Effect of Planting Date and Nitrogen Fertilization Rates on No-till Pumpkins.

摘要

Vegetable growers in the Mountain region of North Carolina are faced with increased land prices resulting from urbanization and reduced farm income from low-commodity prices. Local consumer use of pumpkin (Cucurbita pepo) for jack-o-lanterns and baking provides a fall market for growers to increase production and profitability on-farm. Most soils in these regions are highly erodible and susceptible to drought during the growing season. Little information is available on cultural practices for no-till pumpkin production in this region. Field studies were established to evaluate the yield response of no-till pumpkin to planting date and nitrogen (N) fertilization. Experiments were conducted at the Mountain (MRS), Upper Mountain (UMRS), and the Mountain Horticultural Crops Research Stations (MHCRS) in Summer 2003 and 2004 using no-till cultural practices. Three planting dates were established at 2-week intervals and 0, 40, 80, and 120 kgp"ha-1 N treatments were applied at each planting date in a randomized complete block design. The 80 and 120 kgp"ha-1 N fertilization rates produced greater yields and larger fruit size than the 0 and 40 kgp"ha-1 N rates. Pumpkins planted earliest produced the greatest marketable and total yields for all N rates at all three locations. The latest planting date (9 July) and highest N rate yielded more cull fruit compared with marketable pumpkins with the earlier planting date at the Upper Mountain Research Station. This location has a shorter growing season and cooler summer temperatures than the two other locations. Although the third planting date was late for pumpkin planting, higher N rate treatments at that timing produced marketable yields comparable to earlier planting dates at the two warmer summer locations (MRS and MHCRS). In these experiments, the highest rate applied (120 kgp"ha-1 N) maximized pumpkin yield. This observation would indicate that higher yields might be possible with even greater N rates.