Quantity Of NO3-N Research Articles

Nitrogén, réz és molibdén kölcsönhatások lucerna kultúrában (Medicago sativa L.)

Interactions between the elements N, Cu and Mo were studied on alfalfa in 1996-1999 in a field experiment set up on chernozem loam soil with lime deposits. The ploughed layer of the soil contained 3% humus, around 5% CaCO3 and around 20% clay. Soil analysis showed that the area was well supplied with Ca, Mg, K and Mn had satisfactory Cu content, but was only poorly or moderately supplied with P and Zn. The groundwater depth was 13–15 m and the area was prone to drought. The experiment was originally set up in a split-plot design with 4N × 3Cu = 12 treatments in three replications, giving a total of 36 plots. The N rates, applied as calcium ammonium nitrate, were 0, 100, 200 and 300 kg·ha−1 and the Cu rates, in the form of CuSO4, were 0, 50 and 100 kg·ha−1. In the 5th year of the experiment the 15 m long plots were halved and the two half-plots were separated by a 1 m path. The experiment thus became a strip-split-plot design, consisting of 4N×3Cu×2Mo = 24 treatments in three replications, giving a total of 72 plots. The 48 kg·ha−1 Mo was applied in the form of (NH4)6Mo7O24·4H2O. The main results were as follows: In this chernozem loam soil the N, Cu, Mo treatments did not affect the yield of alfalfa. During the four years studied (1996–1999), a total of 32 t·ha−1 of hay was harvested, with maximum yields (4–5 t·ha−1) at the first mowing. Considering the years, the 2nd year of alfalfa was the most successful with a yield of 11 t·ha−1.With increasing rates of N, the incorporation of N, NO3-N, Ca, Mg, Na, and sometimes Cu increased, while that of K decreased in the hay. Due to the 10–12-year residual effect of CuSO4 the original Cu content of the hay improved by 30–50%, i.e. 2–4 mg·kg–1.A single dose of 48 kg·ha−1 Mo raised the hay Mo content by an order of magnitude to 18–69 mg·kg–1 even after 5–8 years. The Mo content decreased with age and the number of mowings. Nevertheless, the hay became unsuitable for use as animal feed. Mo fertilization also influenced the incorporation of other elements, demonstrably increasing the uptake of N, Ca and Mg and moderating that of K, NO3-N and Cu.As a specific catalyst for the N-binding microorganisms in the soil, Mo is able to increase the soil N supply and thus the N content of the plants. Mo is also necessary for NO3 reduction, so the quantity of NO3-N is reduced through incorporation into proteins in response to Mo. In the present experiment, N-Mo and N-Cu synergism and Mo-NO3 antagonism were manifested.Due to the influence of the different years, mowings and treatments, the minimum and maximum element contents of the hay varied over a wide range. In 12 mowings over the course of four years a total of 1190 kg N, 787 kg K, 768 kg Ca, 154 kg Mg, 128 kg S, 102 kg P, 12 kg Na, 8 kg Fe, 5 kg Al, 4 kg Sr and 2 kg each of Mn and B was taken up per hectare, together with 416 g Zn, 288 g Ba, 256 g Cu and 96 g Mo per ha. The uptake of Mo was 1131 g·ha−1 on Mo-treated soil.The specific nutrient content of 1 t hay was 37 kg N, 25 kg K, 24 kg Ca, 5 kg Mg and 3 kg P (7 kg P2O5). N abundance was associated with elevated specific nutrient content under the given experimental conditions. On this soil atmospheric N fixation was able to cover the N requirements of alfalfa.

Increased stocking rate and associated strategic dry-off decision rules reduced the amount of nitrate-N leached under grazing

The effect of intensive agricultural systems on the environment is of increasing global concern, and recent review articles have highlighted the need for sustainable intensification of food production. In grazing dairy systems, the leaching of nitrate-N (NO3-N) to groundwater is a primary environmental concern. A herd-level factor considered by many to be a key contributor to the amount of NO3-N leached from dairy pastures is stocking rate (SR), and some countries have imposed limits to reduce the risk of NO3-N loss to groundwater. The objective of the current experiment was to determine the effect of dairy cow SR on NO3-N leached in a grazing system that did not import feed from off-farm and had the same N fertilizer input. Five SR were evaluated (2.2, 2.7, 3.1, 3.7, and 4.3 cows/ha) in a completely randomized design (i.e., 2 replicates of each SR as independent farmlets) over 2 y. Pasture utilization, milk production/hectare, and days in milk/hectare increased with SR, but days in milk/cow and milk production/cow declined. The concentration of NO3-N in drainage water and the quantity of NO3-N leached/ha per year declined linearly with increasing SR, and the operating profit/kg NO3-N leached per ha increased. Higher SR was associated with fewer days in milk/cow, resulting in a reduction in estimated urine N excretion/cow (the main source of N leaching) during the climatically sensitive period for NO3-N leaching (i.e., late summer to winter). We hypothesized that the reduction in estimated urine N excretion per cow led to an increase in urinary N spread and reduced losses from urine patches. The results presented indicate that lowering SR may not reduce nitrate leaching and highlight the need for a full farm system-level analysis of any management change to determine its effect on productivity and environmental outcomes.

Impact of piggery slurry lagoon on the environment: A study of groundwater and river Igolinka at the Vostochnii Pig Farm, St. Petersburg, Russia

Pig farms in Leningradskij Oblast, Russia are usually large −20,000 to 60,000 pigs per farm. As these farms discharge pig slurry into the adjacent rivers flowing into the Baltic Sea, there is a potential risk for pollution of both the rivers and the sea. This risk was assessed at the Vostochnii pig complex, which holds 60,000 pigs. The impact of slurry treatment on water quality in the groundwater (GW) and the river Igolinka, the recipient of the treated slurry, was investigated. The results indicated that untreated and treated slurry from pig farm wastewater treatment systems are potential point sources of environmental pollution. Generally, the GW was characterized by rather high contents of ammonium and chemical and biological demand for oxygen (COD, BOD). Similarly, the river exhibited high COD and BOD, contained considerable amounts of suspended substances and total P, and small quantities of NO3-N and NH4-N. Of the biological parameters investigated, the elevated population of fungi and pathogenic faecal bacteria Escherichia coli (100–10,000 CFU E. coli cells ml−1) determined in the river posed a potential health risk. Equally important was the marked total P load in the river, part of which could be transported to the Baltic Sea, where it could trigger eutrophication.

Dynamics of soil and plant nitrogen in cultivated and no-till spring wheat systems following old pasture

Abstract When old pasture is cultivated, nitrogen (N) may be released in quantities that exceed crop demand. No-till cropping is an option that may be more conservative of N. This report considers uptake and distribution of N by a wheat crop established by full cultivation or no-till methods, out of 12-year-old clover/grass pasture. N uptake was more rapid in cultivated soil and in both systems was essentially complete after 40 days. The no-till treatment did show some further N accumulation later in the season during grain fill. Mineral N values and plant uptake rates indicate that N mineralisation was rapid in both systems but only just adequate in no-till. Sampling the soil to 1.5 m depth in the winter following the crop showed both systems to have similar and substantial (about 160 kg N/ha) quantities of NO3-N moving through the profile.