Evaluation of FDR MI2X and New WiTu Technology sensors to determine soil water content in the corn and weed field

Abstract

Accurate determination of soil water contents (SWC) is crucially important in many scientific fields, particularly in agriculture. In this study, the performance of conventional FDR MI2X and New WiTu Technology water sensors was statistically evaluated under the impact of changing vegetative cover type (corn and weeds). A three replicated randomized complete block design (RCBD) field experiment was conducted from late April to August, 2019. The spring corn Nongda-1505 variety was planted and the field was left unsown to allow weeds to grow. To determine the SWC, six WiTu Technology sensors were installed in the middle of each plot. For FDR sensor measurements, PVC tubes were inserted at 30 cm distance from WiTu sensors and soil samples from the 0-20 cm, 20-40 cm and 40-60 cm depths were taken using soil sampling auger for measurement of gravimetric water content. Both FDR and new Technology of WiTu sensors showed varied performance as soil depth increased from the top layer to deep layer. FDR efficiency was significantly high at the topsoil layer (0-20 cm) with an average accuracy level of 98.01% and reduced in the middle soil layer to 91.78%, then increased to 95.13% in the deep soil layer. While, the average accuracy of the WiTu Technology sensor ranged 98.24%, 95.85% and 92.02% for top, middle and deep soil layers, respectively, these results demonstrate that the soil water detection ability of WiTu Technology is high at the soil depth of 0-40 cm, whereas FDR's ability to detect SWC changes is satisfactory in top to deep layers and low in the middle layer. Furthermore, the FDR showed good consistency with WiTu in all soil layers of the corn field, but there was a larger error for the weed field, which indicated a huge difference in the data measured by FDR and WiTu Technology. The SWC estimation of FDR and WiTu technology more fluctuated with changing vegetation cover type. Thus, the findings of this study provide an opportunity to further study on FDR MI2X and New WiTu Technology sensors for deep-rooted crops under the soil and climatic conditions of Zhengzhou, China.