What are Green Manures · The Farmers' Handbook - "The Fields", Chapter es What are Green Manures ? Every farmer knows how much work goes into the production of a basket of compost

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What are

Green Manures ?Green Manures ?

Every farmer knowshow much work goesinto the production of abasket of compost andcarrying it to the fields.But it never seems thatthe farm productiongives an equal return forthe hard work that goesinto making and carry-

ing the compost. Green manures are a method of replacingthat basket of compost with a handful of seed. In this method,the plants that grow from the handful of seed are ploughedback into the soil. After a while in the soil, the plants rotdown to become compost. Plants used in this way are calledGreen Manures. It's a very good way of increasing the fertil-ity of the soil, and can give huge benefits for farmers. So let'sread about it here.

Sesbania beingploughed in as a greenmanure , Surkhet,Western Nepal

The Farmers' Handbook, "The Fields" Chapter 2 - Green Manures

WhyWhy grow GreenManures ?

32 3

• Reduce the need for artificial fertilizers - by using greenmanures the need to bring in fertilizers is reduced. By notusing fertilizers, costs are saved and the soil is not dam-aged. Also, production can be increased to feed the familyfor longer, or excess produce can be sold.

Benefits of Green Manures

• Increase Farm production - using green manures canincrease the production of grains, pulses, vegetables, fod-der, fuel, etc. grown on the farm.

Mr Thek B. Gurung ofGumi VDC - 4, Surkhet,

likes using Sesbania greenmanure on his fields

• Improve the quality ofcrops - crops grown withgreen manures are moretasty and nutritious than thosegrown with chemical fertiliz-ers.

• Improve the soil - where green manures have been regu-larly used the soil is softer, lighter and easier to work. As aresult, the soil has a greater capacity to absorb and storewater and nutrients.

• Protect the soil - by covering the soil, green manures protectit from the damaging effects of hot sun, wind and hard rain.

• Reducing weeds - green manures cover the ground and soreduce the work and cost of weeding.

• Decrease work and expense - less compost needs to becarried. By using green manures, the soil becomes looseand easier to plough or dig.

• Increase in micro-organisms and their activity in the soil- Beneficial micro-organisms live and work around theroots of green manure plants in the soil. They help theplants to catch and create nutrients in the soil. The fertilityisn't just for the plants, it helps to make the soil rich. Themicroorganisms help the plants and the soil, and in returnthe green manures help to protect the microorganisms frombeing damaged by the sun, wind, rain, leaching, etc.

• Increase biomass production in the fields - in an examplefrom Brazil in South America, where 40,000 farmers haveconverted to using green manures, they have calculated thatusing velvet bean as a green manure has produced 50 to140 tons per hectare of extra biomass. This is the equiva-lent of carrying up to 3000 loads of leaf litter! But the greenmanure biomass doesn't need to be carried from anywhere.Wherever the fields are, that's where the biomass is producedand, that's where it rots to form compost.


to grow GreenManures ?HowHow

4 5

There are 2 ways of using green manures :-1. When land is unused, or fallow between crops;2. While crops are still growing in the fields.

1. Using green manures as fallowWhen crop land is empty after crops have been har-

vested, green manure seeds can be sown as thickly as sowingwheat. When the green manure plants are about to flower theycan be cut and left, or ploughed into the soil.

2. Using green manures mixed with crops

This method is used mostly with maize growing. Aneasy method is to sow a green manure at the same time asmaize, and then dig it in when it is time to weed the maize(after 3-4 weeks). At this time green manure seeds can also besown, and the green manure is cut and mulched or ploughedin after the maize is harvested to provide even more fertility.

Green manures are easy to use, but it's important to notecertain things, such as :-• green manures can be used in all seasons;• which-ever type of green manure is being used, they will

give most benefit to the soil if cut and/or ploughed in atflowering time, before seed is set;

• climbing types of green manures can smother the crops theyare growing with. If so, the climbing stems need pullingdown from the crops.

Selecting which green manures to use.There are many plants which can be used as green ma-

nures. In particular, the type of green manure should be se-lected according to the type of crop it is growing with or inbetween. For a large plant like maize, a large green manurelike velvet bean or Sesbania should be used. For a short croplike many vegetables, smaller green manures such as mustardor buckwheat can be used.

Criteria for selection of green manures include :-

• plants are fleshy and soft• fast growing;• fast to decompose;• leguminous;• don't attract pests and diseases;• don't compete with crops;• provide nutrients needed in the soil (more information

about this is given on p.21)

The Farmers' Handbook, "The Fields" Chapter 2 - Green Manures6 7

Low altitude - mustard, peas, broad (fava) bean, fenugreek,tobacco, buckwheat, etc.

Mid altitude - mustard, peas, broad bean, fenugreek, buck-wheat, etc.

High altitude - mustard, peas, broad bean, buckwheat, etc.

Examples of winter-grown green manures

peas

tobacco

broad bean

hemp mustardsunhemp

Low altitude - mustard, buckwheat, amaranth, sunhemp(Crotalaria), Sesbania, Chenapodium, fenu-greek, lab lab, velvet bean, jack bean, tobacco,etc.

Mid altitude - mustard, buckwheat, amaranth, sunhemp(Crotalaria), Sesbania, Chenapodium, fenu-greek, lab lab, velvet bean, jack bean, tobacco,hemp, etc.

High altitude - mustard, mustard, buckwheat, amaranth,sunhemp (Crotalaria), Chenapodium, fenu-greek, tobacco, hemp, etc.

Examples of summer-grown green manures

amaranth

sunhemp

Chenapodiumtobacco

hemp

mustard

Examples of using green manures

Now we'll see some specific examples of green manures.On this page Sesbania is used with rice. On page 17 Sesbaniais used with maize, then on page 18 velvet bean is used withmaize, and on page 20 mustard is used with wheat.

Sesbania and RiceIn this method, Sesbania is sown

before rice is planted. As rice is sown intonurseries, all other paddy areas are fallow,which is when Sesbania can be grown.

How tosow

Sow the Sesbania as densely as wheat or mustardseed. Then lightly till to cover the seed with soil.

TimingSow after winter crop is harvested, or in theSpring. Sesbania will grow faster if the soil is keptmoist, so irrigate if possible. After 4-6 weeks, theSesbania will be 18-36 inches tall. Cut at groundlevel and plough in as the paddy are prepared forplanting rice.

Seed production of Sesbania

When Sesbania is being ploughed in during paddypreparation, transplant a few of the largest, thickest, healthiestplants onto the edges of the paddy - space at 2 metre intervalsalong the terrace edges. These will grow on to produce seedfor green manure use next year. The seed will be ready after 6to 7 monthsmustard

tobaccoChenapodium

buck-wheatbuck-wheat

amaranth

mustardhemp

broad bean


Let's SeeLet's See

8 9

Seed plants will grow at 2 metreintervals on the terrace edges.When between 1-1.5m tall,pinch out the tops. This helps tothicken the stem and preventsthe plant growing too tall, whenthe wind can blow them over.Pinching also produces morebranches, and so more seed.There's a picture of this on p.11.

After the Sesbania hasbeen cut and ploughed in, thepaddies are flooded, and rice isplanted. The fertility from therotting green manure is a goodfood for the rice.

Sesbania seed plantsgrowing on the terraces

Calendar for rice and Sesbania

paddy

terrace

nursery sow Sesb.

seed4-6 w

eeks

sow rice

seeds2-4

weeks

plough inSesbania

transplantseed plantson terraces

plant rice

3-4m

onths

6-7 months

harvestrice

harvestSesbania

seed

Sesbania issown as the

fallow is bro-ken

Sesbaniagerminatesin 6-10 days

Sesbania is thisbig after a

month. Fromnow it can beploughed in.

how to growGreen Manures

how to growGreen Manures


The Sesbaniais cut at itsbase before

ploughing in.

This makesploughing

easier

Land ready forplanting after

Sesbania has beenploughed in

The tips of the Sesbania seedplants are pinched out. This

makes more branches, and theplant has a stronger stem.

After the rice isharvested theSesbania seed

is ripening

The seedplants also

provide a fire-wood yield.

Seed is cleanedand stored for

next season


Sesbania or vel-vet bean is sownas the maize isweeded for the

first time

If maize is alsoweeded by hand

this is still thetime to sow green

manure

Sesbaniagrows

amongst themaize

The Sesbania is readyto plough in after the

maize is harvested

Velvet beangrowing as a

green manure

A Guatemalanfarmer inspecting

the velvet beanafter the maize has

been harvested

The velvet bean is cut at theroots when it starts to flower


Velvet beanflowers andseed pods

Velvet beanafter it has

been cut

This wild"weed" is also agood green ma-

nure plant

Sunhemp used asa green manure

with millet

White clover is sown as a green manure in afruit tree nursery. This keeps weeds down,

conserves water, and adds nitrogen to the soil.

Perennial white clover

Agroforestry on the ter-race edges and velvet beangreen manure in the maize

2 years before, the soil on thisGuatemalan farmer's fields wastoo poor for farming. After usingvelvet bean as a green manure,look how black the soil has be-come and how big the corn is

(also see p.22)


Sesbania roots

Broadbean roots

On the roots of legumeslike Sesbania, broad bean

and velvet bean, smallnodules can be seen. In-side these nodules are

micro-organisms called"rhizobium".

Rhizobium take nitrogen(a very important ele-ment for plant growth)from the air and makesit available for the plant

roots. When they areactive they are this pink

colour.

Sesbania and MaizeIn this method Sesbania is sown withmaize. There are 2 methods of sowingthe Sesbania as a green manure withmaize .

Method 1 :- Sowing Sesbania at the same time as maize.• The maize and Sesbania germinate together. The Sesbania

is dug or ploughed in when the maize is weeded after 3-4weeks, and the fertility from the Sesbania helps the maizecrop.

• Instead of Sesbania, many other types of green manure canbe used to provide nutrients for the maize.

Method 2 :- Sowing Sesbania when maize is being weeded• As maize is being weeded for the first time, 3-4 weeks

after sowing, sow Sesbania as thickly as you would sowwheat. While weeding, the Sesbania seed will be covered.

• After the maize has been harvested, the Sesbania is cut andploughed in as the land is being prepared for the next crop.

• The fertility from the Sesbania will benefit the next wintercrop.

Other green manure types can be used instead ofSesbania, but they need to be tall plants, (like maize), forexample sunhemp. See also velvet bean and maize, p. 18

Sesbania seed productionSow seeds on the terrace edges. Se-

lect as many of the best plants as areneeded for growing on to produce seed.


plough in,or cut andmulch, theSesbania

plough in,or cut andmulch, theSesbania

In this method, velvet bean is grown asa green manure with maize. Velvetbean is sown as the maize is weededfor the first time.

Calendar for maize and SesbaniaMethod 1.

sow maizeand

Sesbania

4-5 months harvestmaize

Method 2.

sowmaize

sowSesbania attime of first

weeding

harvestmaize

3-4 weeks

Velvet bean and maize

• Maize is weeded by hand or ploughed 3-4 weeks aftersowing. At this time, sow velvet bean seed 50cm apart. Theseed is covered with soil when weeding.

• The velvet bean will germinate quicker if it is soaked inwater for 2 days before sowing. While soaking the velvetbean seed, change the water twice a day.

• The velvet bean is a climing type and will grow into a largevine. If it starts to smother the maize before the maize isharvested, it should be pulled off the maize plants onto theground. After the maize is harvested, the velvet bean can beallowed to smother the standing maize stalks to put onextra biomass.

• After the maize has been harvested, the velvet bean is cutand ploughed in as the land is being prepared for the nextcrop, or cut and mulched if the land isto be fallow.

Velvet bean seed production• Plant velvet bean seed on the field edge,

under a suitable tree, and allow it to grow up thetree to produce seed. Don't let it climb on fruit trees as thelarge, thick vine can damage the fruiting of the tree.

• Velvet bean seed will be ready to harvest about 8-10months after sowing.

• Velvet bean seed is not edible for people.Edible climbingbeans can be used instead of velvet bean, such as lablab,Jack bean, etc. These can be allowed to produce a beancrop if timing is appropriate.

Calendar for maize and velvet bean

sowmaize

plough in,or cut andmulch, thevelvet bean

sow velvetbean at time

of firstweeding

harvestmaize

3-4 weeks


In the autumn compatible green manurescan be sown with winter crops. It is diffi-cult to grow green manures together withcrops like wheat or barley, so they areusually grown before the grain crops.

Mustard and Wheat

Timing• The green manure can be sown while land is fallow, after

harvesting the summer crop.• After harvesting the summer crop, such as rice or maize,

the land is ploughed as normal, and mustard is thicklysown.

• The mustard should be ploughed in as it starts to flower.• Then the winter wheat (or any winter crop) is sown.

Instead of mustard, buckwheat or fenugreek canalso be used in the same way as green manures.

Mustard isploughed in atflowering time

for use as agreen manure.Here, wheat is

then sown.

Calendar for wheat and mustard

sowmustard

about 3 weeks

plough inmustard,

sow wheat

harvestwheat

There are many other types of green manure that canbe used as well asthe above examples.

"I sowed sorghum as a green ma-nure. After a month I ploughed it in

and planted potatoes, and got 3times the production !"

Bhim B. Gautam, Gumi, Surkhet

Below is some information about which greenmanures have high amounts of particular nutrients

Type of greenmanure

Nitrogen Phosphorus Potassium

buckwheatmustardtobaccoChenapodiumSesbaniabeans

lots

lotslots

lots

lots

lotslots lots

The Farmers' Handbook, "The Fields" Chapter 2 - Green Manures22

In 1998 Hurricane Mitch struck Central America, especiallyHonduras, Guatemala and Nica-ragua. Strong winds, torrentialrain, landslides and floods killedover 10,000 people and left300,000 others homeless.

But in the south of theLempira region there were nodisasters. No landslides, nodeaths, in fact 84 villages in theregion produced 2000 tonnes ofsurplus grain. To explain theseamazing facts, the government,along with local NGOs andfarmers studied the area andfound that the farmers there hadbeen implementing sustainable,organic agriculture practices thathad protected them from the dan-gers of natural disasters. Since thelast 30 years, over 10,000 farmersin these villages had been imple-menting soil conservation, terrace improvement, agroforestry, greenmanure and integrated pest management strategies to protect the steepslopes in their areas. Because of this, even a huge natural disaster likeHurricane Mitch wasn't able to cause them any serious damage.

Since the beginning of their experiences, the farmers ofLempira have been sharing their lessons with local farming

organisations and with farmers throughout the country and inneighbouring countries too.

A story about Hurricane "Mitch"A story about Hurricane "Mitch"

Farmer Yuwan Aguirrepulls back the thick mat ofbiomass resulting from avelvet bean green manurecrop. This has helped to

protect againts soil erosionand raise production.

æ

Æ

Mr DambarBahadur Regmi

Farmers'ExperienceFarmers'Experience

Ms Hommaya GurungCoordinator, Himalayan Permaculture Group,Surkhet, Nepal

This chapter's author

From Nepal, Surkhet district,Gumi - 3, Mr DambarBahadur Regmi has growngreen manures since 1995.Now let's hear about hisexperience.

I've seen myself the benefitsof growing Sesbania green ma-nure with rice paddy. Ever since Istarted doing this, the productionof rice has increased steadily.Land that used to produce 960kgof rice can now produce up to 1400kg, which is pretty good forthis area. Also, I've spent less buying fertilizers from the sup-plier since using green manures. The soil has become softerand easier to plough, so you need to do less work and still getbetter crops. Rice that's grown this way tastes better, too, andthe mill owner tells us that there's less husk and more grain inmy rice and that of other farmers who've started using green

manures. Now I want to try using other typesof green manure as well as Sesbania.

Dambar Bahadur Regmi

23

Gri

hast

hi C

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unic

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nsSubjects Related to Green ManuresThis book provides enough information to be able to

grow your own green manures. However, this information isalso linked to other methods. For extra benefits let's read,learn and practice from other related chapters.

Read On !Read On !

Compost chapterAs well as green manure, animal compost isalso useful for plant food, but needs to be pro-duced in a well managed way. This chaptershows how to produce a quick rotting, goodquality compost.

Kitchen Garden chapterHow to make and manage a home vegetablegarden for permanence, ease and simplicity ?This chapter shows how to produce a widerange of fresh vegetables by doing less work formore production.

Seed Saving chapterThis chapter gives information on methods toproduce and store various types of qualityseeds, including green manure seeds, at home.

Documents

What are Green Manures · The Farmers' Handbook - "The Fields", Chapter es What are Green Manures ? Every farmer knows how much work goes into the production of a basket of compost