Manures and Fertilizers

Plants need nutrients for healthy growth. These nutrients are available to plants through water-soluble minerals from the ground. If these nutrients deplete from the soil, they can be supplemented by applying organic manures like farmyard manure, green manure, leaf mould, oil cake, earth worm compost, fish / bone meal, sheep droppings and poultry litter. Alternatively the nutrients can be supplied to plants by applying inorganic fertilizers, which are also called as chemical fertilizers. The nutrients are divided in two groups, namely – macro nutrients and micro nutrients. The plants need macro nutrients in larger quantity than the micro nutrients. Macro nutrients are nitrogen, phosphorus and potassium (N = nitrogen, P = phosphorus, K = potassium). Calcium, magnesium, iron, and sulphur are micro nutrients. There are some other nutrients, which are needed by plants in very minute quantities. Such nutrients are called as ‘Trace elements’. Zinc, manganese, copper and boron are the trace elements.

Organic Manures : Organic manures not only supply nutrients to plants but also help in aeration of soil. They help excess water to drain out fast, but at the same time help to retain the moisture in the soil. By using the organic manures soil remains friable and thus encourages growth of hair roots. Organic manures are not water soluble; thus, the plants can not use these by themselves. Certain bacteria work upon these organic manures and gradually turn them to water soluble minerals. As this conversion process is slow and prolonged, the organic manures once applied will continue to provide nutrients to plants for quite some time.

Chemical Fertilizers : Chemical fertilizers are water soluble minerals. So, as soon as they are applied to plants and water given, they dissolve in water and are absorbed by the plants. Thus, a slight overdose of a chemical fertilizer could damage the plant or may even kill it. Due to their water solubility, the chemical fertilizers are easily washed out of soil. This too makes them unavailable to plants. When used with caution and along with organic manures, chemical fertilizers can give good results.

Symptoms of Nitrogen Deficiency (Chlorosis) : Nitrogen encourages growth of chlorophyll and proteins. This helps plants to produce more food. Due to nitrogen deficiency plants get stunted, leaves turn yellowish. Normally lower leaves turn yellow first.

Symptoms of Phosphorus Deficiency : Phosphorus encourages healthy growth of cells. It also helps in fruit and seed formation. Stunted growth of stems, leaves and roots is due to deficiency of this nutrient. Twiggy branches and poor fruit and seed formation is a symptom of phosphorus deficiency.

Symptoms of Potassium Deficiency : Potassium helps in protein formation. It also helps in photosynthesis and in transportation of food. Plants get vigour and resistance to diseases because of potassium. Due to potassium deficiency edges of leaves turn dry and yellowish. Leaves get wrinkled and turn downwards. New shoots start drying.

Fertilizer for flowering and fruiting plants

Super phosphate – 4 kg. Ammonium sulphate – 750 grams, Potassium nitrate – 1.5 kg. Potassium sulphate – 2 kg. Magnesium sulphate – 500 grams, Iron sulphate – 125 grams. 1 level tablespoon of this fertilizer should be applied to a potted rose or fruit plant, once a month. The fertilizer should be applied in a trench dug around the edge of the pot. After putting fertilizer in the circular tench, cover it with soil and feed water.

Except for Super phosphate mix all the ingedients and powder them, Mix Super phosphate in the above and store in airtight container. Note that Potassiu nitrate shoild not be powdered seperately; as on impact it can explode.

Foliar fertilizer

Mix together Urea – 500 grams, Diammonium hydrogen phosphate – 500 grams and Dipotassium hydrogen phosphate – 500 grams and store in air tight container. 3 grams of above mixture is to be diluted in 1 litre of water and sprayed on all parts of plants; particularly undersides of the leaves.

Foliar micro-nutrient

Zinc sulphate – 100 grams, Copper sulphate – 100 grams, Ferrous sulphate – 300 grams, Manganese sulphate – 300 grams, Boric acid – 200 grams. Mix all the ingredients and grind finely. Store in airtight container. 10 grams of this mixture dissolved in 5 litres of water and spray on all parts of the plants; particularly undersides of the leaves.

NPK CONTENTS OF VARIOUS MANURES AND FERTLIZERS
ORGANIC MANURES
Type of manure / fertilizer
Nitrogen %
Phosphorus %
Potassium %
Farmyard manure
0.3 to 0.4
0.1 to 0.2
0.1 to 0.3
Sheep/goat droppings
0.5 to 0.7
0.4 to 0.6
0.3 to 1.0
Poultry litter
1.0 to 1.8
1.4 to 1.8
0.8 to 0.9
Cattle urine
0.9 to 1.2
0.5 to 1.0
Bone meal
3.5
22.0
Fish meal
4.0
3.9
0.3
Sesbania aculeata
0.62
0.15
0.5
Sunn hemp
0.75
0.12
0.5
Castor cake
4.0
2.0
1.0
Neem cake
5.2
1.0
1.4
SIMPLE CHEMICAL FERTLIZERS
Ammonium sulphate
20
Ammonium chloride
25
Ammonium nitrate
18
Potassium nitrate
15
Urea
46
Single super phosphate
16
Triple super phosphate
45
Muriate of potash
50 to 60
Potassium sulphate
50
COMPOUND CHEMICAL FERTILIZERS
Diammonium phosphate (DAP)
18
46
Ammonium phosphate
11
48
Potassium ammonium chloride
13
22
NPK 15:15:15 (Suphala)
15
15
15


Method of finding the required quantity of NPK : If a tree needs 250 grams of nitrogen, 100 grams of phosphorus and 100 grams of potassium, quantity of each chemical can be worked out as follows :

  • 543 grams of urea (46% nitrogen) will give 250 grams of nitrogen (250 x 100 ÷ 46 = 543)
  • 625 grams of single super phospahte (16% phosphorus) will give 100 grams of phosphorus (100 x 100 ÷ 16 = 625)
  • 166 grams of muriate of potash (60% potassium) will give 100 grams of potash (100 x 100 ÷ 60 = 166)