Improving Net Photosynthetic Rate and Rooting Depth of Grapevines Through a Novel Irrigation Strategy in a Semi-Arid Climate

Abstract

Direct root-zone irrigation (DRZ) is a novel subsurface irrigation strategy initially tested in vineyards for economizing water and securing grape production in arid regions with unstable climatic patterns. However, studies are lacking on the responses of grapevine leaf carbon assimilation and deep rooting patterns to the novel irrigation strategy, which are essential for optimizing grapevine growth and alleviating extreme water stress during periods of heat and drought. Thus, a two-year field study was conducted in a commercial vineyard of Cabernet Sauvignon (Vitis vinifera L.) under a semi-arid climate in Washington, USA to compare the differences in leaf gas exchange and root distribution along the 0-160 cm soil profile, combined with measurements of specific leaf area and total carbon and nitrogen content in leaves and shoots to compare DRZ and traditional surface drip irrigation (SD) under three watering regimes. Compared to SD, significantly higher rates of net CO 2 assimilation, stomatal conductance and transpiration in leaves, which positively correlated to midday stem water potential, were found in grapevines irrigated through DRZ in both years. Meanwhile, DRZ reduced total root number by 50-60% and root length density (RLD) by 30-40% in the upper 60 cm soil at high (0.75-0.80 crop evapotranspiration) and moderate (0.60-0.65 crop evapotranspiration) irrigation rates, but no significant differences were found at low (0.45-0.50 crop evapotranspiration) irrigation rate between DRZ and SD. Higher root number and RLD were detected under DRZ within 60-160 cm soil depths, accompanied by a decreased ratio of total carbon to nitrogen content in leaves with slightly increased specific leaf area. Decreased rainfall and increased temperature in 2018 possibly amplified the positive effects of DRZ. Our study indicates that grapevines under DRZ could develop deeper roots for water uptake, which helps ameliorate water stress and improve the photosynthetic rate as well as enhance grapevine adaptation to semi-arid climates.

A 2020 Vision of Subsurface Drip Irrigation in the U.S.

“…Fifteen studies sought to measure a specific response to SDI or to improve SDI performance (table 4 when including the three DRZ studies by Ma et al (2020aMa et al ( , 2020b and Zúñiga-Espinoza et al (2016) from the upper subcategory).…”

“…The irrigation delivery rate (volume per irrigation event) was found (Ma et al, 2019) to be more important for maintaining grape water status than the DRZ depth (e.g., 0.3, 0.6, or 0.9 m), with a moderate delivery rate saving water without greatly reducing yield as compared to the higher delivery rate. Later studies appeared to concentrate more effort on the intermediate 0.6 m depth (Ma et al, 2020a(Ma et al, , 2020b. Another DRZ study in Washington (Chakraborty et al, 2019) found that canopy structures for apple trees and wine grapes were not greatly affected by DRZ depth and were not affected by irrigation delivery rate, although the researchers indicated that winter snowpack may have influenced the results.…”

Narrowing row spacing and adding inter-block promote the grain filling and flag leaf photosynthetic rate of wheat under enlarged drip tube spacing system

“…As an advanced water-saving irrigation technology, drip irrigation can simply, accurately, and stably transport a small amount of water to the roots of crops ( Ma et al., 2020 ), with an irrigation efficiency as high as 75%–95% ( Ward and Pulido-Velazquez, 2008 ). Applying drip irrigation technology to wheat production is the direction of agricultural development in Xinjiang and other arid agricultural areas of China ( Wan et al., 2022 ).…”

Effects of Different Drip Irrigation Patterns on Grain Yield and Population Structure of Different Water- and Fertilizer-Demanding Wheat (Triticum aestivum L.) Varieties

“…However, because Xinjiang is located in the hinterland of Eurasia, more than half of the wheat planting areas have an annual precipitation of less than 100 mm and potential evapotranspiration of up to 2000-3000 mm [5,6]. Drip irrigation technology has been rapidly promoted in wheat production in Xinjiang since 2008 because of its advantages of water saving, yield increasing, and labor saving [7,8]. However, due to the whole drip irrigation system is transplanted from cotton [9,10], the relevant theoretical basis is weak, and its mechanism research is not mature enough [11,12], which makes it difficult to achieve the goal of efficient resource utilization and sustainable income increasing when drip irrigation system were used to wheat production.…”