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Nitrogen Deficiency

Nitrogen Deficiency

Nitrogen Deficiency

deficiency

In a Nutshell

    In mild cases, older, mature leaves turn pale green, with light red discolorations of petioles and veinsIf not amended, they later become uniformly chlorotic first, and later yellowish-white (veins included)Young leaves remain pale green and grow smaller than usualPremature death and shedding of leaves may happenRecovery after application of nitrogen becomes evident after a few days

Hosts: %1$s

· Grape · Raspberry · Gooseberry · Bean · Capsicum & Chili · Eggplant · Carrots · Turnip · Pea · Cabbage · Lettuce · Cotton · Wheat · Soybean · Additional · Spinach · Chard · Onion · Garlic · Leek · Millet · Sorghum · Maize · Strawberry · Blackberries · Currant · Radish · Banana · Citrus · Mango · Papaya · Sugarcane

Symptoms

Symptoms develop first in older leaves and move gradually up to the younger ones. In mild cases, the older mature leaves turn pale green. If not amended, over time a widespread chlorosis develop on those leaves together with a light red discoloration of veins and petioles. Petiole analysis actually allows growers to detect the outset of a nitrogen deficiency in the crop. As the deficiency progresses, these leaves eventually turn yellowish-white (veins included) and may curl or grow deformed. Young leaves remain pale green but grow much smaller than usual. Plant have a spindly aspect due to the reduced branching but their height is usually normal. Plants become more susceptible to water stress and the wilting of leaves is common. Premature death and shedding may happen, which results in considerably lowered yields. Recovery after application of nitrogen in the form of fertilizer becomes evident after a few days.

Trigger

High rates of nitrogen are important during the vegetative growth of the plant. In periods of favorable weather, it is important to provide the fast growing crops with a good nitrogen supply, so that they can reach their maximum vegetative and fruit/grain production potential. Nitrogen deficiencies can be observed in sandy, well-drained soils with little organic matter as they are prone to the leaching of nutrients. Frequent rainfalls, flooding or heavy irrigation wash down nitrogen into the soil and can also lead to deficiencies. Periods of drought stress hinder the absorption of water and nutrients, resulting in unbalanced nutrient supply. Finally, the soil pH also plays a role in the availability of nitrogen to the plant. Both low or high soil pH negatively affect the absorption of nitrogen by the plant.

Biological Control

High levels of organic matter in soils can enhance soil structure and improve the capacity of the soil to retain water and nutrients. Organic matter can be added to soils as manure, compost, peat, or simply with the addition of nettle slag, guano, horn meal or nitrolime. Nettle slag can be sprayed directly on the leaves.

Chemical Control

Amendments can be done using products based on urea, ammonium or nitrate. Nitrogen is often provide as part of base fertilization products containing different rates of this nutrient together with phosphorus and potassium (the so-called N-P-K base trio). Several products are available on the market and split applications are recommended. The grade depends on the soil type and the growth stage of the plant.

Preventive Measures

    Excessive or unbalanced use of fertilizers may result in some micronutrients becoming unavailable to the plantCheck the pH of the soil and lime if necessary to get the optimal rangeProvide fields with good drainage and do no over-waterMake sure to water plants regularly during periods of droughtMake sure to add organic matter from compost, manure or mulch for example