Impacts of soil properties on flow velocity under rainfall events: Evidence from soils across the Loess Plateau

The magnitude and spatiotemporal distribution of precipitation are the main drivers of hydrologic and agricultural processes in soil moisture, runoff generation, soil erosion, vegetation growth and agriculture activities on the Loess Plateau (LP). This study detects the spatiotemporal variations of individual rainfall events during a rainy season (RS) from May to September based on the hourly precipitation data measured at 87 stations on the LP from 1983 to 2012. The incidence and contribution rates were calculated for all classes of rainfall duration and intensity to identify the dominant contribution to the rainfall amount and frequency variations. The trend rates of regional mean annual total rainfall amount (ATR) and annual mean rainfall intensity (ARI) were 0.43 mm/year and 0.002 mm/h/year in the RS for 1983–2012, respectively. However, the regional mean annual total rainfall frequency (ARF) and rainfall events (ATE) were −0.27 h/year and −0.11 times/year, respectively. In terms of spatial patterns, an increase in ATR appeared in most areas except for the southwest, while the ARI increased throughout the study region, with particularly higher values in the northwest and southeast. Areas of decreasing ARF occurred mainly in the northwest and central south of the LP, while ATE was found in most areas except for the northeast. Short-duration (≤6 h) and light rainfall events occurred mostly on the LP, accounting for 69.89% and 72.48% of total rainfall events, respectively. Long-duration (≥7 h) and moderate rainfall events contributed to the total rainfall amount by 70.64% and 66.73% of the total rainfall amount, respectively. Rainfall frequency contributed the most to the variations of rainfall amount for light and moderate rainfall events, while rainfall intensity played an important role in heavy rainfall and rainstorms. The variation in rainfall frequency for moderate rainfall, heavy rainfall, and rainstorms is mainly affected by rainfall duration, while rainfall event was identified as a critical factor for light rainfall. The characteristics in rainfall variations on the Loess Plateau revealed in this study can provide useful information for sustainable water resources management and plans.

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Responses of rhizosphere soil properties, enzyme activities and microbial diversity to intercropping patterns on the Loess Plateau of China

Soil and Tillage Research ◽

10.1016/j.still.2019.104355 ◽

2019 ◽

Vol 195 ◽

pp. 104355 ◽

Cited By ~ 16

Author(s):

Xiangwei Gong ◽

Chunjuan Liu ◽

Jing Li ◽

Yan Luo ◽

Qinghua Yang ◽

...

Keyword(s):

Microbial Diversity ◽

Soil Properties ◽

Loess Plateau ◽

Enzyme Activities ◽

Rhizosphere Soil ◽

The Loess Plateau

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Increased soil aggregate stability is strongly correlated with root and soil properties along a gradient of secondary succession on the Loess Plateau

Ecological Engineering ◽

10.1016/j.ecoleng.2019.105671 ◽

2020 ◽

Vol 143 ◽

pp. 105671 ◽

Cited By ~ 7

Author(s):

Lie Xiao ◽

Kehan Yao ◽

Peng Li ◽

Ying Liu ◽

Enhao Chang ◽

...

Keyword(s):

Soil Properties ◽

Loess Plateau ◽

Secondary Succession ◽

Aggregate Stability ◽

Soil Aggregate ◽

Strongly Correlated ◽

The Loess Plateau ◽

Soil Aggregate Stability

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Estimating Raindrop Kinetic Energy: Evaluation of a Low-Cost Method

Applied Engineering in Agriculture ◽

10.13031/aea.11518 ◽

2017 ◽

Vol 33 (4) ◽

pp. 551-558 ◽

Cited By ~ 2

Author(s):

Jian Wang ◽

Dexter B. Watts ◽

Qinqian Meng ◽

Thomas R. Way ◽

Qingfeng Zhang

Keyword(s):

Soil Erosion ◽

Kinetic Energy ◽

Loess Plateau ◽

Filter Paper ◽

Rainfall Intensity ◽

Low Cost ◽

Rotating Disks ◽

The Loess Plateau ◽

Rainfall Events ◽

Raindrop Impact

Abstract. The Loess Plateau of China is regarded as the most intensively eroded region in the world and soil erosion caused by raindrop impact is a common occurrence on agricultural land within this region. Therefore, understanding the influence of rainfall energy on the soil surface is needed to improve prescriptions for best management practices aimed at mitigating erosion. Disdrometers for measuring rainfall energy are presently available; however, these are relatively expensive and their use may not be justified for determining raindrop energy for predictive soil erosion models in regions where there are limited economic resources. To overcome this constraint, a device was tested for evaluating size and velocity of water drops during rainfall events. This device utilized two rotating disks combined with filter paper to obtain raindrop diameter and velocity which can then be used for determining the kinetic energy of falling raindrops. With this device, raindrop diameter was determined from the resultant raindrop stain left on the filter paper during rainfall events and velocity was calculated from the time it took a falling raindrop to travel between the pair of rotating disks. Measurements were taken for approximately 10 minutes during each of six rainfall events of different intensities over a three month period (from June to August of 2013). The smallest raindrop measured was 0.39 mm diameter and the largest was 5.92 mm diameter. The event average raindrop diameter increased with increasing event rainfall intensity. The minimum raindrop impact velocity was 1.47 m s-1, the maximum was 9.45 m s-1, and the event average terminal velocity increased as event rainfall intensity increased. Estimated raindrop kinetic energy ranged from 0.04 × 10-6 J to 4728.21 × 10-6 J, with event mean raindrop kinetic energy ranging from 40.33 x 10-6 J to 276.94 × 10-6 J. The relationship between estimated event rainfall kinetic energy and event rainfall intensity was represented by an exponential function. The disk device was also compared to an optical disdrometer. The data collected for rainfall intensity, raindrop diameter, and velocity were statistically similar between the two devices. Results from this study show that this low-cost method can be used to estimate rainfall kinetic energy in the Loess Plateau region of Northwest China. Keywords: Loess Plateau, Raindrop diameter, Raindrop velocity, Rainfall intensity.

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