Nitrogen apparent recovery can be used as the indicator of soil nitrogen supply

Abstract

The Nitrates Directive requires considering all possible sources of nitrogen available for crops before decision is made for the use of commercial fertilisers. Soil is one of the nitrogen supplying sources but to quantify the amounts which could be released in a plant available form and take part in yield formation is difficult. Chemical and biological methods developed for laboratory and field conditions do not always give good response or are unpractical for farm conditions. Therefore an indirect soil nitrogen supply assessment method is proposed which could use the data available for each field on every farm. The first step includes estimation of soil total organic nitrogen pool derived from indices of soil organic matter content and soil pH. The second step is the use of soil nitrogen apparent recovery factors, developed from field experiment data. Such factors were developed for winter rye and wheat, spring wheat and barley, winter and spring rape as well as potatoes and are based on 72 field experiments performed in Latvia on mineral soils within a five-year (2008)(2009)(2010)(2011)(2012) period. In average, the following soil nitrogen recovery factors were obtained: for winter cereals -3.3-3.4%, winter rape -2.3%, spring cereals and rape -1.8-2.6% and potatoes -3.8%, calculated from the soil total organic nitrogen pool within 0-20 cm depth. There was strong correlation (r = 0.980, P ≤ 0.01) between apparent recovery values if they were calculated only based on 0-20 cm soil layer or based on 0-40 cm. Therefore it is possible to make calculations only for topsoil data which are commonly available from routine soil tests.

Efficiency of Nitrogen Fertilization of Winter Wheat Depending on Sulfur Fertilization

“…However, Salvagiotti et al [51] stated that wheat fertilization with various N and S doses did not increase the E p value under different weather conditions, and explained that this factor presents low variation under variable environmental conditions. Optimization of N fertilization of crops (providing accomplishment of agronomic, economic, and environmental goals) still constitutes a challenge for science and agricultural practice [65]. Efficient management of N fertilization is a pivotal factor for maintaining economical crop production and long-term environmental quality.…”

Crop Field Level Estimation of Nitrogen Input from Fertilizer Use in Jeju Island, South Korea: Management Methods to Prevent Groundwater NO3-N Contamination

“…Referenced data for the N uptake amount by crop type were collected from the literature survey and are listed in Table S2. We collected uptake data for 12 crops, including white radishes, barley, garlic, broccoli, cabbage, kohlrabi, onions, potatoes, dry-field rice, chives, wheat, and tomatoes [45][46][47][48][49][50][51][52]. For the red cabbage and Brussel sprouts, the amount of N uptake was assumed to be the same as that for cabbage (Table S2).…”