AGRICULTURE HSC mid course revision

Management strategies used to assess and meet market specifications - herd testing

- involves the testing for contaminants in the milk as well as bacterial counts. -If test results show high number of white blood cells, this indicates that mastitis is present and the response to this result should be the farmer treating the herd by teat dipping at milking time. --Farmer- should also test samples from each cow to determine the infection levels of each individual cow. - also essential to ensure no traces of antibiotics are in milk as this can cause harm to consumers.

NAR (Net Assimilation Rate) - what is

- is one measure of growth in plants resulting from the difference between photosynthesis and respiration - it is the average increase in dry matter per unit area of leaf material in a given period

Vitamin D - fat soluble

- made by animals when sunlight acts on a substance in skin called ergosterol -need by body to allow proper formation of bone tissue -without - bones become deformed and young can develop rickets

IPM strategies

- monitoring and identification -Physical controls - habitation modification - exclusion - sealing, putting up screens, air doors -Mechanical controls -sanitation Cultural controls - way you grow it - keeping soils healthy with right type of plants -least hazardous pesticides used only when absolutely necessary. e.g. baits - gel, tamper-proof containers -biological controls - Bt, nematodes, parasitic wasps, beneficial insects

Production Cycles and farm operations to meet market specifications

- numerous operations that must occur on the farm at particular times to ensure the milk produced meets the quality and quantity standards in place and the market specifications. Operations include: -Vaccinations -Pasture sowing routines -Drenching -Farmers must also focus on managing the production cycle of the cattle to uphold milk quality and quantity These include: -mating -Pregnancy testing -Feeding Supplements during pregnancy

NAR (Net Assimilation Rate)- is affected by

- rate of photosynthesis - affected by light intensity, CO2 concentration near leaves, available water, temperature. -Rate of respiration - influenced by available O, sugars and temp. -Available water - needed for metabolic processes -Available inorganic nutrients - N,P,K, etc. - Proportion of non-photosynthetic tissue - more roots, stems, flowers the more respiration -Photoperiod - length of day -Stage of development -Leaf area - Canopy structure - shading -insect damage

Vitamins

- required in small amounts for normal growth and maintenance of animal life -Either water-soluble or fat-soluble - water soluble - B & C -fat soluble - A, D, E & K

market specifications

- the requirements regarding the quality of the milk that needs to be met to ensure that it is suitable for human consumption, allowing the milk to be sold commercially.

ruminant digestive tracts - rumen

-1st stomach sometimes called the paunch -Contains micro organisms that break down the cellulose and lignin contained in plant material and digest the food -Carbohydrate and protein digestion -Protein synthesis occurs -Strong muscular walls enabling the mixing of foods -Acts like a fermentation chamber when breaking down cellulose -Lining is thick and has a velvet like appearance -pH from 6.0-7.0

ruminant digestive tracts - reticulum

-2nd stomach sometimes referred to as the honeycomb -Contains a large population of bacteria, protozoans and anaerobic fungi that produce enzymes -Breakdown of carbohydrates into fatty acids -Protein synthesis -Vitamin B synthesis

ruminant digestive tracts - omasum

-3rd stomach sometimes called the book or the bible -Has an appearance that is page like -60-70% of water from the rumen fluid is removed

Management strategies used to assess and meet market specifications - tagging cows

-A management strategy used to help make milk reach the market specifications include the tagging cows with a computerized tag or a microchip to allow information on their milk production and the quality of their milk to be reached easier and kept more conveniently.

ruminant digestive tracts - rectum

-Any residue is pushed through the rectum and out of the body through the anus -The final product of food after digestion is known as dung or faeces

ruminant digestive tracts - small intestine

-Breakdown of starches, proteins, and fats into soluble compounds by enzymes -Absorption into the bloodstream through the "Villi" of digested products

C4 plants

-C4 plants minimize photorespiration by separating initial fixation and the Calvin cycle in space, performing these steps in different cell types. -open stomata during day -needs more energy -Hot, sunny environments

ruminant digestive tracts - caecum

-Continues with fibre digestion -Micro organisms break down any left over protein

Production Cycles and farm operations to meet market specifications -pregnancy testing

-Cows in calf need more than just ordinary feed. -They need better quality pastures and supplementary feeds to aid in the development of the foetus. -After just over a month after mating, farmers can be notified whether the cow is pregnant. -If the cow shows signs of being not in calf, they can be re-mated or discarded.

Production Cycles and farm operations to meet market specifications -pasture sowing routines

-During winter - pasture growth is known to slow quite significantly. -This calls for the need for planting of winter growing crops (rye grass or oats on coastal areas of New South Wales) at the conclusion of summer or early autumn to guarantee some kind of feed for the herd during the colder months to allow for milk production to continue at a constant rate.

Management strategies used to assess and meet market specifications

-Essential for dairy farmers to receive monthly reports on the production at their farm so they can uphold quality control measures for the dairy product. -Farmers typically keep track of each cow on their farm and each month, one sample is taken from each cow at the morning milking and the evening milking which is to be sent away for testing (known as herd recording). -The samples indicate how much is being produced on the farm. -Testing involves determining the fat and protein content in the milk samples as well as other various tests. -This recording can be time consuming and expensive as it takes longer and more workers.

Production Cycles and farm operations to meet market specifications - mating

-Farmers follow a strict production cycle relating to the mating of cows. -strive to get 7 calves per cow within their lifetime- only possible if they follow are timed cycle carefully. -Once the cow has calved, mating can occur three months later. -This means that the farmers can receive one calf from each cow per year. -Although this cycle is rushed, the cows still need time to come on heat after calving. -Once a cow reaches the stage two months prior to calving, her milk production comes to a complete halt allowing her to conserve her energy and protein to focus on producing a healthy fast-growing calf. - for farmers to gain the most amount of calves from a cow as possible, the cows must have regular lactation rather than a few lactation periods. - farmer aims to bring the cow back to the mating process straight after calving to allow lactation to return as quickly as possible.

ruminant digestive tracts - anus

-Final exit of waste materials is excreted through and leaves the body

fate of energy in animal diets

-Gross energy (GE) = total amount of energy in feedstuff given to animal. -Digestible energy (DE) = energy that is taken in by the animal and not lost as waste. -Metabolisable energy (ME)= energy that is available for the animal to use to fuel functions. -Net energy (NE) = energy that is not lost to metabolism to fuel other functions (eg: body temp, sound, lactation, urine/faeces) and can be used for growth (eg: wool, hide, meat); energy for maintenance and production.

How is growth different from development?

-Growth - involves an increase in size -Development - the sequence of changes that occur in the life of a plant as it grows -Sequence of changes include: germination, growth of stems and leaves, production of flowers, fruits and seeds, and then death of the plant.

IPM example - Black Rot

-Host - cabbage -Target Organism - bacterium - black rot bacteria Control methods: -sterilising seedbeds -not placing seedbeds on land used previously to grow cruciferous crops -rotating crops - do not grow crucifers on the same land more than once every 3-4 years -Sanitising crops - examine seedlings at translating and destroy diseased ones. collect all diseases material as soon as it is noticed. Bury deeply all crop residues at the end of the season. -controlling insects - biting and sucking insects need to be controlled with an insecticide as they can carry bacteria from diseased to healthy plants Evaluate success of program - an integrated comprehensive program is needed to manage black rot successfully. This decreases the chemical use by using a variety of effective methods.

Management strategies used to assess and meet market specifications - iodine use

-Iodine - used to clean machines and manufacturing technology is also not allowed to be presented in the milk packaged for human consumption as it can cause milk to be unsafe. -It is critical to make sure that after machinery in the factory has been cleaned with iodine, there is no residue left on the machines that could cause potential harm to consumers.

value-adding through using Jersey Cows

-It isn't just the factories and processing companies that can value add to products. -Farmers - also highly capable of value adding. -Companies like Norco have purchased and turned their attention from the typical Friesian cattle to the newly demanded Jersey cow. -The dairy industry has seen an increase in demand and interest towards Jersey cow milk. -This is due to the great level of butterfat contained in the Jersey cows milk rather than the typical dairy cows milk. The high butterfat content causes the milk to be significantly creamier.

ruminant digestive tracts -large intestine

-Larger in diameter than small intestine -Removes water -Some further breakdown may occur

Advantages of value-adding

-More profit -More easily purchased due to convenience -Larger and new export markets

IPM benefits

-Promotes sound structures and healthy plants -Promotes the sustainable bio-based pest management alternatives. -Reduces the environmental risk associated with pest management by encouraging the adoption of more ecologically benign control tactics -Reduces the potential for air and ground water contamination -Protects the non-target species through reduced impact of pest management activities. -Reduces the need for pesticides by using several pest management methods -Reduces or eliminates issues related to pesticide residue -Decreases worker, tenant and public exposure to pesticides

Soil Degradation - practices that have led to

-Salinity is a consequent soil degradation problem from deforestation (during Australia's agricultural expansion) and flood irrigation practices in agriculture -particularly in the Wheat Belt and Murray Darling Basin area

Vitamin A -fat soluble

-made by animals from a substance called carotene Deficient in vitamin A: -night blindness -poor resistance to infection -pigs & poultry intensively housed may have these problems if their ration is not formulated correctly -feed to increase - corrected by carrots, fish oil, green feed -Also use vitamin A injections to help increase levels

Graphing

-title -label axis -distinguish what type of graph (continuous = line, dis-continuous = bar or other) -units -dependent on y axis (vertical) -independent on x axis (horizontal)

food conversion ratios

-used to calculate the animal's efficiency in gaining weight from food eaten -Animals that have a low FCR are considered efficient users of feed; for example, poultry can convert 2-3 kg of feed into 1 kg of live weight. -Sheep and cattle are less efficient and have higher FCRs; they can consume greater than 8 kg of feed and convert it into 1 kg of body weight.

Value-adding

-value adding involves raw materials undergoing processing in order to increase the price at which that product can be sold -Value adding products or modifications to current products have been created due to consumer demand and interests -Every year consumers are looking for more convenient products that are nutritious and fit their dietary needs

NAR (Net Assimilation Rate)- how to calculate

- To calculate the NAR samples of the crop or pasture must be cut at the beginning and end of the time interval and the leaf area and dry matter of each time determined. -NAR = W2-W1/ T2 - T1 x 1/ Y2(A1+A2) -W1 = dry weight at beginning -W2 = dry weight at end -T1 = time first sample was taken -T2 = time second sample was taken -A1 = leaf area in first sample -A2 = area of leaf in second sample - units most often grams of DM per square decimetre? of leaf per weak NAR is then a measure of the dry matter gain of the plant over a period

Carbohydrates

- are composed of carbon, hydrogen and oxygen -e.g.starch and cellulose (ruminants use this) -provide energy for movement, reproduction, temp regulation -microbes - responsible for breaking down cellulose found in plant material -plant cell walls - high concentration of cellulose -Grains (e.g.maize) - mainly contain starches (a carbohydrate)

The outcomes of these practices on land/water system -salinisation

Salinity can severly affect agricultural production. This is by: • restricting the type of plants that can be grown in a region • reducing plant yields • contaminating livestock and domestic water • increasing the soil's susceptibility to erosion • poor germination rates • creating a blocky structure and causing surface crusting and lower infiltration and drainage rates

Soil Degradation - methods to alleviate

Several practices have been developed to alleviate dryland salinity: -strategic subsoil drainage of saline water to saline river systems by establishing furrows -physically pumping water from water table to evaporating ponds (very costly) - changing from flood irrigation to efficient drip irrigation - planting native trees on farm (such as along borders) to reduce water table (long term).

Current recommended procedures to alleviate the problem - salinisation

Tackling salinity in irrigation areas has involved lowering the water-table. This has been done through the installation of drainage systems, by storing salty water in large water basins, through more judicious and efficient use of irrigation water, and by actually pumping water from the water table. Also, planting trees has some potential. In drylands,: • re-establishing trees in the catchment areas to reduce the amount of water filtering into the ground water (trees remove the water by transpiration) • fencing off the salt-affected areas and planting them with salt-tolerant with salt-tolerant pastures and crops • using reduced stocking rates on the affected areas, are in keeping with the reduced capability of the land • catchment planning through the application of technology to detect salt affected-areas e.g. using satellite imagery and aerial scanning the only absolutely successful method would involve piping the salty drainage water hundreds of kilometres to sea, but this would be quite expensive.

plant competition - desirable plants

The farmer may plant the seeds too closely together resulting in a high plant density. The consequence of high plant density is plant competition.

Phases of Growth of a plant - Reproductive

during this phase flowers form, fertilisation takes place, seeds and fruit develop and the plant matures and dies.

Experimental Design

variables - independent or dependent -independent - factor that is changed by scientist, not other variables -dependent - factor that is measured and will change based on the independent variable Following steps apply: 1. Identify the experimental unit. 2. Identify the types of variables. 3. Define the design structure.

plant nutrients and pH

-The availability of soil nutrients is greatly inluenced by soil pH and factors such as temperature, drainage and soil pore size. -Soil pH measurements are dependent on the type of measurement carried out and the ratio of soil and water used in the sample. -For any pH measurement of a soil sample, the ratio of soil to water must be stated. -% of base minerals in a soil and soil cation exchange values vary with pH. -Mineral availability also correlates to soil pH values. -In alkaline conditions nitrogen compounds are converted to ammonium salts. - the bacteria needed to continue the nitrogen cycle to produce nitrate salts are not present in alkaline conditions, and so the nitrogen cycle is limited.

ruminant digestive tracts - abomasum

-True stomach or glandular stomach -Gastric juices released to digest proteins -Similar to the stomach of monogastric animals -Microorganisms passed from the rumen are killed and digested as a valuable food source for the animal.

ruminant digestive tracts - duodenum

-U-shaped loop -Bile added to food, raising the pH -Preparation for more digestion and absorption that will take place in the small intestine

ruminant digestive tracts - mouth and oesophagus

-Used to chew food and produce saliva -Transports food down into the rumen and back up from the rumen -Oesophagus transport milk directly to the abomasum for immediate digestion

Quantity and Quality Criteria for Milk and Market Specifications

-When farmers are providing milk for factories, there is certain specifications that need to be addressed. -there are different expectations of percentage of product components in different sections of the production and marketing of milk -milk in Australia must be pasteurised and homogenised for safety and consumer demand, however, recently consumer trends have shown a slight interest in the non-homgenised milks.

Production Cycles and farm operations to meet market specifications -drenching

-Worms - thrive in warm moist conditions -therefore drenching must be performed in order to decline the worm population in the warmer seasons + to allow cows to not have to exert energy to fight the worm infestations. -This allows the energy to be focused on producing the maximum amount of milk possible.

cation exchange capacity

-a measure of the amount of exchangeable ions that can be held by a clay particle -In general, higher CEC = higher fertility. -OM, climate, pH and form and availability of nutrients affect CEC. -Soils with clay and OM have high CEC.

clay

-a negative surface charge -a large surface area to volume ratio, which makes clay particles highly reactive in the soil - the ability to hold water, which causes them to swell on wetting and shrink on drying, which in turn inluences soil drainage, aeration and water entry -the ability to cement other particles together to form soil peds -the ability to store plant nutrients -a strong tendency to coalesce if worked when too wet, and pulverise to powder if worked when too dry.

gross margins

-a planning tool used to compare enterprises of a similar nature, determined as gross income minus variable costs; gross margins must be expressed in terms of per hectare, per animal, or a similar quantitative measure -Gross margin = total income - variable costs

soil physical properties - structure

-an arrangement of soil particles in the soil -Good soil structure has many aggregates - peds held together by organic colloids providing favourable medium for root growth and vigorous plant growth -Aggregates form pores in the soil, increasing WHC and water and root penetration. -Excessive clearing, cultivation and grazing can destroy soil structure. Poorly structured soils have low porosity and infiltration rates, difficult to cultivate, susceptible to erosion due to unbound particles and experience extreme temperature variation. -Increasing OM through green manuring, mulching and crop rotations can help maintain soil structure.

Vitamin E - fat soluble

-antioxidant -prevents damage occurring to cell membranes -not stored in body -animals deficient - have decreased fertility -deficiency in chickens - results in muscle wasting and poor coordination, causing them to stagger around

CAM plants

-cells store organic materials that CO2 was fixed to their materials until morning -close stomata during day, open during night -Very hot, dry environments -succulents

plant competition

-compete for resources in the environment, such as mineral nutrients, water, space, sunlight and carbon dioxide

Fats

-contain C,H & O -used as a source of energy -contain more than 2.25 times the energy value of carbohydrates -3 essential fatty acids: linoleic, linolenic and arachidonic -Fatty acids - regulate body metabolism -if deficient in fatty acids - animal may grow slowly or develop skin conditions -fats - classified as saturated or unsaturated -saturated fats - no double bonds - found in animal meat and butter -unsaturated fats - one or more double bonds between carbon atoms - found in most vegetable oils, fish oils and is used to make polyunsaturated margarine -plants & seeds contain fats - oil seeds such as linseed oil and peanut oil, have a high fat content & are often fed to animals

Vitamin K - fat soluble

-involved in blood clotting

Integrated pest Management

-is the use of two or more methods to control pests and diseases - an effective and environmentally sensitive approach to pest management -relies on a combination of commonsense practices -may include the judicious use of pesticides -GOAL OF IPM - control pests, not eradicate enter population. -more enviro friendly

protein

-more than 20 amino acids in food proteins - only 9 cannot be synthesised by non-ruminants -Complete protein foods - contain all essential amino acids and have a high biological value e.g.meat -protein needs vary from animal to animal -used to make muscle, tissue, wool and hair -are the main constituent of enzymes, hormones and cell protoplasm in an animals body -especially important for growing animals, pregnant animals and for milk production -Protein in animal products - are complete in amino acid makeup -most plant proteins are incomplete -2 main things that effect protein requirements = age + production level -legumes - increased protein content as they make their own nitrogen -expensive - if you don't need to give animals high amounts of protein, then don't. -excess - isn't stored - broken down in liver to form urea and fatty acids -non-protein nitrogenous foods are sources of nitrogen that ruminants can use, such as urea, usually supplied as buret - usually mixed with molasses when fed to ruminants -High levels of nitrogen are toxic to monogastrics

C3 plants

-on hot days they close their stomata part way -produce little sugar then -cool, wet environments

Production Cycles and farm operations to meet market specifications - vaccinations

-operation that must occur during the start of the year = vaccination of the cattle. -In warm summer months - a higher chance for mosquitoes to spread Ephemeral fever (a viral disease that affects cattle where animals show symptoms for only a few days - known as Three Day Sickness). -This disease can lead to the cows drying up as well as a reduced milk production for those infected.

root nodules on legumes

-peas, white clover and beans -plants with heart-shaped leaves and root nodules -These nodules consist of rhizobium bacteria that convert atmospheric nitrogen into nitrates in the soil. This leads to an increase in nitrogen content in the soil which results in enhanced plant growth, particularly grasses, and accounts for legumes' high protein levels (high protein feed for stock). Legumes can hence be used to improve soil fertility in regard to nitrogen content.

Plant Hormones - gibberellins

-produced in germinating seeds and young stems -effects growth and cell division (flowering, stem growth and breaking seed dormancy) -commercial product is gibberellic acid -applied to stimulate growth and maturation of plants

Plant Hormones - auxins

-produced in germinating seeds, young leaves, meristematic tissue (buds, root tips, cambium layer), developing flowers and fruit -elongates and thickens cells of stem and roots (phototropism) -develops fruit -results in terminal bus dominance -commercail product examples (estercide, amide or indoleacetic acid) -applied to crops when elongating and to stimulate reproductive phase or as a flower preservative

plant hormones - cytokinins

-produced in grown roots, developing seeds and cambial tissue (in stem) -effects cell division and root growth -commercial product is kinetin -used as a flower preservative

plant hormones - ethylene

-produced in young growing tissue, ageing leaves, ripening fruit -promotes ripening of fruit and raging of leaves -commercial product ethylene gas -used to ripen cold store fruits

soil physical properties - texture

-refers to the proportions of sand, silt and clay in soil. -Linked to particle size which influences adhesion and cohesion of soil due to differences in surface area. Influences soil strength, aggregation, tillage, drainage and infiltration. Sandy soils have high water drainage and permeability; it does not hold nutrients. Loam soils have sand silt and clay in proportion; mouldable but not sticky and easiest to cultivate. Clay soils have high WHC due to sheet structure and large SA; swelling and shrinking of clay generates cracks in soil for roots to penetrate. Due to negative charge, clay particles hold onto nutrients.

B vitamins - water soluble

-ruminant animals -able to synthesis vitamins in the B complex by the action of microorganisms in the rumen -several different vitamins within B group -e.g. Thiamine (B1) and Riboflavin (B2)

how farmers can manage plant competition

-selecting the optimum sowing rate to control plant density -using weed control measures, which include cultivation and herbicide use.

Solid degradation - salinisation

-soil salinity can be described as the rising of the level of salts in the soil to such concentrations that they adversely affect the growth of plants. -Two types of salinity - dryland and irrigation.

Nutrition

-study of foods and food needs of animals -The energy, proteins, fibre, minerals, vitamins and water are used to maintain life's functions, allow movement, production and reproduction.

CEC is affected by

-the charge level on the clay mineral -the soil pH -the types of ions located in the double layer -organic matter.

Production Cycles and farm operations to meet market specifications -Feeding Supplements during pregnancy

-the most substantial growth of the calf occurs in the last few months of pregnancy. -means the mothers nutritional needs need to be met at a higher standard to ensure the rapid growth of the calf continues.

native pastures

Although native pasture species are often not as nutritionally rich and palatable as introduced pasture, they are better adapted to the environment and so are better able to provide a source of feed during times of drought.

plant competition - undesirable plants

Any plant that is not the desired crop. Seeds may be carried over by wind from a nearby crop field or by shared machinery.

The practices that have led to salinization

Common table salt or sodium chloride (NaCl) is the main cause of salinity and is derived from three main sources: • ocean salt carried inland and deposited by rainfall • weathering of the minerals in soils and rocks • fossils present in the soil profile Sodium, calcium, magnesium and potassium chlorides occur in some rocks and when land is cleared the watertable rises and brings the salts to the surface. Salinity is a common on irrigated land and is promoted by: • irrigating soils containing soluble salts • irrigating sandy soils with high drainage rates and rising water tables • over-irrigating • irrigating with salty water • irrigating soils with an uneven surface where water accumulates and raises the water table

examples of value-adding

Examples of value adding include: -Creating new products from whole milk (cream, cheese, etc) -Increasing shelf life of perishable goods like milk-making different drinking milks that can be stored for up to a few months and can be stored in the cupboard -Modifying the existing whole milk - skim for consumers wishing to reduce their fat intake -Creating convenience by creating larger packaging for dairy products in order for consumers who use the product regularly to buy the product in bulk

Management strategies used to assess and meet market specifications - farmers and factories working together

Farmers and factory owners also need to work together to meet customer expectations to ensure the demand for their dairy products stays constant and doesn't decline. Drinking milk demands by consumers include: -Ensuring milk is sold in a price range that is practical -Keeping the milk produced at a high quality standard -Sold in various types of drinking milks (skim, lite, etc)

plant competition - weeds

May harbour diseases, contaminate product, attract insects and pests, release toxic chemicals and increase production costs in control methods. Weed seeds may be carried by wind, animals or machinery.

introduced pastures

In contrast, introduced pasture species can provide a more balanced and palatable feed source (eg grasses and legumes) during favourable growing seasons, and are better able to improve the soil nitrogen status.

digestion

breakdown of food particles for absorption by the body

Phases of Growth of a plant - germination

To germinate the seeds: -must be viable and: have water and oxygen, correct temp -it absorbs water and swells: then roots emerge then coleoptile. Then roots from seed (seminal roots). Grown node forms near surface from which grows adventitious roots which are the major roots. After germination, the plants tiller or branch.

Water

Water has many functions in the body. It helps in: -maintenance of bodily fluids -transport of nutrients and in the elimination of waste products -regulation of body temp e.g. sweating -digestion by hydrolysis Animals obtain water mainly by drinking, but also in solid food and from metabolic activity in the body.

Soil Degradation - outcomes of these practices

Without deep-rooted plants to maintain its volume - underground water table rose over the years - this brought to the surface salts from the soil and rendering the land waterlogged or too saline for agriculture production (salt in root zone). -Flood irrigation accelerated the process by increasing the load of water percolating through the soil layers to the water table. -Salt left from the evaporation of the water can be washed away by rain into river systems, polluting the water system.

soil physical properties - porosity

amount of space around mineral grains that can be filled by water or air. These contribute to the soil's water permeability and root growth. Large, visible pores are called macropores. Applying gypsum (calcium sulphate) opens up soil quickly.

how can farmers manage weeds - chemical control

applying a selective herbicide that will only kill the specific weeds is preferable. Effective but is expensive, may kill beneficial plants, contaminate the environment and must be used in conjunction with other methods to avoid building up resistance.

Phases of Growth of a plant -Vegetative

in this phase the seed germinates and the plant becomes established. it continues to produce roots, stems and leaves and is building its capacity to make food in preparation for the next phase.

how can farmers manage weeds - biological control

involves using natural predators and pathogens to control the weed. It is beneficial in that it is selective, has minimal resistance, self-perpetuates and does not contaminate the environment. However, it is not widely available for every problem, does not eradicate the organism (only maintains at a manageable level) and is time and labour expensive.

soil physical properties - bulk density

is the weight of the whole soil, including air and organic matter. Note: particle density is just the weight of sand silt and clay.

how screwed is Hailey for this exam?

less than or equal to 20%

physical characteristics prac

soil texture analysis add handful of dirt add water almost to the tp, shake well, place cylinder down and leave to sit for a couple of days then record layers of dirt at the bottom of cylinder rock at bottom fine particles on top

how can farmers manage weeds - grazing

stock animals will graze the desirable plants, resulting in the growth of larger root systems (plant dies back roots to grow new leaves, plant grows back new roots through the old pathways that are even bigger). This gives the desirable plants a competitive advantage over the weeds and reduces space for weeds to establish.

rations for ruminant and mono gastric animals -roughages

such as hay, silage and pasture have relatively high fibre content which can be digested by ruminants to supply energy. Younger pastures and green forage crops are considered more succulent with a high percentage of water (up to 80%) and less fibre content = less efficient in providing energy

rations for ruminant and mono gastric animals - protein animal products

such as meat meals and buttermilk have a high digestibility and protein content. Protein supplements are often fed to dairy cows to increase protein percentage in milk.

rations for ruminant and mono gastric animals - concentrates

such as wheat, barley, oats and triticale have a high protein and energy content, suitable for meeting energy and protein needs for rapidly growing stock or for stock to put on more muscle.