Three types of optical sensors at wavelength ranging from visible to NIR, were used in laboratory environment for determining soil moisture content. Some index was defined to reduce measurement error caused by scatter. Two different sands and clay were tested from air dry to saturated conditions. The test results demonstrated that all tested sensors were very sensitive to soil texture and particle-size distributions. Because the wavelength from visible to NIR varies within the sizes of sand and clay, soil should not be viewed as a material with homogeneous property under optical measurement methods.

A combined penetrometer is an appropriate tool to measure the soil cone resistance and the water-content profile. As arelatively new technique, acombined capacitance-penetrometer for the simultaneous measurement of cone index and soil water content was developed at the Department of Agricultural Engineering of Bonn University in 2002. The objective of this study was the evaluation of the effectiveness and applicability of the innovated penetrometer with a focus on three aspects: (1) A capacitance sensor with two electrode configurations was calibrated for silt loam, sandy loam, and sand. The calibration results show that both electrode configurations have sufficient water-content sensitivity, but soil-specific calibrations seem necessary.(2) Under laboratory conditions, the dynamic resolution and response of the capacitance-penetrometer were validated, and its radius of influence was determined.(3) The field measurement results demonstrate that this measurement technique can be used to improve the interpretation quality of soil cone index data.

A soil moisture sensor with low-cost, reliability and sufficient accuracy has been desired for many years. This paper presented an improved measurement method based on FD principle for determining soil water content. Unlike other measurement principles, a new measurable index, which is independent of the output impedance and the amplitude of the oscillator but relies on the electric impedance of the multi-pin probe, was proposed. Moreover, a model for treating the impedance of the multi-pin soil probe was also discussed and several important electric properties were approached. In order to confirm the theoretical analysis, the necessary experiments were conducted. Finally, using obtained modeling, the relationship between the proposed index and soil volumetric water content was linearly corrected.

根据精细农业研究的实际要求，首先在不考虑外部振动的情况下设计了一种基于冲量原理的谷物流量测量试验装置。该装置由自行研制的冲量传感器、数据采集器和谷物流动模拟箱体组成。试验结果表明这种装置测量误差的绝对值小于5%。在此基础上又进行了谷物产量实时监测系统的试验研究，试验结果表明，在引入外部机械振动的情况下经过滤波处理系统测量误差的绝对值小于8%。

针对一种土壤电导率的测量方法——“电流-电压四端法”，从理论上深入探讨了该方法的测量原理，建立了对应的数学模型。关于Wenner分布、Schlumberger分布和Polar ipole分布3种测量组态计算公式的正确性也通过实验进行了检验。