A few thoughts on agriculture on very fundamental questions

related to life and death of humans

Chong Woon HongSoil Scientist

AdviserRDA International Cooperation

Lecture for the high ranking officials of AFACI member countries.2010 . Aug 13, at RDA Suwon, Korea

To be or not to be is the questionHamlet(Shakespear---@1600)

Why are the people farming?

Is farming a fun?

For farming we need to,

clear the land.

plant the seeds.

supply food and water for the crops.

protect the crops from weeds,insects, diseases, and animals,

harvest , process and store the products.

plow the land.

Lots of sweat, costs, and worries!

Why then are we farming?

In the olden days Kings were instructed by the wisescholars.

“For the Kings, people are the Heaven. For the people, food is the Heaven, Therefore, for the Kings food is the Heaven of Heaven.

Kings practiced farming maintaining King’s farmsin the Royal Palaces as token of the respect to people’s basic needs.

Most formidable organ of human beings, ever hungry endlessly.

Instructions for faming---1429A very wise King(Sejong) ordered the scholars to collect the farming techniquesfrom elderly farmers across the country,and publish a book . A book “Instruction for Farming” was published.

Among other things, the book covers aChapter “How to Harness the Soil”, of which contents are surprisingly logical at even today’s standards.

The ones who are farming are men and women; humans.

They do farming to get the thing they need for their survival.

What are their needs for survival in concrete terms?

Body

Humans need energy For thinking andmoving

Bio energy comes from the sun We worship the sun(as father).

Humans are part of earth. So their body comes from theearth(not the soil alone). We love the earth as mother.

수소 (H) 63

산소 (O) 26

탄소 (C) 9

질소 (N) 1,25

칼슘 (Ca) 025

인 (P) 019

황 (S) 0.06

소듐 Na) 0.06

염소 (Cl) 0.025

마그네슘 (Mg) 0.013

철 (Fe) 0.00004

옥소 (I) 0.00002

20 여 가지 더 매우 조금

98% 99.2

5%

0.75%

Elementalcomposition of human body

The elements constituting about 98% of living bodyAre H. O. C, coming from water(H2O) and carbon dioxide(CO2)

Remainders(17 kinds) comes from the soil, out of whichnitrogen is the most in quantity.

Nitrogen being essential for protein, it is crucial for allliving beings.

Elements needed for formation of human bodyare there on the earth and in the soil

And the source of energy is the sun for free.

Very unfortunately humans, humans cannot constructtheir bodies making use of the elements available fromthe surroundings. Also they cannot make solar energyuseful for their energy…..We should beg the plants to do the jobfor us.

Soil(Water + minerals)

CO2

물 , 양분

CO2

Photosyntheis

다음 끼까지살아남게 돼서 다행이다 !!!

Starch

Rice

Rice Glucose+

Oxygen

CO2 + H2O + Energy

Photosynthesis

H2O

CO2

6CO2 + 6H2O === C6H12O6 + 6O2

Energy

Concentrations of Essential Elements in Higher Plants (Dry tissue)

http://www.foliarfert.com/pages/what_is_foliar_fertiliser.htmhttp://www.foliarfert.com/pages/what_is_foliar_fertiliser.htm

  Element   ppm   %

(weight)Hydrogen 60,000 6Carbon   450,000 45Oxygen 450,000 45Nitrogen 15,000 1.5

Potassium 10,000 1.0Calcium 5,000 0.5

Magnesium 2,000 0.2Phosphorus 2,000 0.2

Sulphur 1,000 0.1Chlorine 100 0.01Boron 20 0.002Iron 100 0.01

Manganese 50 0.005Zinc 20 0.002

Copper 6 0.0006Molybdenu

m0.1 0.00001

96%

Oxisol soil Aridisol soil

ㅎ

Roles of soils in agriculture

Plant roots

Water

Soil solid

Air

Plants do not feed on solid materials of soils

Plants do drink the water sin soil pore,Feed on the nutrients in soil water.

Soil is in a way a container, containingwater, nutrients and air.

Among those nutrients, nitrogen is mostimportant.

As container, soils all over the world are generallyFine, excepting extreme cases.

Problem with many unproductive soils all over the World is in sufficient plant nutrients in the waterIn the soil pores.

Among those nutrients, N is most probable to be Insufficient, because of its nature.

Nitrogen is most abundant element in the atmosphere(78% of atmosphere).

Nitrogen in the atmosphere is in the form of N2, which is notdirectly available to most of higher plants including agriculturalcrops excepting the legumes, like soybeans.

N2 must be changed into NH3, to be available non-legume cropsLike cereals(rice, wheat, maize, potatoes, cassava, etc.) fruitsand most of vegetables

The change of nitrogen(N2) into NH3, is called nitrogen fixation.This change needs H(hydrogen) and energy.

N fixation can take place in the soil by various microbes, eitherIndependently or symbiotically with leguminous plantslike soybeans, clovers, various pea… we call it biological N fixation(BNF).

N can be fixed chemically, at the fertilizer plants.

Use as source of energy,Fossil fuel or end electricity,Which humans cannot eat.

N fixations, biologically and chemically need raw materialsand energy.

2N2 + 3H2 + energy -- 2NH3

Glucose In soybeansPhotosynthetic product(glucose, which human can eat)

should go to root nodule to feed bacteria for N fixation.

As the results,The yield of soybeans is much lower(2 ton/ha)

than the Yields of cereals(6-10 ton/ha) fed with chemical fertilizer.

Cereals fed with fertilizer, do not need to feed bacteria, can use All the photosynthetic product for their own, hence, higher yield(6-10 ton/ha)

Both options; BNF, or CNF, involve pros and cons.People choose the options depending on their needs.

Area Harvested (Ha)

　 item 2008

World Cereals 713443557

World + legumes 74129733

Western Europe

World

SE Asia

Middle Africa

Fertilizer(N) use in different regions

Kg/ha

Yield of cereals in different regions

Yield(ton/ha)

Ghana’s common farming practiceBurning and shifting farming---Typical exploitive farmin

I talked to farmers if some fertilizer is used,Current years yields would high and youwould not need to move other land to burn.I suggested them to test what I told them.

Few of them agreed.I showed them how to plant,how to put fertilizer.

They did by themselves attheir farms

23年 4月 20日 농업기술협력팀 28

Extension officer helped the farmers.In the line, at certain distance.

They learned quickly.

23年 4月 20日 농업기술협력팀 29

One half of their plot did receive fertilizer for comparison

비료 준 포장

Where fertilize was applied

비효실증포농가관행 포장

첫 해에 20 농가 , 2 년 차 400 농가 , 3 년 차 8,000 농가 참여

Rice in Ghana and a Korean Scientist

Adequate fertilizer application rice (African variety ) yield could beIncreased from 2 ton/ha/ha,

Nitrogen (N2) is most abundant on earth(78% of air in the Atmosphere) but least available to plant.

It (N2) should be changed(fixed) to ammonia form(NH3).

This job is being done by symbiotic bacteria on theRoots of leguminous plants and non-symbiotic bacteria like Azosprillum in the soil.----Biological N Fixation---believed to beEnvironment friendly---much praised.

BNF is not free of cost and so much environement friendly as commonly believed.

In corn much of photosynthates go to gain.Yield can be as high as 12 ton/ha.

In soybeans, much part of photisynthatesgo toSymbiotic bacteria.Yield can be as high as 3 ton/ha.

BNF is a slow process and requires landand human labor too.

Another way of N fixation.

Homo sapiens are much knowledgeableand skillful.

With their accumulated knowledge andskills they have worked out an efficientway to fix nitrogen and the outcome of that has been called N fertilizers.

Africa and elsewhere in developing regions there are lots leguminous plants fixing N biologically,Without ceasing, but with that alone…

Change in the per capita cereal production in differentregions since 1960s till now (From FAO Statistics)

Per capita production (kg)

Western Europ

World

Western Europe

Sub-Sahara Africa

Annual per capita production of cereals Sub-Sahara rica, World and Western Europe(from FAO statistics)

N u

sed

(kg

/ha)

Change in the use of N fertilizer in different regions since 1960s till now(From FAO statistics)

Sub-Sahara Africa`

World

Western EuropeN

used

kg

/ha