农业工程学报2018，Vol.34Issue(2)：98-106,9.DOI:10.11975/j.issn.1002-6819.2018.02.013
基于茎秆直径微变化信号强度监测交替沟灌玉米水分状况
Signal intensity of stem diameter fluctuation diagnosing alternate furrow irrigation maize water deficit
摘要
Abstract
In order to evaluate the feasibility of applying signal strength to the diagnosis of alternate furrow irrigation of maize, and find out the most suitable growth period of water deficit index, the experiment was conducted in the experiment station of Key Laboratory of Agricultural Soil and Water Engineering in Arid and Semiarid Area of Ministry of Education, Northwest Agriculture and Forestry University from July to September in 2016. In the experiment, the treatments of conventional furrow irrigation (CFI), alternate furrow irrigation of high water (AFIH) and alternate furrow irrigation of low water (AFIL) were set, and the irrigation amounts of AFIH and AFIL were 2/3 and 1/2 respectively of CFI at every turn. The soil moisture content, stem diameter changes, air temperature, radiation and other meteorological factors were measured. Responses in maximum daily stem shrinkage (MDS) and stem daily increase (DI) to soil water content and meteorological factors were analyzed, 2 signal irrigation indices (SIMDSand SIDI, which were signal MDS and signal DI) were established, and the signal values were calculated by the ratio of measured values to reference values. The reference values were obtained by the regression equation of plant stem diameter indicators and meteorological factors under no water stress condition. However, water-stress index variability may increase with the increase of water stress; high variability index requires multiple measurements to reduce the error, which increases the cost, so the variability (noise value) of index and the intensity also should be considered. High signal value means the change of the indicators derived from stem diameter for soil moisture response is stronger, and high signal value means the variability of the indicators caused by the water difference is acceptable. When soil moisture changes, the signal-to-noise ratio (SNR) in the short term is greater, indicating that the index is more suitable for diagnosing the water status of plants. At the same time, if the large signal value changes can be recorded shortly after rehydration, then the change of stem diameter is more sensitive to soil moisture, that is, the sensitivity of the index is stronger. The SNR and the suitability of indices (SIMDS, SIDI) in each growth period were evaluated. The results showed that MDS and DI were easily affected by meteorological factors, and there was a weak response for the above 2 indices to soil water content. SIMDSand SIDIcould exclude the interference of meteorological factors. The SIMDSand SIDIshowed a better linear relationship with soil moisture. Stem diameter signal indicator could be used in corn moisture status diagnosis under the alternate furrow irrigation. In the different periods, signal indicator and water sensitivity showed significant differences; in jointing period, the SNR of SIDIwas larger, and the decrease range of signal intensity after rehydration was greater than the SIMDS, so SIDIwas more suitable for moisture diagnosis in jointing stage. In heading stage and maturity stage, the SNR of SIMDSwas larger than SIDI, and the sensitivity and correlation with the soil moisture content were better than SIDI, so SIMDSwas more suitable for corn moisture diagnosis in heading and maturity stage.关键词
信号分析/灌溉/水分/日最大收缩量/日增长量Key words
signal analysis/irrigation/moisture/stem maximum daily shrinkage/stem daily increase分类
农业科技引用本文复制引用
杜斌,冉辉,胡笑涛,王文娥,周始威..基于茎秆直径微变化信号强度监测交替沟灌玉米水分状况[J].农业工程学报,2018,34(2):98-106,9.基金项目
国家自然科学基金项目(51179163) （51179163）
