tomato  (l.ycopersicon esculentum  mill.) cv. rio grande  seedlings were nutritionally conditioned with solutions complete fertilizer n(60% no3+40% nh4)-p-k (20-20-20) , n(30%no3+70% nh4)-p-k (15-5-30) , the first two week   n(60% no3+40% nh4)-p-k (20-20-20) and later two week  n(30%no3+70% nh4)-p-k (15-5-30)  and vice versa were  applied in  completely randomized experiment with three replicat...

Nitrogen (N) losses negatively impact groundwater quality. Spring wheat genotypes varying in N-fertilizer recovery were studied (by using lysimeters) for their potential to minimize NO3-N leaching during spring and summer, over a three-year period. Additionally, we examined to what extent root growth and NO3-N leaching explain the well-known difference found between apparent and isotopic N reco...

a three-year field experiment was conducted under conditions of luvic chernozem soil. diversified nitrogen fertilization with 0, 60, 120, and 180 kg n ha-1, and microbial preparations improving soil properties were applied to potatoes, cv. ‘satina’, cultivation. n–no3 concentration in the soil profile (0–0.9 m) in autumn after potato harvesting fluctuated from 28 kg n ha-1 in the n0 treatment t...

The importance of storm frequency as well as the groundwater and hyporheic inputs on nitrate (NO3-N) and ammonium (NH4-N) levels in stream water were studied in a small perennial Mediterranean catchment, Riera Major, in northeast Spain. NO3-N concentrations ranged from 0.15 to 1.9 mg l-1. Discharge explained 47% of the annual NO3-N concentration variance, but this percentage increased to 97% wh...

Nitrate (NO3) profiles in semiarid unsaturated zones archive land use change (LUC) impacts on nitrogen (N) cycling with implications for agricultural N management and groundwater quality. This study quantified LUC impacts on NO3 inventories and fluxes by measuring NO3 profiles beneath natural and rainfed (nonirrigated) agricultural ecosystems in the southern High Plains (SHP). Inventories of NO...

Under low growth-irradiance and/or excessive nitrogen (N) fertilization, the roots of leafy vegetables could take up nitrate (NO3) faster than the plant can convert it to organic nitrogen compounds. NO3 is suspected to have carcinogenic effect in human when eaten in high quantity. In this study, lettuce plants were first grown in an aeroponics system with full nutrients (full NO3) under full su...

The mechanisms linking C/N balance to N uptake and assimilation are central to plant responses to changing soil nutrient levels. Defoliation and subsequent regrowth of grasses both impact C partitioning, thereby creating a significant point of interaction with soil N availability. Using defoliation as an experimental treatment, we investigated the dynamic relationships between plant carbohydrat...

We conducted a series of stepwise NO3 2 additions to investigate the response of NO3 2 uptake to short-term (acute) changes in N concentration in 3 prairie streams. Observed NO3 2 uptake rates increased with short-term elevations in NO3 2 concentration and were consistent with linear and Michaelis–Menten kinetics models. We compiled these data with uptake rates from additional published studies...