基于监测指标复合式控制区的耕地质量监测点布设方法

Farmland quality monitoring point layout method based on compound control zone of monitoring index

为探寻耕地质量监测点布设方法,解决现有监测点空间布局不合理、针对性不强,监测精准化程度差和监测成本过高的问题。该文以耕地地力调查与质量评价成果为数据源,在样点数据分析基础上,采用变异系数法、可视离散化法、克里格插值法、叠加法,以及误差理论和抽样理论,确定监测控制区层级、层级划分区间及与之对应的监测点位数量,形成监测指标复合式控制区,布设监测点位。以克山县为例进行技术应用,将11个指标200个监测点位进行2 200次测试化验,110 kg土壤样本消耗量、44万元监测费用的方案,优化至7个指标30个监测点位进行81次测试化验,4.05kg土壤样本消耗量、1.62万元监测费用,增强了耕地质量监测的针对性,降低了监测成本和资源消耗,且研究布设监测点位数据对耕地地力调查与质量评价数据具有较好的代表性。该方法切实可行,具有很好的应用价值,可以通过较少的投入,获取精准、较大的信息量,可为耕地质量监测点位优化提供方法借鉴。

The purpose of this research was to explore the layout method of the quality monitoring points of cultivated land, and to solve the unreasonable problem of monitoring point space layout. In this paper, the data source of the research was from the results of farmland productivity survey and quality evaluation. The SPSS software was used to establish a histogram of the number of indicators, and whether the data were continuous and were in a normal distribution was intuitively evaluated. The continuous sample data were used to determine the level and hierarchy of the monitored control area by the variation coefficient method, and according to the error theory, combined with the area control principle, the total number of monitoring points was determined and allocated into different zones according to the monitoring control zone area. For discontinuous data, if it was determined that the variation coefficient method in the monitoring control area would result in an invalid monitoring control zone level, in order to avoid this situation, visual discretization method was used to determine the level of monitoring control. The area of concentration of the target concentration was used as the monitoring control area; the data of the monitoring points after interpolation were continuous, therefore, the intermediate value was used as the endpoint value of the interval of monitoring control zone. The compound control area based on the monitoring index was divided by the space interpolation method of Kriging. The locations of the quality monitoring points of cultivated land were based on the spatial form of the control area of the compound monitoring index. The sampling theory was used to carry out a representative analysis of the monitoring points. 1） The research puts forward farmland quality monitoring point layout method based on compound control zone of monitoring index. Compared with other methods, the method takes full account of the lower relationship of the monitoring points; with specific indicators as a logical starting point, a composite control area was formed based on monitoring indicators; the degrees of homogenization and heterogeneity of the monitoring points were consistent with the monitoring indicators, which ensured that the space layout of the monitoring points was reasonable and avoided the disadvantage of redundancy for the monitoring point positions and the corresponding monitoring indices at monitoring point positions. 2） This paper takes Keshan County as an example to apply the method of monitoring point. The original program needs 11 monitoring indicators including organic matter, barrier layer thickness, plough thickness, total nitrogen, available phosphorus, available potassium, soil bulk density, slope, surface rock outcrop, soil pH value, and irrigation guarantee rate, as well as a total of 200 monitoring points and 2 200 tests, in which 110 kg soil sample and the cost of 440 000 yuan will be consumed. But after the optimization with this method, only 7 monitoring indicators are needed, including organic matter, total nitrogen, available phosphorus, available potassium, plough thickness, barrier thickness, and soil bulk density, and during the investigation process, 30 monitoring points and 81 tests are involved, along with only 4.05 kg soil sample and 16 200 yuan which will be consumed. And the monitoring point data in the layout have a good representation for the data of farmland productivity survey and quality evaluation of cultivated land. The optimized plan shows obvious advantages in monitoring pertinence, convenience and monitoring cost, and effectively improves the quality monitoring efficiency of cultivated land. This method is feasible and has good application value. It can obtain precise and a large amount of information by means of less input, which can be used for the reference for the optimization of land quality monitoring points.