Introduction

Concern about the environment has greatly increased in recent years. Evidence of this is provided by the facts that many environmentally-oriented organizations of various types have sprung up around the world, there is much media coverage of environmental issues, and there is clearly a considerably higher level of environmental awareness among the general public than existed just a few years ago.

It makes sense that anyone associated with agriculture should attempt to be aware of the environmental implications of various agricultural practices. Though much research needs to be done to answer specific questions relating to certain environmental concerns, we already are aware of many important benefits associated with grassland agriculture. Furthermore, we know that certain special management techniques can greatly increase such benefits.

General Environmental Benefits or Advantages of Grasslands

Reduced Soil Erosion

Good soil is a precious resource, and thick stands of properly managed grassland plants are quite effective in minimizing soil erosion caused by wind and water. Nearly half the land area of the United States is devoted to grazing lands, and the erosion control provided by pasture and range species growing on this land is extremely important to both environmental and economic stability.

Lowered Nutrient Loss

When soil is lost to erosion, nutrients associated with the topsoil, as well as fertilizer, which may have been applied, is lost as well. Soil nutrient holding capacity is also diminished with erosion, which is likely to result in the need to apply additional fertilizer to restore or maintain fertility. To do this is costly and, because of the loss of good soil, is likely to be less effective than if the loss had not occurred.

Improvement Of Water Quality

Water quality is a major national concern, and the primary contaminant of surface water in many areas (including in the Southeast) is soil particulate matter. Nutrients associated with sediment in runoff water further contaminate water resources, but forage crops reduce both the amount of erosion and the total amount of runoff water. Thus, grasslands make a major contribution to water quality.

Improvement Of Soil Quality

It has long been known that when perennial forage crops are grown on the same land for a period of years, the productive capacity of the soil is enhanced. This is partly due to an increase of organic matter resulting from the deposition of leaves and other plant material. The activity of earthworms, soil microorganisms, and soil insects also contributes to improved soil structure and increased nutrient and water holding capacity of the soil.

Improvement Of Air Quality

During photosynthesis, plants use carbon dioxide and release oxygen into the atmosphere. Though this is not unique to forage crops, by virtue of the large land area they occupy they make a significant contribution toward offsetting the environmentally detrimental trend toward increased carbon dioxide levels in the atmosphere which are enhanced by the burning of fossil fuels.

Low Energy Expenditures

It is generally accepted that minimizing fossil fuel consumption is environmentally desirable. Fortunately, perennial grasslands require much less fossil fuel consumption than do most other types of agricultural production.

Minimal Pesticide Requirement

From an environmental standpoint, it is likewise generally deemed desirable to minimize the extent to which pesticides are used in agricultural production. Pesticides are sometimes used in grassland management, of course, but the level of use is much lower than in many other crop production or land management situations.

Wildlife Enhancement

Many species of game and nongame wildlife benefit from grasslands even when farm managers consider the areas devoted to them to be primarily for the production of livestock. Forage crops provide food in the form of seed and green forage, as well as cover, for birds and wildlife of many types. In fact, numerous forage crops are commonly planted in food plots specifically intended for wildlife purposes.

Recreation

Grasslands offer opportunities for hunting, bird watching, hiking, and other outdoor recreational activities. In addition, many part-time or diversified farmers view the raising of livestock and associated grassland management activities to be an enjoyable hobby as much as they regard it as a means of income.

Rural Beauty

Without question, forage crops greatly enhance the visual attractiveness of millions of acres of land in the United States , including in Alabama . This is a benefit on which we cannot place a dollar value, but it is nonetheless one which is appreciated not only by farmers and other rural dwellers, but also by urban citizens who visit rural areas. Again, if for no other reason, this is significant simply by virtue of the large portion of the environment, which is occupied by grassland plants.

Water Impoundment Structures

Water is a requirement for livestock production, and thus the construction of thousands of ponds, lakes, and other water impoundment facilities has resulted from the utilization of grassland areas as pastures. This offers numerous benefits to wildlife, provides opportunities for fishing and other water-related activities, and further enhances the attractiveness of many areas.

Benefits of Special Grassland Management Practices

Sod Based Rotations

It has long been known that alternately growing row crops and forage crops offers some unique benefits. First, on land that is subject to erosion, minimizing the frequency of tillage by including perennial forages in rotations obviously reduces erosion losses. In addition, there are great crop production benefits associated with increased soil organic matter and improved soil tilth; interruption of disease, insect, and weed cycles; and deeper rooting of row crops made possible by root channels left by a preceding forage stand.

No Tillage Planting

No tillage planting is a relatively new approach to crop production, but one that is gaining in popularity, particularly in forage crop production. In recent years many farmers, as well as many organizations with which farmers are associated, have purchased grassland drills. The result is that many producers now have access to equipment, which allows them to introduce desirable species such as legumes, or to thicken grass stands without risking erosion or destroying existing desirable species.

Strip Cropping

Strip cropping is the practice of growing forage crops and row crops in side-by-side strips on land which is vulnerable to soil erosion. This has the effect of reducing runoff and thus the amount of sheet and rill erosion, which occurs. It also promotes water infiltration and reduces the amount of sediment and associated agricultural chemicals that would otherwise be carried from the field in surface runoff.

Strip cropping can also be used in conjunction with crop rotation. By periodically alternating forage crops and row crops in the strips, the crop rotation benefits discussed above can be realized in addition to the benefits resulting from the practice of strip cropping.

Grassed Waterways And Terraces

In many situations, forage crops can be planted and maintained in gently sloped waterways and/or on terraces in fields devoted to row crop production. This technique provides increased erosion control by stabilizing areas, which are particularly vulnerable and by slowing the speed of runoff water.

The vegetation in a grassed waterway or cannel of a grassed terrace also acts as a filter to remove sediment-attached pollutants from runoff.

Critical Area Stabilization

When critical (eroding) areas need to be stabilized, forage crops are commonly planted to accomplish this objective. When there is disturbed soil, even in urban areas, forage crops are often planted and used with great success. In such cases a good approach is to plant a combination of annuals (which quickly stabilize the soil) as well as two or more perennial species which, though slower to establish, provide long term protective cover.

Permanent vegetative cover can reduce soil loss by up to 95% or more in some cases. Also, uptake of nutrients by the established vegetation can reduce the amounts entering surface waters. Additional benefits are improved appearance of the stabilized area and in many cases enhanced wildlife habitat.

Animal Manure And Waste Disposal

It appears that forage crops are destined to play an ever greater role in disposal of waste materials. In particular, it is logical to dispose of manure from dairy, swine, and poultry enterprises by spreading it on pasture or hay land. This solves two problems at once; it disposes of the manure or waste material in an environmentally acceptable manner while providing nutrients needed for forage growth.

In addition, various other types of wastes such as those generated by food processing industries and from sewage treatment facilities can be applied to land, which has been planted to forage crops to accomplish environmentally safe disposal. Especially when the area is subsequently cut for hay, the result is that nutrients, which might otherwise cause environmental contamination, are removed in the form of hay, which is subsequently used for livestock feed or other purposes.

Riparian Area Management

Natural, undisturbed, or well-managed riparian areas provide significant environmental benefits. Riparian areas include creeks and streams; areas near shores of ponds and lakes that support aquatic vegetation as well as the banks and adjacent wet soils; moist areas near springs, seeps, and areas with a high water table; and other habitats that are wetter than the surrounding uplands.

For an environmentally conscious grassland manager, riparian areas should be of primary concern. Repair or prevention of damage from overuse by livestock and people, and reduced water pollution should therefore be leading goals of riparian area management.

Degraded riparian conditions result in environmentally undesirable effects. These include reduced diversity and cover of desirable herbaceous plants; disappearance of woody streamside plants; trampled, unstable streambanks without overhangs that protect life in the stream; broad channel morphology; and sediments that cover extensive areas of the channel bottom.

Comparisons of riparian areas that were heavily grazed with areas in which there was exclusion of livestock or light grazing, have shown that heavy grazing can cause severe damage. However, they have also shown that riparian vegetation has high potential for recovery. Such comparisons have also revealed that riparian areas can be safely grazed and, in many cases, improved riparian conditions can occur under grazed conditions as a result of using the following cardinal principles of grazing management.

The first principle is proper degree of forage utilization . Grasses and other forages cannot act as effective sediment filters when their leaves and other vegetative parts are kept grazed to four inches or less throughout the growing season. Also, a stubble height of at least four inches is needed at the end of the grazing season to catch sediment until the next growing season.

The second principle, and for riparian zones the most important, is distribution of animals that gives uniform use of both upland and riparian zones without trampling damage and loss of water quality . Without such management, animal preference for riparian locations results in their overutilization. High costs of fencing long and narrow riparian zones, and periodic flooding that occurs in many areas, often prohibit separate fencing of these zones.

Fencing, together with grazing management, offers a better approach. The first step is to use fencing to divide the area into several pastures, each of which include only a limited amount of the total riparian area. This facilitates the use of rotational stocking (rotational grazing) and the result will be greatly reduced livestock damage to the riparian areas and elimination of the need for fencing stream corridors.

The third principle, which can also be achieved through the use of rotational stocking, is allowing the plants within each piece of the riparian zone to receive a rest from grazing during a part of the growing season . Continuous stocking will allow livestock to overgraze sensitive species especially within the riparian areas) and will eradicate them from the pasture. Rotational stocking may also improve production and vigor of the forage if care is taken to maintain sufficient leaf area for photosynthesis.

Filter Strips Or Buffer Areas

Buffer areas are vegetated areas around water bodies that have either been purposely left intact or have been established to achieve the benefits derived from riparian systems. Maintenance of riparian vegetation as streamside buffers is an effective way to reduce the velocity of runoff from upland areas.

Reduction in velocity causes sediment and associated pollutants to be deposited within the buffer area. This filtering action keeps a portion of the sediment from being deposited in the stream channel. Reduction in sedimentation keeps materials attached to sediments, such as phosphorus and heavy metals, from entering water bodies.

In the United States , grasslands account for 26% of annual sediment deposition in surface waters and 25% of nitrogen inputs to surface waters. Natural buffer areas along waterways can be used as filter strips to reduce such nonpoint source pollution. In areas where runoff from grazing produces considerable sediment and nutrient loading in water bodies, planted buffers can also be used as filter strips to reduce sediment and nutrient inputs.

Cover Crops Or Green Manure Crops

Forage crops are often used as cover crops or green manure crops. A cover crop or green manure crop is usually a close-growing grass, legume, or small grain grown primarily for temporary, seasonal soil protection and improvement. Also, cover crops are often used to provide residue for conservation tillage cropping systems. Cover crops add organic matter to the soil. This improves soil tilth and soil structure, which can have long-term crop production benefits. When legumes are used as a cover crop, they add nitrogen to the soil, which can be used by subsequent crops.

Cover crops reduce erosion during periods of the year when the row crop does not provide adequate cover or when row crop residue is removed during harvest of the crop. An actively growing cover crop or green manure crop will utilize available nutrients in the soil, especially nitrogen, thus preventing or decreasing leaching or nutrient loss in runoff water. The nutrients may then become available to the following crop as the cover or green manure crop decays.

Summary

Farmers have a vested interest in protecting the environment because it directly affects both their quality of life and their income. With each passing year, the importance of striving to manage land, including grasslands, in ways, which provide as much environmental benefit as possible is becoming increasingly clear.

A number of important environmental benefits are inherently associated with grassland agriculture, as discussed at the beginning of this publication. However, by use of the special techniques described, the environmental benefits of grasslands can be substantially enhanced far beyond what they otherwise would be.

Refrences

Brooks, K.N., P.F. Folliott, H.M. Gregersen, and L.F. De Bano. 1997. Hydrology and the management of watersheds (2nd ed.). Iowa State University Press, Ames , IA. Heady, H.F. and R.D. Child. 1994. Rangeland ecology and management. Westview Press, Boulder , CO .