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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
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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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3A GUIDE TO FERTILIZER RECOMMENDATION FOR MAJOR CROPS
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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4 A GUIDE TO FERTILIZER RECOMMENDATION FOR MAJOR CROPS
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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5A GUIDE TO FERTILIZER RECOMMENDATION FOR MAJOR CROPS
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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6 A GUIDE TO FERTILIZER RECOMMENDATION FOR MAJOR CROPS
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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7A GUIDE TO FERTILIZER RECOMMENDATION FOR MAJOR CROPS
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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8 A GUIDE TO FERTILIZER RECOMMENDATION FOR MAJOR CROPS
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:
Recommended FYM rate MT/ac 1000Fresh Weight 1 basket manure 3
to baskets/ sendrey:
Recommended FYM rate MT/ha 1000Fresh Weight 1 basket manure 60
to baskets/ sendrey
Recommended FYM rate MT/ac 1000Fresh Weight 1 basket manure 24
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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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10 A GUIDE TO FERTILIZER RECOMMENDATION FOR MAJOR CROPS
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
Wangdiphodrang 32 16 12 20 12 8
+ 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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11A GUIDE TO FERTILIZER RECOMMENDATION FOR MAJOR CROPS
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
CROP/DISTRICT FERTILIZER RECOMMENDATIONS (Kg/ac)
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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12 A GUIDE TO FERTILIZER RECOMMENDATION FOR MAJOR CROPS
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
CROP/DISTRICT FERTILIZER RECOMMENDATIONS (Kg/ac)
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
Wangdiphodrang 40 32 32 28 24 12
Figure 3. Fertilizer Use Trial in potato at Tsento, Paro
- NPK + NPK
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13A GUIDE TO FERTILIZER RECOMMENDATION FOR MAJOR CROPS
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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14 A GUIDE TO FERTILIZER RECOMMENDATION FOR MAJOR CROPS
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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15A GUIDE TO FERTILIZER RECOMMENDATION FOR MAJOR CROPS
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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16 A GUIDE TO FERTILIZER RECOMMENDATION FOR MAJOR CROPS
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
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17A GUIDE TO FERTILIZER RECOMMENDATION FOR MAJOR CROPS
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.
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18 A GUIDE TO FERTILIZER RECOMMENDATION FOR MAJOR CROPS
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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19A GUIDE TO FERTILIZER RECOMMENDATION FOR MAJOR CROPS
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.