Winter Wheat Resistant to Increases in Rain and Snow Intensity in a Semi-Arid System

Martin C Holdrege,Karen H Beard,Andrew Kulmatiski

doi:10.3390/agronomy11040751

Abstract

As the atmosphere warms, precipitation events have been predicted and observed to become fewer and larger. Changes in precipitation patterns can have large effects on dryland agricultural production, but experimental tests on the effects of changing precipitation intensity are limited. Over 3 years, we tested the effects of increased precipitation intensity on winter wheat (Triticum aestivum L.; Promontory variety) in a temperate dryland agricultural system that was on a rotation of crop and fallow years. We used 11 (2.1 × 2.5 m) shelters to collect and redeposit rain and snow as larger, more intense events. Total precipitation was the same in all plots, but event sizes in each plot varied from 1 to 18 mm. Treatments increased soil water availability, but winter wheat biomass and grain yield did not differ among treatments. Similarly, other measured plant growth responses, including vegetation greenness, leaf area index, canopy temperature, photochemical efficiency, root area, and new root growth, did not differ among treatments. Results indicate that at least in the semiarid climate and silt loam soils studied here, anticipated increases in precipitation intensity are unlikely to affect winter wheat production negatively. Further, increased precipitation intensity may mitigate water stress caused by increasing temperatures and encourage the use of wheat varieties that utilize deeper, later season soil water.

Highlights

Rainfed agriculture accounts for 80% of cultivated land and 60% of food production [1]
Biotic Effects The null models best described the twice-monthly normalized difference vegetation index (NDVI) and leaf area index (LAI) measurements in both 2017 and 2019 (Table S4), indicating that treatments did not affect the seasonal trend in vegetation growth (Figure 4)
Consistent with previous observational studies that found winter wheat to be resistant to changes in precipitation intensity [18,26], we found no response of winter wheat to a wide range of precipitation intensity treatments

Summary

Introduction

Rainfed agriculture accounts for 80% of cultivated land and 60% of food production [1]. Because this type of agriculture is not subsidized by irrigation, it is sensitive to climate change, in arid and semi-arid climates [2,3]. Larger precipitation events are likely to change how water moves through the soils and, are likely to affect plant growth in agricultural, and rainfed, systems [6,7,8]. Agricultural systems may be more likely to respond negatively to increased precipitation intensity due to increased overland flow or percolation below the often shallow rooting zones

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