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About Fertilizer Canada


Fertilizer Fundamentals

What is fertilizer?

Simply put, fertilizer combines the nutrients that plants need to grow – potassium, nitrogen, phosphorus, and sulphur– in a form they can digest. Think of it as plant food.

As crops grow, they absorb, or mine, nutrients from the soil. When crops are harvested, so too are the nutrients absorbed by plants. Commercial fertilizers nourish the soil by returning the nutrients that next year’s crop will require.

Are there chemicals in fertilizer?

The four main ingredients in fertilizer: nitrogen, potassium, phosphorus and sulphur come from nature. They are not man-made. Fertilizer manufacturers convert them into a form that plants can use.

Fertilizer producers can blend nutrients into precise combinations to match the unique needs of different farms, crops, and fields. In this way, farmers can feed their soils with the most effective and efficient blend of potassium, phosphorus, and nitrogen to achieve optimal yields.

Do farmers need to use fertilizer?

Farmers use fertilizer to replenish the nutrients drawn from the soil, which plants need to grow. When a crop goes to market, so too does the potassium, phosphorus, and nitrogen it has absorbed from the soil. When farmers fertilize, they put back into the soil the nutrients their next crop will require.

While the same nutrients in fertilizer are naturally found in soil, they are not present in a sufficient supply for today’s high-yield farming. It can take years – even decades – for soil to rebuild the necessary nutrients essential to nurture a good crop.

Where does phosphorus come from?

Phosphorus used in fertilizer comes from the fossilized remains of ancient marine life found in rock deposits. This raw ore is processed to create water-soluble compounds that make the phosphorus available to plants as a nutrient.

Phosphorus helps early plant health and root growth and is involved in seed germination to ensure plants use water efficiently. Phosphorus provides the energy that a plant needs to grow.

Where does potassium come from?

Potassium is the seventh most abundant element in the earth’s crust. Through natural processes, it is filtered into the planet’s seas and oceans. As these bodies of water evaporate over time, they leave behind mineral deposits. Potassium is mined from these deposits.

Where does nitrogen come from?

The air all around us contains nitrogen. In fact, nitrogen makes up about 78 percent of the atmosphere. Fertilizer producers combine nitrogen with natural gas to change it into a form that plants can use.

What are the essential mineral nutrients?
  • Macronutrients: nitrogen, phosphorus, potassium, calcium, magnesium and sulphur
  • Micronutrients: boron, chloride, copper, iron, manganese, molybdenum, nickel and zinc
  • Essential or beneficial for some plant species, not all: silicon, sodium, cobalt
  • Essential for animals but not for plants: selenium

Fertilizer and Food

What role do fertilizers play in feeding a growing world population?

Fertilizers play a role in helping feed the world. Thanks to modern fertilizers, world food production has more than doubled since 1960. Today, an estimated one-third to one-half of our global food supply is directly linked to the use of commercial fertilizers.

If we are to meet future food demands, we will need to double our current levels of production. We can’t do that without fertilizers. Continuing to make better and more efficient use of fertilizer will help us feed the growing population.

Are organic foods better because they are grown without fertilizer?

Most organic growers use fertilizer too. It is made from different ingredients though, such as livestock manure or sewage sludge. However, these natural fertilizers are not available in sufficient quantities to meet the demands of today’s high-yield farming, nor do they provide nutrients in the custom combinations possible with commercial fertilizers. Typically, compared to a farm using conventional fertilizer, organic crops produce one-third to one-half less yield. For example, using enough manure to provide an adequate supply of nitrogen would mean adding four to five times more potassium and phosphorus than a crop needs. So it is easy to over or under fertilize in this type of farming.

There is no concrete evidence to suggest organically grown food is better than food grown with conventional fertilizer. The three main ingredients used in fertilizer – nitrogen, potassium, phosphorus and sulphur – are found naturally in the soil and are required by all forms of life.

Fertilizer and the Environment

Is fertilizer harmful to the environment?

Commercial fertilizer has become an indispensable tool in today’s high-yield farming. It requires careful application and use to protect our environment. Fortunately, advances in agricultural techniques are enabling farmers to apply soil nutrients with pinpoint accuracy, minimizing or avoiding any damage to soil, water, and air.

New soil sampling, use of starter fertilizers, and better timing and placement of nutrients mean producers are producing their crops more efficiently. For example, farmers today are producing one-third more corn for each pound of nitrogen they apply, compared to 20 years ago.

Wouldn’t it be better for the environment to use less fertilizer?

By adopting nutrient stewardship practices, such as 4R Nutrient Stewardship, farmers contribute to the preservation of natural ecosystems by growing more on less land. As a result of advances in agricultural practices, farmers have been able to use fertilizer more efficiently.

It is important to maintain nutrient levels in the soil, for the overall health and longevity of a crop. An insufficient supply also reduces plants ability to withstand harsh weather, disease, and other stresses. Plants require adequate nutrients to maintain soil moisture, which leads to soil erosion from wind or water.

Although dry weather played a key role in the dust bowl conditions of the 1930s, insufficient levels of nutrients were at the root of the vicious cycle of problems that plagued Depression-era farmers. Plants could not help the soil hold enough moisture, which in turn caused increased wind erosion.

Fertilizer and Soil

If there are already nutrients in the soil, why add more?

When farmers use fertilizer, they are replacing what has been absorbed by plants. Each growing season, crops take all the potassium, nitrogen, phosphorus and sulphur they need from the earth. At harvest time, these nutrients go to market along with the plants, leaving a shortage for next season’s crop. By fertilizing their land, farmers are completing the ongoing cycle. This recycling of nutrients ensures that subsequent crops get what they need to grow.

While the same nutrients in fertilizer are naturally found in soil, they are not present in a sufficient supply for today’s high-yield farming. It can take years – even decades – for soil to rebuild the necessary nutrients essential to nurture a good crop.

Are we using more fertilizer, since yields are increasing?

We’ve made great strides in using fertilizer more efficiently and effectively. Although crop yields are increasing, this is more as a result of new and improved farming practices including soil sampling, use of starter fertilizers, and more precise timing and application of fertilizer using the principles of 4R Nutrient Stewardship (Right Source @ Right Rate, Right Time, Right Place®). These changes have enabled farmers to produce three times the yield using roughly the same number of acres of farmland as they did in 1960.

Would it be better to err on the side of under-fertilizing?

Today, farmers are producing higher yields using less fertilizer. Soils do not naturally contain the nutrients necessary to keep pace with growing world demand for food.

Following methods of 4R Nutrient Stewardship, which requires a farmer to test their soil to determine its exact nutrient requirements, allows them to apply only what the crop needs.

What happens to fertilizer when a crop is harvested?

When a crop goes to market, so too do the nutrients that plants have absorbed from the soil. If farmers do not replace the nitrogen, potassium, phosphorus and sulphur this year’s crop has used to grow, next year’s plants will not have the food they need.

Fertilizing helps recycle the nutrients that subsequent crops will need to produce high yields. It is nothing more or less than completing this natural growth cycle.

4R Nutrient Stewardship

What is 4R Nutrient Stewardship?

4R Nutrient Stewardship provides a framework to achieve cropping system goals, such as increased production, increased farmer profitability, enhanced environmental protection and improved sustainability.

To achieve those goals, the 4R Nutrient Stewardship concept incorporates the:

  • Right Source at the
  • Right rate, at the
  • Right time and in the
  • Right place

Properly managed fertilizers support cropping systems that provide economic, social and environmental benefits. On the other hand, poorly managed nutrient applications can decrease profitability and increase nutrient losses, potentially degrading water and air.

4R Nutrient Stewardship requires the implementation of best management practices (BMPs) that optimize the efficiency of fertilizer use. The goal of fertilizer BMPs is to match nutrient supply with crop requirements and to minimize nutrient losses from fields. Selection of BMPs varies by location, and those chosen for a given farm are dependent on local soil and climatic conditions, crop, management conditions and other site specific factors.

Other agronomic and conservation practices, such as no-till farming and the use of cover crops, play a valuable role in supporting 4R Nutrient Stewardship. As a result, fertilizer BMPs are most effective when applied with other agronomic and conservation practices.

The 4R Nutrient Stewardship philosophy is an innovative and science-based approach that offers enhanced environmental protection, increased production, increased farmer profitability, and improved sustainability. The concept is to use the Right Source, at the Right Rate, at the Right Time, in the Right Place. Implications of 4R Nutrient Stewardship system will spread far and wide through agriculture and society as a whole. For fertilizer use to be sustainable, it must support cropping systems that provide economic, social, and environmental benefits. Enhanced understanding, adoption and promotion are the goals of the sponsors of the website behind 4R Nutrient Stewardship.

Who is behind 4R Nutrient Stewardship?

4R Nutrient Stewardship is a concept supported by the global industry. The fertilizer industry’s interest in sustainability reporting is part of a larger business trend. For example, Wal-Mart has adopted sustainability goals that include requiring its suppliers to document sustainable production. The video webcast from their November 12 milestone meeting emphasized agriculture and food products. Can our current crop nutrient recommendation systems provide the data that is needed to verify sustainability?

When Wal-Mart requires this kind of documentation from its suppliers, how far down the value chain will this requirement be passed along? It won’t end with the grower. Growers rely on many sources of recommended practice. In the end those recommendations also must also be documented as to how they came about, and how they contribute to sustainability.

Internationally, sustainable development is recognized to consist of three nonnegotiable elements: economic, social, and environmental. Progress in each of those three areas is essential to sustainability.

What is new about 4R Nutrient Stewardship?

You cannot apply fertilizer or any other nutrient source without making decisions about source, rate, time and place. The innovative piece of 4R Nutrient Stewardship is the way it systematically organizes nutrient management information and provides a framework for guiding decision making and getting to the right decision. This approach requires that practices are consistent with scientific principles and integrate the best available scientific evidence with the producer and/or agronomists experience when making nutrient management decisions.

Is 4R Nutrient Stewardship awfully complicated?

As the consumer environment continues to shift towards a greater transparency around food production and its environmental impact, growers would be wise to adopt and demonstrate a 4R Nutrient Stewardship program.

A 4R Nutrient Stewardship program is about using fertilizer more effectively and efficiently and for growers this translates into getting more value for every dollar spent on fertilizer.

A 4R Nutrient Stewardship program is not necessarily about reducing fertilizer rates but rather using fertilizer wisely, increasing yields and reducing greenhouse gas emissions.

Growers need to build and tell their stories on their farm management practices to those that have influence over farm operations, including consumers, environmentalists, governments and food companies. It is important for growers to own and be ambassadors for 4R Nutrient Stewardship in order to maintain flexibility over their farming practices.

Growers adopting 4R Nutrient Stewardship BMP’s could improve their economic and environmental outcomes and reduce greenhouse gases when applying fertilizer or other crop nutrients to fields. 4R Nutrient Stewardship is a “win-win” for both the environment and farm economics.

What are the risks involved in moving to 4R Nutrient Stewardship?

Adopting 4R Nutrient Stewardship is a relatively low risk decision. The main up-front investment is the time required to set sustainability goals for the farm, document current nutrient management practices and make decisions about practice improvements. The costs of adopting BMPs will vary but since 4R Nutrient Stewardship is adaptive management, new practices can be introduced over a period of several years on a schedule that works for your particular farm. All change involves some risk but most work indicates that improving nutrient management has a positive impact on the economic sustainability of the farm as well as reducing the exposure to environmental liability.

I have a lot of things I could be trying like new crops, seed varieties, pesticides, hedging etc. Why is 4R Nutrient Stewardship the best use of my time and energy?

Chances are your fertilizer bill is one of your largest variable costs and nutrient issues some of the biggest environmental and social pressures on the farm. Our initial work with 4R Nutrient Stewardship, suggests that better nutrient stewardship will give a significant payback in all three areas of sustainability economic, social, and environmental.

The way I am fertilizing my crop now is working fine. Why change?

Is it working fine or simply working? The 4R Nutrient Stewardship approach is aimed at optimizing your nutrient use. So you get more dollars of crop per dollar of nutrient applied and reduce negative off farm impacts at the same time.

What will it cost to switch to 4R Nutrient Stewardship?

Switching to 4R Nutrient Stewardship will not be a free ride but the payback period on the initial set up costs will in all likelihood be quite short. The initial planning costs will depend on the size of the operation, whether a paid crop advisor is involved, and the current level of management and record keeping.

Once the plan is in place, implementation costs will depend on what new or improved practices are being adopted. For example, some practices will be relatively low cost, for example implementing a soil testing program may cost $0.50-$0.75/acre. Buying a new seed drill may on the other hand involve the outlay of several hundred thousand dollars, but of course the initial cost will be amortized over a number of years.

While we can’t say that switching to 4R Nutrient Stewardship will cost a specific amount per acre or per operation, what we do know from earlier work is that nutrient management planning has a positive impact on the bottom line.

Will I get the same yields and crop quality under 4R Nutrient Stewardship?

Yields and quality may change following adoption of 4R Nutrient Stewardship. How big a change depends on your current nutrient management practices? Reducing fertilizer or manure applications in environmentally sensitive areas may reduce yields in those areas but this may be compensated by higher yields in areas with high yield potential that have been under fertilized in the past. Over several years, you will find that regardless of whether yields are higher or lower the return per dollar invested in nutrients has improved.

What is the difference between 4R Nutrient Stewardship and precision agriculture?

Precision agriculture as applied to crop management is about varying practices in relation to variations in the field. The requirement of 4R Nutrient Stewardship is to improve practices used in making source, rate, time and place decisions on a field by field basis. More advanced programs of 4R Nutrient Stewardship will likely include precision agriculture practices like variable rate fertilizer but they are not a required part of the program.

Can I use 4R Nutrient Stewardship if I summer fallow?

Summer fallow can have a number of uses in cropping system. It can be used to control troublesome weeds or in regions with significant water deficit as a practice for reducing the risk of crop failure. In the short term, summer fallowing increases crop available nutrients and there is typically a benefit to the subsequent crop. However, over the longer term summer fallow reduces soil organic matter and results in lower soil fertility. Summer fallowed land also tends to be at higher risk for erosion and off site movement of nutrients into surface waters or movement of nutrients into groundwater through leaching.

One of the key scientific principles of 4R Nutrient Stewardship is to Consider Soil Resource Impacts and when we apply this principle to the practice of summer fallow some flags certainly go up. This doesn’t mean that summer fallow is a “prohibited” practice under 4R but it certainly means that it is a practice that needs to be used cautiously. This means that a good 4R program would over time develop and implement practices such as chem fallow and flex cropping that reduce or eliminate the frequency and impact of summer fallow.

Can I use 4R Nutrient Stewardship with irrigation?

The 4R Nutrient Stewardship system is universal and can be applied to any cropping system including irrigated systems. Irrigated systems can offer some unique environmental challenges such as increased risk of nitrate leaching but adopting 4R can help with the reduction of environmental risk. Irrigation also offers some unique opportunities to manage the timing and placement of nutrients to increase effectiveness.

Will 4R Nutrient Stewardship work for manure? Can I still use manure and fertilizer?

The 4R Nutrient Stewardship approach is based on key scientific principles from the fields of crop and soil science. Since it is principle based it will work for any cropping system and all nutrient sources including fertilizer, manure, and compost. Practices of course will vary depending on the nutrient source or sources used on the farm. Farmers using mixed systems with both fertilizer and manure will in all likelihood find that adopting 4R Nutrient Stewardship will allow them to use their manure more effectively.

Will I have to buy more fertilizer?

Adopting 4R Nutrient Stewardship may lead you to buy more fertilizer, reduce fertilizer use, change the sources you use and/or apply those sources at different rates or at different times and places. The main goal is to make more effective use of nutrients in a way that balances the economic, environmental and social aspects of crop production.

While 4R Nutrient Stewardship is universal and principle based, it is also highly adaptive to the local conditions and circumstances of individual producers and their fields.

Will I have to cut back on fertilizer?

4R Nutrient Stewardship is not about reducing fertilizer use. It’s about ensuring sustainable fertilizer practices that help producers meet economic, social and environmental goals. Meeting those goals may result in fertilizer rates being lowered or raised depending on factors specific to each field. In the end, fertilizer rates will only be reduced where is makes sense to do so.

What if I can't afford new equipment?

In general, 4R Nutrient Stewardship does not require that you use specific equipment. You can implement 4R Nutrient Stewardship by reviewing and improving source, rate, time and place practices using your current equipment. Adopting BMPs that require additional or different equipment would be introduced as part of the on-going cycle of equipment replacement. There are exceptions, such as using a 4R Nutrient Stewardship plan under the Nitrous Oxide Emission Reduction Protocol (NERP), where placement BMPs for banding specify that the fertilizer band must have a lateral spread of less than the row spacing’s.

Who decides what is in a 4R Nutrient Stewardship plan?

The traditional answer to “Who decides what qualifies as a best management practice?” went something like “a team of farmers, researchers, natural resource managers, extension staff and agribusiness professionals.” Today there is still no doubt that the expertise of all these people is important to determining the right management on a practical basis. A sustainability-focused approach, is more comprehensive and includes input from all stakeholders in determining the indicators, measures, benchmarks and targets for performance of the management practices implemented.

The four “rights” of plant nutrition stewardship also have an ethical component. There is a value judgment to choosing the right nutrient source, metering out the right rate at the right time and in the right place. The value judgment is based on how this combination of actions meets sustainability goals. These goals are determined, not by science, but by people—informed by science—who apply their beliefs and values to choose targets for outcomes. For example, in a setting where a pre-plant application of nitrogen optimizes yield but results in excess groundwater nitrate, a stewardship approach would seek a management strategy (perhaps split-application, perhaps a controlled-release source, perhaps a technology yet to be developed) that both optimizes yield and limits nitrate loss to groundwater. If these benefits are understood by the stakeholders, support for changes in technology should be easier to obtain.

Setting sustainability goals involves science communication. Many scientists feel their work is not adequately understood or appreciated, and is not appropriately used in development of policy, regulation and practical recommendations. Science can help define the right management to achieve particular sustainability goals, but scientists must recognize the ethics, beliefs and values of their audience to meaningfully engage public dialogue on such goals.

Do I have to use an agrologist or crop adviser?

You don’t have to use an agrologist or crop advisor to implement 4R Nutrient Stewardship, but working with a professional will likely improve your 4R Nutrient Stewardship program and increase the net benefits you get from it. Agrologists or crop advisors with a strong background in nutrient management can help you with setting yield goals, soil test interpretation, crop monitoring and a number of other activities that are part of the 4R Nutrient Stewardship process. They can also provide a second opinion on the value and/or validity of different products and practices as they relate to the climate and soil types found on your farm. Many producers find that working with the right agrologist or crop advisor is a sound investment in the sustainability of their operation.

For some tips on selecting a crop advisor check out How to Hire an Agronomist or Crop Advisor.

NOTE: There may be instances where a 4R plan is part of a third party requirement and professional sign off is required. For example, under the NERP program producers must implement a 4R plan under the guidance of an Accredited Professional Advisor (APA) with an appropriate background in agronomy and professional credentials such as Professional Agrologist (P.Ag.) or Certified Crop Advisor (CCA). Make sure you understand the credentials and training required when professional sign off is required.

Nutrient Stewardship – For Homeowners

Right Source

What type of fertilizer should I buy?

To make sure you’re buying the right fertilizer for your lawn; review your options at your local lawn and garden centre by reading the bag or asking someone who works there. You can also get your soil tested by a professional or with a home kit, available at most garden centres. Soil testing is the only way to assess the soil’s nutrient status.

A starter fertilizer contains more phosphorus to stimulate new root growth while a fall fertilizer helps to repair summer damage and build strong roots that protect the lawn for winter. All other fertilizers feed evenly for a thick, healthy green lawn.

Can I store unused fertilizer for use next year?

Yes, unused fertilizer can be stored. Keep any leftover fertilizer sealed in its original container in a dry place for use next season. If moisture gets in, you may have lumping of the fertilizer, so be sure to break up any clumps before placing in the spreader.

What are the three numbers on the fertilizer bag and what do they mean?

The three numbers on the bag (such as 10-0-5) indicate the ratio of three key nutrients included in all fertilizers: nitrogen, phosphorus, and potassium, always listed in this order. Meaning, if a bag reads 21-4-3 it contains 21 percent nitrogen, 4 percent phosphorus, and 3 percent potassium.

Nitrogen: Boosts growth and green colour.

Phosphorus: Feeds seedlings and stimulates new root growth.

Potassium: Provides all around vigour and health while strengthening for resistance to disease and stress.

What’s the difference between conventional fertilizers and organic fertilizers?

The three main ingredients in fertilizer — nitrogen, potassium, and phosphorus — come from nature. They are not man-made. Fertilizer companies simply convert them into a form that plants can use.

Fertilizer producers can blend nutrients into precise combinations to match the unique needs of different lawns. In this way, homeowners can feed their lawns with the most effective and efficient blend of potassium, phosphorus, and nitrogen to achieve the best results.

Organic fertilizer is made from different ingredients, such as livestock manure. These natural fertilizers do not provide nutrients in the fine-tuned combinations possible with commercial fertilizers. For example, using enough manure to provide an adequate supply of nitrogen could mean adding four to five times more phosphorus than what plants and lawns need. So, it’s easy to over or under fertilize.

What’s most important is that your plants and lawns can not tell the difference between conventional and organic fertilizers.

Right Rate

Do I have to apply fertilizer using a special spreader? Can I just use my hand?

Properly maintained and calibrated spreaders are designed to deliver an accurate amount of fertilizer evenly across the entire lawn. Uneven application can cause variations in lawn colour and potential burning if over-applied. Never spread fertilizer by hand.

If storage space is an issue, consider a handheld model for smaller lawns.

And don’t be intimidated by your spreader. All the steps for proper application are outlined on your fertilizer product bag.

What setting should I use for my spreader?

The fertilizer product label will tell you which setting to use.

How much fertilizer do I need?

First, you need to know the size of your lawn to know how much fertilizer is required for an application. Multiply your property’s length by its width, and then subtract the area of your house and any hard surfaces like driveways, patios or decks.

Here is a simple tip to help you visualize your lawn area: Picture a full tennis court with a fence around it. The area inside that fence is about 800 m2.

Once you know the size of your lawn, you’ll be able to choose the right amount of fertilizer to apply – the coverage area is outlined on the fertilizer product bag.

I just applied lawn fertilizer. Do I need to water the lawn right away?

It depends on the type of fertilizer you used for your lawn. Be sure to read the bag for application and watering instructions.

Dry fertilizers are taken up by the plant within 24 hours and act as a slow release – feeding the lawn slowly and evenly over a six to eight-week period with no watering required. Other fertilizers require a light watering following application.

Right Time

When should I apply fertilizer?

Feed your lawn every other month beginning in April. A lawn fed three to four times a year develops a deep root system to resist heat, drought, and wear. It also develops thick green top growth to naturally resist weeds, disease, and insects.

Tip: Canadian holidays are an easy way to remember best times to feed your lawn. Think Easter, Victoria Day, Labour Day, and Thanksgiving.

Why is it necessary to fertilize my lawn in the fall?

A thick and healthy lawn requires a strong root system. As the root system of the grass plant grows most vigorously in fall, feeding your lawn with an application of fertilizer in fall helps promote root growth. At the same time, fertilizing your lawn in the fall will prepare your green space for a long winter and help it recover in the spring.

Is it okay to apply fertilizer during the hot summer months?

Do not apply fertilizer when the temperature is above 30 °C. Fertilizing in very hot and dry conditions can burn your lawn.

I am planning to de-thatch my lawn. Should I apply fertilizer before or after I de-thatch?

Apply fertilizer after you de-thatch.

I am planning to reseed my lawn. When should I apply fertilizer?

Apply a starter fertilizer after you seed. Starter fertilizers promote root growth, which will help new grass establish itself quickly.

Right Place

I just laid sod. Should I fertilize it?

Apply a starter fertilizer after you sod. Starter fertilizers promote root growth, which will help new grass establish itself quickly.

Do I use the same fertilizer for my garden?

No as different plants require different levels of nutrients. Choose a garden fertilizer or plant food and read the label to make your selection depending on the type of flower, shrub, or vegetable.

Is fertilizer safe for my pets and kids?

Fertilizer particles do not pose a safety risk to you, your kids, or your pets. To avoid picking up any fertilizer particles on footwear or feet, we recommend waiting 24 hours if children and pets want to play on the lawn.

My property backs onto a pond. Is it safe for me to fertilize my grass?

Use a low phosphorus or phosphorus-free fertilizer, but if you suspect a phosphorus deficiency is limiting the growth of your grass, take a soil test before buying a fertilizer containing phosphorus. Leave a buffer zone when applying to keep the fertilizer out of the water because phosphorus can promote algae growth.

Applying fertilizer properly will help to ensure fertilizer stays where it belongs – on the grass.

Is fertilizer bad for the environment?

No, when used correctly, fertilizer plays an important role in helping healthy, green grass grow, and healthy turf has many environmental benefits. Healthy green space has a dramatic cooling effect compared to hard surfaces, acts as a water filtration system, produces lots of oxygen, reduces water run-off and provides a soft, safe outdoor space for people and pets to rest and play. Dense grass also helps trap significant amounts of dust and dirt particles; an acre of grass will absorb hundreds of kilograms of sulphur dioxide per year.