what is Sustainable agriculture?

Every day, farmers and ranchers around the world develop new, innovative strategies to produce and distribute food, fuel and fiber sustainably. While these strategies vary greatly, they all embrace three broad goals, or what SARE calls the 3 Pillars of Sustainability:
Profit over the long term
Stewardship of our nation’s land, air and water
Quality of life for farmers, ranchers and their communities           
There are almost as many ways to reach these goals as there are farms and ranches in America. A cattle rancher might divide his rangeland into paddocks in a rotational grazing system to better manage soil and water resources while improving animal productivity. A field crop farmer might implement a rotation to break up pest cycles, improve soil fertility and cut costs, or use cover crops—non-cash crops grown for their benefit to the soil and ability to suppress weeds. A fruit and vegetable grower might try a new marketing approach
such as selling directly to restaurants in a nearby city to gain a larger share of the consumer food dollar. No one recipe works on every farm and ranch. But to give a flavor of sustainable agriculture at work, we have profiled the sustainable operations of eight of SARE’s many cream-of-the-crop grantees—including producers, researchers and educators. To get a more complete picture, view 61 in-depth profiles in SARE’s book The New
American Farmer, 2nd edition at www.sare.org/newfarmer.
Best Practice Sampler
It is impossible to list all the innovative and varied practices farmers and ranchers use to improve sustainability,
so consider SARE’s list below a sampling, not a prescription, of best practices.
Marketing
Farmers and ranchers can boost their financial sustainability by using a greater diversity of marketing techniques:
processing on-farm; creating value-added products and a strong brand identity; conducting market
research to match product to demand; selling direct to consumers at farmers markets, community-supported
agriculture (CSA) enterprises, roadside stands or through the Web; and delivering to restaurants, small grocers
and local institutions—to name just some techniques.
Community Vitality
Thriving communities—rural and urban—are a key to quality of life for all. When farmers and ranchers hire
help and sell in nearby communities, for example, they contribute to the local economy. In turn, they have a
nearby hub for raising their families and a possible market for their products.
Ecological Insect And Weed Management
Ecological pest management avoids single-bullet solutions that can harm beneficial insects, and instead uses a
combination of many complementary strategies—for example, biological controls such as trap crops for insect
pests, physical removal of weeds and insects, application of chemicals if necessary, and other methods such as
selecting crops that smother or shade out weeds and creating habitat for beneficial insects.
Grazing
Management-intensive, or rotational, grazing systems keep animals moving from pasture to pasture to provide
high-quality forage and reduce feed costs. An added bonus is that—with a little attention from the farmer or
rancher—grazing animals distribute manure across the field, which contributes to soil fertility and reduces the
need for purchased fertilizer inputs.
Conservation Tillage
Many soil conservation practices—contour tillage, reduced tillage and no-till, to name a few—help prevent soil
loss from wind and water erosion. Conservation tillage systems also help minimize soil compaction, conserve
water and store carbon to help offset greenhouse gas emissions.
Cover Crops
Growing plants such as rye, clover or vetch after harvesting a cash crop can provide multiple benefits, including
weed and insect suppression, erosion control and improved soil quality. Cover crops are now grown on millions
of acres across the country.
Crop, Livestock And Landscape Diversity
Growing a greater variety of crops and livestock—especially genetically diverse open-pollinated plants and
heritage breeds—can make a farm more resilient to diseases and pests, as well as extremes in weather and
market conditions. Certain agroforestry techniques—inter-planting trees with crops and growing shade-loving
specialty crops, for example—help conserve soil and water, provide wildlife habitat and increase beneficial
insect populations.
Nutrient Management
Well-managed and properly applied on-farm nutrient sources—such as manure and leguminous cover crops—
build soil, protect water quality and reduce purchased fertilizer costs.
On-Farm Energy Conservation And Production
Farmers and ranchers are using energy-saving devices, windmills and solar power, while also learning how to
grow and process their own fuel. These practices not only make farm operations more profitable, clean and
efficient, they help reduce dependence on foreign oil and reduce greenhouse gas emissions.
A Whole-Farm Approach
A whole-farm approach combines the practices listed above into one integrated management system that
works with nature: Reducing tillage and careful application of on-farm nutrient sources, for example, build soil
organic matter; energy costs are reduced when fuel is produced from waste or renewable sources; pests are
controlled by plant and landscape diversity; income is boosted by more efficient use of on-farm resources—
and the list goes on.

the soil lec ( 3 )

DRAINING THE SOIL

A wise man was once asked, "What is the most valuable improvement ever made in agriculture?" He answered, " Drainage." Often soils unfit for crop-production because
they contain too much water are by drainage rendered the most valuable of farming lands.
Drainage benefits land in the following ways :
1. It deepens the subsoil by removing unnecessary water from the spaces between the soil particles. This admits air. Then the oxygen which is in the air, by aiding decay, prepares plant food for vegetation.
2. It makes the surface soil, or topsoil, deeper. It stands to reason that the deeper the soil the more plant food becomes available for plant use.
3. It improves the texture of the soil. Wet soil is sticky. Drainage makes this sticky soil crumble and fall apart.
4. It prevents washing.
5. It increases the porosity of soils and permits roots to go deeper into the soil for food and moisture.
6. It increases the warmth of the soil.
7. It oermits earlier working in spring and after rains.
8. It favors the growth of germs which change the unavailable nitrogen of the soil into nitrates ; that is, into the form of nitrogen most useful to plants.
9. It enables plants to resist drought better because the roots go into the ground deeper early in the season. A soil that is hard and wet will not grow good crops. The nitrogen-gathering crops will store the greatest quantity of nitrogen in the soil when the soil is open to the free circulation of the air. These valuable crops cannot do this when the soil is wet and cold. Sandy soils vi"ith sand}' subsoils do not often need drainage ; such soils are natiu^ally drained. With claj' soils it is different. It is ven* important to remove the stagnant
water in them and to let the air in. \\'hen land has been properly drained the other steps in
improvement are easily taken. After soil has been dried and mellowed by proper drainage, then commercial fertilizers, barnyard manure, cowpeas, and clover can most readily do
their great work of impro\ing the texture of the soil and of making it fitter for plant growth.
Tile Drains. Tile drains are the best and cheapest that can be used. It would not be too strong to say that draining by tiles is the most perfect drainage. Thousands of practical tests in this countn,^ have proved the superiorit\- of tile draining for the foUovi-ing reasons :
1.Good tile drains properly laid last for years and do not fill up.
2. They furnish the cheapest possible means of removing too much water from the soil.
3. They are out of reach of all cultivating tools.
4. Surface water in filtering through the tiles leaves its nutritious elements for plant growth.

IMPROVING THE SOIL

We hear a great deal about the exhaustion or wearing out of the soil. Many uncomfortable people are always declaring that our lands will no longer produce profitable crops, and
hence that farming will no longer pav. Now it is true, unfortunately, that much land has been
robbed of its fertility, and, because this is true, we should be most deeply interested in ever)thing that leads to the improvement of our soils. When our countn,' was first discovered and trees were growing ever\where, we had virgin soils, or new soils that xeae rich and jHoductive because they were filled with vegetable matter and plant food. There are not many virgin soils now because the trees have been cut from the best lands, and these lands have been :^rmed so carelessly that the vegetable matter and available plant fc-.od have been laigeH" used up. Xow that fresh land is scarce it is ver\' oecessaiy to restore fertility' to these exhausted lands. \\'hat are some of the wa}-s in which this can be done ? There are several things to be done in tning to reclaim wMn-out land. One of the first of these is to till the land wdL Many of you may have heard the stor\' of the dying father who called his sons about him and whispered feebly, " Thoe is great treasure hidden in the garden." The sons could hardly wait to bun- their dead father before, thud, thud, thud, their picks were going in the garden. Day after day they dug ; they dug deep ; they dug wide. Not a foot of the crop-worn garden escaped the probing of the pick as the sons feverishly searched for the expected treasure. But no treasure was found. Their work seemed entirely useless.  Let US not lose ever\' whit of our labor ; let us plant diis pick-scarred garden," said the eldest. So the garden was planted. In the fall the hitherto neglected garden yielded a har\-est so bountiful, so unexpected, that the meaning of their father's words dawned upon them. " Truly," they said, " a treasure was hidden there. Let us seek it in all our fields."
The ston^ applies as well to-day as it did when it was first told. Thorough culture of the soil, frequent and intelligent tillage—these are the foundations of soil-restoration. Along with good tillage must go crop-rotation and good drainage. A supply of organic matter will prevent hea\y rains from washing the soil and carr}'ing away plant food. Drainage will aid good tillage in allowing air to circulate between the soil particles and in arranging plant food so that plants can use it. But we must add humus, or vegetable matter, to the soil. You remember that the virgin soils contained a great deal of vegetable matter and plant food, but by the continuous growing of crops like wheat, corn, and cotton, and by constant
shallow tillage, both humus and plant food ha\e been used up. Consequently much of our cultivated soil to-day is hard and dead. There are three ways of adding humus and plant food t this lifeless land : the first way is to appl}' barnyard manure (to adopt this method means that livestock raising must be a part of all farming) ; the second way is to adopt rotation of crops, and frequently to plow under crops like clover and cowpeas ; the third way is to apply commercial fertilizers. To summarize : if we want to make our soil better \ear
by year, we must cultivate well, drain well, and m the most economical way add humus and plant food.

the soil lec ( 2 )

 TILLAGE OF THE SOIL

A good many years ago a man hv the name of Jethro Tull lived in England. He was a farmer and a most successful man in every way. He first taught the English people and the world the value of thorough tillage of the soil. Before and during his time farmers did not till the soil veiy intelligently. They simply prepared the seed-bed in a careless manner, as a great many farmers do to-day, and when the crops were gathered the fields were not large.
Jethro Tull centered attention on the important fact that careful and thorough tillage increases the available plant food in the soil. He did not know why his crops were better
when the ground was frequently and thoroughly tilled, but he knew that such tillage did increase his yield. He explained the fact by saying, " Tillage is manure." We have
since learned the reason for the truth that Tull taught, and, while his explanation was incorrect, the practice that he was following was excellent. The stirring of the soil enables the air to circulate through it freely, and permits a breaking down of the compounds that contain the elements necessar}' to plant growth. You have seen how the air helps to crumble the stone and brick in old buildings. It does the same with soil if permitted
to circulate freely through it. The agent of the air that chiefly performs this work is called carbonic acid gas, and this gas . is one of the greatest helpers the farmer has in cariy-ing on his work. We must not forget that in soil preparation the air is just as important as any of the tools and implements used in cultivation. If the soil is fertile and if deep plowing has always been done, good crops will result, other conditions being favorable.If, however, the tillage is poor, scanty har\'ests will always result. For most soils a two-horse plow is necessary to break up and pulverize the land. A shallow soil can always be improved by properlv deepening it. The principle of greatest importance in soil-preparation is the gradual deepening of the soO in order that plant-roots mav have more comfortable homes. If tlie farmer has been accustomed to plow but four inches deep, he should adjust
the plow so as to turn live inches at the next plowing, then sLx, and so on until the seed-bed is nine or ten inches deep. This gradual deepening \\ill not injure the soil but will put it quickly in good condition. If to good tillage rotation of crops be added, tlie soil will become more fertile each succeeding year. The plow, harrow, and roller are all necessary to good tillage and to a proper preparation of the seed-bed. The soil must be made compact and clods of all sizes must be crushed. Then the air circulates freely, and pa>ing crops are the rule and not the exception. Tillage does these things: it increases the plant-food
supplv, destroys weeds, and influences the moisture content of the soil.

THE MOISTURE OF THE SOIL

Did any one ever explain to you how important water is to the soil, or tell you why it is so important .'' Often, as you know, crops entirely fail because there is not enough water
in the soil for the plants to drink. How necessar}' is it, then, that the soil be kept in the best possible condition to catch and hold enough water to carr\' the plant through dr}-, hot
spells ! Perhaps you are ready to ask, " How does the mouthless plant drink its stored-up water ? "
The plant gets all its water through its roots. You have seen the tiny thread-like roots of a plant spreading all about in fine soil; they are down in the ground taking up plant food and water for the stalk and leaves above. The water, carrying plant food with it, rises in a simple but peculiar way through the roots and stems. The plants use the food for building new tissue, that is, for growth. The water passes out through the leaves into the air. When the summers are dry and hot and there is but little water in the soil, the leaves shrink up. This is
simpU' a method they have of keeping the water from passing too rapidly off into the air. I am sure you have seen the corn blades all shriveled on ver\- hot days. This shrinkage
is nature's way of diminishing the current of water that is steadily passing through the plant.
A thrifty farmer will tr)- to keep his soil in such good condition that it will have a supply of water in it for growing crops when dr)- and hot weather comes. He can do this by
deep plowing, by subsoiling, by adding any kind of decaying vegetable matter to the soil, and by growing crops that can be tilled frequently. The soil is a great storehouse for
moisture. After the clouds have emptied their waters into this storehouse, the water of the soil comes to the surface, where it is evaporated into the air. The water comes to the
surface in just the same way that oil rises in a lamp-wick. This rising of the water is called capillarity. It is necessar)- to understand what is meant by this big word. If into a pan of water you dip a glass tube, the water inside the tube rises above the level of the water in the pan. The smaller the tube the higher will the water rise. The greater rise inside is perhaps due to the fact that the glass attracts the particles of water more than the particles of water attract one another. Now apply this principle to the soil. The soil particles have small spaces between them, and the spaces act just as the tube does. When the water at the surface is carried away by drying winds and warmth, the water deeper in the soil rises through the soil spaces. In this way water is brought from its soil storehouse as plants need it. Of course when the underground water reaches the surface it evaporates. If we want to keep it for our crops, we must prepare a trap to hold it. Nature has shown us how this
can be done. Pick up a plank as it lies on the ground. Under the plank the soil is wet, while the soil not covered by the plank is dr}-. Why ? Capillarit}- brought the water to the surface,
and the plank, b\- keeping away wind and warmth, acted as a trap to hold the moisture. Now of course a farmer cannot set a trap of planks over his fields, but he can make a
trap of dry earth, and that will do just as well. When a crop like corn or cotton or potatoes is cultivated, the fine, loose dirt stirred by the cultivating-plow will make a mulch that ser\-es to keep water in the soil in the same way that the plank kept moisture under it. The mulch also helps to absorb the rains and prevents the water from running off the surface. Frequent  cultivation, then, is one of the best possible ways of saving moisture. Hence the farmer who most frequently stirs his soil in the growing season, and especially in seasons of drought, reaps, other things being equal, a more abundant harvest than if tillage were neglected.

the soil lec ( 1 )

 origin' of the soil

The word soil occurs many times in this Httle book. In agriculture this word is used to describe the thin layer of surface earth that, like some great blanket, is tucked around
the wrinkled and age-beaten form of our globe. The harder and colder earth under this surface layer is called the subsoil. It should be noted, however, that in waterless and sun-dried regions there seems little difference between the soil and the subsoil.
Plants, insects, birds, beasts, men, —all alike are fed on what grows in this thin layer of soil. If some wild flood in sudden wrath could sweep into the ocean this earth-wrapping
soil, food would soon become as scarce as it was in Samaria when mothers ate their sons. The face of the earth as we now see it, daintily robed in grass, or uplifting waving acres
of com, or even naked, water-scarred, and disfigured by man's neglect, is ver)- different from what it was in its earliest davs. How was it then } How was the soil formed }
Learned men think that at first the surface of the earth was solid rock. How was this rock changed into workable soil } Occasionally a curious boy picks up a rotten stone,
squeezes it, and finds his hands filled with dirt, or soil. Now, just as the boy crumbled with his fingers this single stone, the great forces of nature with boundless patience crumbled,
or, as it is called, disintegrated, the early rock mass. The simple but giant-strong agents that beat the rocks into powder with a clublike force a millionfold more powerful than the club force of Hercules were chiefly (i) heat and cold; (2) water, frost, and ice; (3; a ven- low form of vegetable life; and (4) tiny animals—if such minute bodies can be called animals. In some cases these forces acted singly ; in others, all acted together to rend and crumble the unbroken stretch of rock. Let us glance at some of the methods used by these skilled soil-makers. Heat and cold are working partners. You already know that most hot bodies shrink, or contract, on cooling. The early rocks were hot. As the outside shell of rock cooled
from exposure to air and moisture it contracted. This shrinkage of the rigid rim of course broke mam* of the rocks, and here and there left cracks, or fissures. In these fissures water
collected and froze. As freezing water expands with irresistible power, the expansion still further broke the rocks to pieces. The smaller pieces again, in the same wa}, were acted
on by frost and ice and again crumbled. This process is still a means of soil-formation.
Running water was another giant soil-former. If you would understand its action, obser\'e some usually sparkling stream just after a washing rain. The clear waters are discolored by
mud washed in from the surrounding hills. As though disliking their muddy burden, the waters strive to throw it off. Here, as low banks offer chance, they run out into shallows
and drop some of it. Here, as they pass a quiet pool, they deposit more. At last they reach the still water at the mouth of the stream, and there they leave behind the last of their mud load, and often form of it little three-sided islands called deltas. In the same way mighty rivers like the Amazon, the Mississippi, and the Hudson, when they are swollen by rain,
bear great quantities of soil in their sweep to the seas. Some of the soil they scatter over the lowlands as they whirl seaward ; the rest they deposit in deltas at their mouths. It is  estimated that the Mississippi carries to the ocean each year enough soil to cover a square mile of surface to a depth of two hundred and sixty-eight feet. The early brooks and rivers, instead of bearing mud, ran oceanward either bearing ground stone that they themselves
had worn from the rocks by ceaseless fretting, or bearing stones that other forces had  already dislodged. The large pieces were whirled from side to side and beaten against
one another or against bedrock until they were ground into smaller and smaller pieces. The rivers distributed this rock soil just as the later rivers distribute mudd\- soil. For ages
the mo\"ing waters ground against the rocks. \'ast were the waters ; vast the number of years ; vast the results. Glaciers were another soil-producing agent. Glaciers are
streams " frozen and mo\"ing slowly but irresistibly onwards, down well-defined valleys, grinding and pulverizing the rock masses detached by the force and weight of their attack."
Where and how were these glaciers formed ? Once a great part of upper North America was a \-ast sheet of ice. Whatever moisture fell from the sky feU as snow. No one knows what made this long winter of snow, but we do know that snows piled on snows until mountains of white were built up. The lower snow was by the pressure of that above it packed into ice masses. By and by some change of climate caused the masses of ice to break up somewhat and to move south and west. These mo\ing masses, carr\-ing rock and frozen earth, ground them to powder. King thus describes the stately movement of these snow mountains : " Beneath the bottom of this slowly moxing sheet of ice, which with more or less difficultA* kept itself conformable with the face of the land over which it was riding, the sharper outstanding points were cut away and the deeper river canons filled in. Desolate and rugged rocky wastes were thrown down and spread over with rich soil." The joint action of air, moisture, and frost was still another agent of soil-making. This action is called  u'cathcriug. Whenever you have noticed the outside stones of a spring-house, 3^ou have noticed that tiny bits are crumbling from the face of the stones, and adding little by little to the soil. This is a slow way of making additions to the soil. It is estimated that it would take 728,000 years to wear aw^y limestone rock to a depth of thirty-nine inches. But when you recall the countless years through which the weather has striven against the rocks, you can readily understand that its never-wear)ing actixity has added immensely to the soil.
In the rock soil formed in these various ways, and indeed on the rocks themselves, tiny plants that live on food taken from the air began to grow. They grew just as )-ou now see
mosses and lichens grow on the surface of rocks. The decay of these plants added some fertility to the newly formed soil. The life and death of each succeeding generation of these
lowly plants added to the soil matter accumulating on the rocks. Slowly but unceasingly the soil increased in depth until higher vegetable forms could flourish and add their dead
bodies to it. This vegetable addition to the soil is generally known as Imunts. In due course of time low forms of animal life came to live on these plants, and in turn by their work and their death to aid in making a soil fit for the plowman.Thus with a dehberation that fills man with awe, the powerful forces of nature splintered the rocks, ciTimbled them,
filled them with plant food, and turned their flinty grains into a soft, snug home for vegetable life.