Crop-livestock integration provides opportunities to mitigate environmental trade-offs in transitioning smallholder agricultural systems of the Greater Mekong Subregion

CONTEXT: The Greater Mekong Subregion has been undergoing rapid agricultural transformation over the last decades, as traditional diverse subsistence-oriented agriculture is evolving towards intensified commercial production systems. Negative environmental impacts often include deforestation, nutrient pollution, and greenhouse gas (GHG) emissions. OBJECTIVE: This study aims to explore the potential of crop-livestock integration to mitigate trade-offs between economic and environmental impacts of smallholder farming systems at different stages of agricultural transition and degrees of agricultural diversity across the Greater Mekong Subregion. METHODS: We chose a ‘middle ground’ between detailed modeling of few, representative farming systems and modeling of large household populations. 24 low and high diversity farms were selected in Laos (Xieng Khouang province), Cambodia (Ratanakiri province) and Vietnam (Central Highlands) from a survey dataset of 1300 households. These farming systems were simulated with the whole-farm bio-economic and multi-objective optimization model FarmDESIGN, calculating operating profit, GHG emissions and nitrogen (N) balance. Two optimizations (‘business as usual’ vs. ‘crop-livestock integration’) were performed, generating ‘solution spaces’ or alternative configurations aiming to maximize profitability, keep farm N balanced and minimize GHG emissions. RESULTS AND CONCLUSIONS: Agricultural systems across the sites differed in their production orientation and management practices, representing various stages of agricultural transition. Nitrogen balances varied between sites, being negative in Ratanakiri (average 20.5 kg N ha 1 y 1) and Xieng Khouang ( 36.5 kg N ha 1 y 1) and positive in the Central Highlands (73 kg N ha 1 y 1). Negative balances point to unsustainable mining of nutrients due to sale of cash crops without sufficient inputs, and positive balances to the risk of environmental contamination. Total GHG emissions ranged from 0.52–8.12 t CO2e ha 1 and were not significantly impacted by stage of agricultural transformation or agricultural diversity. GHG sources in Ratanakiri and Xieng Khouang were determined by crop residue burning while in Central Highlands fertilizer and livestock were main emitters. High diversity farms obtained higher operating profits (10,379 USD y 1) than low diversity farms (4584 USD y 1). Crop-livestock integration, a combination of measures including introduction of improved forages grasses, manure recycling and residue feeding, and reduction of residue burning, resulted in larger ‘solution spaces’, thus providing farmers with more options to mitigate agro-environmental trade-offs. SIGNIFICANCE: These findings underline the potential of crop-livestock integration to support sustainable intensification pathways in the Greater Mekong region. Public and private investment in further research and extension is needed to develop and scale context-specific crop-livestock integration practices

Improving Lao goat production when resources are limited

Lao People's Democratic Republic (Lao PDR) is a small and developing nation in South-east Asia. Agriculture is its lifeblood, employing 61% of the labour force in 2019, compared to 2.6% in Australia (The World Bank 2021). Small family farms are predominant, relying on rice and crop cultivation to feed the household and generate surplus for income. Livestock are essential for providing manure, consuming non-edible plants and household waste, and serving as a bank account, to be sold when cash is needed. While these systems are vital for human survival, as a tool for household economic growth, there is room for improvement. Goats are gaining popularity among Lao farmers due to their strong export potential. Neighbouring Vietnam is a major importer of Lao goats which receive a price premium of 30% over Vietnamese crossbred goats and Lao farmers keep approximately 70% of the slaughter value (Gray et al. 2019). The objective of this study was to assess the current level of inputs to understand the scope to improve goat production. A structured survey was conducted of 70 smallholder farmers raising goats in the main goat raising province of Savannakhet in central Lao PDR and was approved by University of New England Human Ethics Committee (HE19-218). The survey was conducted in the local language, responses were recorded using mobile acquired data software CommCare® (Dimagi Ltd. Cambridge, MA, USA), and descriptive statistics were generated. Farm capital was limited, with a low annual income (AU$1558/year, range = AU$249–6981), a dependence on family labour, and participation in a diverse range of enterprises to ensure household resilience to shocks. This meant there would be trade-offs to high-input investments in goat raising. Farmers reported limited access to animal health services and most relied on neighbours (67%) and family (57%) for information. Farmers had reasonable access to water and land (3.6 ha, range = 0–20 ha). Most farmers (64%) depended completely on free grazing of communal land for goat nutrition and grazed goats for 6 h/day in the wet season and 8 h/day in the dry season. This was predominantly unsupervised. This illuminated increasing grazing duration as a possible low risk intervention to boost nutrition. Uncontrolled breeding resulted in year-round kidding which coincided with low nutrition availability for goats in the late dry and early and late wet seasons (Fig. 1). Increased cropping activity likely reduced grazing duration and nutrition available for goats in the late wet season. Growing forages utilising available land with strategic feeding and/or fodder conservation were recommended. Most farmers viewed disease as the main constraint to production, particularly facial lesions (most likely Orf" 87%) and diarrhoea (57%). Disease management was reactive and unregulated, with 61% of farmers responding by opting for drugs to treat illness, and when asked how they obtained them, 74% purchased them themselves from stores. Increasing farmer disease knowledge through participatory training sessions and explanation of low-cost, accessible and practical treatments are being implemented to directly empower farmers as animal health services are limited. Improving goat house hygiene is one of the low-input preventive strategies that are also being pursued. These data reflect a low-input system with limited capital. A project has commenced optimising current inputs to maximise productivity outputs while maintaining a low-input system. Social and lifestyle benefits are also being monitored as they are required to motivate households to adopt new management strategies when resources are limited

Sale of fresh forage: a new cash crop for smallholder farmers in Yasothon, Thailand

This paper describes the emergence of a new cash-crop enterprise the sale of fresh forage for smallholder farmers in Yasothon, northeast Thailand. In 1999, a group of 13 farmers started to produce forages for sale to beef cattle producers and traders. By 2006, this had grown to the extent that more than 600 farmers were growing and selling fresh forage. A study was carried out to describe the forage-for-sale production system and to evaluate its profitability and sustainability. Methods used included farmer group discussions, semi-structured interviews with individual farmers, weighing of forage samples and soil and plant analyses. The main forage species grown for sale was Panicum maximum cv. Simuang (purple guinea grass), a high-yielding, upright, leafy grass. Production was very intensive with plants grown at a spacing of 50 × 50 cm, with high rates of both organic and inorganic fertilisers and some irrigation. Average forage yields were 33 t DM/ha/yr in the establishment year and 46 t DM/ha/yr in subsequent years. Mean protein concentration (DM basis) in forage offered for sale was 10% in the wet season and 14% in the dry season. Net returns were very high (US$2500 3800/ha/yr), which far exceeded the gross return of US$590/ha/yr from rice production. Farmers replanted guinea grass after 2 3 years. Prices for fresh forage were highest in the late dry season (US$0.042/kg), when prices were almost twice those during the peak of the wet season (US$0.025/kg). Only farmers with access to irrigation could supply during this time and, by 2006, the production of forage for sale had shifted towards irrigated areas. An issue of concern is the imbalance between nutrient off-take by removal of cut forage and current fertiliser applications, which are urea and chicken manure. Chicken manure has an N:P:K nutrient ratio of 1:1:0.7. The use of these fertilisers results in an oversupply of 200 400 kg/ha of phosphorus per year and a large deficit of potassium. One possible solution would be to substitute cattle manure, with a more suitable N:P:K ratio of 1:0.3:0.8, for chicken manure. Cattle manure is available locally and used on-farm by farmers raising cattle but is not traded extensively. Another option would be to make use of single-nutrient fertilisers to better balance fertiliser applications and nutrient off-take. Unfortunately, these are not readily available in north-east Thailand. The sale of fresh forage has emerged as a new farm enterprise, providing high returns for smallholder farmers with access to markets and irrigation facilities. The system must be fine tuned by balancing nutrient supply more closely with nutrient off-take to ensure the long-term sustainability of the venture

Nutritive value of tropical forage plants fed to pigs in the Western provinces of the Democratic Republic of the Congo

The nutritive value of 20 forage plants commonly used for feeding pigs in the Democratic Republic of the Congo was studied to determine chemical composition, protein amino acid profiles, mineral content, and in vitro digestibility using a two-step method combining an enzymatic pepsin and pancreatin hydrolysis followed by a 72 h gas-test fermentation. The highest protein contents (270–320 g/kg DM) were obtained for Vigna unguiculata, Psophocarpus scandens, Leucaena leucocephala, Manihot esculenta, and Moringa oleifera. Grasses, Acacia mangium, and Eichhornia crassipes, showed the lowest crude protein (CP) and highest NDF contents. Cajanus cajan and Trypsacum andersonii had the most balanced amino acid profile, being deficient in lysine and slightly deficient in histidine, while Megathyrsus maximus displayed the highest number of essential amino acids deficiencies. High mineral contents were obtained from, in ascending order, with M. oleifera, V. unguiculata, E. crassipes, Ipomea batatas and Amaranthus hybridus. In vitro dry matter digestibility ranged from 0.25 to 0.52, in vitro CP digestibility from 0.23 to 0.80, in vitro energy digestibility from 0.23 to 0.52. M. esculenta, M. oleifera, I. batatas, Mucuna pruriens, V. unguiculata, P. scandens and A. hybridus showed high digestibilities for all nutrients. Gas production during fermentation of the pepsin and pancreatin-indigestible fraction of the plants varied from 42 ml/g DM for A. mangium to 202 ml/g DM for I. batatas (P<0.001). Short-chain fatty acid production during fermentation varied from 157 to 405 mg/g of the pepsin and pancreatin indigestible fraction. It is concluded that some of these species are interesting sources of proteins and minerals with a good digestibility that might be used more economically than concentrate, especially in smallholder production systems, to improve pig feeding, mineral intake and intestinal health in pigs reared in the tropics