Characteristics of Dried Soil Layers Under Apple Orchards of Different Ages and Their Applications in Soil Water Managements on the Loess Plateau of China

doi:10.1016/S1002-0160(15)30035-7

Pedosphere

Volume 25, Issue 4, August 2015, Pages 546-554

https://doi.org/10.1016/S1002-0160(15)30035-7 Get rights and content

Abstract

Negative soil water balance (i.e., water input < water output) can lead to soil desiccation and subsequently the occurrence of a dried soil layer (DSL). The DSLs are generally studied at a specific sampling depth (e.g., 500 cm), and the actual extent of DSLs remains unknown due to the challenge of collecting deep soil samples. To investigate the characteristics of actual DSLs under different ages of apple orchards and ascertain the optimal age of apple orchards for avoiding/controlling the formation of DSLs, soil samples were collected to a depth of 1 800 cm under apple orchards of different ages in Changwu on the Loess Plateau of China. As the ages increased, soil water content (SWC) and mean SWC in DSLs showed an overall decreasing trend, whereas while DSL thickness and the quantity of water deficit (QWD) in DSLs demonstrated an increasing trend. The DSL was the thickest (1 600 cm) under the 17-year-old orchard, the forming velocity of DSL thickness was the highest at the apple tree growth stage of 9–17 years (168 cm year⁻¹), and the highest increasing velocity of QWD (–181 mm year⁻¹) was also observed at this stage. The thickness of DSL was significantly correlated with growth age and root depth of apple trees (r > 0.88), whereas the QWD and mean SWC in DSLs were found to have no correlation with them. The optimal age of apple orchards for avoiding/controlling the formation of DSLs was about 9 years. This information provided pertinent references for the management of deep water resources by controlling the growth age of plants.

References (27)

L P Bai et al.
Effect of soil drought stress on leaf water status, membrane permeability and enzymatic antioxidant system of maize
Pedosphere
(2006)
H S Chen et al.
The characteristics of soil water cycle and water balance on steep grassland under natural and simulated rainfall conditions in the Loess Plateau of China
J Hydrol
(2008)
H S Chen et al.
Soil desiccation in the Loess Plateau of China
Geoderma
(2008)
M B Huang et al.
Use of the SHAW model to assess soil water recovery after apple trees in the gully region of the Loess Plateau, China
Agr Water Manage
(2006)
Y S Li et al.
Pasture yield and soil water depletion of continuous growing alfalfa in the Loess Plateau of China
Agr Ecosyst Environ
(2008)
W Z Liu et al.
Soil water dynamics and deep soil recharge in a record wet year in the southern Loess Plateau of China
Agr Water Manage
(2010)
D S Mendham et al.
Soil water depletion and replenishment during first- and early second-rotation Eucalyptus globulus plantations with deep soil profiles
Agr Forest Meteorol
(2011)
H Schume et al.
Soil water depletion and recharge patterns in mixed and pure forest stands of European beech and Norway spruce
J Hydrol
(2004)
L Wang et al.
Soil desiccation for Loess soils on natural and regrown areas
Forest Ecol Manag
(2008)
X C Wang et al.
Validation of the EPIC model and its utilization to research the sustainable recovery of soil desiccation after alfalfa (Medicago sativa L.) by grain crop rotation system in the semi-humid region of the Loess Plateau
Agr Ecosyst Environ
(2012)

X L Wang et al.

Crop yield and soil water restoration on 9-year-old alfalfa pasture in the semiarid Loess Plateau of China

Agr Water Manage

(2008)

Y Q Wang et al.

Vertical distribution and influencing factors of soil water content within 21-m profile on the Chinese Loess Plateau

Geoderma

(2013)

Y Q Wang et al.

Impacts of land use and plant characteristics on dried soil layers in different climatic regions on the Loess Plateau of China

Agr Forest Meteorol

(2011)

Cited by (99)

Partitioning and controlling factors of evapotranspiration: 1. Hydrological modeling constrained with isotope-based water balance decoupling
2024, Agriculture, Ecosystems and Environment
Exploring the components of evapotranspiration (ET) is essential but challenging because of the difficulties in ET partitioning. This study aims to improve the accuracy in partitioning ET under farmland and apple orchards by the hydrological model HYDRUS-1D constrained with isotopes, and further identify the effects of land use change on soil water balance (SWB). In particular, the long-term average SWB was first decoupled by combining multiple isotopes (δ²H, δ¹⁸O, and δ³H), and then used to constrain HYDRUS-1D to improve model performance. With the isotope-based partitioned SWB, some hydrological model parameters difficult to be obtained experimentally were inversely optimized. Consequently, the performance of HYDRUS-1D in ET partitioning was greatly improved. Specifically, with the isotope method as a reference, the HYDRUS-1D with optimized parameters had errors of 20%±2.1, 4%±2.0, and 6%±0.8 for evaporation (E), transpiration (T), and ratio of transpiration to evapotranspiration (T/ET), which were much smaller than those from the model with default parameter (171%±34.5, 57%±5.8, and 58%±5.8). The apple orchards increased T by decreasing other SWB components. The framework of optimizing hydrological model by isotope-based SWB decoupling is promising in improving model accuracy, and the partitioned SWB components can be used to promote our understanding of ecohydrological processes.
A mosaic pattern of apple orchards and farmland affects the distribution of soil water and nutrients in their adjacent areas on the Chinese Loess Plateau
2024, Catena
With the vigorous promotion of apple tree planting on the Chinese Loess Plateau (CLP), a mosaic pattern of apple orchards and traditional farmland has emerged in the region. However, the interaction between adjacent farmland and apple orchards in terms of soil water and nutrient migration remains unclear. This study aimed to investigate the spatial distribution of the soil water content (SWC) and soil nutrients, as well as their interactions, in 0–10 m soil layers of apple orchards of different stand ages and adjacent farmland under the orchard-farmland land use pattern. The results revealed a significant decrease in average-depth SWC in the orchards in the 0–10 m soil profile (R² = 0.90) with increasing orchard age, accompanied by a significant increase in soil water deficit (SWD, R² = 0.94). The annual growth rate of SWD was found to be as high as 5.94 mm·m⁻¹·y⁻¹. Deep soil and surrounding farmland were identified as important sources of soil water for apple tree growth, particularly in older orchards; a 25-year-old orchard absorbed approximately 10.8 % of soil water towards farmland with a horizontal distance of 7 m. The distribution of soil organic carbon (SOC) and total nitrogen (TN) in the 0–10 m soil profile exhibited a similar pattern, decreasing and then stabilizing with increasing depth. However, the peak depth and accumulation of soil nitrate (NO₃^–-N) significantly increased with orchard age. The migration and accumulation of NO₃^–-N in the soil provided a scientific basis for the transport of soil water, with NO₃^–-N accumulation (405.32 mg kg⁻¹) observed in the deep soil (3–6 m) of farmland located 5 m away from a 30-year-old orchard, confirming the exchange of soil water and nutrients between the orchard and the farmland. The stand age of the orchards was identified as the main environmental factor influencing soil water transport under the orchard-farmland land use pattern. Overall, our findings provide valuable insights into the interaction between apple orchards and farmland under the mosaic pattern, which can contribute to a more rational layout of apple orchards and farmland in the future, promoting the efficient utilization of soil water and nutrients on the CLP.
Impacts of re-vegetation on soil water dynamics in a semiarid region of Northwest China
2024, Science of the Total Environment
Understanding how vegetation (shrub) cover in drylands affects local-to-regional soil water dynamics and associated water balances is of immense importance because of the abundance of afforestation projects worldwide. Vegetation's role in the control of soil water presents a particular challenge to soil water storage (SWS) management in the drylands of China. To address this knowledge gap, we conducted a two-year study in the Mu Us Desert of northwest China. The study involved the acquisition of in-situ soil water measurements within the first 180 cm of soil at three sand dune sites characterized by their differences in % shrub cover. The sand dunes varied from a vegetation-free, bare-ground sand dune site (BF) and two partly vegetated sites, one with medium-level (40 %) and another with high shrub cover (80 %; MF and HF, respectively). Results revealed that the site with the high shrub cover (HF) suffered a net reduction in soil water content (SWC) by up to 32.7 and 39.8 % in the shallow and deep subsoil (0–100 and 100–180 cm), respectively, when compared to corresponding changes at the BF site. Soil water content was shown to be largely influenced by site properties, namely shrub biomass and litter density (p < 0.05). Due to aboveground vegetation and rainfall interception by the litter, 32.2 mm of effective rainfall was reduced to the soil for every 10 %-increase in shrub cover. Bands of soil water depletion during the dry year did not fully recover during the following wet year, resulting in the development of a dried soil layer with an average SWC of 4.6–7.8 %. Increased evapotranspiration (ET_total) led to a decrease in SWS and relative extractable soil water (REW), which caused ET_total at HF to be lower than the rate observed at MF. These findings highlight the need for improvements in current restoration strategies, meant at striking a balance between vegetation restoration and SWC by developing optimal plant-community cover and mosaicked vegetation systems.
Intensive land restoration projects alter mechanisms underpinning spatiotemporal soil moisture variability at a catchment scale: A case study in China
2024, Journal of Hydrology
Soil moisture (SM) is a critical factor for material circulation and energy exchange in Earth’s critical zone, but it is spatially and temporally variable. This study aimed to provide new insight into spatiotemporal SM variability and its associative controls in areas where land restoration projects have been implemented. Specifically, we compared environmental controls on spatiotemporal SM variability in deep soil layers (0–500 cm) of two paired catchments, one of which was treated by the Gully Land Consolidation (GLC) project and the other which was not, where the slopes of both catchments had initially been impacted by the Grain for Green (GFG) program. For this purpose, we used the empirical orthogonal function (EOF) to decompose spatial and temporal SM anomalies. Two dominant spatial and temporal EOF anomalies (EOF1 and EOF2) were obtained from six soil layers in both catchments, with an explained variance of 86%–97% and 32%–53%, respectively. These spatial anomalies that derived from spatial structures exhibited similar characteristics and controls in both catchments, while underlying temporal SM dynamic mechanisms differed. Temporal dynamics of the treated catchment were lower in the gully area (a relative flat region), while the opposite was true for the gully area (at a lower elevation) in the untreated catchment. The GLC and GFG programs both altered catchment scale temporal SM dynamic forcings. Results obtained from this study are helpful for understanding spatiotemporal SM variability with associated the hydrological processes in areas where the intensive land restoration projects have been implemented at a catchment scale.
Patterns and drivers of seasonal water sources for artificial sand-fixing plants in the northeastern Mu Us sandy land, Northwest China
2024, Pedosphere
Understanding plant water-use patterns is important for improving water-use efficiency and for sustainable vegetation restoration in arid and semi-arid regions. However, seasonal variations in water sources and their control by different sand-fixing plants in water-limited desert ecosystems remain poorly understood. In this study, stable isotopic ratios of hydrogen (δ²H) and oxygen (δ¹⁸O) in precipitation, soil water, groundwater, and xylem water were determined to document seasonal changes in water uptake by three representative plant species (Pinus sylvestris var. mongolica Litv., Amygdalus pedunculata Pall., and Salix psammophila) in the northeastern Mu Us sandy land, Northwest China. Based on the depth distribution and temporal variation of measured gravimetric soil water content (SWC), the soil water profile of the three species stands was divided into active (0.01 g g^-1 < SWC < 0.08 g g^-1, 20% < coefficient of variation (CV) < 45%), stable (0.02 g g^-1 < SWC < 0.05 g g^-1, CV < 20%), and moist (0.08 g g^-1 < SWC < 0.20 g g^-1, CV > 45%) layers. Annually, P. sylvestris, A. pedunculata, and S. psammophila obtained most water from deep (59.2% ± 9.7%, moist layer and groundwater), intermediate (57.4% ± 9.8%, stable and moist layers), and shallow (54.4% ± 10.5%, active and stable layers) sources, respectively. Seasonally, the three plant species absorbed more than 60% of their total water uptake from the moist layer and groundwater in the early (June) dry season; then, they switched to the active and stable layers in the rainy season (July–September) for water resources (50.1%–62.5%). In the late (October–November) dry season, P. sylvestris (54.5%–66.2%) and A. pedunculata (52.9%–63.6%) mainly used water from stable and moist layers, whereas S. psammophila (52.6%–70.7%) still extracted water predominantly from active and stable layers. Variations in the soil water profile induced by seasonal fluctuations in precipitation and groundwater levels and discrepancies in plant phenology, root distribution, and water demand are the main factors affecting the seasonal water-use patterns of artificial sand-fixing plants. Our study addresses the issue of plant water uptake with knowledge of proportional source-water use and reveals important implications for future vegetation restoration and water management in the Mu Us sandy land and similar desert regions around the world.
Tritium and trees: A bomb peak perspective on soil water dynamics in semi-arid apple orchards
2023, Catena
Understanding the relationship between agroforest age and soil water dynamics is crucial for effective land and water resources management. However, the complexities of these dynamics, such as soil water recharge and depletion, hamper in-depth understanding, particularly in water-scarce regions. In this study, we examined soil water recharge and depletion in relation to the stand age of apple trees, a widely planted and representative deep-rooted agroforest, over four years in a semi-arid region on China’s Loess Plateau (CLP). We collected soil cores to >20 m depth from four apple orchards (referred to as ‘agroforests’) with variable stand ages (established in 2008, 2005, 1998, and 1994). For comparison, we selected adjacent cropland as land use prior to agroforestry practices (‘control’). We measured soil water content and tritium distributions to model soil water dynamics and estimate water ages across different soil profiles. Our results show that recharge amounts (and depths) in shallow soils were 298.4 mm (7 m), 303.4 mm (6.6 m), 300.6 mm (5.4 m), and 483.1 mm (7.6 m), whereas deep soils had net depletions of 111.1 mm, 391.9 mm, 192.8 mm, and 108.9 mm for AP2008, AP2005, AP1998, and AP1994, respectively. The tritium peak depths, which indicate the 1963 bomb peak depth, significantly differed between agroforested and non-agroforested plots. In particular, agroforestation reduced the seepage velocity of soil water over 20 years. Furthermore, our tritium tracer water age model suggests that the age of transpired deep soil water exceeded 200 years in the oldest orchard. These findings highlight a complex interaction between newly infiltrated water and existing water, possibly due to variations in soil pore size distributions. The results of this study offer valuable insights into the ecohydrological impacts of agroforestation on the CLP and in similar climatic regions.

View all citing articles on Scopus

View full text

Article preview

Pedosphere

Abstract

References (27)

Effect of soil drought stress on leaf water status, membrane permeability and enzymatic antioxidant system of maize

Pedosphere

The characteristics of soil water cycle and water balance on steep grassland under natural and simulated rainfall conditions in the Loess Plateau of China

J Hydrol

Soil desiccation in the Loess Plateau of China

Geoderma

Use of the SHAW model to assess soil water recovery after apple trees in the gully region of the Loess Plateau, China

Agr Water Manage

Pasture yield and soil water depletion of continuous growing alfalfa in the Loess Plateau of China

Agr Ecosyst Environ

Soil water dynamics and deep soil recharge in a record wet year in the southern Loess Plateau of China

Agr Water Manage

Soil water depletion and replenishment during first- and early second-rotation Eucalyptus globulus plantations with deep soil profiles

Agr Forest Meteorol

Soil water depletion and recharge patterns in mixed and pure forest stands of European beech and Norway spruce

J Hydrol

Soil desiccation for Loess soils on natural and regrown areas

Forest Ecol Manag

Validation of the EPIC model and its utilization to research the sustainable recovery of soil desiccation after alfalfa (Medicago sativa L.) by grain crop rotation system in the semi-humid region of the Loess Plateau

Agr Ecosyst Environ

Crop yield and soil water restoration on 9-year-old alfalfa pasture in the semiarid Loess Plateau of China

Agr Water Manage

Vertical distribution and influencing factors of soil water content within 21-m profile on the Chinese Loess Plateau

Geoderma

Impacts of land use and plant characteristics on dried soil layers in different climatic regions on the Loess Plateau of China

Agr Forest Meteorol

Cited by (99)

Partitioning and controlling factors of evapotranspiration: 1. Hydrological modeling constrained with isotope-based water balance decoupling

A mosaic pattern of apple orchards and farmland affects the distribution of soil water and nutrients in their adjacent areas on the Chinese Loess Plateau

Impacts of re-vegetation on soil water dynamics in a semiarid region of Northwest China

Intensive land restoration projects alter mechanisms underpinning spatiotemporal soil moisture variability at a catchment scale: A case study in China

Patterns and drivers of seasonal water sources for artificial sand-fixing plants in the northeastern Mu Us sandy land, Northwest China

Tritium and trees: A bomb peak perspective on soil water dynamics in semi-arid apple orchards