Fertilizer Requirements

8/12/2019 Fertilizer Requirements

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IA GUIDE TO FERTILIZER RECOMMENDATION FOR MAJOR CROPS

TABLE OF CONTENTS

Preface

1. Background to fertilizer recommendations 1

1.1. Nutrient elements 1

2. Soils of Bhutan 2

2.1. Soil nutrient status classes 2

3. Recommended fertilizers 3

3.1. Commonly aailable fertilizers 3

3.1.1. Recommended fertilizers 3

3.1.2. Other fertilizers 3

3.2. Fertilizer protability 3 3.3. Nutrient contents of fertilizers 3

3.4. Timing/method of application 4

3.4.1. Basal dressing 4

3.4.2. Top-dressing 4

3.4.3. Split application 4

3.5. Balanced fertilizer use 4

3.5.1. Nutrient uptake and remoal by major crops 5

3.5.2. Practical guidelines for effectie fertilizer use 5

4. Fertilizer rate calculations 6 4.1. The best way to calculate fertilizer rate 6

4.2. The easy way to calculate fertilizer rate 6

4.3. The easiest way to calculate fertilizer rate 7

4.4. FYM/compost rate calculation 8

5. Fertilizer recommendations 9

5.1. Fertilizer recommendations for rice (Oryza satia L.) 9

5.2. Fertilizer recommendations for wheat (Triticum aestium L.) 10

5.3. Fertilizer recommendations for maize (Zea mays L.) 11

5.4. Fertilizer recommendations for potato (Solanum tuberosum L.) 12 5.5. Fertilizer recommendations for chilli (Capsicum annum L.) 13

5.6. Fertilizer recommendations for other egetables 14

5.7. Fertilizer recommendations for citrus (Citrus reticulata) 15

5.8. Fertilizer recommendations for apple (Malus domestica) 16

5.9. Fertilizer recommendations for areca-nut (Areca catechu) 16

6. Glossary of terms 18

7. References 19

ANNUAL FERTILIZER_2.indd 1 1/15/2009 11:01:52 PM


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IIIA GUIDE TO FERTILIZER RECOMMENDATION FOR MAJOR CROPS

PREFACE

The Fertilizer Recommendation Guide for Important Crops has been prepared by the

National Soil Serices Centre (NSSC) with the intention to proide some general guid-

ance to the Etension Agents, Farmers, Researchers and others on the type and rateof fertilizer to be used on arious crops.

The National Soil Serices Centre (NSSC) conducted numerous Farmer-Etension Fer-

tilizer Use Trials (FEFUT) in different Dzongkhags during the Sustainable Soil Fertility

and Plant Nutrition Management (SSF&PNM) Project, which was funded by the Dutch

Goernment between 1996 and 2001. After the end of the Project, the Soil Fertility

and Plant Nutrition Management Unit (SF&PNM) of the Centre continued with the on-

farm trials together with on-station trials in collaboration with the Dzongkhag staff

and research centres, respectiely. The trials conducted were mainly on important

eld crops.

The results of these trials hae been used as the basis for the fertilizer recom-

mendations presented here. For those crops and places for which trials hae not

been conducted in recent times, the fertilizer recommendations deeloped by the

Department of Agriculture from the results of the FAO Fertilizer Project trials that

were conducted between 1986 and 1989 hae been used with slight modications.

The modications reect the soil analysis results of the many soils samples collected

across the country from arious farming systems and the nutrient uptake and re-

moal by aerage yields of the crops in the concerned Dzongkhag. The publicationscited under References were also consulted.

Please note that the fertilizer recommendations gien here are the best estimates

aailable but are still general recommendations for the Dzongkhags. The optimum

recommendations for specic locations can be made only after soil sampling and

soil analysis at the Soil and Plant Analytical Laboratory (SPAL) at NSSC. This is most

important, especially for cash crops, for maimising sustainable yields and prot.

Therefore soil sampling and analysis are strongly recommended for more crop- and

site- specic fertilizer recommendations.



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IV A GUIDE TO FERTILIZER RECOMMENDATION FOR MAJOR CROPS



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1A GUIDE TO FERTILIZER RECOMMENDATION FOR MAJOR CROPS

1

BACKGROUND TO FERTILIZER RECOMMENDATIONS

1.1. Nutrient elements

Crop growth is inuenced by a number of factors of which plant nutrient aailability

is one important factor. There are 16 nutrient elements considered essential for

plant growth.

Essential elements are usually categorised into three groups as shown in the follow-

ing table.

Table 1. Essential plant nutrient

PRIMARY NUTRIENTS SECONDARY NUTRIENTS MICRONUTRIENTS

Carbon (C)

Hydrogen (H)

Oygen (O)

Nitrogen (N)

Phosphorus (P)

Potassium (K)

Calcium (Ca)

Magnesium (Mg)

Sulphur (S)

Iron (Fe)

Zinc (Zn)

Copper (Cu)

Boron (B)Molybdenum (Mo)

Chlorine (Cl)

Manganese (Mn)

Primary nutrients are reuired in larger uantities;

Secondary nutrients are needed in lesser amounts than primary nutrients; and

Micronutrients are reuired in small uantities.

Carbon, hydrogen and oygen are obtained from air and water while the other

thirteen elements are referred to as fertilizer elements and hae to be obtained

from the soil.

An essential plant nutrient element has the following characteristics:

It plays a specic role in the plant growth and deelopment;

In its absence, the completion of the life cycle of the plant cannot be

achieed;

If decient, it causes a setback to plant growth, and the plant shows isual

symptoms of the deciency.



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2 A GUIDE TO FERTILIZER RECOMMENDATION FOR MAJOR CROPS

2SOILS OF BHUTAN

The soils of Bhutan ary in teture as shown below for selected Dzongkhags in the

different regions:

Table 2. Soils of Bhutan

REGION/DZONGKHAG SOIL TExTURE

West:

Haa, Paro, Thimphu Mostly loam to clay loam

West Central Region:

Punakha, Wangdiphodrang Mostly loam to clay loam

East Central:

Bumthang Mostly Sandy clay

East:

Monggar, Pemagatshel,

Samdrupjongkhar, Trashigang Mostly silty clay loam, loam and clay loam

South:

Samtse, Serpang, Tsirang Mostly Sandy loam to loam

2.1. Soil nutrient status classes

The overall soil nutrient status or chemical properties of the soils in Bhutan:

The pH of the soils is within the low to medium range.

The echangeable Al saturation percentage is low to ery low indicating no

aluminium toicity.

The organic matter content is moderate.The C:N ratio is good with alues within the range of 11 to 14.1, typical for

agricultural soils.

Phosphate and potassium contents are low in most soils. Howeer phosphate

deciency is considered more seere in Bhutanese soils as the underlying geol-

ogy is rich in potassium.

The percent base saturation (BS%) are low or ery low in most soils, indicating

less fertile soils.

The cation echange capacity (CEC) is low in most soils indicating low content

of elements such as Ca and Mg in the soils.



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3RECOMMENDED FERTILIZERS

3.1. Commonly available fertilizers

3.1.1. Recommended fertilizers

Urea (46% nitrogen N);

Single super phosphate (SSP) (16% phosphorus P2O

5);

Triple super phosphate (TSP) (46% phosphorus P2O

5);

Muriate of potash (MoP) (60% potassium K2O);

These are all simple fertilizers (containing only one primary nutrient). By using the

correct amounts of all three in combination, the eact primary nutrient reuire-

ments of any crop can be applied.

3.1.2. Other fertilizers

Other fertilizers are available and are effective but have some disadvantages.

CAN (Calcium ammonium nitrate 26% N): does not store well and has a high costper kg N nutrient;

Suphala (15:15:15 N: P2O

5: K

2O) is a compound fertilizer (containing more than

one nutrient) that contains N, P2O

5, K

2O in eual uantities. Crops usually need

most N and least K2O and so Suphala must be used with the recommended fertil-

izers to meet the crop nutrient reuirements and to not use too much P2O

5&

K2O. The solubility of the phosphate form is low in comparison to SSP.

3.2. Fertilizer profitability

The results of numerous FarmerEtension Fertilizer Use Trials (FEFUT) conducted

indicate that it is usually more economical to use combinations of single nutrient

fertilizers (e.g. Urea, SSP and MOP) than to use a compound fertilizer (e.g. Suphala)

supplemented with single nitrogen fertilizers in any crop.

3.3. Nutrient contents of fertilizers

The nutrient concentration or content of a bag of fertilizer differs between fertilizers. It

is written as a gure (%), which indicates the kg of the nutrient in 100 kg of fertilizer.



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FERTILIZER N P2O

5 K

2O FERTILIZER N P

2O

5 K

2O

Urea 46 0 0 MoP 0 0 60

SSP 0 16 0 Suphala 15 15 15

TSP 0 46 0

3.4. Timing/method of application

Three main terms are used to indicate the time to apply fertilizer.

3.4.1. Basal dressing

Application of fertilizer or manure at or before sowing or planting the crops. Slow nutri-

ent releasing fertilizers such as SSP, MoP and Suphala are best applied as basal dressing.

3.4.2. Top-dressing

Application of fertilizer or manure when the crop is standing in the eld. Fast dissol-

ing fertilizers such as urea are best applied by top-dressing.

3.4.3. Split application

Application of fertilizer or manure in split doses at different stages of crop growth toaoid nutrient losses through leaching or olatilisation. Urea is best applied in splits

especially in light tetured soils and in areas with high rainfall, because it is ery

soluble and does not stay in the rooting zone.

3.5. Balanced fertilizer use

This is the most important principle when applying fertilizers to crops, in order

to ensure sustainable soil fertility and crop yields. It means the application of

fertilizers and manures to supply all the essential plant nutrients (primary, sec-ondary and micro), which the soil cannot proide in the amounts reuired for

optimum crop growth and yield. Without balanced fertilizer applications, soil

nutrient mining can take place due to the remoal of soil nutrients through plant

uptake. Soil fertility status declines rapidly resulting in the reduced crop growth

and yield.



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3.5.1. Nutrient uptake and removal by major crops

Nutrients taken up and remoed by crops in the harested product and the by-prod-

ucts should be replaced with eternal inputs (fertilizers, manures, etc.) to aoid de-

pleting soil nutrient reseres. Table 4 shows for each of the main crops in Bhutan theamount of the primary nutrients that a crop yielding 1 mt (metric tonne) of product

remoes from the soil.

Table 3. Crop nutrient uptake and removal by crops yielding 1 mt produce

CROP N P2O

5 K

2O

Rice 18 3 17

Wheat 23 10 20

Maize 25 10 32

Potato 5 2 8

Chilli 32 3 42

Pea & Bean 24 6 16

3.5.2. Practical guidelines for effective fertilizer use

Use single super phosphate and Muriate of potash (MoP) as a basal dressing

before planting or sowing the crop. Howeer in areas with light tetured soils

and high rainfall, apply MoP in two or more splits to aoid losses through

leaching.

If urea is the only source of nitrogen, apply half the recommended rate as a

basal dressing and use the remaining half to top-dress at the appropriate growth

stage of the crop. If using a compound fertilizer like Suphala, use urea to top

dress in two or more splits.

Always use FYM or compost at the rate of 2-3 t/acre to help maintain soil struc-

ture and fertility.

Do not use fertilizer rates higher than the recommended rates as this wastes

money. Fertilizer rates lower than the recommended may be used but yields and

protability will be less than for the recommended rates.To apply the eact recommendations, use single nutrient fertilizers (urea, SSP

or TSP and MoP) together, or with a compound fertilizer (Suphala). If using

Suphala (15:15:15), apply it at the rate needed to supply the amount of which-

eer recommended nutrient rate is the lowest (P2O

5or K

2O). Then use single

nutrient fertilizers, either as basal or top-dressing, to supply the additional

amounts that the crop needs of other nutrients (usually N and P2O

5).



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4FERTILIZER RATE CALCULATIONS

To conert nutrient recommendations (kg/ha or kg/ac) into how many kg of fertilizer

per hectare or per acre are reuired, use the appropriate formula from below.

4.1. The best way to calculate fertilizer rate

Kg/ha Kg/ac

Recommended nutrient rate kg/ha 100Nutrient % of fertilizer

Recommended nutrient rate kg/ac 100Nutrient % of fertilizer

From kg/ha to gm/m2, diide by 10 From kg/ac to gm/m2, diide by 4

4.2. The easy way to calculate fertilizer rate

Table 4. The easy way

NUTRIENT kg TIMES EqUALSFERTILIZER kg

TIMES EqUALSNUTRIENT kg

Nitrogen 2.2 Urea 0.46 Nitrogen

Nitrogen 6.7/5.9 Suphala (15/17) 0.15/17 Nitrogen

Phosphorus 6.25 SSP 0.16 Phosphorus

Phosphorus 2.2 TSP 0.46 Phosphorus

Phosphorus 6.7/5.9 Suphala (15/17) 0.15/17 Phosphorus

Potassium 1.7 Muriate of potash 0.60 Potassium

Potassium 6.7/5.9 Suphala (15/17) 0.15/17 Potassium

Phosphorus 5.0 Bonemeal 0.20 Phosphorus

Nitrogen 5.5 Diammonium phosphate 0.18 Nitrogen

Phosphorus 2.2 Diammonium phosphate 0.46 Phosphorus

Nitrogen 4.0 Calcium ammonium nitrate 0.25 Nitrogen



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4.3. The easiest way to calculate fertilizer rate

Table 5. The easiest way

NUTRIENT-FERTILIZER CONvERSION CHART

NUTR-

IENT

(kg)

N

UREA

(kg)

P(P20

5)

SSP

(kg)

K(K20)

MOP

(kg)

N/P/K

(N/P20

5/K

20)

SUPHALA

(kg)

NUTR

-IENT

(kg)

N

UREA

(kg)

P(P20

5)

SSP

(kg)

K(K20)

MOP

(kg)

N/P/K

(N/P20

5/K

20)

SUPHALA

(kg)

15% 17% 15% 17%

1 2.2 6.3 1.7 6.7 5.9 21 45.7 131.3 35.0 140.0 123.5

2 4.3 12.5 3.3 13.5 11.8 22 47.8 137.5 36.7 146.7 129.4

3 6.5 18.8 5.0 20.0 17.6 23 50.0 143.8 38.3 153.4 135.2

4 8.7 25.0 6.7 26.7 23.5 24 52.2 150.0 40.0 160.0 141.1

5 10.9 31.3 8.3 33.4 29.4 25 54.3 156.3 41.7 166.7 147.0

6 13.0 37.5 10.0 40.0 35.3 26 56.5 162.5 43.3 173.4 152.9

7 15.2 43.8 11.7 46.7 41.2 27 58.7 168.7 45.0 180.0 158.8

8 17.4 50.0 13.3 53.4 47.0 28 60.9 175.0 46.7 186.7 164.6

9 19.6 56.3 15.0 60.0 52.3 29 63.0 181.3 48.3 193.4 170.5

10 21.7 62.5 16.7 66.7 58.8 30 65.2 187.5 50.0 200.0 176.4

11 23.9 68.8 18.3 73.4 64.7 31 67.4 193.8 51.7 206.6 182.4

12 26.1 75.0 20.0 80.0 70.6 32 69.6 200.0 53.3 213.3 188.2

13 28.3 81.3 21.7 86.7 76.4 33 71.7 206.3 55.0 220.0 194.0

14 30.4 87.5 23.3 93.4 82.3 34 73.9 212.5 56.7 266.7 200.0

15 32.6 93.8 25.0 100.0 88.2 35 76.1 218.8 58.3 233.3 205.8

16 34.8 100.0 26.7 106.7 94.0 36 78.3 225.0 60.0 240.0 211.7

17 37.0 106.3 28.3 113.4 100.0 37 80.4 231.3 61.7 246.6 217.6

18 39.1 112.5 30.0 120.0 105.8 38 82.6 237.5 63.3 252.3 223.5

19 41.3 118.8 31.7 126.7 111.7 39 84.8 243.8 65.0 260.0 229.4

20 43.5 125.0 33.3 133.4 117.6 40 87.0 250.0 66.7 266.7 235.2



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4.4. FYM/compost rate calculation

To calculate how many baskets of FYM are reuired per langdo or per drey seed area,

use the appropriate formula from below (mt = 1000kg):

Table 6. FYM or compost rate calculation (MT = metric tonnes = 1000kg)

MT/ha MT/ac

to baskets/ langdo wetland:

Recommended FYM rate MT/ha 1000Fresh Weight 1 basket manure 10

to baskets/ langdo wetland:

Recommended FYM rate MT/ac 1000Fresh Weight 1 basket manure 4

to baskets/langdo dryland:

Recommended FYM rate MT/ha 1000Fresh Weight 1 basket manure 7.5

to baskets/langdo dryland:


to baskets/ sendrey:

Recommended FYM rate MT/ha 1000Fresh Weight 1 basket manure 60

to baskets/ sendrey




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5FERTILIZER RECOMMENDATIONS

Remember:

A yield target will be reached only when the correct amount of nutrients is supplied

at the right time to match the crops nutrient reuirement during the season.

High input farmers are aiming for yield maimisation i.e. best yield with no

resource constraint.

Low input farmers are aiming for prot maimisation i.e. best return on lim-

ited resources.

Recommendations are presented as kilogram per acre of the main nutrient e.g.

26:16:16 means 26 kg N + 16 kg P2O

5+ 16 kg K

2O per acre.

5.1. Fertilizer recommendations for rice(Oryza sativa L.)

Table 7. Fertilizer recommendations for rice

CROP/DISTRICT FERTILIZER RECOMMENDATIONS (kg/ac)

RICE

HIGH-RESOURCE FARMERS LOW-RESOURCE FARMERS

N P2O

5 K

2O N P

2O

5 K

2O

LOCAL vARIETY

Gaylephu 32 20 8 20 16 8

Paro 28 16 16 24 12 8

Punkaha 28 16 14 16 8 8

Thimphu 30 16 12 20 16 8

Trongsa 24 14 8 20 12 8

Tsirang 36 16 8 20 16 8

Wangdiphodrang 24 14 14 16 12 8

HIGH YIELDING vARIETY

Gaylephu 32 20 12 30 12 8

Paro 32 20 8 32 16 8

Punakha 32 16 8 28 16 16

Samchi 32 20 16 24 16 12

Thimphu 32 20 8 30 20 8

Trashigang 28 24 12 20 16 8

Tsirang 36 24 12 28 16 8

Wangdi-phodrang 32 20 8 28 16 16



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urea into 2 eual doses ( at tillering; at stem elongation) can further im-

proe yields;

Use more splits with long duration arieties and in the dry season;

Apply more urea when the crop demand for N is large (between mid-tillering

and owering);

Do not apply urea top-dressing when heay rainfall is epected;

Do not apply urea on to standing water, under windy conditions before canopy

closure, or at midday when the water temperature is highest;

When top-dressing, close the terrace water inlets and outlets for at least three

days; and,

Use 2-3 tonnes/acre of FYM/compost at land preparation and plough or culti-

ate it into the soil before sowing, planting or transplanting.

5.2. Fertilizer recommendations for wheat (Triticum aestivum L.)

Table 8. Fertilizer recommendations for wheat

CROP/DISTRICT FERTILIZER RECOMMENDATIONS (Kg/ac)

WHEAT

(HIGH YIELDING)

HIGH-RESOURCE FARMERS LOW-RESOURCE FARMERS

N P2O5 K2O N P2O5 K2O

Bumthang 24 16 12 20 12 8

Gaylephu 24 16 8 20 12 0

Paro 32 16 16 24 12 12

Punakha 32 16 12 20 12 8

Thimphu 28 20 16 20 16 16

Trongsa 24 16 8 20 12 8

Tsirang 24 16 8 20 12 0


+ NPK with split N application

- NPK

Figure 1. Farmer-Extension Fertilizer Use Trial in rice at

Kekhorthang in Tsirang

Apply the entire

dose of SSP, MOP

and Suphala as a

basal dressing;

If half the urea isapplied as basal

dressing, then top-

dress the other half

at actie tillering

stage (20-30 days

after transplant-

ing) or after rst

weeding. Splitting

the top-dressed



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Apply the entire dose of SSP, MOP*

and Suphala as a basal dressing;

If half the urea is applied as basal*

dressing, then top-dress the other

half immediately before the rstirrigation, at crown root initiation

stage (20-40 days after sowing de-

pending on altitude);

Figure 2. Farmer-Extension Fertilizer Use

Trial in wheat at Tsento, Paro.

creased by increasing N supply at grain initiation and grain formation. Howeer,

too much N at this stages can delay ripening and can lower the uality of grain

protein;

60% of the epected maimum total nutrient uptake (N+P2O

5+K

2O) occurs by the

middle or end of shooting; this is why nutrients must be applied during early

growth;

Use 2-3 tonnes per acre of FYM/compost at land preparation for best results;Wheat grows on all types of soils ecept on ery light sandy soils or peat soils.

5.3. Fertilizer recommendations for maize (Zea mays L.)

Table 9. Fertilizer recommendations for maize


MAIZE HIGH-RESOURCE FARMERS LOW-RESOURCE FARMERS

(LOCAL vARIETY) N P2O

5 K

2O N P

2O

5 K

2O

Dagana 40 28 16 32 24 12

Gaylephu 40 32 20 32 20 8

Tsirang 40 28 16 32 24 12

Apply the entire dose of SSP, MOP and Suphala as a basal dressing;

If half the urea is applied as basal dressing, then top-dress the other half at rst

weeding at knee high stage;

To aoid unproductie tillering and

secondary shoots, restrict nutrient

supply (especially N) to early growthstages (i.e. start of tillering);

Grain protein content can be in-



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Apply N annually. Maize is often grown in coarse tetured soils where N leaching

is high. Applying N fertilizers as a side-dressing is effectie;

Grows best in rotation with another crop, especially a legume;

Maize takes up oer half the N and P and 80% of the K before the crop reaches

the reproductie stage. Apply these major nutrients early so that they are aail-able when the crop needs them in the growing season;

Use 2-3 tonnes / acre of FYM/compost at land preparation;

Maize does well on any soil with adeuate drainage and pH 6.0 7.2.

5.4. Fertilizer recommendations for potato (Solanum tuberosum L.)

Table 10. Fertilizer recommendations for potato


POTATO HIGH-RESOURCE FARMERS LOW-RESOURCE FARMERS

N P2O

5 K

2O N P

2O

5 K

2O

Bumthang 40 32 24 32 36 16

Chhukha 32 20 12 24 16 8

Gaylephu 32 24 16 24 20 8

Haa 32 24 12 24 16 8

Paro 40 32 32 28 28 12

Thimphu 40 28 12 28 20 8

Trashigang 40 32 32 36 32 12

Tsirang 40 32 12 32 24 8


Figure 3. Fertilizer Use Trial in potato at Tsento, Paro

- NPK + NPK



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Apply the entire dose of SSP, MOP and Suphala as a basal dressing;

If half the urea is applied as basal dressing, then top-dress the other half

at earthing up when the leaes are about 10-15 cm long, or at tuber initia-

tion;

Potato uses large amounts of N, freuently more than the total applied as fer-tilizer. Therefore, recommend adeuate amount of N fertilizer and adice it to

be applied in at least two to three split applications. Howeer, ecess N at or

before tuberization can delay tuber growth and reduce yields.

Phosphorus (P) is immobile in soil and therefore does not moe from where it is

placed. P fertilizers should either be mied into the seedbed before planting or

banded at planting;

Potato reuire high leels of aailable soil potassium (K). Potassium is relatiely

immobile in the soil. For best results, K fertilizers should be applied pre-plant

and mied into the seedbed;

Where large amounts (e.g. 100 kg/ac) are to be applied, apply K in two to threesplits with 6-8 weeks between each split;

Place fertilizers close to but not in contact with seed tubers for more efcient

fertilizer use;

Potato grows on most soils but haresting is easier on light and medium tetured

soils;

The desirable soil pH range is of 6.0 7.0. Soil pH aboe 7.0 can damage skin

uality.

5.5. Fertilizer recommendations for chilli (Capsicum annum L.)Trials on integrated use of FYM and inorganic fertilizers with a local chilli ariety

were conducted for four years (2001 2004) at NSSC in Semtokha. The results clearly

showed the benet of the integrated use of FYM and inorganic fertilizers in terms of

yield and uality [5.17 tons ac-1with the highest rate of NPK of 24-18-18 kg ac-1and

the highest yield of 4.78 tons ac-1with the higher rates of 4 tons ac-1of FYM applica-

tion]. Most of our farmers use only FYM and some leaf litters while growing chillies,

the results of the study can be used as a reliable guide for our condition. The use of

fertilizer at the rates below in addition to farmers traditional practice of FYM/leaf

litter is recommended.

Table 11. Fertilizer recommendations for chilli

CROP/AREA NUTRIENT(Kg/ac)

CHILLIHIGH INPUT1 LOW INPUT1

N P2O

5 K

2O N P

2O

5 K

2O

Rain fed 24 18 18 16 8 8

Irrigated 28 24 24 20 12 12



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Apply the entire dose of SSP, MoP and Suphala as a basal dressing;

If half the urea is applied as basal dressing, split the other half into 2 top-

dressings at 30 and 60 DAP;

Use 2-3 tonnes per acre of FYM /compost at land preparation;

Needs deep, well-drained soils, rich in organic matter and pH of 6.5 7.5

5.6. Fertilizer recommendations for other vegetables

Recommended nutrient rates for common commercial egetables are summarized in

Table 12 below; and in Table 13,14 & 15 for tree crops.

Table 12. Fertilizer recommendation for other important vegetable crops

CROP TIMEMT/ac NUTRIENT (Kg/ac)

COMMENTSFYM N P

2O

5 K

2O

Asparagus1styear2ndyear

BasalSide

2060

3640

1680

Apply FYM / compost at transplanting.From the 2ndyear, side dress fertilizer

Bean Basal 5-8 10 30 0 Grows on wide range of soils, pH 5.5-6.8.

Legume so needs little N.Brinjal Basal

TD1616

28 12 Best temperature for growth 25-30oC.TD (top-dress) 30 DATP

Cabbage BasalTD1

TD2

5-6 2010

10

30 0 Grows on all soil types if no waterlogging.Ideal pH 6-6.8. 1st top-dressing 30 DATP2nd top-dressing 60 DATP

Carrot Basal 8 4 24 Needs K for proper deelopment of roots.

Cauli-ower

BasalTD1

TD2

5-6 2010

10

30 0 Reuires well-drained soils, pH 6-6.8.1st top dressing 30 DATP2nd top dressing 60 DATP

NPK = 24:18:18 kg ac-1

FYM = 4 ton ac-1

NPK = 0.FYM = 4 ton ac-1

Figure 4. Chilli Nutrient trial



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CROP TIMEMT/ac NUTRIENT (Kg/ac)

COMMENTSFYM N P

2O

5 K

2O

Chinese

Cabbage

Basal

TD1

TD2

5-6 20

10

10

30 0 Reuires well-drained soils, pH 6-6.8.1st top dressing 30 DATP

2nd top dressing 60 DATP

Cucumber Basal

TD

8-10 18

12

14 10 Reuires good moisture & FYM/OM.

Loamy soils best, pH 5.5-6.8.

Top dress 4-6 weeks after planting.

Garlic Basal

TD

8-10 20

20

30 30 Top dress after 6-8 weeks, if reuired.

Lettuce Basal 4-5 8 16 8 Needs continuous moisture so irrigation

/water source essential

Onion Basal

TD

8-10 20

20

30 30 Grows on any soil with good FYM/OM.

Bulbs may be poor on heay wet soils.Optimum pH 6.0-6.8. Top-dress 30 DAP.

Pea Basal 8-10 20 30 30 Grows on all soils, ecept if waterlogged

or compacted. Legume so needs little N.

Radish Basal 4-5 20 20 20 Grows best in light OM-rich soil pH 6.6-6.8.

Saag and

Spinach

Basal 8-10 20 0 0 Grow well in all soils; prefer well drained

and adeuate FYM/OM. pH 6-6.8.

Tomato Basal

TD

4-8 20

15

20 10 Grows best on rich, well drained soils. pH

5.5-6.8. Top-dress 30 DAP.

NB: TD = Top dressing; DAP = Days after planting; DATP = Days after transplanting FYM =

farmyard manure; OM = any organic matter e.g. FYM, compost, leaf litter

5.7. Fertilizer recommendations for citrus (Citrus reticulata)

Table 13. Nutrient recommendation for citrus

PLANT

NUTRIENT

NON BEARING TREES

(G/TREE/YR)

BEARING TREES

(G/TREE/YEAR) TIME OF APPLICATION

NUTRIENT FERTILIZER NUTRIENT FERTILIZER

N 50-100 110g 220g

Urea

150-250 330-550g

Urea

After harest & prior to

spring ushP

2O

5 20-50 126g 315g

SSP

50-100 315g 630g

SSP

After harest & prior to

spring ush

K2O 100-150 170g 255g

MoP250-350 425g 595g

MoPAfter harest & prior tospring ush

Micro-

nutrients

To be applied based on soil & plant analysis result When trees hae the

most fully epanded

leaes

FYM To be applied based upon aailability



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5.8. Fertilizer recommendations for apple (Malus domestica)

Table 14. Nutrient recommendation for apple

PLANT

NUTRIENTS

NON BEARING TREES(G/TREE/YR) BEARING TREES(G/TREE/YEAR) MATURED BEARING TREES(G/TREE/YEAR)

NUTRIENT FERTILIZER NUTRIENT FERTILIZER NUTRIENT FERTILIZER

N 46-69 100 150g

Urea

46-69 100-150g

Urea

69-92 150-200g

Urea

P2O

5 16 100g SSP 24-32 150-200g

SSP32-48 200-300g

SSP

K2O 60-90 100 150g

MoP

90-120 150-200g

MoP

120-150 200-250g

MoP

Micro-nutrient

To be applied based on soil & plant analysis result

FYM Depending upon the aailability of farmyard manure, incorporate about abasket each around the tree without touching the tree trunks.

For apple, split N application, half in December-March with full P & K; other

half in June

Irrigate/moisten the soils after fertilizer application.

5.9. Fertilizer recommendations for areca-nut (Areca catechu)Table 15. Nutrient recommendation for areca-nut

PLANT

NUTRIENT

YEAR 1

(G/PALM/YEAR)

YEAR 2

(G/PALM/YEAR)

YEAR 3 ONWARDS

(G/PALM/YEAR)

NUTRIENT FERTILIZER NUTRIENT FERTILIZER NUTRIENT FERTILIZER

N 34 75g urea 67 147g urea 100 220g urea

P2O

5 13 81g SSP 27 169g SSP 40 250g SSP

K2O 47 80g MoP 94 160g MoP 140 238g MoP

For areca-nut, apply farmyard manure in planting pit and yearly, 1-3 baskets/

palm/year, according to tree size. FYM and compost may be applied in single

dose in September October.

The fertilizers may be applied in two split doses: one third of the fertilizer may

be applied in May June and two third along with the organics during Septem-

ber October.

The rst dose of fertilizers may be applied in basins of about 1 m radius, made

around the palm to a depth of 15-20cm



21/23


The second dose of fertilizers can be applied to the base of each palm all around

and mied with the soil by a light forking.

Please note that:

All chemical fertilizers should be mied with the soil. Keep a distance of one or two

feet away from the tree when fertilizer is being mied with soil. Most of the feeder

roots that take up the nutrients from the soil are in the region under the tree canopy

and applying nutrients in this area ensures proper uptake by the roots,

The soil should be moist or a light irrigation should be applied after the application

of fertilizers. The fertilizers must be dissoled to release nutrients and these nutri-

ents can only be reached to root zone by water.

The ecess application of chemical fertilizers aboe the recommended dosage may

not be economical.

Last word

The aboe tables are general recommendations only.

The best recommendations can be made only after soil and plant analysis at the

Soil and Plant Analytical Laboratory (SPAL) NSSC.

This is especially important for cash crops.



22/23


6GLOSSARY OF TERMS

ANION:a negatiely charged ion (NO3

-, PO42-, SO

42-)

CARBON TO NITROGEN RATIO (C:N):Organic matter is broken down by microbes,

which use carbon for energy. Microbes reuire about one nitrogen atom for each 25

carbon atoms. This is a carbon-to-nitrogen ratio (C:N) of 25:1. If the organic matter

has a higher C:N, microbes will need more nitrogen than is in the organic matter and

will take from the soil. Microbes are more efcient than crops in obtaining nitrogen

from the soil. If there is not enough nitrogen for both the microbes and the crops,

the crops can suffer from nitrogen deciency. Organic matter with a C:N ratio less

than 25:1 should not be a problem.

CATION EXCHANGE CAPACITY (CEC):dened as the degree to which a soil can ad-

sorb and echange cations.

CATION:a positiely charged ion (NH4+, K+, Ca2+, Fe2+, etc.).

EXCHANGEABLE ALUMINIUM SATURATION:In highly acid soils, aluminium can be-

come more aailable and more toic to the plant. Echangeable Al saturation per-centage in soil becomes high when basic nutrients such as calcium and magnesium

are replaced by acidic elements such as aluminium.

PERCENT BASE SATURATION:Percent base saturation tells what percent of the e-

change sites are occupied by the basic cations. The percent base saturation is re-

lated to the pH, chemistry of dominant soil and soil formation.

SOIL ORGANIC MATTER: Soil organic matter improes soil structure, moisture, aera-

tion, cation echange capacity and decomposition of organic matter releases nutri-

ents, which can be used by plants.

SOIL PH:The soil pH alue is a measure of soil acidity or alkalinity. Soil pH directly

affects nutrient aailability to plants. The pH scale ranges from 0 to 14, with 7 as

neutral. Numbers less than 7 indicate acidity while numbers greater than 7 indicate

alkalinity.



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7REFERENCES

Department of Agriculture. (1989).Etension publication No. 8. (Oct. 1989). Fertilizer recommendations for rice,

wheat, potato and maize production.

RNRRC-Bajo. Research Recommendations for egetable cultiation. April 1998

Dobermann and T. Fairhurst (2000).Rice. Nutrient Disorders and Nutrient Management. International Rice Research

Institute & Potash & Phosphate Institute/Potash & Phosphate Institute of Canada.

Oford Graphic Printer Pte. Ltd.

D.J Halliday and W. Wichmann (1991).IFA World Fertilizer Use Manual. International Fertilizer Industry Association.

SSF&PNM (2000).

Agro forestry and Soil Fertility Surey report. Department of Research and Deel-

opment Serices. Ministry of Agriculture, Bhutan.

SSF&PNM (2001).IPNS Manual. Working with farmers for improed soil fertility & plant nutrition

management. Department of Research and Deelopment Serices. Ministry of Ag-

riculture, Bhutan.

RNRRC-BAJO (1998)Research Recommendations for vegetable Cultiation. REID, Ministry of Agricul-

ture. Bhutan.

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