Saturday, August 6, 2011

Field Crop Production



 Introduction

Producing high yields has always been an important part of farming. When input costs were low compared to crop returns, the best way to farm was to fertilize for maximum yields and then, add a little extra. The feeling was that you could lose more with too little input than with too much. With the costs of fertilizer, fuel and other inputs increasing and crop prices not keeping pace, the emphasis has changed. Inputs are carefully measured so that the yield for each unit is worth more than the cost of the input. The greatest yields do not necessarily give the greatest profit.
Conventional tillage leaves less than 30% residue
In recent years, the focus has widened to include environmental factors in the crop production equation. It is no longer acceptable to ignore what happens beyond the fence because of the way we farm.
Best management practices are tools for meeting today's agricultural goals. To be a best management practice, an action must maintain or increase crop returns while minimizing the impact on the environment. There is no one system for all farms. The combination of practices appropriate for your farm will depend on individual problems and opportunities.

Mulch tillage leaves more than 30% residue

The first part of this book will help you understand the basics such as soil management, residue management, crop rotation, pest management, nutrient management as well as the importance of using a systematic approach to change. The next three sections focus on different types of tillage, conventional tillage, mulch tillage, and no-till/ridge tillage. And finally, the book provides some non-tillage options that improve the environment.
The book cannot provide you with all the possible information. Rather, it gives you the basics and provides references for further reading. Some terms used may be unfamiliar. To avoid confusion, we are using the following definitions for the different types of tillage:
Conventional tillage is any system which attempts to cover most of the residue, leaving less than 30% of the soil surface covered with residue (or crop remains) after planting. Usually, the moldboard plow is used along with a variety of other tillage tools.
Mulch tillage is any system where soil is disturbed between harvesting one crop and planting the next. However, in this case, more than 30% of the soil surface is left covered with residue after planting. Chisel plows, offset discs or modified moldboard plows are the common implements. Other terms that you may hear to describe this system are reduced tillage, minimum till or conservation tillage.
No-till is any system where the soil is not disturbed between harvesting one crop and planting the next. Some tillage may be done by attachments to planting equipment to assist seed and fertilizer placement.

Ridge tillage is a specific form of no-till where crops are planted on pre-formed ridges. Inter-row cultivation is done after the crop has emerged in order to control weeds and re-form the ridges.
You may wish to change your cropping system for many different reasons such as: to save money, to increase yields, to save labour, to solve erosion problems, or to reduce pesticide use. Whatever the reason, the first stage of change is to assess where you are now and what your goals are. Once you have done that, this book should help outline some of the options available.
Conventional Tillage
Advantages
·         Familiar to most farmers and machinery widely available.
·         Incorporates manure without specialized equipment.
·         Soil warms faster in the spring than with less tillage.
·         Allows maximum frost action on soil. This breaks the soil into smaller clumps.
·         Low levels of surface residue permit high levels of water evaporation. This allows earlier planting and is a plus for poorly-drained soils.
Disadvantages
·         More equipment is needed than in reduced tillage systems.
·         Low residue levels make soil vulnerable to crusting and erosion by wind and water.
·         Tillage stimulates weed growth and reduces levels of organic matter.
·         Working wet soil may cause compaction and the development of plow pans.
·         During the growing season, high evaporation resulting from lack of residue can reduce crop yields.
Mulch Tillage
Advantages
·         Most of the same advantages as conventional tillage.
·         Residue left on soil surface reduces erosion and water run-off.
·         Labour inputs are lower than in conventional tillage.
·         Fewer trips over the field reduce costs.
·         Management skill levels required similar to conventional tillage.
Disadvantages
·         Tillage stimulates weed growth.
·         High residue levels can slow soil warm-up in the spring.
·         Primary tillage will not be effective under wet conditions.
·         High residue levels require attachments on the planter.
No-Till/Ridge Tillage
Advantages
·         Lower input and capital expenses.
·         Labour inputs per acre are greatly reduced.
·         More organic matter is located near the surface, which improves soil structure.
·         High levels of residue drastically reduce soil erosion.
·         Increased biological activity in soil, which improves structure and increases the speed of pesticide breakdown.
Disadvantages
·         High residue levels can slow soil warm-up.
·         Success depends on the characteristics of the soil.
·         Fewer options are available to work in manure.
·         Above-average management skills are required

This section provides tools which can help farmers control soil erosion and protect water resources. When soil moves off individual fields or the farm, it takes valuable nutrients, pesticides and organic matter. Farmers cannot afford the economic loss, nor the adverse environmental impacts of allowing soil to wash or blow away.
Some conservation practices will cost money. But, money spent in a rational manner is a sound investment. Increased yields and reduced production costs will make up for short-term losses in as little as two or three years. An investigation into how much erosion has taken place on fields helps plan the best use for land.
Conservation practices (such as those outlined in this section) allow safe removal of surplus water that falls on the land or offer protection against damaging winds. However, a good conservation plan also must include wise use of fertilizers (whether commercial or livestock manure), careful handling of pesticides, enhancement of fish and wildlife habitat and maintenance of wetlands. Conservation will protect the land and improve its production base. It also increases land value.
It is impossible to recommend a single preferred list of management options to Ontario farmers. Practices must be tailored to individual fields on each farm. Each conservation plan must meet the objectives of the individual producer.
Contouring and Grass Field Borders
On short, gentle slopes, contour farming provides good protection against erosion. Tilling and planting across the natural slope create a series of dams which hold back water until it can soak into the ground.
For all but severe storms, contour farming on fields as steep as a 9% slope will cut erosion rates in half.
Contouring has no 'out-of-pocket' expenses and it can increase yields by 5 to 10%. Fuel and machine costs decrease, when compared to land farmed up-and-down the slope.
Getting started in contouring is not difficult. Expect that because of slope irregularities, it may not always be possible to stay on the level. When laying out your system, smooth curves at ridge tops and drainage ways and square the rows with field edges to eliminate 'point-rows'.
These adjustments should maintain a 0.5 to 1% grade along rows. A grass waterway or tile outlet terrace must then be considered to carry surface water down the slope.
Contour strip cropping with corn and small grain reduces erosion by up to 50% when compared with up-and-down the hill farming. It also doubles the allowable slope length limit shown in the table.
Tools which make laying out contours easy include specially-designed gauges (shown), hand and stationary levels.
The full benefits of contouring are obtained if all field operations are on the contour.
The following limits should be considered when planning for contour farming.
Land Slope (%)
Maximum Slope Length
(Metres)
(Feet)
1-2
120
400
3-5
90
300
6-8
60
200

Slope Length Limits for Contouring
On longer slopes, contouring can be effective by using it in combination with conservation tillage, terraces, strip cropping or contour buffer strips.
Erosion can be severe where headlands are farmed up-and-down the hill. Grass field borders will limit erosion and provide an area to turn farm equipment. Yield increases through contouring should easily offset production losses from land seeded into grass field borders.
Strip Crop Farming
Strip crop farming refers to planting alternating strips of a row crop with a cereal crop or forage. This practice combines the soil and moisture savings of contouring with the soil building advantages of a crop rotation. There are four kinds of strip cropping: contour, field, contour buffer and wind strip cropping. The system you choose depends on the crops that can be grown, the kind of erosion (wind or water), the topography and the soil type.
Contour Strip Cropping
Crops are arranged in bands at right angles to the natural slope of the land. In nature, slopes are seldom perfectly uniform. Therefore, compromise in the contour layout. While it is difficult to imagine, if both strip edges are on the contour, all strips will be irregular in width. Consider alternating irregular-width strips with one or more even-width strips.
Take extra time and care to plan your rotation to ensure good erosion control. Laying out contour strip cropping is complicated, so get technical assistance.
Field Strip Cropping
This is the most common form of strip cropping. It maintains strips of uniform width across the slope. As with contour strip cropping, this system can reduce erosion by up to 75% when compared to up-and-down hill farming. In laying out this type of system, be sure to use recommended strip widths. Adjust these dimensions to blend with equipment widths, especially planters and sprayers. An even number of passes along each strip will allow field operations to start and finish at the same end of the field. Grass field borders become an integral part of any strip cropping system. They provide access lanes to each strip, protect against erosion and offer habitat to wildlife.
Contour Buffer Strip Cropping
Permanent strips of grass or forage laid out between even-width strips of crops in regular rotation, also limits erosion. Grass strips as narrow as four metres (13 feet), making up as little as 10% of the entire field, may reduce erosion rates by up to 55% while doubling the slope length limits for contouring.
Buffer strip locations are based on crop rotation and the severity of slope. On irregular slopes, grass strips will be of different widths to make annually-cropped strips even.

Wind Strip Cropping
Wind erosion can be a hazard, especially for soils on level land. For good erosion control, alternate strips should be even in width, parallel and laid out crosswise to the prevailing winds.
Available in Published Version of Field Crop Production
·         Maximum Strip Widths and Slope Length limits for Contour and Field Strip Cropping - Chart
·         Soil Loss Reductions and Slope Length limits for Contour Buffer Strip Cropping - Chart
·         Recommended Widths for Wind Strip Cropping - Chart
·         Legislation
·         Provincial and Federal Statutes
·         Land Use Capability

 

Primary Tillage Equipment

The Moldboard Plow

The moldboard plow lifts and fractures the soil. It also incorporates residue, manure and fertilizer. Plowing is a first step in providing a good seedbed. An uneven job of plowing will require extra tillage passes in the spring to level over the ridges left by the plow.
Most moldboard plows work best within a specific speed range. At low speeds, the plow may not fracture the soil and will leave more residue on the surface. By increasing the speed, the soil clumps will be broken down into finer sizes and the plow will bury more residue.

Managing Residue with the Moldboard Plow

In situations with large volumes being plowed, such as with grain corn, plows may plug with residue. Use a plow with high clearance (greater distance between the beam and the plow bottom) because they are designed to handle large volumes of material. They may even handle residue immediately after harvest without discing or chopping stalks first. This reduces labour and energy inputs.
For the best residue management:
·         Use the stubble bottom plow or European bottom plow to leave residue on the surface. (The sod bottom or general purpose bottom plow buries more residue).
·         On plows with variable furrow width, narrow the furrows to increase residue cover.
·         Remove covering blades attached to the top of the moldboard to increase surface residue.
Plows that leave each furrow on its edge, as done by the European models, manage residue better than those which invert the soil. Inverting the soil leaves crop residue in a single, continuous layer beneath the surface. This "mat" of residue traps water above it which reduces water soaking into the subsoil. This in turn, leads to run-off and reduces soil moisture reserves during droughts. By trapping water near the surface, the mat may delay field operations and hurt crop growth during wet weather. Further buried layers in the soil are subject to nitrogen loss through a process called denitrification.
Moldboard plows with bottoms that place the soil on edge leave residue in strips which avoids problems. Residue forms a "wick" which helps water evaporate and traps snow.

Best Management Practices for Equipment and Tillage

·         Read the instruction manual for your equipment. Learn how to set it and operate it properly.
·         Properly maintain equipment. Down time during busy seasons is very costly if planting or harvesting is delayed.
·         Check machinery regularly (daily or even twice a day when in use). Catching a problem in its early stages saves money and time. Early detection may prevent the small problem from developing into a large one.
·         Operate the machine at the suggested speed and load. This gives peak performance and longer life.
·         Replace parts when they are worn. Worn parts will not perform properly and will increase the horsepower requirement.
·         Tillage equipment operates best when it is level in all directions. Level it front to back and side to side. Check that all depth gauge wheels operate at the same depth. These adjustments create even tillage.
·         Combine operations on each field pass to reduce the number of trips over the field.
·         Use only the implements necessary to create an ideal seedbed. Soil conditions and results will help you decide which combination of equipment is best. Once you've created a good seedbed, stop tilling.
·         Work the soil across the slope to eliminate water erosion.
·         Work at the proper depth to prepare an adequate seedbed. Tilling too deep costs money and creates more wear and tear on machinery.
Best management practices for conventional tillage are numerous. If used properly, a conventional system can be environmentally friendly and save you some money. Take a look at the section on Non-tillage Options for best management ideas that you can try on your farm.

Soil Management
The goal of every farmer is to have healthy, productive soils that have:
·         Consistently high yields
·         Minimal erosion by wind or water, and
·         Minimal losses of nutrients or pesticides.
On the surface:
·         Soil is covered with crop residue to protect it from wind and water erosion. The residue also slows moisture loss during the growing season
·         Water moves into soil soon after a rainfall and will not pond on the surface.
Below the surface:
·         The soil favours root growth by having a proper mix of large and small pores
·         Organic matter helps hold moisture
·         The soil has sufficient fertility
·         Organic matter and soil life (bacteria, fungi, earthworms, insects, etc.) help to cycle nutrients.
Let's take a closer look at the make-up of soil.
A shovel full has four parts:
·         Mineral material
·         Air
·         Water
·         Organic matter.

Soil Suitability
When deciding what tillage system is best, you should consider the type of soil on your farm. Suitability depends on soil texture and drainage characteristics.
Yield Potential
I = Increase
E = Equal
D = Decrease
*Compared to moldboard plow
Erosion Potential
S = Severe
H = High
M = Medium
L = Low
Suitability Rating
1  = Very Suitable
2  = Well Suited
3   = Moderately Suited
4   = Not Well Suited
5 = Not Recommended
+ Coulters on planting equipment to till a narrow strip of soil will improve rating.
Suitability Rating
The suitability rating combines yield potential, need for erosion control and relative ease of management of the tillage system on that soil (timeliness, effective equipment operation, an adequate and functioning tile drainage system, etc.)
Residue Management
Crop residue is beginning to be recognized as a resource rather than a nuisance. Residue is an important source of organic matter. If it is left on the soil surface or worked into the top few inches of the soil, organic matter levels can be maintained or increased. This helps improve soil structure and leaves the soil more manageable.
Residue management is an important part of farming operations. In the past few years, farmers, researchers, and extension personnel have come to recognize that careful management of residue is the most cost-effective means we have of reducing erosion.
Residue
·         Protects the soil surface from the impact of rain
·         Reduces soil erosion
·         Reduces soil crusting and sealing
·         Adds organic matter to soil
·         Helps rain to soak into the soil
·         Reduces the loss of soil water to the air. 
Crop
Straw : Grain
Barley
1.5:1
Corn
1.0:1
Oats
2.0:1
Rye
1.5:1
Winter Wheat
1.7:1
Spring Wheat
1.3:1
Estimated Straw to Grain Ratios for Selected Crops

Crop Yields and Residue
All crops yield differently and supply various amounts of residue. Generally, higher-yielding crops produce more residue. Remember this when planning a residue management program for your farm.
The table (on the right) shows the estimated straw to grain ratios for selected crops. For example, if a winter wheat crop yields 70 bushels/acre, there would be about 70 bu/ac X 60 lbs/Bu X 1.7 or 7140 pounds/acre (8,000 kg/ha) of residue. Of course, this number is an estimate and will vary with hybrid/variety, weather and the amount of straw removed at harvest.
Residue Cover %
Corn Stalks
Cereal Straw
kg/ha
(lbs./ac.)
kg/ha
(lbs./Ac)
20
700
(625)
400
(360)
30
1000
(890)
500
(450)
40
1500
(1340)
800
(715)
50
2000
(1780)
1000
(890)
60
1500
(2230)
1300
(1160)
70
3400
(3035)
1700
(1520)
80
4300
(3840)
2200
(1960)
90
5800
(5175)
3000
(2680)
95
7800
(6960)
4000
(3570)
Relating Residue Cover to Weight of Residue

Best Management Practices for Residue Management
·         Spread residue evenly behind the combine to eliminate windrows.
·         Know the amount of residue you will be dealing with by checking crop selection and tillage system.
·         Choose residue levels that will reduce soil erosion.
·         Use tillage equipment matched to your soil type, the amount of residue and farming needs.
·         Modify planting equipment to handle residue left on the soil surface.
·         Residue left on the soil surface or worked into the soil will maintain or increase organic matter.
Available in Published Version of Field Crop Production
Soil Management
·         Soil Texture
·         Soil structure - Drainage, Soil Compaction
·         The Effects of Loss of Soil Organic Matter - Chart
·         Soil Suitability - Soil Moisture, Texture, Protection from Erosion
Residue Management
·         Good Residue Management Starts with Harvest
·         Residue Management Options in Reduced Tillage
·         Erosion and Residue Management
·         Residue Cover and Soil Loss Reduction for Various Tillage Systems - Chart

Crop Rotation and Cover Crops

Crop Rotation

Rotating crops is a best management practice because:
·         It reduces the risk of crop disease
·         It reduces the population of pests specific to one crop
·         It will increase the yields from a crop grown as part of a rotation compared to continuous cropping
·         It can reduce soil erosion and run-off
·         It spreads the workload for planting and harvesting over a longer time period as seasons vary with each crop
·         It can complement each crop under rotation. For example, growing legumes provides nitrogen for non-legumes. And, alternating crops that successfully compete with weeds will reduce pressure on crops that do not
·         By increasing crop yields and reducing inputs, profits on the combined crops can be higher
·         Growers can stagger planting and field operations to avoid time pressures
·         Special features of the farm can be taken into account, such as water resources, the nearness to markets and processing plants, special skills and labour availability.

Crop rotations can increase net returns

At the same time, there are few precautions that should be taken:
·         Planting times may conflict with critical phases of other crops such as weed control or an application of fertilizer that will boost yields
·         New management skills may be needed
·         Problems in one crop may make it difficult to manage another effectively.
The yields of corn and soybeans will improve if they are rotated with each other. By including a cereal in the rotation, yields and erosion control are improved. Adding a forage hay crop to the rotation improves yields and soil conditions even further.
If you are a cash cropper and cannot find land to put into forages, see if you can make a deal with a livestock producing neighbour. That way, you have a market for the forage grown and get the benefits in your rotation.

Nutrient Management

Plants need 20 different nutrients for growth and seed production. Some are required in very small amounts while others make up the largest part of the plant. The most common elements in plant tissue (carbon, hydrogen, and oxygen) come from the air and water. Nutrients like calcium, magnesium and sulphur are common in Ontario soils; although they are used by plants in fairly large amounts, they are not usually considered in fertilizer programs.
Primary nutrients (nitrogen, phosphorus, and potassium) are the elements that most often have to be increased for crop growth. Plants use all three in large quantities. These elements make up the largest part of the farmer's fertilizer bill.
Micronutrients are used by plants in tiny amounts. They should be added when the plant shows signs of deficiency or when a soil test shows they are necessary.

Special Considerations for Manure

In most of Ontario, manure is applied to large areas of farmland. Manure is a valuable resource that contains all nutrients. Properly managed, it can supply nutrient requirements and add organic matter to the soil. However, excessive rates that exceed crop needs are hazardous to the environment. They increase the risk of nutrients escaping into surface and groundwater.

Best Management Practices for Nutrient Management

·         Match nutrient requirements to crop needs and soil test levels. If a certain crop does not require much of a nutrient, don't over apply it. For example, if legumes do not need nitrogen, don't feed it to them. Put them into a rotation to benefit other crops that follow. Recognize that excess nutrients are potential pollutants.
·         Include the contributions from previous crops and manure when deciding how much commercial fertilizer is needed.
·         Complete regular soil tests for phosphorus, potassium and pH. Test for nitrogen when growing corn.
·         Reduce soil erosion to eliminate phosphorus and organic matter losses.
·         Maintain organic matter levels with manure, cover crops and residue to help cycle nutrients.

Pest Management

Pest management includes the control of plants, insects or diseases that compete with a crop and restrict its growth. The intent of best management practices is to prevent problems by using crop rotation and maintaining good soil fertility and structure. After all, a healthy, well-fed plant is best able to fight off pests.
Weed control aims to reduce nuisance plants to the point where the cost of damage to potential yield is less than the cost of control.
It is necessary to be balanced in your approach. Best management practices reduce the use of pesticides to the absolute minimum for your tillage system.
Some ways to reduce pesticide use are:
·         Grow crops aggressively to compete with weeds.
·         Use cover crops and companion crops as biological weed control.
·         Scout fields for weed problems carefully and regularly.
·         Rotate your crops.
·         Rotate the pesticide family.
·         Keep accurate records.
·         Use tillage to control weeds.
·         Band herbicide over the row.
·         Use herbicides applied after crop emergence rather than soil-applied ones.
·         Consider the economic threshold of control.
·         Keep in mind that weeds appearing late in the season do not reduce yields as much.
·         Avoid rescue treatments.
·         Evaluate weed control.

Working Herbicides into Soil Requires Extra Management

Some herbicides are more effective if incorporated. This also reduces loss to run-off because the herbicide is placed below the soil surface. When you are incorporating herbicide, it's important to spray onto an even surface so that distribution is even. A rough surface may concentrate herbicide in valleys and clear it from ridges as shown in the diagram (below). Read the product label carefully to know what type of incorporation is required. Some herbicides (Treflans and Edge) are immobile in the soil. While this is good for the environment, it becomes very important to thoroughly mix the soil so that herbicides are at the proper depth. Sprayed pesticide only goes half as deep as the depth of tillage on the first pass.

Field Planning and Records

Planning what will happen in a field and then recording the details are important in evaluating your practices. Records help establish the conditions that led to success but they are particularly important if something goes wrong. Looking back at your notes may help determine what caused the problem. Working from memory alone does not provide enough information for useable answers.
Records for each field should include:
·         All applications of pesticides, fertilizers and manure.
·         The variety of seed used.
·         Include both rates and dates of operations.
·         Record weather conditions when doing field operations.
·         Note yields and crop quality.
Evaluate the success of your management and compare your results to research programs. There may be further improvements that you haven't considered.

No comments:

Post a Comment