Ag Science - Soil management

Arable meaning

Land that is ploughed and used to grow crops

What is fodder ?

Food, especially dried hay or straw for cattle and other livestock

How many elements are essential for plant growth ?

17

What are three essential elements ?

Carbon, hydrogen and oxygen

What are the macronutrients for plants ?

Nitrogen, phosphorus, potassium, calcium, magnesium, sulfur

What are the micronutrients for soil ?

Iron, zinc, manganese, copper, boron, molybdenum, chlorine, nickel

Where are macronutrients and micronutrients derived from ?

Organic parent materials

What form are macronutrients and micronutrients found in ?

ionic form

What causes a deficiency in essential minerals ?

Low soil fertility e.g. sandy soil

Unsuitable pH (reduced availability of nutrients)

What are the most important macronutrients ?

Nitrogen, phosphorus and potassium

What are the essential functions of nitrogen in plant and animals ?

Component of chlorophyll, which is needed in photosynthesis

Component of amino acids, which are needed to create protein

Component of DNA, which is responsible for growth and reproduction in plants

Component in ATP, a compound responsible for the control of metabolic energy in the plant

What does sufficient nitrogen cause in plants ?

Rapid plant growth

Dark green vegetation

High protein content in seeds

What does nitrogen deficiency cause in plants ?

Slow growth, small plants

Pale green or yellow due to lack of chlorophyll

Necrosis (death) in older leaves as nitrogen is used in younger leaves

What form is phosphorus found ?

Ionic compounds

What is phosphorus soluble in ?

water

How is phosphorus taken up in plants ?

In soluble form

What is phosphorus uptake largely dependent on ?

The pH of the soil

At what pH levels does phosphorus form compounds that are insoluble in water and unavailable to plants ?

At pH levels below 5 and above 7.5

What are the essential roles of phosphorus in plants ?

Required for optimum growth and reproduction

Involved in energy transfer in the plant

Production and development of new cells

Transfer of DNA in new cells

Seed formation and development

What does sufficient phosphorus cause in plants ?

Vigorous growth

Early maturing

Increased resistance to plant disease

Improved flower formation

Increased stalk/stem strength

What does phosphorus deficiency cause in plants ?

Stunted growth

Lack of fruit or flowers

Wilting

Discoloured blue-purple leaves

Delayed maturity

What important functions does potassium carry out in the plant ?

Protein synthesis

Translocation of carbohydrates

Regulation of plant stomata and water use

Promotion of disease resistance

Activation of plant enzymes

What does sufficient potassium cause in plants ?

Increased crop yields

Increased root growth

What does potassium deficiency cause in plants ?

Reduced crop yields

Scorching of leaves (browning) along leaf margins

Slow growth

Poorly developed root system

Weak stalks leading to lodging in cereals

Low sugar content in fruit

Chlorosis (yellowing of leaves)

What is lodging ?

The tendency of cereal crops to bend over so that they lie almost flat on the ground. This makes it difficult to harvest the crop and reduces the yield

What nutrients does soil not suffer the same level of depletion compared to other nutrients ?

Calcium, magnesium and sulfur

What mineral is most likely to be deficient in soil ?

Sulfur

Why are calcium and magnesium deficiencies less common ?

Both elements are present in lime, which is spread to raise pH levels

What is the role of calcium in plants ?

Needed for cell wall formation

What is the deficiency symptom of calcium in plants ?

No development of terminal buds

What is the role of magnesium in plants ?

Part of chlorophyll molecule

What is the deficiency symptom of magnesium in plants ?

Chlorosis of lower plant leaves

What is the role of sulfur in plants ?

Contained in amino acids for protein

What is the deficiency symptom of sulfur in plants ?

Chlorosis of upper plant leaves

What can a deficiency in a plant cause ?

A deficiency in the livestock that eats it

What disease does a deficiency in Iron cause ?

Chlorosis leading to reduced yield/poor-quality fruit in pears and raspberries

Anaemia in pigs

What disease does a deficiency in Zinc cause ?

Yield reduction in cereals, stunted growth and reduced flowering in legumes

What disease does a deficiency in Manganese cause ?

Grey speck in oats, marsh spot in peas, speckled yellow in sugar beet

What disease does a deficiency in Copper cause ?

Swayback in sheep, and curled, distorted ears in wheat

What disease does a deficiency in Boron cause ?

Heart rot/crown rot in sugar beet and carrots

What disease does a deficiency in Molybdenum cause ?

Whiptail (narrow distorted leaves) in cauliflower

What happens as soils become increasingly acidic or alkaline ?

The availability of particular nutrients is reduced or in some instances is unavailable

What pH range are most nutrients available ?

pH 6 and 7

What does soil testing allow ?

Allows farmers to determine the nutrients available on their land and to determine how suitable an area is for crop growth

What can soils be tested for ?

A variety of nutrients, lime requirement and for pH

How long is a soil test valid for ?

5 years

What are the guidelines for taking a soil sample ?

Divide the area to be sampled into regions 2-4 ha in size

Take samples from a wide range of areas, accounting for differences including different soil types, previous cropping history and slopes

Avoid taking samples from areas that are not typical for the area, e.g. entrances and exits to fields, around drinking troughs, beside ditches and on marshland

What are the guidelines for taking a soil sample ? (2)

Do not sample for P and K for at least 3 months after the last P and K application

Do not sample for lime for at least 2 years after the last application

Samples should be taken using a soil auger. At least 20 samples should be taken in a W shape across the field. The samples should be 10cm in depth

Samples from the same field should be stored together and sent to Teagasc for analysis

When is a soil test best carried out ?

Every 2 to 3 years

What numbers are soil index ranked ?

1 to 4

What is the index description for soils ranked 1 to 4 ?

1 - very low

2 - low

3 - medium

4 - sufficient

What is a fertiliser ?

An inorganic, manufactured material that may contain one or more of the essential elements required for crop growth

What is manure ?

An organic material that consists of the wastes of plants and animals

What are the most important elements required for crop growth ?

Nitrogen, phosphorus and potassium

What are the most commonly used straight nitrogen fertilisers in Ireland ?

Urea and calcium ammonium nitrate (CAN)

What is a straight (simple) fertiliser ?

Contains only one of the essential elements

What is a compound fertiliser ?

Any fertiliser that contains two or more elements. Compound fertilisers are often produced by the combination of two or more straight fertilisers

What type of fertiliser is CAN ?

A fast-acting fertiliser

Why is the nitrogen in CAN available on a long-term basis ?

The nitrate in CAN is immediately available for uptake by crops. The ammonium ions are slower-acting as they must be converted to the nitrate form. The combination of fast-acting and slow-acting fertilisers means that nitrogen is available on a long-term basis when CAN is spread on the land

What form is CAN sold in and what does it allow ?

Granulated form, which allows for uniform spreading

What does hygroscopic mean ?

A substance is described as hygroscopic if it can absorb moisture from the atmosphere

Why must CAN be stored carefully ?

It is hygroscopic

What happens if CAN is not kept in airtight conditions ?

The granules will cake together and cannot be spread on the land

What does urea contain in comparison to CAN ?

A higher concentration of nitrogen, which means less fertiliser is needed for spreading on the land

What type of fertiliser is urea ?

A slow-acting fertiliser

Why is urea a slower acting fertiliser than CAN ?

It must be converted from urea to ammonium form and then into nitrate before it is available to crops

What is a disadvantage to urea ?

It undergoes volatilisation

What is volatilisation ?

A process in which the ammonium ions produced are converted to ammonium gas, which is then lost to the atmosphere

When does volatilisation mostly occur ?

When the weather is warm and dry

What are the risks to CAN and urea ?

Oxidising - can cause or contribute to the combustion of other materials

Volatilisation of the fertiliser to produce toxic gases such as ammonia gas

Cause irritation or burning to the eyes, skin and respiratory system

How can you control CAN and urea ?

Use a automated sprayer to spread the fertiliser

Wear goggles to protect eyes, gloves and overalls to protect skin and respiratory protection to protect the lungs from exposure to the fertiliser

What is a common compound (N-P-K) fertiliser used in Ireland ?

10-10-20

Used for grassland, potatoes, cereals

How should you handle, use and store fertilisers ?

Store bagged fertiliser at least 10m away from a waterway or drain and where there is no risk of flooding

For indoor storage, do not store fertilisers beside other combustible materials (e.g. hay or straw) or other chemicals such as pesticides or oil

Store fertilisers of the same type together

Do not store bagged fertilisers near sources of heat or heating systems

Handle bags carefully to avoid damage

Clean up any fertiliser spills to prevent it from entering a drain or watercourse

How should you handle, use and store fertilisers ? (2)

When cleaning fertiliser spreaders do not allow washings to enter a watercourse

Always wear gloves when handling fertiliser to prevent it getting into open cuts or wounds

Wear a mask if opening or filling spreaders in an enclosed area

When emptying a large bag of fertiliser into a spreader do not stand under the bag when it is suspended or cut it open from the bottom; instead, cut the bag on the side in a cross shape

Ensure all machinery used to spread fertiliser (tractor and spreader) are in good working order

How can fertiliser be applied ?

Placed in soil

Broadcast

Top-dressing

Placed in soil

fertiliser is applied to the land when the seeds are sown. The seed drill sows the seed and applies the fertiliser in a band close to the seed so that nutrients are available to the crop

Broadcast

fertiliser is spread (broadcast) on the soil using a fertiliser spreader and then harrowed into the soil. This may take place prior to sowing

Top-dressing

fertiliser is spread on an established crop

What does farmyard manure consist of ?

Animal dung, animal urine and straw from winter bedding

How can FYM be applied to the land ?

With a muck spreader

What does slurry consist of ?

Animal dung and urine

How is slurry collected ?

In a tank underneath the floor in slatted housing

What are the health and safety risks associated with slurry ?

drowning and gas poisoning

What are the gases that slurry produce ?

Hydrogen sulfide (H₂S), ammonia (NH₃), methane (CH₄), carbon dioxide (CO₂)

Why is slurry agitated ?

To give a uniform consistency and to liquefy the slurry which has settled in the tank over several months

What is agitation ?

Rapid stirring of a liquid

What are the precautions when agitating slurry ?

Remove livestock from slatted sheds

Ensures nobody enters the building

Keep the shed well ventilated, with all doors open to provide a draught

It is recommended to agitate the slurry tank on a windy day to maximise ventilation in the shed and allow the gases to be dispersed by air currents

What are the precautions when agitating slurry ? (2)

Agitate the slurry form outside the shed

Ensure that at least two persons are present; do not stand near the slats as the toxic gases are emitted

Persons and livestock should not enter the shed for 30-60 minutes after agitation or until they are certain that gases have dispersed

Persons entering the shed should wear breathing apparatus

What type of manure is straw ?

Green manure

What factors can soil drainage be affected by ?

Soil type: a heavy clay soil which has smaller pores will lead to less infiltration than a soil with a high sand content

Precipitation: some parts of the country are subject to high levels of precipitation. Coupled with a soil with a poor infiltration rate, this can lead to waterlogging very quickly

Percolation: the amount of water that drains through the soil. This is dependent on the soil type and its capacity to drain water

Groundwater: this is where the water table in located below the soil surface, and it is at this point that the soil is saturated with water. Soils with a high water table do not have much capacity for growth

What is poaching ?

Damage caused to wet or waterlogged land where land is cut up by livestock movement on wet soils. It causes surface vegetation to be removed and soil to be washed away. Soil may also be compacted

Groundwater drainage system

This system makes use of a series of underground pipes which collect water from the permeable layer of soil and transport it to an outfall

Shallow water drainage system

used where there is little permeability of the soil at any level, so the objective is to improve drainage capacity by using a subsoiler, or through mole drainage using a mole plough

What is the outfall ?

The point where a drain empties into a river, lake or sea

What is a mole plough ?

Creates cylindrical channels in the soil which increases the drainage ability of a soil with low permeability. This type of drainage is called mole drainage