Nitrogen excess - IRRI Rice Knowledge Bank (2024)

FAQs

What happens if there is too much nitrogen? ›

Excess nitrogen in the atmosphere can produce pollutants such as ammonia and ozone, which can impair our ability to breathe, limit visibility and alter plant growth. When excess nitrogen comes back to earth from the atmosphere, it can harm the health of forests, soils and waterways.

As an essential nutrient to plant growth, nitrogen is a critical input to enhance agricultural productivity. However, excess nitrogen can leach into soil and water and contaminate drinking water sources with nitrate, a water-soluble chemical compound of nitrogen. Too much nitrate consumption can pose a health risk.

Apply available organic materials (farmyard manure, crop residues, compost) on soils containing a small amount of organic matter, particularly in rainfed lowland rice and intensive irrigated rice systems where rice is rotated with other upland crops such as wheat or maize.

Nitrogen is an essential plant nutrient being a component of amino acids, nucleic acids, nucleotides, chlorophyll, enzymes, and hormones. N promotes rapid plant growth and improves grain yield and grain quality through higher tillering, leaf area development, grain formation, grain filling, and protein synthesis.

You can lay mulch over the soil with too much nitrogen to help draw out some of the excess nitrogen in the soil. In particular, cheap, dyed mulch works well for this. Cheap, dyed mulch is generally made from scrap soft woods and these will use higher amounts of nitrogen in the soil as they break down.

Using phosphorus-free fertilizers can attribute greatly to a reduction of nitrogen pollution in the world's ecosystem. Correctly using fertilizers by only applying it in periods where there is less rainfall and when it is needed can effectively reduce water runoffs and infiltration of nitrates underground.

Chemical fertiliser overuse can contribute to soil acidification and soil crust, thereby reducing the content of organic matter, humus content, beneficial species, stunting plant growth, altering the pH of the soil, growing pests, and even leading to the release of greenhouse gases.

Grow healthier roots. Early applied nitrates promote the growth of well-developed roots, which are important for capturing nutrients and is a precursor to higher nitrogen use efficiency.

Nitrogen (N) deficiency appears as a general pale yellowish-green plant with slow growth and reduced tiller development. If the deficiency persists, plants remain pale green, have reduced growth, and the stand appears thin.

As far as N source, urea is a better choice than ammonium sulfate as it will move more easily into the soil. Ammonium will tend to stay at the surface where there is greater chances of losses. Therefore, apply the highest amount of N as urea as possible. You will also need to apply starter fertilizers around this time.

How much nitrogen is needed for rice? ›

In the previous lessons we explained that the crop needs nutrients to grow and mature normally. The rice crop needs the following uptake of N, P and K to produce 1 ton of grain per hectare: Nitrogen (N):15-20 kg.

A nitrogen flush is the process of using nitrogen gas to remove oxygen from food packaging, thus increasing its shelf life. Because nitrogen is the heavier gas, it sinks to the bottom, pushing out the oxygen. It's similar to placing a stone in a cup of water, causing the water to spill out.

Nitrogen management has a dual purpose in society. One purpose is to optimize the beneficial effects related to especially food production. The other purpose is to decrease the negative effects of excess nitrogen, especially on human health and biodiversity.

Fossil Fuels: Electric power generation, industry, transportation and agriculture have increased the amount of nitrogen in the air through use of fossil fuels.

Excess nitrogen can cause overstimulation of growth of aquatic plants and algae. Excessive growth of these organisms, in turn, can clog water intakes, use up dissolved oxygen as they decompose, and block light to deeper waters.

Signs of Nitrogen Toxicity

Extremely dark green leaves. “Burning” of leaf tips, causing them to turn brown. Some leaves turning yellow, due to abundance of nitrogen but lack of other nutrients.

Ammonia: The most toxic nitrogenous waste is ammonia. Its excretion requires a huge quantity of water. The least toxic nitrogen-containing waste is uric acid.

Excess nitrogen pollutes air, soil and water; increases greenhouse gas emissions; and impacts biodiversity and ecosystem functioning.

Free-living nitrogen-fixers include the cyanobacteria Anabaena and Nostoc and genera such as Azotobacter, Beijerinckia, and Clostridium.

What are 3 sources of nitrogen? ›

Major sources include fertilizer application to crop, nitrogen fixation by leguminous crops, and livestock waste released from feedlots and husbandry operations (fig.

When nitrogen fertilizer is applied faster than plants can use it, soil bacteria convert it to nitrate. Water-soluble nitrate is flushed out of soils in runoff, where it pollutes groundwater, streams, estuaries, and coastal oceans. In farming communities, it's not uncommon for nitrate to render drinking wells unusable.

Too much fertilizer can actually kill the plant and excess fertilizer can runoff into streams and lakes causing toxic algal blooms that are harmful to aquatic life and even people and their pets. Excess fertilizer runoff from lawns and agricultural applications also contribute to aquatic “dead zones” in coastal areas.

The richest organic sources of nitrogen are manures, ground-up animal parts (blood meal, feather dust, leather dust) and seed meals (soybean meal, cottonseed meal).

Mitigation measures include higher manure storage capacity, rules for timing for application of manure, limits for the maximum amount of N that may be applied to different crops, and better cover of catch crops in autumn and winter (Kronvang et al. 2008).

To review, plants suffering from nitrogen deficiency tend to be pale yellow-green in color and have slow or stunted growth. Yellowing from lack of nitrogen starts at the older leaves and moves on to newer leaves as the deficiency continues with yellowing patterns varying by crop.

Nitrogen can be lost from agricultural lands through soil erosion and runoff. Losses through these events normally don't account for a large portion of the soil N budget, but should be considered for surface water quality issues.

Resin-coated urea (RCU) and polyurethane-coated urea (PCU) are two kinds of CRU that can increase both crop yields and NUE and reduce N loss^{7,20,23,26,27}. With respect to rice production, split application of N fertilizer is usually recommended for improving NUE and crop yields²⁸.

What form of nitrogen is taken by rice? ›

Nitrogen (N) is one of the essential macronutrients for rice (Oryza sativa L.) growth and one of the main factors to be considered for developing a high-yielding rice cultivar. In a paddy field, ammonium (NH₄⁺) rather than nitrate (NO₃⁻) tends to be considered the main source of N for rice (Wang et al., 1993).

Anabaena azollae is the microorganism living in the leaves of Azolla pinnata (fern) and is responsible for nitrogen fixation and thereby acts as a biofertilizer. Hence option d) is correct Azolla pinnata is the biofertilizer in Indian rice fields.

Nitrogen deficiency can be corrected by applying either organic or inorganic fertilizers, but nitrate or ammonium-based fertilizers work the most quickly. Nitrogen deficiency of soil can be removed by applying urea.

The best way to avoid or remedy nutrient deficiencies is to make sure you are eating a balanced, nutrient-rich diet, Patton says. “I encourage food first, but if you are at an increased risk of a nutrient deficiency, you may benefit from taking a multivitamin,” she says.

Add mulch to your soil, and stop fertilizing if you want to reduce the amount of nitrogen in your soil. Mulch uses up nitrogen as it breaks down, so applying a layer of dried wood or sawdust in high-nitrogen parts of your garden can suck up nitrogen. Nitrogen also leaches out of soil naturally.