Managing rice straw remains a challenge in Asia where more rice, and hence, more straw, is grown each year to meet rising demand. The widespread burning of rice straw is a major contributor to dangerously high levels of air pollution in South- and Southeast Asia associated with health issues. At the same time, researchers, engineers, and entrepreneurs are developing a range of alternative uses that turn rice straw into a commodity around which sustainable value chains can be built to benefit rural people. The best alternative to burning rice straw in any one location depends on context. However, available information remains scattered in different media and no publication yet exists that helps people learn about, and decide between, rice straw management options. This book provides a synthesis of these options and integrates knowledge on relevant areas: sustainable rice straw management practices, rice straw value chains, and business models. The book is also based on new research and practice data from research organizations and innovators in Vietnam, the Philippines, and Cambodia.

Laser-controlled land leveling (LLL) can help improve rice production's spatial and temporal management, leading to optimized water and crop management. This research resulted in sustainable performance indicators to illustrate that LLL is a sustainable technology for rice production. The assessment was conducted in Cambodia, the Philippines, Thailand, Vietnam, and India. Benefits of LLL include saving land use, water, and agronomic inputs, increasing yield, and decreasing postharvest losses resulting in saving energy of 3.0–6.9 GJ ha⁻¹and decreasing emissions by 1151–1486 kg CO₂-eq ha⁻¹. Additionally, LLL application can obtain a net profit of USD 52–84 ha⁻¹per rice production season in the countries studied. The result demonstrated that LLL is a sustainable technology as well as strongly supports sustainable rice production. The study would lead to better adoption of this technology through its evidence-based promotion.

The increasing utilization of rice combine harvesters in the Philippines has made collection of scattered rice straw difficult and laborious. While there are high demands for using rice straw, e.g., for feed or mushroom production, rice straw is predominantly burned in the field due to labor shortages and the high manual cost of collection, particularly for scattered rice straw harvested by combine harvesters. This study conducted an assessment and evaluated the feasibility of mechanized collection of rice straw by comparing the performance of two types of baler (i.e., roller and piston type) for two seasons—2019 wet and dry seasons at the International Rice Research Institute (IRRI) and in Nueva Ecija, the Philippines. The study collected data on fuel consumption, manpower requirements, and field capacity by operating the balers to collect scattered rice straw in the field and piled rice straw that was left in the field after threshing. The round baler operated at 35% lower effective field capacity (EFC) on piled rice straw than on scattered rice straw, while the square baler operated at 2.33 times and 5.79 times higher EFC compared with the round baler on piled and scattered rice straw, respectively. The square baler used for collecting scattered rice straw is more appropriate under Philippine conditions, with a significantly lower baling cost by about 68% and an average EFC that is 4.43 times higher compared to the round baler. With the increasing demand for rice straw as feedstock for ruminants and for other alternative uses, using mechanical balers to gather scattered rice straw in the field is a sustainable option for farmers to utilize the straw for value-adding purposes. This is a foremost study conducted in the Philippines to guide policy makers, development workers, and end-users on the suitability of either square balers or round balers to gather scattered rice straw in the field after rice harvesting with combines.

Rice production in the Central Plains of Thailand plays a key role in the country’s food security. However, the overuse of inputs coupled with the rising production costs are making it increasingly difficult for smallholder rice farming to remain economically and environmentally sustainable. Replicated production-scale field trials of Cost Reduction Operating Principles (CROP)—Thailand’s national package of best management practices for rice production—were established in tandem with laser land leveling (LLL), mechanical drum seeder, and the application of two biofertilizer products (i.e., PGPR II, that contains Azospirillum brasilense Sp. TS29 and Burkholderia vietnamiensis S45; and LDD #12, that contains Azotobacter tropicalis, Burkholderia unamae and Bacillus subtilis) and compared with farmer’s practices (FP). Performance indicators (PI) promoted by the Sustainable Rice Platform (SRP) were used to assess economic and environmental indicators. CROP + PGPR had significantly higher net income (79%) and nitrogen-use efficiency (57%) compared with FP. Pesticide use (28%), seed (60%), inorganic fertilizer N (41%) and total production costs (19%) were reduced in all CROP treatments compared with FP. These results demonstrate that the application of CROP, LLL, mechanical drum seeder, and biofertilizers can substantially improve the economic and environmental sustainability of rice production in the Central Plains of Thailand.

We developed an inflatable solar dryer for mushroom drying, which was adapted from the Solar Bubble Dryer^TM originally designed for paddy drying. The improved dryer with an added perforated elevated floor ensured the quality without any requirement of mixing or turning of the mushrooms during drying. Its drying performance and economic feasibility were evaluated through determination of the drying parameters including moisture content (MC) reduction, mushroom quality, energy efficiency, greenhouse gas emissions, and cost-benefits ratio. Mushroom MC was reduced from 90% down to 40–60% within 2–4 h, corresponding to the drying rate at this stage of 10–20% h⁻¹. At the next stage, it took about 4–6 h corresponding to a drying rate of 2–10% h⁻¹ to reach the required product MC of 8–10%. The color of the dried mushrooms still remained white-cream. The drying process required 4.57 MJ, emitted 0.33 kg CO₂e, and required an input cost of 1.86 $US kg of dry product. For the specific case in the Philippines, this can generate a net profit of 468–1468 $US⁻¹ year⁻¹ and the investment will break even in 1.3–4.0 years corresponding to the selling price of dry mushroom of 10–12 $US kg⁻¹. The study developed a solution to improve the solar bubble dryer and verified its drying process for mushroom drying at farm scale. It would add a significant value to farmers’ income as well as a diversified source of nutrient-rich food.

Insect pests in storage are causes of major losses worldwide. Acoustic sensors can detect the presence of insects in grain through their sound signature, thus enabling early warning to farmers and traders. This research investigates the applicability of an affordable acoustic sensor, which uses micro-electromechanical systems (MEMS) microphone adapted to detect the sound produced by insect pests. Three major insect pests that commonly feed on paddy and milled rice (the lesser grain borer, Rhyzopertha dominica; the rice weevil, Sitophilus oryzae; and the red flour beetle, Tribolium castaneum), were collected in rice mills and grain storage warehouses in Laguna The Philippines, and reared at the International Rice Research Institute. Baseline sound recordings were replicated for each insect over three days using a completely randomized design (CRD). Recorded sounds were analysed to determine the sound profiles of each insect. Waveforms, root mean square (RMS) energy values, frequency domain, and spectrograms provided characteristics for the sound signal signature specific to each insect. Primary insect pests (R. dominica and S. oryzae) were differentiated from the secondary insect pest (T. castaneum) through signal analyses. Such data are useful to enable insect pest classification, which can be incorporated into more effective and timely postharvest pest management tools.