Effects of planting patterns on rainwater use efficiency and potato tuber yield in seasonally arid areas of southwestern China

Abstract

China is the top potato producing country in the world, and Yunnan Province (in Southwest China) makes a significant contribution (10.1 %) to the total production. The uneven rainfall distribution causes seasonal spring drought in the region. To resolve this issue, we evaluated the effects of cultivation modes on the soil temperature, soil water content, and potato yield. Four cultivation modes were evaluated: A1, flat-planting at sowing, double ridges after emergence; A2, double ridges in plastic film covered with soil, potato planted along the larger ridge side; A3, double ridges in plastic film mulching covered in soil; and A4-control (CK), double ridges, consisting of two different plastic film covering modes (A2, A3) and two covering modes without a plastic film (A1, A4). The field experiments were conducted for three years (2014, 2015, and 2016) in three regions (S1, S2, and S3) of Yunnan in southwestern China. The results showed that the effects of cultivation patterns on the soil temperature and humidity were not the same in the three ecological regions. Before mound closure, compared to the CK treatment, higher soil temperature was observed at the S1 and S2 regions using the A3 mode, which was 5.15 °C and 3.4 °C, respectively. The soil moisture was 4 % (S1), 50.8 % (S2), and 10.0 % (S3) higher with the A2 mode than under the CK mode in the three ecological zones, but the soil moisture was 27.1 % lower with the A3 mode than that with the CK mode at S2. Multiple regression analysis revealed the optimum surface soil temperature (18.9–20.8 °C) and water content (58.6 %–70.4 %) for seedling emergence and potato tuber yield. The emergence, tuber growth, and yield were mainly related to the soil temperature and soil water content at S1 and S2, respectively, while at S3, both factors contributed significantly. Overall yield differed significantly at the cultivation sites, but the average yield was similar in each year at each site. The highest stable potato yield occurred with the A3 mode at S1, and with the A2 mode at S2 and S3. Our research provides suitable methods for potato production in different rain-fed and seasonally arid areas.