Cover Crop Effects on Corn Plant Sap Flow Rates and Soil Water Dynamics

Abstract

Cover crops (CC) are used for soil quality improvement. However, the effects of CC on soil water availability for cash crop is yet inconclusive. Plant sap flow measurement techniques are among the most reliable methods to evaluate water stress and water consumption by measuring the whole‐plant transpiration. The objective of the study was to quantify plant sap flow dynamics in corn (Zea mays L.), soil water dynamics, and corn yields in response to CC and no cover crop (NCC) management. The study was conducted at Bradford Research Center, University of Missouri, Columbia, in 2017 and 2018. A Dynamax Flow32‐1K sap flow measurement system and a CR1000 data logger with Dynagage sensors were used to measure sap flow rates. Volumetric soil moisture (VSM) content was estimated at 15‐min intervals by Campbell CS‐616 sensors installed at 10‐, 20‐, and 30‐cm soil depths in 2018. The NCC corn plants had greater daily average sap flow rates early and lower sap flow rates later in the season compared with CC. The CC treatment showed significantly greater VSM than NCC, with 14, 12, and 4% greater values at 10‐, 20‐, and 30‐cm depths, respectively. Corn yield in 2017 was significantly greater in NCC treatment than in the CC treatment, with values of 8.07 Mg ha−1 in CC and 9.41 Mg ha−1 in NCC. This study revealed that soils of CC treatment maintained greater soil moisture conditions and provided more water to corn plants for a longer period.