Spatial distribution of soil water, soil temperature, and plant roots in a drip-irrigated intercropping field with plastic mulch

Abstract

a b s t r a c tIntercropping and drip irrigation with plastic mulch are two agricultural practices used worldwide. Coupling of these two practices may further increase crop yields and land and water use efficiencies when an optimal spatial distribution of soil water contents (SWC), soil temperatures, and plant roots is achieved. However, this coupling causes the distribution of SWCs, soil temperatures, and plant roots to be more complex than when only one of these agricultural practices are used. The objective of this study thus was to investigate the effects of different irrigation treatments on spatial distributions of SWCs, soil temperatures, and root growth in a drip-irrigated intercropping field with plastic mulch. Three field experiments with different irrigation treatments (high T1, moderate T2, and low T3) were conducted to evaluate the spatial distribution of SWCs, soil temperatures, and plant roots with respect to dripper lines and plant locations. There were significant differences (p < 0.05) in SWCs in the 0-40 cm soil layer for different irrigation treatments and between different locations. The maximum SWC was measured under the plant/mulch for the T1 treatment, while the minimum SWC was measured under the bare soil surface for the T3 treatment. This was mainly due to the location of drippers and mulch. However, no differences in SWCs were measured in the 60 100 cm soil layer. Significant differences in soil temperatures were measured in the 0 5 cm soil layer between different irrigation treatments and different locations. The soil temperature in the subsoil (15 25 cm) under mulch was higher than under the bare surface. The overlaps of two plant root systems in an intercropping field gradually increased and then decreased during the growing season. The roots in the 0 30 cm soil layer accounted for about 60% 70% of all roots. Higher irrigation rates produced higher root length and weight densities in the 0 30 cm soil layer and lower densities in the 30 100 cm soil layers. Spatial distributions of SWCs, soil temperatures, and plant roots in the intercropping field under drip irrigation were significantly influenced by irrigation treatments and plastic mulch. Collected experimental data may contribute to designing an optimal irrigation program for a drip-irrigated intercropping field with plastic mulch.

Simulation of soil water flow and heat transport in drip irrigated potato field with raised beds and full plastic-film mulch in a semiarid area

“…The soil temperatures between the P1 and P3 treatments were similar, although the average soil temperature for the P1 treatment was 0.1-0.7 o C higher than for the P3 treatment (Fig.8). Li et al (2017) also reported small soil temperature differences in different irrigation treatments. The soil temperature for the P2 treatment was the lowest among the three treatments.…”

Evaluating soil nitrate dynamics in an intercropping dripped ecosystem using HYDRUS-2D

“…Root samples for corn and tomatoes under good growth conditions were collected from a soil transect using a method of Li et al (2017) during the elongation stage (June 12 and 8 in 2014 and 2015, respectively), the tasseling stage (June 25 and 18 in 2014 and 2015, respectively), the filling stage (July 11 and 18 in 2014 and 2015, respectively), and the maturation stage (August 20 and 23 in 2014 and 2015, respectively). These samples were collected every 5 cm down to a depth of 50 cm where higher roots density occurred, and then every 10 cm below the 50-cm depth until no roots were found.…”

“…For example, the results of an experiment in a corn/soybean intercropping ecosystem under full irrigation indicated that the corn roots not only penetrated deeper than those of soybean but also extended into the soybean part of the field to absorb more resources (Gao et al, 2010). Similarly, there were significant differences in the crop root systems in the tomato/corn intercropping ecosystem during the growing season, while the crop root systems of the two species overlapped and competed for soil water and nitrogen (Li et al, 2017).…”

Dynamics and Distribution of Soil Salinity under Long-Term Mulched Drip Irrigation in an Arid Area of Northwestern China

“…Moreover, there are great differences in root system distribution in the different growth stages of cotton [39]. These differences will result in differences in root water uptake [38], leading to differences in soil water content distribution with horizontal location and soil depth [40].…”