Enabling the Processing of Sentinel-1 TOPS Data with the Open-Source DORIS Software (PPT)

Part of Session 3 - Sentinel-1 TOPS InSAR resultsMathematical Geodesy and Positionin

Soil Water Content and Root Patterns in a Rain-fed Jujube Plantation across Stand Ages on the Loess Plateau of China

Planting economic trees is one of the primary parts of the large-scale ecological rehabilitation project (known as Grain for Green' project) initiated in 1999 on the Loess Plateau of China. Knowledge of soil water dynamics and fine roots patterns is critical to water management for orchards in this region. Here we investigated the distribution of root-zone soil water variation and fine roots with a range of stand ages (2, 6, 10 and 15years) in a rain-fed jujube (Ziziphus jujuba) plantation on the Loess Plateau. Soil water in the 0- to 3-m depth was monitored using portable Time Domain Reflectometry, and root samples were taken with a hand auger (phi=9cm). The results showed soil water storage in the 0- to 06-m soil layers in all stands increased remarkably following apparent rainfall events. However, there was no clear change in soil water storage below 06m throughout the growing season. Generally, fine root length density increased with the increase of stand age, which were unevenly distributed in the vertical and horizontal directions around the tree trunks in young stands (2 and 6years), and the fine roots were uniformly distributed radically from the tree trunk in mature stands (10 and 15years). Additionally, a high-density zone of fine roots was observed in the middle of the inter-row in mature stands, and the specific length of fine roots in young stands was higher than observed in mature stands. The results presented here would be helpful to water management in the rain-fed jujube plantations on Loess Plateau and potentially for other semi-arid orchards. Copyright (c) 2016 John Wiley & Sons, Ltd

Soil water effects of agroforestry in rainfed jujube (Ziziphus jujube Mill.) orchards on loess hillslopes in Northwest China

Soil water is the most critical factor influencing the growth and productivity of crops on the Loess Plateau of China. The popular clean-cultivation soil management practice in rainfed jujube orchards in this region causes a variety of environmental problems, including serious soil erosion and soil quality degradation. Agroforestry is a promising avenue to cope with this problem but its effect on soil water in the root zone is yet to be elucidated. In this study, two different agroforestry systems were established in jujube orchards on the hillslopes of the Loess Plateau, to test the effects on root-zone soil water. The Hemerocallis fulva and fodder Brassica napes were planted between jujube rows. The results showed that both agroforestry systems clearly improved soil water at depths of 0-20 cm and 20-60 cm under jujube trees, however, they apparently reduced the inter-row soil water at depths of 60-120 cm and 120-180 cm in different years compared to the control. A simple method, based on the difference of soil water content between inter-row crops and jujube trees (SWDR), was introduced to judge the possibility of water competition happening. The analyses based on this method showed that in the jujube- H. fulva intercropping system, H. fulva frequently competed soil water with jujube trees in the 0-120 cm depth primarily in the relatively dry period (May to July). However, there was almost no water competition occurred in the jujube-B. napes treatment. Overall, fodder B. napes may be more appropriate than Hemerocailis fulva for intercropping with jujube trees. The results here can provide insights into ground management practice of sloping orchards in water-limited areas