Irrigation Schedule of Microporous Infiltration Irrigation for Lingwu Jujube Based on Lower Limit of Soil Moisture

In order to find out the effect of lower limit of soil moisture control on microporous infiltration irrigation of Lingwuchangzao (Ziziphus jujuba Mill.cv. 'Lingwuchangzao') and the optimal irrigation amount in each growth period, the six-year-old Lingwuchangzao was used as the research object. Adopting the GC-003 Internet of Things control system and soil moisture sensor monitoring, six different treatments for different lower limits of soil moisture were set for the four growth periods of jujube trees. The relationship between the change of photosynthetic characteristics, and morphological indicators, water use efficiency, yield, water consumption law and irrigation water amount of jujube trees was studied. The results showed that the increase of lower soil water limit during flowering and fruiting bearing periods and during fruit expansion was beneficial to the photosynthesis of jujube trees; the decrease of lower water limit during sprouting and leaf spreading period and the increase of lower water limit during flowering and fruit bearing period were favorable for the growth of morphological indicators of jujube trees. T6 treatment, that was, the lower limits of soil moisture during sprouting and leaf spreading period was 65%θf(θf was field water holding capacity), and during flowering and fruiting bearing period was 75%θf, during fruit expansion was 75%θf, and during fruit maturation was 65%θf, the lower limit was higher in each growth period, which had significantly different photosynthetic characteristics and morphological indicators from other treatments (P<0.05). With the increase of the lower water limit, the water consumption and yield of jujube trees were increased. The water consumption and yield of T6 treatment were the highest, but the water use efficiency of T3 treatment(the lower limits of soil moisture during sprouting and leaf spreading period was 55%θf, during flowering and fruiting period was 75%θf, during fruit expansion was 65%θf, and during fruit maturation was 65%θf)was the best, and there was no significant difference with the yield of T6 treatment(P>0.05). The yield of T6 treatment was only 5.68% (2018) and 0.90% (2019) higher than that of T3 treatment. Compared with T6 treatment, T3 treatment decreased the irrigation water volume by 22.57% (2018) and 13.59% (2019). The most suitable lower limit of irrigation water during the four growth periods of jujube were: during sprouting and leaf spreading period was 55% θf, during flowering and fruiting bearing period was 75%θf, during fruit expansion was 65%θf, and during fruit maturation was 65%θf, and all the upper limit were 90% θf. The study results can provide scientific basis for planting Ningxia Lingwuchangzao with microporous infiltration irrigation and water management. © 2020, Chinese Society of Agricultural Machinery. All right reserved.