把土壤变成海绵

A devastating problem that's getting worse

在美国，洪水和干旱加起来造成的损失估计高达340美元.自1980年以来的40亿美元. And farmers and 农场主 are among the most affected, as floods and droughts devastate livestock, 作物, 和土壤.

Taxpayers share in the burden through subsidized federal crop insurance programs. Insurance payouts due to floods or droughts totaled $38.在2011年至2016年期间，这一数字预计将继续上升，因为617888九五至尊娱乐变化带来了更多的极端天气.

这些灾难的影响并不局限于农民或为他们投保的纳税人. Communities located downstream from farming regions feel the effects as well, 洪水毁坏房屋, 企业, 和基础设施.

海绵土壤可以拯救我们

Farmers can't make it rain—or make it stop. 但他们可以做一些事情，使他们的土地不那么容易受到极端天气的影响.

Over the past several decades, 农业已经越来越多地转向以几种一年生作物为主的系统——典型的是玉米和大豆——在生长季节之间，田地常常是光秃秃的. This trend has degraded soil structure, leaving it less like a sponge and more like concrete, which exacerbates the damage done by floods and droughts. 为了对抗这些影响, 农民已经尝试了投资灌溉设备或排水系统等选择. 但这些并不总是长期的解决方案，它们本身也会产生破坏性的影响.

有一个更好的方法:通过建立具有海绵状蓄水能力的更健康的土壤来解决问题的根源. Several farming practices have been linked to improved soil health, 他们有一个共同点:他们全年都把有活根的植物种在土壤里.

报告发现了什么?

Incorporating more than 150 field-scale experiments from six different continents, 该分析评估了具体做法对土壤特性的影响，如水进入和通过土壤的速率(渗透速率)。, the spaces between soil particles (pore space or “porosity”), and the amount of water made available to plants. The authors identify "continuous living cover," which can be achieved through incorporating deep-rooted perennials, 覆盖作物, consistently and effectively improving soil health.

该报告随后展示了如果在中西部一个具有代表性的农业州大规模采用持续的生活保障措施，将如何改善洪水和干旱的后果, 从爱荷华州已经是最贫瘠和最容易被侵蚀的地区开始.

Some of the report's findings:

• 在分析的70%的实地研究中，保持土壤不耕并覆盖有活的植物可以提高其吸收水分的能力.
• Water infiltration rates improved by 59 percent with perennial 作物, 35 percent with 覆盖作物, and 58 percent with improved grazing practices.
• 将爱荷华州大约三分之一的农田——如今利润最低、最易被侵蚀的土地——转变为多年生作物, or to corn or soybeans grown with a winter cover crop, would result in significant water savings. 在最近的极端天气事件中，它将减少高达20%的水径流，并减少相同数量的洪水频率.
• 在1988年和2012年的严重干旱期间，每次都造成了超过300亿美元的损失，采用土壤改良措施可以使作物可利用的水分增加16%.

建议

报告中强调的做法可以给农民带来巨大的利益, 纳税人, and surrounding communities. But there are also significant barriers to their adoption, including up-front costs and the need for training and technical assistance. 还需要更多的研究来帮助农民优化特定作物的土壤改良措施, 土壤, and weather conditions they work with.

To help overcome these barriers, the report offers several policy recommendations:

• Expand incentives and strengthen up-front financial support 帮助农民采取土壤管理措施，提高抗洪抗旱能力. 这包括在联邦保护管理计划中加强对良好土壤管理实践的支持, 通过区域保护合作计划促进州和地区的解决方案, 并通过环境质量激励计划鼓励合作解决方案.
• Provide incentives in the federal crop insurance program to reduce flood and drought risks up-front through good soil management. 这包括将土壤质量和管理指标纳入保险费计算, improving enforcement of minimum conservation requirements for policy holders, incorporating ecological principles, 通过推广整个农场的保险政策，而不是一次只保险一种作物，来鼓励多样化的农场.
• 投资研究 将多年生植物和其他土壤管理实践纳入各种农业景观的最佳效益.