A is expanding into the tropical forests and savannas of South America, Southeast Asia, and subSaharan Africa, fueled by growing global demand for food commodities and attracted by vast expanses of inexpensive land in a climate well suited for intensive agricultural production. However, the capacity of these regions to keep pace with demand may be affected by a largely overlooked factor: the largescale conversion of remaining undeveloped land to planted pastureand croplands disrupts the climaterelated ecosystem services that such lands provide to farmers, ranchers, and local communities (Strand et al. 2018). In addition, agricultural productivity, profitability, and food security will likely be adversely impacted by shifts in seasonality and rainfall patterns. These landuse– climate feedbacks could initiate a selfperpetuating cycle of declining agricultural yields and increasing cropland expansion. To address this topic, we focus on the “climate risk” (defined below) faced by the soy (Glycine max)–maize (Zea mays) doublecropping (DC) system in the northern Mato Grosso, Brazil. This region straddles the southern fringe of the Amazon biome and the northern fringe of the cerrado (Brazilian savanna) biome (Figure 1). In 2012, 7.1% of the world’s soybeans and 1.4% of the world’s maize were produced in this region, and between 2004 and 2012, soybean production increased 58% and maize production increased 359% (mainly as a second crop). Located along the Amazon’s arc of deforestation (the region in southern and eastern Amazonia where the highest rates of deforestation are found), northern Mato Grosso has lost about 10.9 million ha of rainforest and 8.3 million ha of cerrado over the past several decades, yet 76% of rainforest and 66% of cerrado still remain intact (Dias et al. 2016). The long rainy season characteristic of northern Mato Grosso accommodates production of two crops per growing season (Arvor et al. 2014). This DC system has become ubiquitous throughout the region because it provides more revenue per plot, greater income diversification, and reduced pest pressure, as well as helping to maintain a more stable pool of farm labor (Richards et al. 2015). Double cropping has also been an important factor in landuse intensification. Because the region’s agriculture is almost exclusively rainfed, yields of both crops are subject to fluctuations in weather patterns. Doublecropped agriculture requires a rainy season that consistently starts within a specific date range, lasts long Climate risks to Amazon agriculture suggest a rationale to conserve local ecosystems

中文翻译：

---

亚马逊农业面临的气候风险表明了保护当地生态系统的理由

A 正在扩展到南美洲、东南亚和撒哈拉以南非洲的热带森林和热带稀树草原，受到全球对粮食商品不断增长的需求的推动，并被大片廉价土地和适合集约化农业生产的气候所吸引。然而，这些地区跟上需求的能力可能受到一个很大程度上被忽视的因素的影响：剩余未开发土地大规模转变为种植牧场和农田，破坏了这些土地为农民、牧场主和当地社区提供的与气候相关的生态系统服务。斯特兰德等人，2018 年）。此外，农业生产力、盈利能力和粮食安全可能会受到季节性和降雨模式变化的不利影响。这些土地利用-气候反馈可能会引发农业产量下降和农田扩张增加的自我延续循环。为了解决这个话题，我们重点关注巴西马托格罗索州北部大豆（Glycine max）-玉米（Zea mays）双作（DC）系统面临的“气候风险”（定义如下）。该地区横跨亚马逊生物群落的南部边缘和塞拉多（巴西稀树草原）生物群落的北部边缘（图 1）。2012年，全球7.1%的大豆和1.4%的玉米产自该地区，2004年至2012年间，大豆产量增长58%，玉米产量增长359%（主要作为二茬作物）。位于亚马逊的森林砍伐弧线（亚马逊南部和东部的森林砍伐率最高的地区），在过去的几十年里，马托格罗索北部失去了大约 1090 万公顷的热带雨林和 830 万公顷的塞拉多，但 76% 的热带雨林和 66% 的塞拉多仍然完好无损（Dias 等人，2016 年）。马托格罗索州北部的长雨季特点使每个生长季节可以生产两种作物（Arvor 等人，2014 年）。这种 DC 系统在整个地区变得无处不在，因为它提供了更多的每块土地收入、更大的收入多样化、减少了虫害压力，并有助于维持更稳定的农业劳动力储备（Richards 等人，2015 年）。双熟也是土地利用集约化的一个重要因素。由于该地区的农业几乎完全靠雨养，两种作物的产量都受天气模式波动的影响。