U100_E_토양검정

 토양검정(Soil Test Interpretation Guide)

 

U100_008_Soil Test Interpretation Guide 복사방지된 파일임.

 

E.S.Marx, J. Hart, and R.G Stevens

 

Regular soil testing is an important element in nutrient management. You can use soil tests as a diagnostic tool or to identify trends through time. To obtain meaningful test results, you must sample soil correctly, at the same time each year, and you must maintain records. For more information see EC628, How to take a soil sample… and why(see “For more information,” page 7)

Soil testing laboratories use different test methods, which may influence results and sufficiency ranges. Therefore, the sufficiency ranges in this publication are accurate only for the test methods listed.

Soil tests used to evaluate fertility measure the soil nutrients that are expected to become plant-available. They do not measure total amounts of nutrients in the soil. Measurements of total nutrient content are not useful indicators of sufficiency for plant growth, because only a small portion of the nutrients are plant-available.

적당한 토양 양분 수준은 식물의 종류에 따라 다르다. 유사하게 영양과잉, 양분 불균형 또는 적정량 보다 적은 양분 조건에 대한 식물 내성도 다르다. 만약 양분 과잉상태라면, 원인을 찾기 위해 관리상태를 되돌아 보아야 한다.

양분 농도는 토심에 따라 변한다. 그러므로 시료채취의 깊이는 결과에 영향을 준다. 적당한 시료채취 깊이를 결정하기 위해서는 반드시 토양 검정의 목적을 생각해야 한다. 식물을 재식하기 전 양분의 가용성을 추정하기 위해서는 대부분의 뿌리활동이 일어나는 깊이의 토양을 채취한다. 영년생 작물에 있어 때로는 비료가 토양 표면에 뿌려지는 낮은 토심의 토양을 채취하는 것이 표면 조건을 평가하기 위해 사용된다. 깊은 토심의 시료를 채취하는 것도 과수원에서 문제를 진단하기 위해 필요할 수도 있다. 

Soil test values do not vary greatly from year to year. 측정값의 큰 변화는 토양샘플의 대표성이 없거나(시료를 잘못 채취) 또는 실험실의 실수를 나타낼 수 있다. 의심이 갈 때는 다시 분석하기 위해 새로운 샘플을 채취하여 실험실(기술센타)에 의뢰한다.

This publication provides general guidelines for interpreting soil test results. Fertilizer guides for many individual crops are available from your county office of the OSU Extension Service or Washington State University Cooperative Extension, or from Extension and Experiment Station Communications, Oregon State University(see ”For more information”)

 

Nitrogen(N)

 

식물이 이용 가능한 질소(Plant Available Nitrogen : Nitrate and Ammonium)

 

식물이 이용가능한 질소는 질산(NO3-)과 암모늄(NH4+)이다. NO3- 와 NH4+의 토양 농도는 생물학적인 활동에 따라 다르므로, 온도, 습기와 같은 조건 변화에 따라 변동한다. 질산은 비가 많거나, 관수량이 많으면 쉽게 토양으로 부터 유실된다. 토양검정은 샘플링 시점의 NO3-와  NH4+의 농도를 알 수 있지만, 미래의 조건을 반영하지는 않는다.

질소검사를 위해 시료를 모을 때는 NO3-와  NH4+의 농도의 변화를 방지하기 위해 차게 하거나 즉시 말려야 한다.

 

Ammonium-Nitrogen(NH4+-N)

 

Ammonium-Nitrogen does not accululate in the soil, as soil temperature and moisture conditions suitable for plant growth also are ideal for conversion of NH4+-N to NO3—N. Ammonium-nitrogen concentrations of 2-10ppm are typical. Soil NH4+-N levels above 10ppm may occur in cold or extremely wet soil, or if the soil contains fertilizer residue.

 

Nitrate-Nitrogen(NO3—N)

 

West of the Cascades. 토양질산태 질소의 측정은 질소관리를 평가하기 위한 수확 후 "결과물"로서 아주 유용하다. 수확 후 토양에 남은 질산태 질소는 겨울 동안 강우로 유실될 수 있으며, 지면 및 지하수를 오염시킨다. 잔류 질산 수준이 지속적으로 높다면, 다음해에는 질소 시비량을 줄인다.

 

Table 1. 질소 관리를 평가하기 위한 토양 잔류 질산태 질소

 

	NO3—N in surface foot(ppm)*
낮음	<10ppm
중간	10-20
높음	20-30
과다	>30

 

Mid season measurement of soil nitrate is used for field corn production. See EM8650, The Pre-sidedress Soil Nitrate Test(PSNT) for Western Oregon and Western Washington, for more information.

 

East of Cascades. 건조한 지역에서 토양 질산은 키울 작물의 기대하는 근군 깊이의 NO3-N을 측정함에 의해 평가할 수 있다. 만약 결과가 ppm으로 표시되면, Table 13을 이용하여 lb/acre로 환산된다.[Table 13] 그런 다음, 시비량을 결정하기 위해서는 필요량에서 토양질산을 빼면 된다. 

토양속의 질산을 잘못 계산하면 질소 시비량이 과다 할 수 있다. 또한 관수용 물도 NO3-함량을 분석해야 하며, 결과에 따라 시비량을 줄여야 한다. 적절한 관수는 질소효율을 증가시키고 질산의 유실을 감소시킨다.

 

Total Nitrogen

 

Total nitrogen analysis measure N in all organic and inorganic forms. Total nitrogen does not indicate plant-available N, and is not included in standard soil testing programs.

A Typical agricultural slil in the Willamette Valley contains about 0.10 to 0.15% N, or approximately 5,000lb N/acre in the surface foot. only 1-4% of this total N becomes plant-available during a growing season. East of the Cascades, soils tend to have smaller amounts of total N.

Total N analysis, while not recommended as part of a standard soil testing program, may be better than organic matter analysis for estimating soil N supplying capability.

 

Phosphorous(P)

 

The Bray P1(for acid soils) and the Olsen sodium bicarbonate(NaHCO3)(for alkaline soils) tests estimate plant-available phosphorous. Soil testing laboratories also use several other extraction methods. For interpretation of results from other extraction methods, contact the laboratory that performed the analysis.

Phosphorous soil tests are an index of P availability. The test values cannot be used to calculate available lb P2O4/acre.

When sampling soil, you must be aware of previous P management. Phosphorous is relatively immobile in soil. If phosphorous has been applied in a fertilizer band, concentrations of P may persist where the band was placed. Avoid fertilizer bands when collecting soil samples.

 

Table 2. Phosphorous soil test.

 

	West of Cascades(Bray P1 test)  ppm P	East of Cascades(Olsen test)  ppm P
Low	<20	<10
Medium	20-40	10-20
High	40-100	20-40
Excessive	>100	>40

 

The phosphorous application rate necessary to correct P deficiencies varies depending on soil properties. Phosphorous availability decreases in col., wet soils, In many situations, banded phosphorous applications are more effective than broadcast applications.

Phosphorous applications generally are not recommended if tests are high or excessive. High soil phosphorous combined with surface runoff can cause excessive growth of plants and algae(조류) in surface waters, damaging aquatic ecosystems.

 

Cations

 

Of the three primary cations(potassium, calcium, and magnesium), potassium requires the most management attention. Few crops have responded to calcium and magnesium in the Pacific Northwest.

If extremely high levels of a single cation exist, plant deficiencies of other cations may occur due to competition for plant uptake.

The soil test ranges in Table 3, 4, and 5 are for the ammonium acetate extraction method. If a sodium bicarbonate(NaHCO3) extraction is used, test values may be slightly lower.

 

Potassium(K)

 

Excessive soil potassium levels can result in elevated K levels in grass forage crops, which may be detrimental to animal health.

 

Table 3 Extractable potassium(K)

	K
Low	<150ppm*	<0.4meq/100g soil
Medium	150-250ppm	0.4-0.6 meq/100g soil
High	>2000ppm	>0.6-2.0 meq/100g soil
excessive	>800 ppm	>2.0 meq/100g soil

* See table 13 for conversions from ppm to meq/100g soil.

 

Calcium(Ca)

 

Ca deficiencies usually are found only on very acid soils. They can be corrected by liming with calcium carbonate(CaCO3)

 

Table 4 Extractable calcium(Ca)

 

	Mg
Low	<1000ppm*	<5 meq/100g soil
Medium	1000-2000ppm	5-10 meq/100g soil
High	>2000ppm	>10 meq/100g soil

* See table 13 for conversions from ppm to meq/100g soil.

 

Magnesium(Mg)

 

Mg deficiencies on acid soils can be corrected by liming with dolomitic lime. Mg toxicity can occur on serpentine soils in southwest Oregon.

 

Table 5 Extractable Magnesium(Mg)

 

	Mg
Low	<60ppm*,	<0.5 meq/100g soil
Medium	60-180ppm,	0.5-1.5 meq/100g soil
High	>180ppm,	>1.5 meq/100g soil

* See table 13 for conversions from ppm to meq/100g soil.

 

Sulfate-sulfur(SO4---S)

 

식물은 황(SO4-)의 형태로 흡수한다. 비가 많이 오는 지역은 황이 쉽게 유실되며, 토양검정 데이타는 식물 성장과 잘 연계되지 못한다. Cascades 동쪽 건조지에서는 토양검정 결과가 아주 유용할 수 있다. 또한 관수되는 물도 황산형태의 황을 상당량 포함할 수 있다. 식물 분석은 종종 황의 부족증상을 진단하는데 유용하다.

 

Table 6 Sulfate sulfur, east of the Cascades.

 

	SO4-2-S ppm
Low	<2
Medium	2-10
High	>10

 

Micronutrients

 

붕소와 아연 이외의 미량성분 부족은 흔치 않다. 모든 미량 성분의 가용성은 pH에 크게 의존하고, 가용성은 pH가 증가함에 따라 감소한다.(몰리브덴은 예외인데, 이것은 pH가 증가하면 가용성이 증가한다.) 부족은 pH가 6.5 이하인 토양에서는 거의 일어나지 않는다.

붕소와 아연을 제외한 미량성분에 대한 토양 검정은 부족이 의심될 때에만 권장된다. 만약 미량 성분 부족이 의심되면, 토양 검정보다 조직검사가 좋은 진단 도구가 될 수 있다.

 

Boron(B)

 

Crops such as alfalfa, table beets, brassicas, caneberries, and root crops have responded to boron fertilization on B-deficient soils in western Oregon. Tree fruits and alfalfa are examples of crops sensitive to lo boron levels east of the Cascades.

While low levels of boron may limit plant growth, high concentrations can be toxic. When applying boron, apply uniformly and mix thoroughly with the soil.

 

Table 7 Boron by the hot water extraction method.

 

	B(ppm)
Low	<0.5
Medium	0.5-2
High	>2

 

Zinc(Zn)

 

Zinc values above 1.0 ppm using the DTPA extraction method are sufficient. Zinc deficiencies have been identified in some crops in certain regions. Corn, beans, grapes, hops, onions, and deciduous fruit trees are especially sensitive to low levels of available zinc. Deficiencies sometimes are associated with high soil P concentrations, soils high in fine clay and silt, or soils with high pH.

 

Copper(Cu)

 

Copper values above 0.6ppm using the DTPA extraction method are sufficient. Copper deficiencies are uncommon. Deficiencies have been identified on muck soils such as those in the Klamath area in Oregon and the Colville area in Washington.

 

Manganese(Mn)

 

Manganese values above 1.5 ppm using the DTPA extraction method are sufficient. Manganese deficiencies generally occur only in soils with pH 7.0 or above. Manganese toxicity may occur on acid soils. on alkaline soils east of the Cascades, Mn availability may increase in acidified microzones where fertilizers have been placed. These acidified microzones can alleviate Mn deficiencies sometimes encountered on high pH soils. In some instances, however, acidic microzones can result in Mn toxicity.

 

Iron(Fe)

 

철에 대한 토양 분석은 권장되지 않는다. 대부분의 테스트 방법은 철의 형태를 분별할 수 없으며, 그래서 식물 영양적인 면에서는 거의 의미가 없다. 철 결핍은 산성토양에서는 흔치 않다.

부족증상이 발생되면, 이들은 흔히 진달래 또는 진달래속의 나무 같은 산성식물이 적합하지 않은  높은 pH에서 자라는 것과 연관되어 있다. 황산암모늄(유안)같은 산성 비료도 문제를 해결하는데 도움이 될 수 있다.

알칼리 토양에 철을 시비하는 것은 킬레이트 형태를 사용하지 않는 한 비효율적이다. 포도원 전체에 대해 철의 가용성을 증가시키기 위해 pH를 낮추는 것은 경제적이지 않다. 그러나, 비료에 황같은 산성 물질을 첨가하는 것은 비료 물질이 있는 주변의 좁은 구역을 산성화시킬 수 있고, 철의 가용성을 높일 수 있다.

가끔 철의 엽면 시비도 과일, 잔디, 또는 다른 고가의 작물에 있어 부족을 교정하기 위해 사용된다.

 

Molybdenum(Mo)

 

Soil Mo concentrations are too low for most labs to evaluate. Molybdenum deficiencies are rare, and are of concern mostly for leguminous crops. Molybdenum-deficient legumes appear chlorotic. Liming to raise soil pH may alleviate deficiencies. Molybdenum-coated seed also can be used.

Excessive molybdenum in forage can harm animal health. If you suspect excessive molybdenum in your forage(마초, 사료용 풀), determine Mo content by forage analysis.

 

Chloride(Cl-)

 

Soil testing for chloride is not a common practice, and little data exists for interpretation of test results. Evidence indicates that wheat sometimes benefits from chloride applications. The Value in Table 8 are based on wheat research in Montana and South Dakota. Little informations exists on chloride soil testing in Washington and Oregon.

 

Table 8 Chloride soil test ranges for wheat in Montana and South Dakota, 2 foot sampling depth.

 

	ppm	lb/acre
Low	0-4	0-32
Medium	4-8	32-64
High	>8	>64

 

PH, lime requirement(LR)

 

Soil pH is a measure of soil acidity. Most crops grow best if the soil pH is between 6.0-7.5.

 

Table 9 Soil pH ranges.

 

	pH
Strongly acid	below 5.1
Moderately acid	5.2-6.0
Slightly acid	6.1-6.5
Neutral	6.6-7.3
Moderately alkaline	7.4-8.4
Strongly alkaline	above 8.5

 

Soil pH can be increased by liming. The soil pH test indicates if lime is needed. The lime requirement test determines how much lime is needed. Accurate lime recommendations cannot be made without performing an SMP or similar test.

 

SMP¹* lime requirement test.

 

The SMP lime requirement test is used to estimate the amount of lime required to raise the pH of 6 inches of soil. The SMP test is performed by mixing soil with a buffered pH 7.5 solution and determining the pH of the mixture. During the reaction, the soil’s reserve acidity lowers the pH of the SMP solution. Soils with low SMP values have high reserve acidity and high lime requirements.

Some soils may have a low pH(<5.3) and a fairly high SMP buffer value(>6.2). This condition can be caused by the application of fertilizer. In this case, the low pH value is temporary, and the pH of the soil will increase as the fertilizer completes its reaction with the soil.

Sandy soils also may have a low pH and high SMP buffer value. This condition occurs because sandy soils have low amounts of reserve acidity due to low cation exchange capacity(CEC). In such cases, a light application of lime(1-2t/a) should suffice to neutralize soil acidity.

Table 10 is used to determine the amount of lime required, based on the SMP test, to raise soil pH to a desired level. The target pH is determined by the crop to be grown and possibly by other factors.

Without an SMP or similar test, there is no way to know how much lime is required to adjust soil pH to a desired level. Accurate lime recommendations cannot be made solely on the basis of soil pH.

 

Table 10 SMP lime requirement-field scale.

 

SMP Buffer	Tons/acre of 100-score lime needed to raise pH of 6inches of soil to the following pH’s
	5.3	5.6	6.0	6.4
6.7	-	-	-	-
6.6	-	-	-	1.1
6.5	-	-	1.0	1.7
6.4	-	-	1.1	2.2
6.3	-	-	1.5	2.7
6.2	-	1.0	2.0	3.2
6.1	-	1.4	2.4	3.7
6.0	1.0	1.7	2.9	4.2
5.9	1.4	2.1	3.3	4.7
5.8	1.7	2.5	3.7	5.3
5.7	2.0	2.8	4.2	5.8
5.6	2.3	3.2	4.6	6.3
5.5	2.6	3.6	5.1	6.8
5.4	2.9	3.9	5.5	7.3
5.3	3.2	4.3	6.0	7.8
5.2	3.6	4.7	6.4	8.3
5.2	3.9	5.0	6.9	8.9
5.0	4.2	5.4	7.3	9.4
4.9	4.5	5.8	7.7	9.9
4.8	4.8	6.2	8.2	10.4

 

Table 11 SMP lime requirement-gardens.

If the SMP lime requirement test is	Apply this amount of lime(lb/1,000ft2)
5.4 or below	250
5.5-6.0	150-250
6.0-6.5	100-150
above 6.5	0

Some plants, such as blueberries, rhododendrons,azaleas, and cranberries, grow best in acid soils. Fertilizers such as ammonium sulfate can help maintain acidic conditions.

 

Sodium(Na)

 

Sodium is not a plant nutrient and therefore is not necessary for plant growth. High levels of sodium are detrimental to soil tilth and plant growth.

Sodium levels are evaluated based on Exchangeable Sodium Percentage(ESP). The ESP is the percent of the cation exchange capacity(CEC) occupied by Na.

ESP values above 10% are of concern. Excessive sodium levels can occur naturally or can result from irrigation with high-sodium water. Reclamation involves establishment of drainage followed by gypsum application and leaching with low-sodium water.

 

Soluble Salts(SS)

 

Soluble salt problems usually are associated with arid regions such as eastern Oregon and Washington. Soils with high levels of soluble salts are called saline soils. Soils high in sodium are called sodic soils(see “Sodium”). Saline-sodic soils are high in both soluble salts and sodium. Soluble salts are measured by electrical conductivity(EC) of a saturated paste soil extract.

 

Table 12 Soluble salts.

 

	전도도(mmhos/cm*)	ppm salt**
Low	<1.0	<640
Medium	1.0-2.0	640-1,280
High	>2.0	>1,280

* mmhos/cm is equivalent to decisiemen/m

** Multiply mmhos/cm by 640 to estimate ppm salt.

 

Because salts move readily with water, salt problems often are transient. Salt toxicity can occur, and salts may leach before soil is tested. Low salt values, therefore, do not always rule out salt toxicity as a cause of problems.

Salt tolerance varies greatly among plant species. Seedlings are especially sensitive to high salt concentration. Excessive fertilization and poor irrigation water quality are sources of salts.

 

Organic Matter

 

Maintenance of soil organic matter is one of the most important goals of soil management. Accurate measurement of soil organic matter is difficult.

Many laboratory methods are used. Most methods are indirect ; they measure soil carbon and make an assumption about the percent carbon content of organic matter. The Walkley-Black method is common and gives consistent results. The loss on ignition method can give inconsistent results and tends to overestimate organic matter.

When estimating potential nitrogen release of a soil, total N testing is preferred to organic matter determination. Neither approach provides accurate estimates of soil N availability. If you are monitoring changes in organic matter over time, use the same lab for all analysis.

 

Cation Exchange Capacity(CEC)

 

CEC is a measure of a soil’s capacity to retain and release elements such as K, Ca, Mg, and Na. Soils with high clay or organic matter content tend to have a high CEC. Sandy soils have a low CEC. Soil CEC is relatively constant over time, so there is no need for repeated analysis.

CEC often is determined by the ammonium acetate(NH4OAc) or sodium acetate(NaOAc) method. While these methods are standard in many regions, there are potential sources of error. Errors are most likely to occur for soils containing appreciable amounts of CaCO3 or gypsum.

Some labs estimate CEC based on soil texture, organic matter content, cations, and pH. Such estimates often are inaccurate. The “sum of bases” method for calculating CEC of alkaline soils can give inaccurate results, especially if there are significant amounts of free CaCO3.

CEC determination can be important for predicting behavior of pesticides and other chemicals in soils.

 

Base saturation

 

Base saturation is the percentage of the CEC that is occupied by cations other than hydrogen(H) and aluminium(Al). Soils with low base saturation generally are acidic. Base saturation and pH increase together.

 

Table 13. Conversions

 

열1을 열2로: 나눔	열 1	열 2	열2를 열1로 : 곱함
390	ppm K	meq K/100g soil	390
200	ppm Ca	meq Ca/100g soil	200
121	ppm Mg	meq Mg/100g soil	121
230	ppm Na	meq Na/100g soil	230
1	meq/100g soil	cmol/kg soil	1
2*	lb/acre(7 inch depth)	ppm	2*
3.65*	lb/acre(1 foot depth)	ppm	3.65*
43.56	lb/acre	lb/1,000 sq ft	43.56
43,560	square feet	acres	43,560
2.471	acres	hectares	2.471

 

[U100_001] Oregon Univ.

1. * : stands for Shoemaker, MacLean, and Pratt-the people who developed the test. [본문으로]

U100_008_Soil Test Interpretation Guide -NH4, NO3 함량 .pdf

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