Tree Wind Breaks in Central Asia and Their Effects on Agricultural Water Consumption

Abstract

Across Central Asia, agriculture largely depends on irrigation due to arid and semi-arid climatic conditions. Water is abstracted from rivers, which are largely fed by glacier melt. In the course of climate change, glaciers melt down so that a reduced glacier volume and reduced water runoffs are expected to be available for irrigation. Tree wind breaks are one option to reduce water consumption in irrigated agriculture and build resilience against climate change. This paper therefore assesses the water consumption of major crops in Kyrgyzstan and adjacent areas, i.e., cotton (Gossypium hirsutum L.), wheat (Triticum aestivum L.), corn (Zea mays L.), rice (Oryza sativa L.), potato (Solanum tuberosum L.), and barley (Hordeum vulgare L.) in combination with tree wind breaks. Crop water consumption was assessed through the Penman Monteith approach. Tree wind break types investigated were single rows from poplars (Populus spec.) and multiple rows with understory vegetation by elm (Ulmus minor L.) and poplar, respectively. Tree water consumption was determined through sapflow measurements. The seasonal reference evapotranspiration (ETo) for field crops was 876–995 mm without wind breaks and dropped to less than half through multiple row wind breaks with understory vegetation (50 m spacing). Tree water consumption was 1125–1558 mm for poplar and 435 mm for elm. Among the wind break crop systems, elm wind breaks resulted in the highest reductions of water consumption, followed by single row poplars, at spacing of 50 and 100 m, respectively. However, elm grows much slower than poplar, so poplars might be more attractive for farmers. Furthermore, single row wind breaks might by much easier to be integrated into the agrarian landscape as they consume less space.

Adapting to Climate Change with Opuntia

“…It regulates the ecosystem by lessening the impact of wind and water erosion. The dense cactus vegetation can substantially reduce soil evaporation, and when intercropping systems are used, cacti can reduce the amount of water necessary for healthy plant growth [ 27 , 28 ]. It is reported that in Tunisia and Algeria, Prickly-pears are planted in contour-like patterns to maximize the efficiency of water runoff harvesting and to control soil erosion on hillslopes [ 29 ].…”

Comparison of the water consumption levels of four shelterbelt tree species in a typical arid oasis in Northwest China

“…In the case of limited water resources in arid oases, oasis expansion and oasis agriculture development, coupled with the application of water-saving facility agriculture and considering the impact of climate change, not only altered the water consumption trend in shelterbelts but also restricted the water resource supply [11,17,18] . Solar radiation, rainfall, air temperature and humidity affect the transpiration rate and water consumption of shelterbelts, and normal shelterbelt development cannot occur without a timely supply of ecological water [5,19,20] . Climate change and frequent agricultural activities have caused an imbalance in the water resource distribution in oases, leading to the crowding out of ecological water resources in shelterbelts [21][22][23] .…”

Growth Rates of Poplar Cultivars across Central Asia

“…Traditionally, poplars were planted along field borders and irrigation ditches to gain wood as construction material, without occupying much space of adjacent crop fields. During Soviet Union times, those poplar rows along field borders were propagated as tree wind breaks to reduce wind speed, improve the micro climate, and help to increase crop yields [2][3][4][5]. Thereby, the effects on the microclimate and crop yields were the main target rather than the wood resources potentially provided from such tree wind breaks [6][7][8].…”