Nitrate Monitoring for Pumpkin Production on Dryland and Irrigated Soils
Year: 1988
Type: article
Abstract: Field experiments were conducted in 1985 and 1986 to determine in-season indexes for petiole NO 3 -N in dryland-grown and irrigated pumpkins ( Cucurbita moschata Poir.). The level of NO 3 -N in petioles of recently mature leaves was a good indicator of the seasonal N status for pumpkins on irrigated sand, and to a lesser degree for pumpkins on dryland loam. Petiole NO 3 -N concentrations decreased with time and with decreasing N rate at both sites, with the rate and extent of decrease considerably greater on the irrigated sand. The optimum time of sampling was at about initial fruit set or early fruiting. Critical (10% yield reduction) and minimum sufficiency (lowest concentration before yield reduction) levels for petiole NO 3 -N at early fruiting were estimated at 6300 and 8000 μg·g −1 , respectively, in dryland and 4000 and 6700 μg·g −1 , respectively, for irrigated plantings. Deficiency symptoms were associated with NO 3 -N concentrations <1500 μg·g −1 . Soil NO 3 -N levels proved unsatisfactory as a NO 3 -N index in dryland soil, but meaningful relationships ( R 2 = 0.31) were obtained between fruit yield and soil NO 3 -N on irrigated sand. Fertilizer N requirements for 90% and 100% of marketable yield were estimated at 44 and 158 kg N/ha for dryland and 125 and 225 kg N/ha for irrigated pumpkins, respectively. However, N fertilizer rates of 202 and 269 kg N/ha delayed harvest 9 days on irrigated sand and 15 days on dryland loam, compared to lower N rates.
Institution: University of Illinois Urbana-Champaign
Language: English
Subfield: Soil Science
Domain: Life Sciences
SDG: Zero hunger
Open Access status: hybrid
Estimated APC paid: $3,500
OpenAlex ID: W4289845561