soil fertility Final exam

soil health

The fitness of a specific kind of soil to function within its surroundings, support plant and animal productivity, maintain or enhance water and air quality, and support human health and habitation

types of soil acidity

residual acidity, exchangeable acidity, active acidity

topographic wetness index TWI

Predicts the spatial distribution of soil water content due to differences in topography across a landscape

sensing for soil pH and lime on the go

direct soil measurement

ENM

effective neutralizing material

Broadcast spreader calibration

effective swath width is where the rate is about 50% of the amount at the center example is 6ft left and 6ft right of center effective swath width is 12ft

permaculture

features of natural regenerative ecosystems and human culture. Focus on use of perennial plants and establishing associations of plants with compatible roots and canopies.

basic carbon saturation ratio

ideal ratios of calcium, Mg, K in soil for plant growth

Biodynamic agriculture

include crop diversification, the avoidance of chemical soil treatments, decentralized production and distribution, and the consideration of celestial and terrestrial influences on biological organisms Use different preparations to aid fertilization and composting with belief that these preparations mediate terrestrial and cosmic forces into the soil.

soil sampling tools

shovel, push probe, screw auger, bucket augers

SALT INDEX (SI)

the ratio of the increase in osmotic pressure of the salt solution produced by a specific fertilizer to the osmotic pressure of the same weight of NaNO3, which is based on a relative value of 100.

sustainable agriculture

the successful management of resources for agriculture to satisfy changing human needs while maintaining or enhancing the quality of the environment and conserving natural resources

Crop growth models

use crop growth simulation models such as a maize N to determine EONR

Tool Fusion

use multiple tools such as a crop growth model to develop initial recommendation and then adjust with canopy reflectance

Maximum return to N (MRTN)

uses hundreds of N fertilizer corn yield response studies to develop an equation for average response. Adjusts equation to include the current fertilizer and grain prices to calculate the N rate that returns the most profit or economically optimal N rate (EONR)

methods of fertilizer injection

• Broadcast • Localized placement or banding - Starter or pop-up - Deep - Surface (before planting) - Side-dressing, top-dressing . (after planting) • Foliar Sprays • Fertigation • Injection • Variable rate application

Soil testing and recommendation programs were developed primarily with research conducted with fertilizer response trials. Briefly discuss what challenges soil testing may have for assisting organic agricultural production.

• Conventional soil testing programs use soil extracting solutions that were developed for fertilizer-based agriculture and may not correlate well with plant growth in organic agricultural systems due to the importance of soil organic nutrient fractions • Do not have well-researched interpretation information for soil tests with organic agricultural systems • Do not have extensive calibration research trials with organic amendments so nutrient recommendations are not well developed for the environmental conditions in the state. • Difficult to predict nutrient availability from manure and other organic amendments and have effects of other nutrients in those amendments.

Discuss three important factors that might affect selection of a manufactured fertilizer.

• Nutrient content • Nutrient availability and chemical reactivity and form - solubility of the product - particle size and form • Cost and availability • Acid, neutral or base-forming • Salt index • Convenience of use (e.g safety, storage, ease of application and purchase)

COMPOST

"the product resulting from the controlled biological decomposition of organic material that has been sanitized through the generation of heat and stabilized to the point that it is beneficial to plant growth"

SQ indicators are

"those soil properties and processes that have the greatest sensitivity to change in soil function"

micronutrients comes from

(Boron, Copper, Iron, Manganese, Molybdenum, Zinc): Liquid or powdered seaweed extract, kelp meal, rock powders, chelates made with natural chelating agents.

secondary minerals come from

(Calcium, Magnesium and Sulfur) Kelp and seaweed extracts and powders; dolomite, gypsum, keiserite, langbeinite, limestone, potassium sulfate and rock phosphate from mined sources; oyster, clam, lobster and crab shells; composts made from a variety of materials.

Fertigation

-Application of fertilizer through an irrigation system. - Allows for less field operations which can be costly - Can assist in plant-nutrient synchrony - Can have less possible leaching losses if managed correctly.

Banding

-Banding is used to localize placement of a liquid or solid fertilizer below the soil near plant roots. - Advantages: reduce losses through precise application of nutrients and may assist with plant immobile nutrients -Disadvantages: slow, expensive (requires specialized equipment.

Sidedress

-Post emergence application of fertilizer generally to the side of the crop row. - Can improve plant-nutrient synchrony - Allows for adjustment of fertilizer application especially during season

common ways to acidify soil are

1. Add ammonium-based fertilizers 2. Add elemental S (flowers of sulfur), iron sulfate or aluminum sulfate 3.Acidifying a calcareous field soil is generally not cost-effective.

Other characteristics of selected soil indicators may include:

1. Correlate well with ecosystem processes 2.Integrate soil physical, chemical, and biological properties and processes 3.Be accessible to many users and applicable to field conditions 4.Sensitive to variations in management and climate 5.When possible, be components of existing databases

Goals of nutrient management

1. Cost effective 2. Efficient (conserve resources) 3. Maintain/enhance soil quality 4. Protect the surrounding environment

DISADVANTAGES OF COVER CROPS

1. Cost of seeding 2. Loss of economic production while the cover crop is growing 3. In Midwest, short cover crop growing season and establishment time constraints 4. Possible lowered soil temperature in spring 5. Depletion of soil water at planting time 6. Possible weed issues associated with cover crop 7. Extra time for management

ORGANIC AGRICULTURE STANDARDS

1. Land should have no prohibited substances applied to it for at least 3 years before the harvest of an organic crop. 2.Crop rotation would be implemented 3.The use of genetic engineering (included in excluded methods), irradiation and sewage sludge is prohibited. 4.Soil fertility and crop nutrients are managed through tillage and cultivation practices, supplemented with animal and crop waste materials and allowed synthetic materials. 5. Preference given to the use of organic seeds and other planting stock, but a farmer could use non-organic seeds and planting stock under certain specified conditions. 6.Crop pests, weeds, and diseases are controlled primarily through management practices including physical, mechanical and biological controls. When these practices are not sufficient, a biological, botanical, or allowed synthetic substance may be used.

NITROGEN MANAGEMENT

1. Non-legume cover crops scavenge, catch or trap N (especially nitrate) that would be lost during fallow periods (e.g., cereal rye, annual ryegrass, oilseed radish). 2. Legume cover crops fix N depending on species, time of growth and other factors. 3. To maximize N availability best to terminate growth at vegetative stages when C:N ratio is low. 4. Cover crop that is terminated early and added to soil for nutrition of subsequent crop is known as a green manure.

BENEFITS OF COVER CROPS

1. Reduce erosion and runoff 2. Improve soil quality (i.e. soil physical, biological and chemical properties) 3. Retain nutrients that would otherwise be lost (e.g. leaching or denitrification) 4. Add N through fixation (leguminous cover crops) 5. Combat weeds 6. Break disease cycles 7. Currently has major institutional support (e.g., NRCS, SARE)

SOIL DEGRADATION AND CLIMATE CHANGE

1. Soil degradation can be accelerated or mitigated by several factors (e.g., climate, soil resilience, landscape factors, management practices). 2. Due to variation in these and socio-economic factors, the impacts of climate change on soil quality will not be uniform across all agricultural regions and are predicted to have more severe implications for food production in food-insecure countries

lime requirement

1. The amount of liming material required to change the soil pH to a specific desired value. 2. based on measurement of salt pH

USAID

1. U.S. Government agency responsible for providing bilateral assistance. 2.t's primary objectives are to further U.S. interests in the world and to improve the quality of life in developing countries. 3. USAID currently supports nine Collaborative Research Support Programs (CRSPs) and Feed the Future Innovation Labs for Collaborative Research in diverse areas such as horticulture, sustainable agriculture, integrated pest management, nutrition, sorghum, millet and peanut production and aquaculture. 4. A major current initiative is Feed The Future (FTF). FTF will address barriers to food security with two objectives: increase agricultural growth and improve nutrition in food insecure nations.

PRACTICES USED IN PRECISION AGRICULTURE

1. Yield monitoring and mapping 2. Grid sampling, sensor-based mapping (e.g., soil ECa) and remote sensing 3. Variablerateapplication - Variable rate fertilizer . . . application - Variable rate lime application - Variable rate herbicide application - Variable rate seeding 4. Variablesourceapplication

instruments of soil fertility evaluation

1. chlorophyll meter 2. penetrometer 3. soil characterization lab

advantages of plant testing

1. directly measures nutrient taken up by plant 2. can detect "hidden hunger" 3. sufficiency levels can be established for each crop 4. nutrient levels in perennial crops can be monitored 5. Availability of quick test kits for plant tissue 6. profits can be increased

CAUSES OF FOOD INSECURITY

1. drought/extreme weather 2.pests, livestock disease, soil erosion, soil infertility, other ag probs 3. land tenure issues 4. military conflict 5.corruption and political instability 6. health issues such as aids 7. rapid population growth

What are some values of plant production

1. food 2. feed 3.fiber 4.fuel 5.other/ defendant on MK

elements of sustainable agriculture

1. long-term productivity and stability 2. economic viability 3.conservation and enhancement of environmental quality 4. improved quality of life 5. socially acceptable

advantages of soil testing

1. measure available plant nutrients contained in soil 2. insufficient or excessive use of fertilizers or manures can be avoided 3. timely testing allows for amending soils in time to improve crop growth 4. Effects of management can be observed overtime 5. profits can be increased

objectives of soil testing

1. provide information on soil characteristics that will affect growth and yield (available plant nutrients) 2.to recommend nutrient amendments when needed to improve soil fertility and profits for growers (fertilizer and lime) 3. to minimize the potential for environment pollution

advantages of liming

1. reduction or elimination of Al+3, Mn+3, and H+ toxicities 2. improved nutrient availability 3. addition of Ca+2 and possible Mg+2 4. increased rates of decomposition, nitrification, and N fixation 5.possible improvements in soil structure 6. can also alter effectiveness of some agro- chemicals and incidence of plant diseases 7. Enhance biodegradation of an organic pollutant or convert a potentially tacit trace element into insoluble form

goals of sampling and processing

1. representation - samples represents a given area or population 2. minimize sample contamination, degradation or other changes from point of collection 3. prepare samples for analysis: uniformity, convenience of operation, storage 4. appropriate turn around time

steps for soil testing

1. soil sampling and processing 2. soil analysis 3. interpretation 4.recommendations and other information (client cropping history) 5. soil test database, extension agents, clients

soil test program steps

1. talk to growers and look at soil resources (type soils that are there, bench mark soils) 2. appropriate extracting solutions for the soils ; ppm or bray test 3. correlation, test relate to plant preformance 4. interprate results

criteria for good soil extracting

1. the extracting should extract all or part of the available form of nutrients in soil variable properties 2. the amount of nutrient extracted should be measured with reasonable accuracy and speed 3. the amount extracted should be correlated with and response of each crop to the nutrient under various conditions

nutrient content of a plant tissue dependent on

1. type of plant sampled 2. plant part sampled 3. stages of growth

limitations of testing for soil and plant tissue testing

1. water availability, plant disease, insect pests 2.soil and plant analysis has limited use if correlated with fertilizer rates and crop yields 3. soil or plant samples may not be representative of area or crop 4. costs and turn-around time may be too great to be useful for growers

N loss%

1.Broadcast without cultivation (20-25%) 2.Broadcast with cultivation (5%) 3. Knifing (5%) 4. Irrigation (30%)

MAJOR MANAGEMENT PRACTICES THAT AFFECT SOIL ORGANIC MATTER

1.Composition and quantity of added organic material 2. Tillage 3. Residue management 4. Fertilization 5. Soil erosion 6. Disposal versus fertilization

CALIBRATION OF APPLICATION EQUIPMENT

1.Determination of the rate of application (amount/unitarea) and the uniformity and pattern of application. 2.Can use tarps or plastic trays (dry product) of known area distributed over the application swath 3.Pass over at known speed and setting and determine amount in each tray. 4.Fertilizer blends may have non-uniform spreading because of different particle sizes of the blended components. Acceptable CV ≤ 20%.

IMPORTANT CHARACTERISTICS OF FERTILIZERS

1.Nutrient content 2.Nutrient availability and chemical reactivity and form -solubility of the product -particle size and form 3. Cost and availability 4. Acid, neutral or base-forming 5. Salt index 6. Convenience of use (e.g safety, storage, ease of application and purchase)

PARTICULATE ORGANIC MATTER TEST

1.Particulate organic matter (POM) fraction refers to all soil organic matter (SOM) particles less than 2 mm and greater than 0.053 mm in size (Cambardella and Elliot, 1992). 2. POM is biologically and chemically active and is part of the labile (easily decomposable) pool of SOM. 3. Possibly the most easily decomposable fraction of nonliving SOM after microbial biomass 4.Sensitive to management especially tillage.

WATER-STABLE AGGREGATES

1.Soil aggregates are groups of soil particles that are bound to each other more strongly than to surrounding soil particles. 2.Structure of surface soil is commonly granular or blocky but a degraded soil can be crusted, platy or structureless. 3. Stable aggregates are important for erosion resistance, water availability and root growth. 4. This method determines the proportion of aggregates (1 - 2 mm in size) which do not break down into smaller units smaller than 250 μm when exposed to water.

forms of fertilizer types

1.Solid, liquid or suspensions 2. Slow release fertilizers 3. Organic chelates versus salts to provide micronutrients 4. Organic versus inorganic sources

sensing for soil pH and lime in the lab

1:1 soil solution measurement

sampling and processing for tilled soil: sampling depth

6-8 inches no till - 2 inches assess nitrogen, go deeper due to mobility

AgLiming

A soil amendment containing calcium carbonate, magnesium carbonate, and other materials used to neutralize soil acidity and furnish calcium and magnesium for plant growth

Precision farming

An information and technology- based farm management system to identify, analyze and manage variability within fields for optimum profitability, sustainability and protection of the land resource also called sites specific farming, prescription farming

law of diminishing return

As the limiting growth factor (e.g. plant nutrients) is added in units of equal size, then each increment of yield response is smaller than the preceding increment.

costs of plant production

labor land ag machines fuel seed herbicide and pesticides cost of nutrient input

Consultative Group on International Agricultural Research

CGIAR

phosphorus comes from

Composted manures high in phosphorus (poultry, guano); colloidal, soft and hard rock phosphate; mycorrhizae to activate rock phosphate.

forms of limestone

Conventional aglime Pelletized limestone Fluid lime = very fine lime mixed with water for nitrogen and a suspending agent

COVER CROPS

Cover crops are non-commodity crops that are either inter-seeded into living cash crops or planted onto bare fields during fallow periods. Some considerations are species selection, use of multispecies mixtures, optimizing the planting and/or kill date, use for forage and tillage system.

potassium comes from

Cover crops that activate potassium; mined granite, greensand, basalt, feldspar, langbeinite and potassium sulfate.

Missouri system is based on determination of the ENM needed to reach a target pH and the ENM needed to reach a target pH and the ENM contained in the liming material as affected by its quality

ENM is a measure of the amount of calcium equivalents per acre

advantages of pelletized lime

Ease of application Reduced dust during application Can mix the pelletized lime with fertilizers and other soil amendments.

effectiveness of liming + CCE + fineness factor =

Effective calcium carbonate (ECC)

nitrogen comes from

Green manures and leguminous cover crops; composted animal manures; bacterial inoculants for soil, legumes and compost; soy, cottonseed and vegetable meal; blood, fish or feather meal; and foliar sprays in conjunction with a soil building program.

VALUE OF SOIL HEALTH/QUALITY CONCEPT

Integrates the physical, chemical and biological components and processes of soil interconnected with landscapes Based on the capacity of a soil to support a particular function (e.g., as a medium for plant growth, as physical support for buildings and roads) Helps the public to understand the value of soils similar to water and air resources. The concept may also be important to determine the sustainability of an agroecosystem.

Conservation Farming

Minimum mechanical soil disturbance (e.g., conservation tillage and direct seeding) Permanent organic soil cover(e.g., residues, cover crops) Diversification of crop species grown in sequences and/or associations (e.g., crop

critics of soil quality concept

Quality of soil management rather than soil quality management should be goal of soil science Development of soil quality index is too subjective and value-laden and not sufficiently "scientific". Soil quality concept cannot be related to air and water quality concepts since soil does not exist in a pure state. Research on soil quality has been biased towards the temperate zones since in the tropics the overarching concerns are food insecurity, rural poverty and ecosystem degradation

IntheUnitedStatesfocusofresearchon management practices for increasing soil quality have included:

Reducing tillage intensity Increasing soil organic matter Use of cover crops or improved fallow periods Crop rotation Agroforestry systems Organic systems Soil conservation

soil acidification

Some plants grow better at low pH (e.g. azaleas, blueberries, rhododendron). Also lower pH may be desirable for disease control (e.g. potatoes)

developing countries

countries that have not achieved a significant degree of industrialization relative to their populations, and have, in most cases, a medium to low standard of living. Other terms are less developed countries (LDCs), least economically developed countries (LEDCs), "underdeveloped nations" or Third World nations, and "non-industrialized nations".

field methods of soil analysis

Visible and Near Infrared Spectrometry

Calcium carbonate equivalence (CCE) is a measure of the quantity of acid that a material can neutralize relative to pure CaCO3.

a measure of the quantity of acid that a material can neutralize relative to pure CaCO3. Can be calculated or measured in the laboratory using an acid titration Aglime materials in Missouri are required to have a minimum CCE of 65%

Build-up and maintenance

add extra fertilizer to replace and build-up soil fertility

pre-plant or pre-sidedress nitrate tests

adjusts yield-goal recommendations based on soil nitrate testing

Canopy reflectance sensors

assesses the size and color of plants to calculate N fertilizer rates

Yield goal based systems

based on yield goal and crop requirement. Adjusted for soil organic matter and other factors

sufficiency level of available nutrients

measurable levels of each soil nutrient below which a nutrient response to add fertilizer is likely

fineness factor

measure of the effectiveness of a liming material due to particle size distribution Aglime materials in Missouri must have a minimum of 90% by weight of particles passing a 8-mesh sieve.

developed countries

most economically developed countries (MEDCs), First World nations and "industrialized nations".

soil quality vs soil health

refers to the capacity of a soil to perform a specific desired ecosystem function, refers to the state of the whole soil system and its ecological attributes