Supplementary Tables (S1-S7 Tables).

India is the world’s largest edible oil importer, and soybean oil accounts for a major portion of those imports, with implications for the Indian economy. Despite being the 4th largest globally in terms of harvested soybean area and 5th largest in terms of production, India is still heavily dependent on imports to meet the vegetable oil requirement for its population. It is therefore imperative to understand the dynamics and trends in India’s soybean production to help the country achieve self-sufficiency in edible oils. This study provides the first spatially explicit analysis of soybean in India, using long-term spatial and temporal statistics at national and subnational levels, using spatial and temporal statistical analysis models to examine the historical trends and its future prospects. Our analysis details the overall soybean expansion across the country and the increase in production but we also note that the annual growth rate has declined in each consecutive decade even though the area continues to expand. The average national yield has been stagnant at around 1 T/Ha but for some of the low-producing districts, a higher yield of more than 3 T/ha is reported. For most major producing districts, soybean yields are below 1.5 T/Ha. The state of Madhya Pradesh which was the major soybean producer is now matched by the state of Maharashtra in terms of production, however, Madhya Pradesh still has the largest area under soybean. We analyzed soybean hotspot expansion in India and found that the mean center of the soybean area and production has shifted approximately 93 km towards the south and 24 km to the west as the crop is rapidly being adopted in the southern and western parts of India expanding the hotspot in these parts. District-level analysis showed that the total number of districts constituting hotspots of soybean cultivation in India has increased from 29 to 42 in three decades. Furthermore, analysis of soybean oil and meal consumption with respect to the national population, import, export, domestic production, GDP per capita, and price of soybean oil and meal suggests that soybean oil and meal are highly correlated with GDP per capita and population, indicating that consumption of soybean oil and meal is likely to increase as GDP per capita increases, and future demand is expected to rise with the anticipated growth in the Indian population. Increased soybean production can play a significant role in increasing national food security for India and reducing dependence on foreign oil imports and also help the economy with soy meal exports. Understanding the spatiotemporal variability in area and yield will help target interventions to increase production. Given the overall low yields with high variability in production, particularly in recent years primarily due to successive extreme rains and droughts in major producing districts and the overall need to increase production to meet the country’s demand, there is a pressing need for government policies and research aimed at narrowing the yield gap and developing soybean varieties that are more productive and resilient to climate change.

印度是全球最大的食用油进口国，大豆油在其食用油进口中占据核心份额，这一现状对印度国民经济影响深远。尽管印度大豆收获面积位列全球第四、总产量位居全球第五，但其仍高度依赖进口以满足国内民众的植物油需求。因此，厘清印度大豆生产的动态与趋势，对该国实现食用油自给自足至关重要。本研究首次针对印度大豆开展空间显性分析（spatially explicit analysis），依托国家及次国家层面的长期时空统计数据，运用时空统计分析模型探究其历史趋势与未来前景。分析不仅揭示了全国范围内大豆种植规模的扩张与总产量的提升，同时也指出：尽管种植面积持续扩大，但每十年的年均增长率均呈下滑态势。全国平均单产长期停滞在约1吨/公顷，但部分低产县的单产可达3吨/公顷以上；而多数主产县的大豆单产均低于1.5吨/公顷。曾为大豆主产省的中央邦（Madhya Pradesh），如今其总产量已与马哈拉施特拉邦（Maharashtra）不相上下，但中央邦的大豆种植面积仍居全国首位。我们还分析了印度大豆种植热点区域的扩张情况，发现随着印度南部与西部省份快速推广大豆种植，大豆种植面积与总产量的几何中心已分别向南偏移约93公里、向西偏移24公里，热点区域也随之向这两大区域拓展。县级层面分析显示，三十年间印度大豆种植热点县的总数已从29个增至42个。此外，结合全国人口、进出口、国内产量、人均GDP以及大豆油与豆粕价格开展的消费分析表明：大豆油与豆粕的消费量与人均GDP、人口规模高度相关，意味着随着人均GDP提升与印度人口增长，大豆油与豆粕的消费量有望持续攀升，未来需求预计将随人口增长而进一步扩大。扩大大豆生产对提升印度国家粮食安全、降低食用油进口依赖意义重大，同时还可通过大豆粕出口助力国民经济发展。明晰种植面积与单产的时空变异特征，有助于精准制定增产干预措施。鉴于当前整体单产水平偏低且生产波动较大——近年来主产县接连遭遇极端降雨与干旱灾害更是加剧了这一问题——加之国内亟需提升产量以满足国内需求，印度亟需出台相关政策并开展研究，以缩小单产差距、培育高产且更适应气候变化的大豆品种。