The impact of drought stress on the yields and food value of selected forage grasses

Mariola Staniak

doi:10.5586/aa.1663

Abstract

The aim of the study was to compare yields and nutritional value of selected species and cultivars of forage grasses under the optimal moisture conditions and long-term drought stress. The regenerative capacity of plants after dehydration was also assessed. The pot experiment was conducted in years 2009–2010 in IUNG-PIB’s greenhouse in Puławy, Poland. Nine cultivars of four species: Dactylis glomerata (‘Amera’, ‘Minora’), Festuca pratensis (‘Skra’, ‘Fantazja’), Festulolium braunii (‘Felopa’, ‘Agula’, ‘Sulino’), and Lolium multiflorum (‘Gisel’, ‘Lotos’) were investigated in well-watered conditions (70% field water capacity – FWC) and under a long-term drought stress (40% FWC).The study showed that stress caused by soil moisture deficiency significantly reduced yields of D. glomerata, F. pratensis, F. braunii, and L. multiflorum. The total yield of dry matter under stress conditions was about 31% lower, compared to the performance achieved on the optimally moisturized treatment. The smallest reduction in dry matter yield under the conditions of water deficit was recorded for D. glomerata, which makes it the most resistant to stress, followed by F. pratensis. The resistance of F. braunii and L. multiflorum to stress was similar and significantly lower. There was a various response of different grasses to the water stress. On the basis of the value of the DSI (drought susceptibility index), the tested cultivars were ranked depending on the sensitivity to drought, starting with the most resistant cultivar: ‘Minora’, ‘Skra’, ‘Fantazja’, ‘Amera’, ‘Sulino’, ‘Agula’, ‘Gisel’, ‘Lotos’, and ‘Felopa’. The digestibility of dry matter and nutrient value of the grasses depended on both the level of soil moisture and grass species. Under the water stress, the digestibility and protein value increased compared to the control objects. Lolium multiflorum and F. braunii had the best nutritional value, while D. glomerata – the weakest.

Highlights

In Poland there are more and more frequent periodic water shortages on large areas of country, which cause large losses in agricultural production [1,2,3,4]
The results of the research have confirmed that D. glomerata, F. pratensis, F. braunii, and L. multiflorum had significantly lower dry matter yields in condition of water stress
The smallest reduction in dry matter yield under stress was recorded for D. glomerata and F. pratensis, while significantly higher for F. braunii and L. multiflorum

Summary

Introduction

In Poland there are more and more frequent periodic water shortages on large areas of country, which cause large losses in agricultural production [1,2,3,4]. Severe droughts occurred in the years of: 2005, 2006, 2008, 2010, 2011, 2013, and 2015 [5]. According to Doroszewski et al [6], after 2000 in Poland, in spring and early summer, CWB values have been getting lower and lower, which means that droughts are becoming more and more severe. This coincides with a period when plants have the highest demand for water, which leads to a number of negative environmental and economic consequences

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Conclusion