LECTURER FOUR
Introduction and definition of terms
1.1 Introduction
.
The lecture covers:
1. Lecture objectives 2. Definition of soil conservation 3. Benefits of soil conservation 4. Soil conservation practices 5. Further activities 6. summary 7. suggestions for further reading.
1.2 Lecture objectives
By the end of this course the learner should be able to:
Explain the benefits of soil conservation.
Outline the soil conservation practices.
1.3 e-tivity
Soil conservation
Numbering, sequencing: 1.3
Title: Soil conservation practices and benefits
Brief summary of task:
- read the document below at Url
- read the online documents below and open the links provided to watch you tube videos (section 1.13)
Spart or simulator: soil conservation
Individual task: using bullet points/paragraphs,
a) discuss the benefits of soil conservation
b) Outline the soil conservation practices
Interaction begins:
a) post two questions related to soil conservation
b) provide feedback to learners views.
E-moderator interventions:
a) ensure learners are focused on discussions.
b) stimulate further learning.
c) provide feedback on learning progress.
d) Close e-tivity.
Schedule and time: this should take 30 minutes.
1.4 Soil conservation
What Is Soil Conservation And What Does It Focus On?
Soil conservation is a set of farming techniques and practices to avoid degradation, erosion and depletion in particular. Soil conservation methods target long-term use with a thought of the future. By taking proper and timely actions, farmers boost the performance of their fields for the years to come.
A major objective of conservation of the soil is maintaining its biodiversity of inhabiting eco-communities that contribute to its fertility in their own ways. They add organic matter, split perished organisms to release nutrients, improve water infiltration, and aeration. Ensuring proper conditions for living bodies in the earth is vitally important for vegetation that grows there since microorganisms adjust the organic matter for plant needs.
Different types of soil conservation methods prevent earth runoff, pollution, sedimentation in water objects, and protect bare surfaces from cracking and erosion due to water, wind, and excessive heat.
Soil conservation strategies rely on three basic steps:
Obtaining proper knowledge of the land resource use.
Monitoring fields and detecting critical zones.
Controlling and estimating the efficiency of applied soil conservation techniques.
1.5 Benefits Of Soil Conservation
To maintain an adequate amount of organic matter and biological life in the soil. These two components account for 90 to 95 percent of the total soil productivity
Boosts earth quality and productivity. Maintaining the natural environment for earth-dwelling organisms increases fertility and reduces the necessity of chemical fertilizing, thus boosting yields and saving costs at the same time.
Mitigates erosion. Soil conservation methods to reduce erosion and depletion help agriculturalists to avoid the expansion of new lands when territories become infertile.
Promotes water infiltration and increases its storage. The soil conservation technique of minimum tillage vs. conventional plowing affects soil moisture by reducing cracking and evaporation as well as rising the infiltration rate.
Aids air and water purification. The importance of soil conservation relates to water supplies, and the earth functions as a natural filter to purify water. Soil conservation mitigates the concentration of pollutants and sediments. In its turn, water is the basic condition to dissolve nutrients for plants. Soil carbon sequestration and reduced chemical applications contribute to air purity, too.
Gives food and shelter for wildlife. Land with growing vegetation is a living environment for animals; it is not only the source for nourishment but their home as well.
To save citizens money. Soil erosion costs us an addition $9.1 million each year, and probably much more according to recent research.
For aesthetic reasons. To provide more attractive and picturesque scenery.
To help create an environment free of pollution where we can live safely.
For the future of our children, so that they may have enough soil to support life. It has been said that the land has not so much been given to us by our forefathers, but has been borrowed from our children.
To save farmers money. Erosion is currently costing farmers over $90 milliona year in lost income due to lower crop yields, and the loss of nutrients from the soil.
1.6 Soil Conservation Practices
Different types of soil conservation methods ensure long-term usage of land and keep it productive for future generations. Let’s consider their benefits in regard to soil conservation.
Conservation Tillage
The soil conservation technique aims at addressing wind and water erosion by covering the earth with vegetation (either crops or their residues) and limiting the number of tilling operations. Another significant aspect is to choose the proper time for field operations, depending on the soil types. For example, clay ones are better to till after harvesting while other types are better to plow before seeding. Also, handling wet soils leads to their compaction.
No-till farming assists in soil conservation as well since it implies no or minimum disturbance and planting seeds into the crop residue. The basic idea is not to leave soil bare, as bare areas are highly prone to erosion, and plants keep it in place with their root systems. Additionally, vegetation accumulates moisture for future crops.
Contour Farming
The soil conservation method proves efficient in slope territories and suggests planting species along the contour. Rows up and down the slope provoke soil erosion due to water currents while rows along the contour restrain it.
Strip Cropping
In this case, farmers combine high-growing crops with low-growing ones for the sake of wind protection, like when corn grows in strips with forage crops. The practice works even better when high-growing crops are intensified in the sides where winds blow most frequently. An extra benefit is the organic matter material from the low crops.
Windbreaks
As the name suggests, this soil conservation practice is used to reduce the power of winds and its disruptive effect on soil. These are trees or bushes to shelter crops from snow and winds planted in several rows. Depending on the number of rows, we can distinguish windbreaks properly (up to five rows) and shelterbelts (six and more). Windbreak vegetation also provides a living environment for wildlife and eliminates soil abrasion on crops due to strong wind blows.
Crop Rotation
Crop rotation vs. monocropping farming suggests changing agro species instead of planting one and the same for many subsequent seasons. Farmers applying this soil conservation method reap numerous benefits. Crop rotation helps them improve the earth structure with diverse root systems, to mitigate pest establishments, and to add nitrogen to the land with legumes known as nitrogen-fixing plants.
The choice of crops to rotate is specific for each agricultural enterprise and highly depends on historical weather and productivity data. Some plants proved to be efficient in recent years, and some did not. Such information is available on Crop Monitoring alongside daily weather and forecasts up to two weeks ahead, including precipitation, min/max temperatures, and anticipated risks. Furthermore, vegetation indices such as NDVI, MSAVI, NDMI, and ReCI help to inspect crop health at each growth stage. With this toolkit set, Crop Monitoring assists in comprehensive analysis of the field and crops states.
Cover Crops
This soil conservation technique is another way to avoid bare soils and additionally benefit from planting cover crops – secondary species – in-between growing cash crops for different reasons like to:
- produce forage and grazing material for cattle;
provide green manure;
assist in weed control;
retain moisture;
ensure a natural environment for microorganisms and minor animals;
balance nitrogen concentration (either releasing or accumulating it with certain plants).
Buffer Strips
These are trees and bushes on the banks of water bodies to prevent sediment, water wash offs. Their roots fix the soil to avoid slumping and erosion, canopies protect from excessive sunlight to water inhabitants and falling leaves are a source of organic matter and food of minor aquatic animals.
Grassed Waterways
A grassed waterway is just what it is called. This is a furrow for water streams covered with grass. It is connected to a ditch, pit, or current to collect water, and the grassroots keep the earth in place, protecting it from water erosion, and thus contributing to soil conservation
Step Away From Synthetic Fertilizers And Pesticides
Chemicals application to control weed and pest infestations are harmful to the environment and undesired in soil conservation. This is why switching to alternative ways to address the problem is highly important in agriculture and organic farming in particular. These alternatives are biological and cultural options when fertility is restored with green and animal manure, compost, crop rotation, and other methods of non-chemical control.
Integrated Pest Management
Pests are a great nuisance to agriculturalists and have been a major issue to tackle while chemicals poison nature leaking to water and the atmosphere. It is important to eliminate synthetic herbicides replacing them with organic ones or establishing biological enemies of pests whenever possible, rotating crop species to minimize increasing pest populations in the same field for years, and using alternative techniques in complex.
Soil Conservation With Crop Monitoring
The key goal of soil conservation is protecting it from degradation in any way, including depletion of fertility and erosion. The main task in reducing erosion is to cover lands with crops or residues to avoid bare areas since they are highly subject to disruption due to winds, the flow of water, and rain splashes.
In respect to the conservation of the soil, Crop Monitoring helps farmers to reveal bare territories in time so that they could keep their lands fertile and productive as long as possible. The online software assists in field scouting and can point out critical areas relying on satellite-retrieved data. Once the problem is suspected, farmers can assign tasks to scouters via the mobile application to check it with a human eye, monitor the task completion, and take proper actions.
Salinity management
Salinity in soil is caused by irrigating with salty water. Water then evaporates from the soil leaving the salt behind. Salt breaks down the soil structure, causing infertility and reduced growth.
The ions responsible for salination are: sodium (Na+), potassium (K+), calcium (Ca2+), magnesium (Mg2+) and chlorine (Cl−). Salinity is estimated to affect about one third of the earth's arable land. Soil salinity adversely affects crop metabolism and erosion usually follows.
Salinity occurs on drylands from overirrigation and in areas with shallow saline water tables. Over-irrigation deposits salts in upper soil layers as a byproduct of soil infiltration; irrigation merely increases the rate of salt deposition. The best-known case of shallow saline water table capillary action occurred in Egypt after the 1970 construction of the Aswan Dam. The change in the groundwater level led to high salt concentrations in the water table. The continuous high level of the water table led to soil salination.
1.7 Organic farming
Organic farming is an agricultural system which originated early in the 20th century in reaction to rapidly changing farming practices. Certified organic agriculture accounts for 70 million hectares globally, with over half of that total in Australia. Organic farming continues to be developed by various organizations today. It is defined by the use of fertilizers of organic origin such as compost manure, green manure, and bone meal and places emphasis on techniques such as crop rotation and companion planting. Biological pest control, mixed cropping and the fostering of insect predators are encouraged. Organic standards are designed to allow the use of naturally occurring substances while prohibiting or strictly limiting synthetic substances. For instance, naturally occurring pesticides such as pyrethrin and rotenone are permitted, while synthetic fertilizers and pesticides are generally prohibited. Synthetic substances that are allowed include, for example, copper sulfate, elemental sulfur and Ivermectin. Genetically modified organisms, nanomaterials, human sewage sludge, plant growth regulators, hormones, and antibiotic use in livestock husbandry are prohibited. Organic farming advocates claim advantages in sustainability, openness, self-sufficiency, autonomy/independence, health, food security, and food safety.
Organic or ecological growing involves minimizing or eliminating the use of synthetic fertilizers and pesticides, and nurturing rich, long term balanced soil fertility through techniques such as crop rotation, conservation tillage and adding compost and manure to the soil.
Fertilizers usually only replace macro-nutrients (phosphorus, nitrogen, and potassium) and do not provide the organic matter that natural fertilizers do. Most insecticides are non selective. In addition to killing target pests, they can kill insects and microorganisms that are essential to soil fertility.
Organic soil management can be applied on any scale from a small backyard to a large commercial farm, although the techniques for each will vary. The basic principle is taking into account the needs oforganisms that live in the soil - ensuring the natural cycling of nutrients, and the return of organic matter to the soil. Organisms that are beneficial to the soil, to plants or that will help control pest organisms will all be maintained.
In organic growing the goal is never to completely eliminate pests. Even pesticides cannot do this. Rather, the objective is to establish a balanced soil ecology with an acceptable level of damage by pests.
1.7.1 Organic farming methods
Fertilizers
Since synthetic fertilizers are not used, building and maintaining a rich, living soil through the addition of organic matter is a priority for organic farmers. Organic matter can be applied through the application of manure, compost, and animal by-products, such as feather meal or blood meal. Due to the potential for harbouring human pathogens, the USDA National Organic Standards mandate that raw manure must be applied no later than 90 or 120 days before harvest, depending on whether the harvested part of the crop is in contact with the ground. Composted manure that has been turned 5 times in 15 days and reached temperatures between 55–77.2 °C (131–171 °F) has no restrictions on application times. Compost adds organic matter, providing a wide range of nutrients for plants, and adds beneficial microbes to the soil.
Given that these nutrients are mostly in an unmineralized form that cannot be taken up by plants, soil microbes are needed to break down organic matter and transform nutrients into a bioavailable “mineralized” state. In comparison, synthetic fertilizers are already in mineralized form and can be taken up by plants directly.
Soil is maintained by planting and then tilling in cover crops, which help protect the soil from erosion off-season and provide additional organic matter. The tilling in of nitrogen-fixing cover crops, such as clover or alfalfa, also adds nitrogen to the soil. Cover crops are commonly planted before or after the cash crop season or in conjunction with crop rotation and can also be planted between the rows of some crops, such as tree fruits. Researchers and growers are working to develop organic farming “no-till” and reduced-tillage practices in order to further reduce erosion
Pest control
Organic pesticides are derived from naturally occurring sources. These include living organisms such as the bacteria Bacillus thuringiensis, which is used to control caterpillar pests, or plant derivatives such as pyrethrins (from the dried flower heads of Chrysanthemum cinerariifolium) or neem oil (from the seeds of Azadirachta indica). Mineral-based inorganic pesticides such as sulfur and copper are also allowed.
In addition to pesticides, organic pest control integrates biological, cultural, and genetic controls to minimize pest damage. Biological control utilizes the natural enemies of pests, such as predatory insects (e.g., ladybugs) or parasitoids (e.g., certain wasps) to attack insect pests. Pest cycles can be disrupted with cultural controls, of which crop rotation is the most widely used. Finally, traditional plant breeding has produced numerous crop varieties that are resistant to specific pests. The use of such varieties
and the planting of genetically diverse crops provide genetic control against pests and many plant diseases.
1.7.2 Reasons For Organic Farming
The population of the planet is skyrocketing and providing food for the world is becoming extremely difficult. The need of the hour is sustainable cultivation and production of food for all.
The Green Revolution and its chemical-based technology are losing its appeal as dividends are falling and returns are unsustainable. Pollution and climate change are other negative externalities caused by the use of fossil fuel based chemicals.
In spite of our diet choices, organic food is the best choice you’ll ever make, and this means embracing organic farming methods. Here are the reasons why we need to take up organic farming methods:
1. To Accrue the Benefits of Nutrients
Foods from organic farms are loaded with nutrients such as vitamins, enzymes, minerals and other micro-nutrients compared to those from conventional farms. This is because organic farms are managed and nourished using sustainable practices. In fact, some past researchers collected and tested vegetables, fruits, and grains from both organic farms and conventional farms.
The conclusion was that food items from organic farms had way more nutrients than those sourced from commercial or conventional farms. The study went further to substantiate that five servings of these fruits and vegetables from organic farms offered sufficient allowance of vitamin C. However, the same quantity of fruits and vegetables did not offer the same sufficient allowance.
2. Stay Away From GMOs
Statistics show that genetically modified foods (GMOs) are contaminating natural foods sources at real scary pace, manifesting grave effects beyond our comprehension. What makes them a great threat is they are not even labeled. So, sticking to organic foods sourced from veritable sources is the only way to mitigate these grave effects of GMOs.
3. Natural and Better Taste
Those that have tasted organically farmed foods would attest to the fact that they have a natural and better taste. The natural and superior taste stems from the well balanced and nourished soil. Organic farmers always prioritize quality over quantity.
4. Direct Support to Farming
Purchasing food items from organic farmers is a surefire investment in a cost-effective future. Conventional farming methods have enjoyed great subsidies and tax cuts from most governments over the past years. This has led to the proliferation of commercially produced foods that have increased dangerous diseases like cancer.
It’s time governments invested in organic farming technologies to mitigates these problems and secure the future. It all starts with you buying food items from known organic sources.
5. To Conserve Agricultural Diversity
These days, it normal to hear news about extinct species and this should be a major concern. In the last century alone, it is approximated that 75 percent of the agricultural diversity of crops has been wiped out. Slanting towards one form of farming is a recipe for disaster in the future. A classic example is a potato. There were different varieties available in the marketplace. Today, only one species of potato dominate. This is a dangerous situation because if pests knock out the remaining potato species available today, we will not have potatoes anymore. This is why we need organic farming methods that produce disease and pest-resistant crops to guarantee a sustainable future.
6. To Prevent Antibiotics, Drugs, and Hormones in Animal Products
Commercial dairy and meat are highly susceptible to contamination by dangerous substances. A statistic in an American journal revealed that over 90% of chemicals the population consumes emanate from meat tissue and dairy products.
According to a report by Environmental Protection Agency (EPA), a vast majority of pesticides are consumed by the population stem from poultry, meat, eggs, fish and dairy product since animals and birds that produce these products sit on top of the food chain.
This means they are fed foods loaded with chemicals and toxins. Drugs, antibiotics, and growth hormones are also injected into these animals and so, are directly transferred to meat and dairy products. Hormone supplementation fed to farmed fish, beef and dairy products contributes mightily to the ingestion of chemicals. These chemicals only come with a lot of complications like genetic problems, cancer risks, growth of tumor and other complications at the outset of puberty.Four Principles of Organic Farming
1. Principle of Health
Organic agriculture must contribute to the health and well being of soil, plants, animals, humans and the earth. It is the sustenance of mental, physical, ecological and social well being. For instance, it provides pollution and chemical-free, nutritious food items for humans.
2. Principle of Fairness
Fairness is evident in maintaining equity and justice of the shared planet both among humans and other living beings. Organic farming provides good quality of life and helps in reducing poverty. Natural resources must be judiciously used and preserved for future generations.
3. Principle of Ecological Balance
Organic farming must be modeled on living ecological systems. Organic farming methods must fit the ecological balances and cycles in nature.
4. Principle of Care
Organic agriculture should be practiced in a careful and responsible manner to benefit the present and future generations and the environment.
As opposed to modern and conventional agricultural methods, organic farming does not depend on synthetic chemicals. It utilizes natural, biological methods to build up soil fertility such as microbial activity boosting plant nutrition.
Secondly, multiple cropping practiced in organic farming boosts biodiversity which enhances productivity and resilience and contributes to a healthy farming system. Conventional farming systems use mono-cropping that destroys soil fertility.
1.8 Conservation agriculture
Conservation agriculture (CA) can be defined by a statement given by the Food and Agriculture Organization of the United Nations as "A farming system that promotes minimum soil disturbance (i.e. No-till farming), maintenance of a permanent soil cover, and diversification of plant species. It enhances Biodiversity and natural biological processes above and below the ground surface, which contribute to increased water and nutrient use efficiency and to improved and sustained crop production."
1.8.1 Key principles of conservation agriculture
The Food and Agriculture Organization of the United Nations (FAO) has determined that CA has three key principles that producers (farmers) can proceed through in the process of CA. These three principles outline what conservationists and producers believe can be done to conserve what we use for a longer period of time.
The first key principle in CA (Conservation Agriculture) is practicing minimum soil disturbance which is essential to maintaining minerals within the soil, stopping erosion, and preventing water loss from occurring within the soil. In the past agriculture has looked at soil tillage as a main process in the introduction of new crops to an area.
It was believed that tilling the soil would increase fertility within the soil through mineralization that takes place in the soil. Also tilling of soil can cause severe erosion and crusting which leads to a decrease in soil fertility. Today tillage is seen as destroying organic matter that can be found within the soil cover.
No-till farming has caught on as a process that can save soil organic levels for a longer period and still allow the soil to be productive for longer periods (FAO 2007). Additionally, the process of tilling can increase time and labor for producing that crop. Minimum soil disturbance also reduce destruction of soil micro and macro-organism habitats that is common in conventional ploughing practices.
When no-till practices are followed, the producer sees a reduction in production cost for a certain crop. Tillage of the ground requires more money in order to fuel tractors or to provide feed for the animals pulling the plough. The producer sees a reduction in labor because he or she does not have to be in the fields as long as a conventional farmer.
The second key principle in CA is much like the first in dealing with protecting the soil. The principle of managing the top soil to create a permanent organic soil cover can allow for growth of organisms within the soil structure. This growth will break down the mulch that is left on the soil surface. The breaking down of this mulch will produce a high organic matter level which will act as a fertilizer for the soil surface. If CA practices were used done for many years and enough organic matter was being built up at the surface, then a layer of mulch would start to form. This layer helps prevent soil erosion from taking place and ruining the soil's profile or layout. The presence of mulching also reduce the velocity of runoff and the impact of rain drops thus reducing soil erosion and runoff.
According to the article “The role of conservation agriculture and sustainable agriculture”, the layer of mulch that is built up over time will become like a buffer zone between soil and mulch and this will help reduce wind and water erosion. With this comes the protection of the soil's surface when rain falls on the ground. Land that is not protected by a layer of mulch is left open to the elements (Hobbs et al. 2007). This type of ground cover also helps keep the temperature and moisture levels of the soil at a higher level rather than if it was tilled every year (FAO 2007).
The third principle is the practicing diverse crop rotations or crop interactions. According to an article published in the Physiological Transactions of the Royal Society called “The role of conservation agriculture and sustainable agriculture,” crop rotation can be used best as a disease control against other preferred crops (Hobbs et al. 2007). This process will not allow pests such as insects and weeds to be set into a rotation with specific crops. Rotational crops will act as a natural insecticide and herbicide against specific crops. Not allowing insects or weeds to establish a pattern will help to eliminate problems with yield reduction and infestations within fields (FAO 2007). Crop rotation can also help build up soil infrastructure. Establishing crops in a rotation allows for an extensive buildup of rooting zones which will allow for better water infiltration (Hobbs et al. 2007).
