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Green Manuring and Cultivation Practices

Green Manuring and Cultivation Practices:

Introduction to Green Manuring:- Well, composting your field or garden is one of the expensive and tedious tasks. Especially commercial growers should spend a lot of money for these garden composts. Apart from this, inorganic fertilizers became expensive. Using chemical fertilizers has a very bad effect on soil life and fertility hence there should be an alternative method of providing nutrient to the soil. This is possible only through growing green manure crops. What is green manuring? well, it is nothing but a process of turning green crops cultivated in the field into manure by incorporating back into the soil. The crops grown for this purpose are called green manure crops. Green manure crops provide organic matter which can play a major role organic farming by reducing compost cost drastically. Green manuring helps farmers to increase the soil fertility or restores the previously lost nutrients. Once can be sure that these green manure crops are environmentally friendly which can reduce the application of chemical fertilizer and herbicides as part of agricultural practices.

Ways To Grow Green Manuring Crops:- There are two ways one can grow and use green manure.

When lands are ideal or fallow between crops:

In this method, Once the main crop is harvested, the growing field becomes ideal. In this empty land, you can sow the green manure seeds thickly. Depending on green manure crop, it may be some time to get these crops to flowering stage. When they are about a flower, you can plough them back into the soil or you can the crop and leave in the field.

When there is already a crop growing in the field (mixed crop method):

This process is mostly used in maize growing areas. In this method, seeds of green manure are sown at the same time of maize crop. You can dig this green manure crop when it is time to carry the weeding operation in maize crop usually after a month if sowing. At this in point in time, you can sow the green manure seeds and it can be cut and left in the field after harvesting the maize crop. You plough the soil with these green manure to make the soil more fertile. You should be aware of certain things before growing green manure crops.

Green manure crops should be cut and left in the field or plough the crop back into the soil before seed set or at the flowering stage.

You can grow green manure crops in all seasons without any problem.

If you are growing climbing green manure crop, they may smother the main crop hence climbing stems needs to be pulled from the main growing crops.

Green Manuring Crops:-What type crops can be grown for green manure? choosing a particular green manure crop depends on the main crop it is growing with or in between. Usually, in case of tall growing crops like maize (corn), tall green manure crops like velvet bean or Sesbania should be taken into consideration. In case of short growing crops such as vegetables, you can choose to have green manure crops like mustard green manure or buckwheat green manure.

The following are some of the green manure crops used for Green Manuring

Green Leaf Manuring:- Green leaf manuring is the process of collecting green leaves and incorporating into existing crop fields. It is nothing but gathering green biomass from nearby sites and adding to the soil. In this method, we don’t grow green manure crops rather we collect green leaves of other areas and supplement in the soil.

The following trees and shrubs are used as green leaf manures in preparation of Green Manuring

Purpose or Objective of Green Manuring:- The main purpose of green manuring is to fix the nitrogen ‘N’  in the soil so that main crops can take advantage of this. Green manuring also helps in adding organic matter in the soil thus improving the fertility. Organic farming or Organic agriculture is the main segment of growing crops can be benefited very well with green manures.

Note: For growing green manure crops, you should be aware of cultivation practices of the same.

Other related objectives of green manuring: Apart from the main objective of green manure, the following also indirectly support green manuring concept.

Selection Criteria for Crops in Green Manuring:- Well, you must choose best green manure crops for improving soil nutrients. The following should be taken into consideration.

Nutrient Content of Green Manuring:

The following table shows Nitrogen (N) content and accumulation of green manures. 

Green Manure Name Nitrogen (%) Nitrogen Accumulation kg/ha Biomass Dhaincha 2.55-3.21 130 to 185 26 Sithagathi 2.29-3.10 115 to 160 20 Sunnhemp 2.80-3.15 80 to 130 17 Manila agathi 3.20-3.37 175 to 220 25 Wild Indigo 2.90-3.22 75 to 115 16.8 Pillipesara 2.16-2.77 85 to 125 17.5

 In case of Non-conventional green manuring:

Non conventional green manures Total Nitrogen (N %) C:N Ratio Total Phosphorus P (%) Total PotashK (%) Trees (leaves or twigs) Neem
Delonix elata
Delonix regia
Peltophorumferrugenum
Cassia nigricans 2.83
3.51
2.76
2.63
2.73 70:1
27:1
32:1
34:1
– 0.28
0.31
0.46
0.37
0.18 0.35
0.13
0.50
0.50
0.50 Weeds Adathoda vesica
Parthenium hysterophorus
Eicchornia crassipes
T portulacastrum
Ipomoea cornea
Calotropis gigantea
Cassia pistula 1.32
2.68
3.01
2.64
2.01
2.06
1.60 60:1
30:1
29:1
32:1
43:1
64:1
120:1 0.38
0.68
0.90
0.43
0.33
0.54
0.24 0.15
1.45
0.15
1.30
0.40
0.31
1.20

(The above table source is from agritech.tnau.ac.in).

Cultivation Practices of Green Manure Crops:

DHAINCHA (Sesbania aculeata)

Green Manuring Crops – Sithagathi (Sesbania speciosa)

Green Manuring Crops – Sunnhemp (Crotalaria juncea)

Green Manuring Crops – Manila Agathi (Sesbania rostrata)

Green Manuring Crops – Pillipesara (Phaseolus trilobus)

Green Manuring Crops – Wild Indogo(Tephrosia purpurea)

Read about Green Fodder.

Read about Custard Apple Cultivation.


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