve as an effective barrier to prevent or reduce annual weeds. Leaf mulch residue that persists season-long for crops such as pumpkin may also provide a natural, physical barrier by preventing fruit from coming into direct contact with the soil, thereby resulting in cleaner fruit for consumers to handle and purchase.
Studies conducted to determine the effects of various production systems and mulches on yield, plant and soil moisture properties, soil erosion, weed control, disease, and fertility with various horticultural crops have shown benefits of mulch (Abdul-Baki and Teasdale, 1997; Acosta-Martinez et al., 1999; Christine et al., 1998; Doring et al., 2005; Hasan et al., 2005; Schonbeck 1998; Wyenandt, 2004), but few studies have been done with pumpkin. A study by Rutledge (1999) determined that vetch residue kept weed competition levels low and resulted in higher quality fruit at harvest with a cleaner, glossier, and brighter appearance compared with pumpkins that were conventionally grown.
Leaf mulching on agricultural land may also benefit local municipalities by providing a cost-effective method to use collected leaves. In New Jersey, 5 million cubic yards of leaves are collected each year by local municipalities for composting or use on farms because state regulations prohibit the disposing of leaves into landfills or with local incineration (Derr and Kluchinski, 1995). In 1994 in New Jersey, a study of municipalities and local farm operators who applied municipal leaves to their land indicated that on-farm mulching had the potential to reduce the cost of municipal leaf management while providing organic matter to the soil and monetary incentives to the farmers through tipping fees paid by municipalities to farmers averaging $3.00/yard3 (Derr and Kluchinski, 1995). However, a potential concern with the use of municipal leaves as a soil-surface mulch in vegetable production is the high carbon to nitrogen ratio (C:N) of shade tree leaves. Shade tree leaves have a C:N ratio of ≈50:1, and heavy applications of such leaves are likely to cause immobilization of soil N (Heckman and Kluchinski, 1995, 1996). The high C:N ratio of leaves would suggest that higher than normal N fertilizer application rate may be necessary when growing vegetable crops such as pumpkin with municipal leaf mulch.
The objectives of this study were to determine the effects of leaf mulch and sidedress nitrogen rate on pumpkin yield and fruit quality.
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