GrassCARB: a tool to identify grassland sites for enhanced soil organic carbon sequestration

农民和他们的顾问收集并发送土壤样本进行分析，以确定他们的土壤有机质（SOM）浓度，当整个英格兰的草地被考虑为农业环境计划时。到目前为止，自然英格兰已经有了一个10000个土壤分析的数据库。他们经常问的问题是：我们应该期望在特定领域的土壤中发现多少土壤有机质？目前还没有有效的方法来回答这个问题。该项目的目的是为自然英格兰的顾问提供一个简单的工具（GrassCARB），该工具将提供土壤中有机物可能浓度的估计，以及相关不确定性的估计。根据已发表的研究，GrassCARB模型将使用已知影响草地中SOM浓度的因素组合来开发。例如，低洼潮湿地区的农田通常比干旱地区的土壤有机质更多。此外，粘土状物质占较大比例的土壤往往比砂状（砂状）物质占主导的土壤具有更大的浓度。我们可以利用这个和其他来自国家尺度数据集的信息，以及每次土壤分析提供的信息，来改进对SOM浓度的预测。此外，距离较近的田地通常比距离较远的田地具有更多相似的性质，因此我们将使用GrassCARB土壤数据库中的测量位置来改进我们对SOM浓度的局部预测。一旦模型建成，我将使所有的农场顾问从自然英格兰通过一个简单的网络界面，他们可以访问。每次使用该模型时，都可以将新站点的SOM数据添加到模型中。我将用一组农场顾问来测试这个模型，并提供一组使用说明。然后，GrassCARB可以用来确定那些SOM浓度低于预期的地点——在这些地方，土地管理的变化可能导致SOM在几年内储存，从而有助于土壤碳封存。这是作为巴黎气候协议一部分支持的每英里4英里倡议的主要目标。我将调查GrassCARB与英国和国际上其他土壤倡议的关系。

Farmers and their advisers collect and send soil samples for analysis to determine their soil organic matter (SOM) concentration when grassland sites across England are considered for Agri-Environment schemes. To date Natural England have a database of 10 000 soil analyses. The question they often ask is: how much soil organic matter should we expect to find in the soil in a particular field? Currently there is no effective way to answer this question. The aim of this project is to provide advisers from Natural England with a simple tool (GrassCARB) that will provide an estimate of the likely concentration of organic matter in the soil, and an estimate of the associated uncertainty. The GrassCARB model will be developed using a combination of factors which, based on published studies, are known to influence SOM concentrations in grasslands. For example, fields in low-lying, wetter areas typically have more soil organic matter than those in dry parts of the landscape. Also, soils with a larger proportion of clay-sized material tend to have larger concentrations than soils dominated by sandy (sand-sized) material. We can use this and other information from national scale datasets, and that provided with each soil analysis, to improve the predictions of SOM concentration. It is also the case that fields close together typically have more similar properties than those further apart, and so we will use the locations of measurements in the soil database in GrassCARB to improve our local predictions of SOM concentrations.Once the model has been built I will make it accessible to all the farm advisers from Natural England through a simple web-interface which they can access. Each time the model is used, SOM data from new sites can be added to it. I will test the model with a set of farm advisers and provide a set of instructions on its use. GrassCARB could then be used to identify those sites with lower than expected SOM concentrations - these are places where changes in land management could lead to storage of SOM over a few years and therefore contribute to soil carbon sequestration. This is the main objective of the 4 per mille initiative which was supported as part of the Paris climate agreement. I will investigate how GrassCARB relates to other soil initiatives in the UK and internationally.