The early-stage effect of alley cropping system on the soil moisture and temperature of drought-prone silt-loam soil in European temperate transitional climate

Abstract

Silvoarable agroforestry system combines tree cultivation and crop production in the same field and can improve microclimatic conditions and water management during weather extremes caused by climate change. This research aimed to evaluate the effect of the integration of tree alleys into arable fields on soil moisture, infiltration, and temperature regime in the drought-prone location of the university farm Amálie (Czechia) during the vegetation seasons of the first two years following tree alley establishment. Soil and air temperatures, as well as soil moisture, were monitored by 51 microclimatic stations in the alley cropping experimental plot. Furthermore, infiltration tests were conducted using an improved single-ring infiltration method, and thermal surveys were performed using an unmanned aerial vehicle. We observed that diurnal temperature amplitudes during the summer seasons were consistently lower in tree alleys than in adjacent arable fields—an effect largely driven by the dense herbaceous understory, which moderated soil heat flux through improved shading, evapotranspiration, and ground cover, despite the limited canopy development of the young trees. During heatwaves, the daily maximum topsoil temperatures in tree alleys were more than 5 °C cooler. Surprisingly, significantly lower maximum temperatures were also observed in deeper soil layers, with temperatures at 25 and 50 cm being 3 and 2 °C cooler, respectively. Furthermore, results showed that tree alleys facilitated greater water recharge during part of intensive rainfall events. The measured infiltration capacity of tree alleys was also considerably higher than that of recently harvested arable fields. Overall, promising early-stage data indicate that tree alleys serve as stabilizing elements of the local microclimate during hydro-meteorological extremes by reducing temperature maxima and by improving infiltration and soil water recharge following intensive rainfalls.