Hung Nguyen, James Quilty, Bjoern Ole Sander, Carlito Balingbing, Simon Munder, Martin Gummert

With the contributions of related research within IRRI-projects

Preventing Straw Burning in the Field - How to Manage Straw More Sustainably

AGRITECHNICA Asia, Bangkok, March 16, 2017

17-Mar-17

Combine Harvesting as a Game ChangerDriven by labor shortage, high collection cost

Combine harvester

Previous harvesting system

Some provinces in Cambodia and Vietnam now completely combine harvested

Spread by combine harvesters in the field

Bulky (loose form: 70-80 kg/m3)

Intensive labor during harvesting

Asia: around 60% (300m tonnes/year) of rice straw burnt in the field for disposal

Images: NASA / Earth Observatory :Punjab, India

What should we do with rice straw?

Burn?

Collect/ remove?

Incorporate?

Components N P2O5 K2O

Content, %dm 0.5-0.8 0.2-0.3 1.4-2

kg/ ton straw 5-8 1.6-2.7 14-20

Lost during burning (%)

100 25 20

for what and how?

Rice production

In-field options

Processing and utilization routes of rice straw (IRRI-BMZ rice straw project)

Burning

Mulching

Incorporation

Off-field options

Agricultural uses

Carbonization (Bio-char) Composting

Livestock (bedding, fodder)

Industrial uses

Building materials (fiber board, brick, etc.)

Hi-end materials (silica, biofiber)

Energy

Thermal (combustion, gasification, pyrolysis)

Bio-chemical: AD, Fermentation, etc.

Heat, electric power, syngas

Biogas, ethanol, hydrogen, etc.

Pre-processing

Densification(whole bale

compaction, briquetting and

pelletizing)

Ensilaging

Leaching

residue Waste

field

Life cycle assessments identify better, more sustainable practices

Harvesting

Mushroom

Chopping

Drying and storage

Collection, handling, and transportation

Required depending on

processing

In-field options Incorporation with decomposition supported by Tricoderma

Combine harvester + straw chopping + spreading + Tricoderma spraying

Incorporation

Straw shredding and urea spraying IRRI-BMZ rice straw project

Carbonization and composting – IRRI-BMZ rice straw project, conducted by Hohenheim University

Compost turner mixing green stalks into a windrow for decomposition experiments –on-going research

Biomass and char conversion for wood chip.

For rice straw ≈ 40 minutes

Service cost: 26-35 $US/t

Net profit = 10 – 20 $US/t

Off-field straw management

Published in: http://www.sciencedirect.com/science/article/pii/S0378429016302854

Market of rice straw

YearSpread in the field ($US/ha)

Baled straw at the field ($US/ton)

Baled straw at the market ($US/ton)

2013 15 96 115

2014 20 80 100

2015 30 62 95Increase bale density by 400% (94 390 kg m-3). Reduce transportation cost by 60% for a 60 km driving distance using trucks. Net profit $US 6.2/ton (for compressing)

Compress 10 roll-bales 1 square bale

Or fermented-packaging

Source: TGU, NLU and IRRI, on-going research

Case study in Vietnam

Wet straw collection (wet season) need to dry?

Research of solar dryer for rice straw

Source: NLU and IRRI, on-going research

Rice straw mushroom production

19.9%

25.8%

4.8%1.2%0.6%

47.7%

Total cost of using 1 ton straw formushrom production: 5 million VND

Land used (rental)

Rice straw (at 15-18% MCwb)

Spawns

Activators

Watering (power consumption)

Labors (for all operations)

Net profit = US$123 (±14) per ton of straw used.

Straw chopping and pelletizing

Testing ongoing

Pelletizing cost: 21 USD/ton (for depreciation, energy, labor,…)

Potential for energy, cattle feeds

Source: TGU, NLU-IRRI ongoing research

Cross-flow furnace for rice straw and paddy drying

Energy: combustion

ENERTIME project at IRRI: Feasibility of 1MW power plant

Organic Ranking Cycle (ORC)

Rice straw AD power plant 1.2 MWe (assessed in India)

18 MWh/day (Self-consumption 3 MWh/day).

Residential time = 21+21 days

Energy efficiency = 15-25%

+ Fertilizer

Challenges: Collection, transportation, storage, pretreatment/chopping

Anaerobic digestion (AD)

IRRI-designed Batch AD – hermetic bag

• Low cost

• Portable

• Residue after AD can easily be unloaded and used as fertilizer

• Energy efficiency 15-25% + fertilizer (Residential time = 100 days)

Limitations: small scale, on-going development

Published in: http://www.sciencedirect.com/science/article/pii/S235248471630018X

Assuming collected rice straw is used for bioenergy and

mushroom production

Economic (investment,

profit, ..)

Environment, energy

Social (livelihood,

labor,..)

Quantified bySustainability/ Lifecycle assessment Best practices

Paddy 14%

Milled rice

Storage, mill

Husk

Best/better practices?

0

1

2

3

4

5

6

7

8

9

10

11

Completeromoval Partial

removal Strawburning Straw

retained

Annu

al G

HG

E (M

g C

O2-

eq h

a-1

year

-1)

In-field burningstraw

Mushroomproduction

Direct fieldemission

Mechanizedoperations

Herbicide

Fertilizer

Seeds

GHG emissions of rice production with different rice straw management practices?

Source: Nguyen V Hung et al., working paper

0.0

0.4

0.8

1.2

Annual paddy yield(10.2 Mg/ha)

Grain quality: headrice recovery (55.4%)

Net energy balance(4.7)

GHGE (7.3 Mg CO2-eq/ha)

Human toxicity (0.19Mg 1,4 DB-eq/ha)

Partial removal (control = 1) Complete straw removalIn-field burning Straw retained and incorporated

Source: Nguyen V Hung et al., working paper

LCA of rice production with different straw management practicesMatters (1kg) kg 1,4 DB-eq

Diesel burned 7.5Nitrogen 4.1K2O 0.5P2O5 2Herbicide 56

Particulates 0.82

Burn GHGE, pollutions, and nutrient losses Incorporate all straw: Increase 30-50% GHGE + short turn

around time for decomposition causing Methane toxicity

Partial removal Remained stubble

Incorporation supported by mechanical (shredding/

chopping) or bio-chemical (Tricoderma) treatments: still

developed and verified

Mechanized collection, baler (net profit: 10-20 USD/ton –

case in Vietnam)

What can we do better for rice straw?

Negative practices

Better practices

Some implications so far:

For what?

Scalable options (widely current use)

Mushroom + 120 USD/ton

Cattle feed Intake 1 kg/day/100kg live weight

Increase digestibility by leaching, ensilaging with Urea: needs to be developed and verified

Others: Biochar, bioenergy, hi-end materials for industry still needs to be verified for commercialized

No “one solution fits all” identify and develop good(suitable) practices corresponding to the specific riceproduction value chain/environment/market.

Contacts and further information: www.irri.org; www.ricestraw.irri.orgEmail: m.gummert@irri.org; hung.nguyen@irri.org

Thank you

IRRI joint-research group: Climate change – Agronomy – Postharvest and Mechanization on Rice straw

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