The Effect of Controlled Tile Drainage on Growth and Grain Yield of Spring Barley as Detected by UAV Images, Yield Map and Soil Moisture Content

Abstract

Controlled tile drainage (CTD) practices are a promising tool for improving water balance, water quality and increasing crop yield by raising shallow groundwater level and capillary rise due to drainage flow retardation. We tested the effect of CTD on growth and grain yield of spring barley, at a study site in central Bohemia using vegetation indices from unmanned aerial vehicle (UAV) imagery and Sentinel-2 satellite imagery. Tile drainage flow was slowed by fixed water level control structures that increased soil moisture in the surrounding area according to the terrain slope. Vegetation indices based on red-edge spectral bands in combination with near-infrared and red bands were selected, of which the Normalized Red Edge-Red Index (NRERI) showed the closest relationships with shoot biomass parameters (dry biomass, nitrogen concentration and uptake, nitrogen nutrition index) from point sampling at the tillering stage. The CTD sites showed significantly more biomass using NRERI compared to free tile drainage (FTD) sites. In contrast, in the period prior to the implementation of CTD practices, Sentinel-2 satellite imagery did not demonstrate higher biomass based on NRERI at CTD sites compared to FTD sites. The grain yields of spring barley as determined from the yield map also increased due to CTD (by 0.3 t/ha, i.e., by 4%). The positive impact of CTD on biomass development and grain yield of spring barley was confirmed by the increase in soil moisture at depths of 20, 40 and 60 cm compared to FTD. The largest increase in soil water content of 3.5 vol% due to CTD occurred at the depth of 40 cm, which also had a higher degree of saturation of available water capacity and the occurrence of crop water stress was delayed by 14 days compared to FTD.

A New Concept of Flashboard Risers in Controlled Drainage Structures

“…CD is expected to contribute to more sustainable water development over conventional drainage by giving the farmer more flexibility in terms of water management [17]. In the literature, we can also find other WCS synonyms such as drainage control structures (DCS) [18][19][20], outlet control structures (OCS) [13,21,22], water level control structures (WLCS) [23][24][25][26][27][28], water table control structures (WTCS) [10,29,30], and hydraulic control structures (HCS) [31]. All of these structures allow farmers to set the drainage outlet at a definite level between the ground surface (undrained condition) and the drain depth (conventional drainage) [12].…”

“…Yet, another type of WCS is to use PVC pipes consisting of a drainage T-branch, polypropylene gate, and a PVC pipe vertically connected to the T branch. In this case, Duffkowa et al [28] used a fixed WLCS at a few drainage laterals connected with each other by a T branch. It helps to maintain the groundwater level at 40 cm below the soil surface.…”

Predicting the Optimum Corn Harvest Time via the Quantity of Dry Matter Determined with Vegetation Indices Obtained from Multispectral Field Imaging

“…Imaging agricultural areas is enabled through satellites and hyperspectral or multispectral cameras [1]. These are employed not only in remote sensing, but also, for example, in detecting dying trees infested with pests [2], rotten or mechanically damaged fruit and vegetables [3], recognizing fecal pollution [4], establishing cold-induced deterioration of cucumbers [5], measuring fruit ripening [6], classifying wheat kernels infected with fungi [7], and many other applications [8,9]. Recently, the actual approach and associated methodologies have been developing substantially.…”