How to grow Napier Pakchong 1: cutting age, feeding and silage

Cattle and buffalo need roughage, and in Thailand Napier grass is a roughage crop that farmers use widely (Thongruang et al. 2021). The variety the Department of Livestock Development (กรมปศุสัตว์, DLD) has promoted is Napier Pakchong 1 (หญ้าเนเปียร์ปากช่อง 1). Many people know it as the tall grass in the plot behind the pen. Fewer know that the day you cut it changes what your animals get from it.

This guide follows the plot from bare soil to a stack of silage. Each step uses one of the DLD documents or research papers linked below. Where two DLD documents give different numbers, I show both. Where a number is my own arithmetic, I say so.

What Pakchong 1 is

Pakchong 1 is a hybrid Napier grass. A Kamphaeng Phet provincial agriculture leaflet that cites the DLD as its source describes it as a cross between giant Napier grass and pearl millet (หญ้าเนเปียร์ยักษ์ x หญ้าไข่มุก) (Kamphaeng Phet Provincial Agriculture and Cooperatives Office). A 2021 research paper gives the same cross in Latin: Pennisetum purpureum x Pennisetum americanum (Thongruang et al. 2021, Khon Kaen Agriculture Journal). The Philippine Carabao Center, which planned to bring the variety in, credits its development to Dr. Krailas Kiyothong of the DLD (PCC).

The DLD's own planting manual says the variety was selected and promoted by its Bureau of Animal Nutrition Development (สำนักพัฒนาอาหารสัตว์). It describes the plant like this (DLD Pakchong 1 manual):

• A perennial grass that grows in upright clumps, 2–4 metres tall, with a strong root system.
• It likes well-drained, fertile soil and bright sun.
• It does not tolerate standing water and does not tolerate trampling by animals.
• It has no dormant season and produces all year. The leaf edges aren't sharp and the leaves have few hairs.

The provincial leaflet adds that it sets no seed, so it spreads only from stem cuttings and carries no risk of becoming a weed (Kamphaeng Phet leaflet).

Why the DLD promotes it

The same leaflet says the DLD has encouraged farmers to plant Napier, reckoning that one rai can feed no fewer than 5 cattle, and that since 2011 (พ.ศ. 2554) it has stepped up the distribution of Pakchong 1 cuttings to livestock farmers across the country (Kamphaeng Phet leaflet). The DLD manual gives a similar figure under intensive management: one rai can support 5–6 milking cows (DLD manual).

Yield depends heavily on how well the plot is managed. The manual gives two figures (DLD manual):

A plot keeps producing for about 8–9 years. A DLD training deck lists Pakchong 1 as its silage forage and notes that it is well suited to silage (DLD forage management slides).

If you only remember one row of that table, make it the second one. If your plot is rain-fed, plan your herd size on 35–40 tonnes, not 80.

Step 1: Prepare the plot

The DLD manual says Pakchong 1 grows in every region of Thailand, on loam, sandy loam and clay loam. It needs good drainage and about 1,000–1,200 mm of rain a year (DLD manual).

Soil preparation, as the manual describes it:

1. First ploughing with a 3- or 4-disc plough.
2. Second ploughing with a 7-disc plough.
3. Harrowing with a rotary tiller, going across the field in both directions (east–west, then north–south).
4. Work in 2–4 tonnes per rai of organic fertiliser, manure or compost.
5. Add a base fertiliser such as 15-15-15 at 50–100 kg per rai, depending on the soil.

The DLD training slides add that after the first ploughing you can leave the soil for about four weeks so the weeds die and rot (DLD slides).

Poor soil needs more work. A case study of one agricultural extension unit of Thailand's Armed Forces Development Command found low nutrients and acidic, sloping land that held little water. It recommended lime at 0.5 tonnes per rai and more organic matter (Jongwannasiri 2021, AFDC Journal). If you are unsure about your soil, have it tested before you plant.

Step 2: Plant stem cuttings

Pakchong 1 has no seed, so you plant pieces of stem. The DLD manual describes three ways (DLD manual):

Standing cuttings (ปักท่อน). Take stems from a healthy plot, about 3 months old and even in thickness. Cut them on a slant into pieces with 2 nodes each. Push them into the soil at a 30° angle. Plant in rows with a spacing (row x hill) of 120 x 80 cm or 100 x 100 cm. You'll need 400–600 kg of cuttings per rai.

Cuttings laid in furrows. Make furrows 120 cm apart, like a sugarcane field. Lay the stems end to end, with each tip overlapping the next stem's base by about 20 cm. Chop them shorter so they lie flat, then cover them with soil.

Planting machine. On big plots, a sugarcane planter behind a tractor plants about 4 rai an hour, using 600 kg of cuttings per rai.

Two DLD documents give slightly different rates. The training slides say cuttings about 90 days old, 300–500 kg per rai, 2 pieces per hole (DLD slides). Both are DLD guidance, so treat them as a range. Weed 2–4 weeks after planting and again after every harvest (DLD manual).

Above: a pearl millet x dwarf Napier hybrid in Hawaii. It is a cousin of Pakchong 1, from the same kind of cross, but not the same variety.

Step 3: Cut at the right age

This is the step that matters most for your feed bill.

The DLD manual says to make the first cut 60–75 days after planting, then cut every 60 days, which gives 5–6 cuts a year. Cut as close to the ground as you can (DLD manual). The training slides say every 60–75 days after the first cut (DLD slides).

The manual also gives the trade-off in one sentence (DLD manual):

Younger grass has more protein. Older grass has more dry matter, which means more actual feed per tonne you carry.

CUTTING AGE napier pakchong 1                                   
                                                                
                                                                
                             v             as the grass ages    
                                                                
                                           yield   ███████····· 
                                                                
                                           fibre   ████████···· 
     /    /    /  \    \    \    \                              
    |-  -|    |-  \|    |/  \|    |/       protein █████████··· 
   \|    |/  \|    |/  \|    |/  \|                             
    |/  \|    |/  \|    |/  \|    |/                            
    |    |    |    |    |    |    |        cut close to         
_________________________________________  the ground           
    .  .        .  v     .     .     .                          
day +--------------+--------------+        bars: illustrative   
   0              30     45      60                             
                                                                

What one field trial found

A 2021 trial in the Khon Kaen Agriculture Journal compared Pakchong 1 with sweet grass (หญ้าหวาน) at three cutting ages (Thongruang et al. 2021). The plots were on Phetchaburi soil series, planted without fertiliser, spaced 0.5 x 0.5 m and cut 15 cm above the ground. Here are the Pakchong 1 results from its Tables 1 and 2 (full paper, PDF):

How to read it:

• Yield almost tripled from 30 to 60 days.
• Fibre (NDF) and lignin rose with age. Lignin is the woody part that animals digest poorly. Across both grasses, the 60-day cut had significantly higher NDF and lignin than the 30- and 45-day cuts.
• Protein drifted down, but the authors report that the Pakchong 1 differences between 30, 45 and 60 days were not statistically significant.

The protein figures are lower than the DLD's 8–12%. These plots were unfertilised, on a soil series the paper describes as low in fertility, but the paper doesn't test why. The direction is the same in both: older grass gives more bulk but more fibre. A different 2024 study on watering rates reported about 10–13% CP across three cuts, taken 70, 115 and 150 days after planting (Wasantiwong et al. 2024, RMUTP Research Journal). Soil, water, fertiliser and season all move these numbers.

Practical takeaway. Follow the DLD's 60-day rhythm as your default. If the grass is heading towards 70–75 days and turning woody, cut it. Don't wait for extra height.

Step 4: Feed it fresh, or make silage

Fresh

The DLD manual says Pakchong 1 can be fed fresh-cut, as silage, or in a total mixed ration (TMR) (DLD manual). The DLD slides add an important tip: chop it. If you give animals long stems, they pick off the leaves and leave the stems (DLD slides).

Silage

Silage keeps green grass in an airtight, moist state so you have feed when fresh grass is short. The DLD manual says Pakchong 1 has about 18% water-soluble carbohydrate (WSC), enough to make silage without additives (DLD manual). The method in the manual:

1. Cut at 60–70 days. Grass younger than 60 days holds too much water for silage.
2. Chop to 2–3 cm (about 1 inch) so it packs tightly. Aim for about 60–70% moisture.
3. Pack it hard into a pit, bag or other container, by trampling or driving a tractor over it. Removing air is the most important part.
4. Seal it completely against air and rain. For a big pit, cover it with plastic and weigh the plastic down.
5. Wait 3–4 weeks, then open. Silage left open for a long time spoils.

                                                            
 [chopper]==,                                               
            .                             SILAGE            
              ·     ·          ·                            
                    ·                     1 chop 2-3 cm     
                                                            
_____│                            │____   2 press out air   
     │                            │                         
     │                            │       3 cover tight     
     │                            │                         
     │                            │       4 wait 3-4 wks    
     │                            │                         
     │                            │                         
     │                            │                         
     │                            │                         
     └────────────────────────────┘                         
                                                            
                                                            

Good Pakchong 1 silage, according to the manual, is greenish-yellow with a mild sour, pickled-fruit smell. It shouldn't be slimy or mouldy. Moisture should be 65–70% and the pH 3.5–4.2. Burnt-brown silage means it overheated while fermenting. Black silage should not be fed (DLD manual).

The manual lists eight ways to store it: trench pits, concrete-walled pits, tower and pipe silos, vacuum bags, rolled bales, recycled factory containers, and ground piles.

Step 5: Rotate plots so there is grass all year

If you cut the whole field on one day, you have a glut for a week and nothing for two months. The fix is simple. Split the field into plots and cut them in turn.

Here's my own arithmetic on the DLD's 60-day cycle. With six plots, you cut one plot about every 10 days, and each plot still gets its full 60 days to regrow. With four plots, it's one every 15 days. Pick the number that fits your herd and how often you can harvest.

ROTATING PLOTS cut one plot, the rest keep growing  
                                                    
                                   .--.             
                                  (    )            
    cut                                             
     v//                                            
   / | |   / / /                                    
   \ \ \   \ \ \   / / /                            
   | | |   | | |   | | |   /  //                    
   \ \ \   \ \ \   \ \ \   \ \ \   ' ' '            
   | | |   | | |   | | |   | | |   | | |   ' ' '    
  ▀▀▀▀▀▀▀ ▀▀▀▀▀▀▀ ▀▀▀▀▀▀▀ ▀▀▀▀▀▀▀ ▀▀▀▀▀▀▀ ▀▀▀▀▀▀▀   
     A       B       C       D       E       F      
6 plots x 10 days = each plot regrows 60 days       
                                                    

After each cut, the DLD manual says (DLD manual):

• Feed the stubble right away. Put 0.5–1 kg of manure around each clump plus about 1 tablespoon of urea per clump (10–20 kg per rai) while the soil is moist.
• Water. Young plants need about 4 mm per plant per day for the first 20 days. Growing plants (21–60 days) need 4.5 mm. That's about 360 m³ per rai per 60-day cycle, given once or twice a week depending on soil moisture and weather.
• Weed after each harvest.

Rotation also fits silage. When the rains bring more grass than your herd can eat, let one or two plots go to 60–70 days and ensile them for the dry season.

Common mistakes

1. Planting where water stands. Pakchong 1 does not tolerate waterlogging (DLD manual).
2. Letting animals graze the plot. It does not tolerate trampling. It is a cut-and-carry grass (DLD manual).
3. Leaving tall stubble. Cut close to the ground so the clump regrows well (DLD slides).
4. Feeding long, unchopped stems. Animals eat the leaves and waste the stems (DLD slides).
5. Making silage from young grass. Under 60 days it's too wet (DLD manual).
6. Skipping fertiliser after cutting. The manual says to feed the stubble right after harvest (DLD manual).
7. Planning on the best-case yield. 80 tonnes per rai needs irrigation and fertile soil. Rain-fed plots give about 35–40 (DLD manual).
8. Leaving a silage pit open. Opened silage that isn't used spoils (DLD manual).

A last word

Pakchong 1 isn't magic. It's a grass that responds to care. Give it drained soil, manure, water after cutting and a steady 60-day rhythm, and it gives a lot back. Write down the date you cut each plot and roughly how much you carried away. After a season, your own notebook will tell you more about your plot than any table here.

For questions about forage crops, the provincial leaflet points to the provincial livestock office (สำนักงานปศุสัตว์จังหวัด) in every province (Kamphaeng Phet leaflet).

Sources

• Department of Livestock Development, Bureau of Animal Nutrition Development. คู่มือการปลูกหญ้าเนเปียร์ปากช่อง 1 (Pakchong 1 planting manual)
• Apinan Jindanirdul, Department of Livestock Development. พืชอาหารสัตว์ที่สำคัญ & การจัดการแปลงพืชอาหารสัตว์ (important forage plants and plot management, training slides)
• Kamphaeng Phet Provincial Agriculture and Cooperatives Office. หญ้าเนเปียร์ leaflet (source: DLD)
• Thongruang S., Kleawkleaur K., Prombut P., Manatrinon S. (2021). Comparisons in yields, forage characteristics, sweetness and nutritive values of sweet grass and Napier Pak Chong 1 grass at different cutting ages. Khon Kaen Agriculture Journal 49(5): 1092–1102. Full text (PDF)
• Wasantiwong K., Kingkaew J., Punquejana W. (2024). The effect of watering rate on Napier Pak Chong 1 grass yield and quality using a soil moisture sensor module. RMUTP Research Journal Sciences and Technology 18(1).
• Jongwannasiri S. (2021). ปัจจัยที่มีผลต่อการเจริญเติบโตของหญ้าเนเปียร์ปากช่อง 1 (factors affecting the growth of Napier Pakchong 1). AFDC Journal 45(3).
• Philippine Carabao Center. Super Napier seen to boost local dairy production
• Photo: Napier grass (Non-hybrid), Salil Kumar Mukherjee, CC BY-SA 4.0, Wikimedia Commons
• Photo: Cenchrus purpureus cv Pearl Millet x Dwarf Napier habit, Ulupalakua Ranch, Maui, Forest and Kim Starr, CC BY 3.0 US, Wikimedia Commons
• Photo: Silage bags, Thomas Nugent, CC BY-SA 2.0, Wikimedia Commons