The Value of Presidedress Soil Nitrate Testing as a Nitrogen Management Tool in Irrigated Vegetable Production

Abstract

<jats:p>The utility of presidedress soil nitrate testing (PSNT) in irrigated lettuce (<jats:italic>Lactuca sativa</jats:italic> L.) and celery (<jats:italic>Apium graveolens</jats:italic> L.) production was evaluated in 15 commercial fields in California from 1996 to 1997. Fields were selected in which soil NO<jats:sub>3</jats:sub>-N (5- to 30-cm depth) was &gt;20 mg·kg<jats:sup>–1</jats:sup> at the time the cooperating grower made the first sidedress N application. The grower's N regime was compared with reduced N treatments established by reducing or eliminating one or more sidedress applications. All fields were sprinkler and/or furrow irrigated, with minimal in-season precipitation. Reductions in seasonal N application averaging 143 and 209 kg·ha<jats:sup>–1</jats:sup> N in lettuce and celery trials, respectively, had no effect on marketable yield in any field. Crop biomass N at harvest in the lowest N treatment in each field averaged 94% (lettuce) and 88% (celery) of that in plots receiving the full grower N program. Based on controlled-environment aerobic incubation of soil from 30 fields in long-term vegetable rotations, in-season N mineralization averaged 1% to 2% of soil organic N. A soil NO<jats:sub>3</jats:sub>-N “quick test” procedure utilizing a volumetric extraction of field-moist soil and measurement by nitrate-sensitive colorimetric test strips was evaluated and proved to be a practical on-farm method to estimate soil NO<jats:sub>3</jats:sub>-N concentration. Lettuce midrib NO<jats:sub>3</jats:sub>-N concentration at cupping stage was poorly correlated with current soil NO<jats:sub>3</jats:sub>-N level. We conclude that PSNT can reliably identify fields in which sidedress N application can be delayed or eliminated without affecting crop performance.</jats:p>

Yield and Nitrogen Balance of Greenhouse Tomato (Lycopersicum esculentum Mill.) with Conventional and Site-specific Nitrogen Management in Northern China

“…Several N recommendation systems for controlling N fertilization in open-field vegetable production, are carried out in some intensive vegetable crop production regions in Europe and North America, such as N min method (Wehrmann and Scharpf 1986), KNS system (Lorenz et al 1989), N-Expert system (Fink and Scharpf 1993), and pre-sidedress soil nitrate testing (PSNT) technique (Hartz et al 2000). To ensure cropspecific N demand, considering crop N uptake, soil N min buffer and inevitable N loss (including leaching, denitrification, NH 3 volatilization, etc.…”

Winter-killed Cereal Rye Cover Crop Influence on Nitrate Leaching in Intensive Vegetable Production Systems

“…The mild year-round climate allows for the cultivation of two to three coolseason vegetable crops per year, with lettuce (Lactuca sativa) being the dominant crop in both value and acreage (Monterey County Agricultural Commission, 2012). Vegetable production fields often receive N fertilizer applications in excess of crop uptake or the amount of N needed for maximum yield and product quality (Bottoms et al, 2012;Breschini and Hartz, 2002;Hartz et al, 2000;Heinrich et al, 2013). This tendency for overfertilization occurs because N fertilizer is a small part of the overall production budget for the high-value vegetable crops grown in the region (e.g., Tourte and Smith, 2010) and growers do not want to risk an economic loss for these crops that have exacting market standards for size, color, and quality.…”

Effects of Incorporation of Green Manure Crops on the Growth of Watermelonand Soil Nitrate Nitrogen Concentration

“…Jeon et al (2009) Values are means with standard errors in parentheses (n=3). (Binford and Hansen, 2000;Hartz et al, 2000;Heckman et al, 2002). 25 mg/kg (Heckman et al, 1995), 10-40 mg/kg (Kang et al, 2011…”