【Objective】Soil salinization is a severe environmental factor that inhibits plant growth and productivity. Nanomaterials hold potential in enhancing plant stress resistance. Among them, nano-silica (SiO2 NPs) has been proven to promote plant growth and alleviate environmental stress. SiO2 NPs can significantly enhance plant resistance to both biotic and abiotic stresses. They improve plant growth under stress conditions by maintaining water balance, protecting cell membrane integrity, and promoting nutrient absorption. However, as a representative of nanobiotechnology, the application of silica nanoparticles(SiO2 NPs)under saline-alkali stress conditions and their effects on apple seedlings have not been sufficiently studied.【Methods】Under the rain shelter, apple rootstock seedlings of Qingzhen No.1 were subjected to saline-alkali stress. Then, they were irrigated with different concentrations of exogenous SiO2 NPs(25,50,100, and 200 mg · L-1). The CK group was irrigated daily with pure water, whereas the SA-T4 group was irrigated daily with 500 mL of saline- alkali solution. Saline- alkali stress was established after three consecutive days of irrigation. Subsequently, groups T1 to T4 were irrigated daily with suspensions of silicon dioxide nanoparticles at corresponding concentrations, while the CK and SA groups were irrigated with clear water(approximately 100 mL). Starting from the day after the application of exogenous substances, leaves and roots were collected from the upper-middle part of the plants on the 0th,6th,12th, and 18th days of treatment. These leaves and roots were quickly frozen in liquid nitrogen and stored at-80℃for subsequent related index detection. By analyzing seedling development, ion homeostasis, antioxidant activity, and osmotic regulation, the regulatory mechanisms of applying exogenous silicon dioxide nanoparticles at different concentrations under uniform saline-alkali stress conditions were explored.【Results】Saline-alkali stress significantly inhibited seedling growth, resulting in a reduction of photosynthetic pigments, leaf chlorosis, the accumulation of hydrogen peroxide(H2O2) and superoxide anion(O2-), an increase in malondialdehyde(MDA)content and relative electrical conductivity (REC), the disruption of osmotic regulation substances (soluble sugar (SS), soluble protein (SP), proline (Pro)), and an abnormal elevation of antioxidant enzyme systems (CAT, POD, SOD activity). It also disrupts the ion balance. Exogenous SiO2NPs treatment effectively reversed the stress effects, and the 50 mg · L-1(T2)treatment yielded the best results. The application of SiO2NPs significantly alleviated the negative impacts of saline-alkali stress on the apple rootstock Qingzhen No.1, including an increase in leaf area, plant height, stem diameter, and photosynthetic pigments. Furthermore, SiO2NPs could reduce REC, MDA, H2O2, and O2-, and enhance the activity of major antioxidant enzymes such as POD and CAT. In terms of ion balance regulation, SiO2NPs could mitigate the toxic effects of excessive Na+ on cells by inhibiting the absorption and transport of Na+ in roots and reducing the loss of K+, thereby maintaining a stable Na+/K+ ratio and ensuring normal cellular physiological functions. To further elucidate the alleviation mechanism of SiO2NPs on salt-alkali stress in the Qingzhen No.1 apple rootstock, this study employed the paraffin sectioning technique to observe and quantify the microanatomical characteristics of leaves, aiming to evaluate the mitigation effects under different concentrations of SiO2NPs treatments. The leaf microstructure revealed that under control(CK)conditions without salt-alkali stress, the palisade tissue cells of Qingzhen No.1 leaves were fully differentiated, with regular morphology. They were tightly arranged in elongated columns beneath the upper epidermis, exhibiting minimal intercellular spaces. In contrast, the spongy tissue cells were loosely arranged, with well-developed intercellular spaces, forming a continuous ventilation system that ensured efficient gas exchange. However, under SA treatment, the normal anatomical structure of the leaves was significantly disrupted. The thickness of the palisade tissue decreased by 42.05% compared with the control. Cell elongation along the longitudinal axis was inhibited, the arrangement became disordered, with evident cellular deformation and enlarged intercellular spaces. The volume of spongy tissue cells was simultaneously reduced by 30.41%, accompanied by abnormal expansion of intercellular spaces, which resulted in a loose internal spatial structure and compromised tissue integrity in the leaves. The application of exogenous SiO2NPs could significantly alleviate the damage to the leaf anatomical structure induced by salt-alkali stress. Among them, the T2 treatment showed the most pronounced mitigation effect. Based on the comprehensive analysis of various physiological and molecular indicators, the alleviation effects of different treatment groups on saline- alkali stress were ranked as follows: CK (1.115 7)＞T2(0.833 9)＞T1(0.041 4)＞T3(-0.293 6)＞T4(-0.574 6)＞SA(-1.122 9). This confirmed that 50 mg·L-1 SiO2NPs mitigated saline-alkali stress damage through synergistic multi-pathway actions: enhancing photosynthetic performance, optimizing antioxidant defense, and regulating the osmotic adjustment system.【Conclusion】It can be concluded that under the experimental conditions, exogenous SiO2NPs could alleviate saline-alkali stress in apple rootstocks. The 50 mg · L-1SiO2NPs treatment showed the most significant effect by restoring the growth inhibition caused by saline-alkali stress. This concentration exerts its synergistic effects through multiple pathways: reducing the content of the oxidative stress indicator MDA by 59.27% and REC by 40.11%; regulating osmotic adjustment substances such as proline to increase their content by more than 56.55%; and lowering the Na+/K+ ratio to 0.079, thereby mitigating ion toxicity. In conclusion,50 mg · L-1 SiO2NPs could effectively mitigate the damage of saline-alkali stress on apple seedlings. This study would provide new insights for the prevention and control of saline-alkali stress in apples and also demonstrate the application potential of nanomaterials in enhancing crop stress resistance.

Water scarcity and water-related soil erosion are severely exacerbated by inappropriate human activities and global climate change. Hence, to find a suitable technology to mitigate drought and soil erosion, three consec-utive field experiments were conducted to explore the impact of ridge-furrow cropping with biochar amendment on soil water storage, runoff, sediment yield, soil nutrient losses, alfalfa (Medicago sativa L) fodder yield, crop water productivity (WPc), and economic benefit from 2019 to 2021. This experiment was conducted in a split- plot design, taking biochar amendment patterns (no biochar amendment and biochar amendment at a rate of 3x104 kg ha1) as a main plot and ridge-furrow technologies (traditional planting, open-ridging, and tied-ridging) as a split-plot. The combination of biochar amendment with ridge-furrow technology, especially tied-ridging technology, increased soil water storage, and captured runoff, sediment, and related soil nutrient losses, consequently increasing alfalfa fodder yield, WPc, and income. During this study, compared to traditional planting, open-ridging depicted an increase in soil water storage by a range of 9.8-39.6 mm, an alfalfa fodder yield boost ranging from 9.8% to 38.6%, and a WPc increase ranging from 0.1 to 16.5 kg ha1 mm1. On the other hand, tied-ridging showed greater improvements with soil water storage increasing by 29.1-65.1 mm, alfalfa fodder yield growing by 11.6-44.4%, and WPc advancing by 0.9-17.5 kg ha1 mm1. The mean decrease in runoff, sediment, and nutrients (total nitrogen, total phosphorus, and organic matter) loss for open-ridging was 17.9%-37.7%, 46.4%-75.5%, and 40.4%-75.3%, respectively, while for tied-ridging, it was 22.3%-55.5%, 62.1%- 87.6%, and 49.0%-87.3%, respectively. Compared to no biochar amendment, soil water storage, alfalfa fodder yield, and WPc for biochar amendment increased by 9.1%-20.4%, 5.8%-52.7%, and 4.6-7.8 kg ha1 mm1, respectively, while runoff, sediment, and nutrients loss for biochar amendment decreased by 32.2%-40.9%, 25.5%-55.5%, and 35.9%-53.3%, respectively. Structural equation modeling analysis indicated that the signif-icant direct effect of biochar amendment and ridge-furrow technology on WPc was 0.20 and 0.62, respectively, whereas the significant direct effect of runoff and actual crop evapotranspiration on alfalfa fodder yield was 0.40 and 0.94, respectively. Tied-ridge cropping combined with biochar addition was a highly suggested approach for addressing soil erosion and enhancing alfalfa fodder yields in the Loess Plateau in China. This technology could mitigate soil water scarcity and soil erosion, and give farmers the confidence to invest in this technology in dryland regions.

Intercropping has demonstrated its potential to boost crop yields and optimize land utilization in numerous instances. Yet, the specific mechanisms underlying the enhancement of intercropped plants’ relationships through improved crop management practices remain unclear. We conducted a comprehensive analysis of multiple studies across diverse regions to gain deeper insights into the impact of intercropping systems on crop yields. This investigation explored the influence of various factors, including different intercropping strategies, patterns of rainfall and temperature, and soil nutrient levels, on the production of maize, soybeans, and wheat crops. To quantify the magnitude of these effects, we employed the odds ratio as the effect size metric. Our findings reveal that, in regions with rainfall amounts of ≤ 200 mm, maize yields in both maize-wheat and maize-soybean intercropping systems were significantly affected (p = 0.0002) compared to regions with higher rainfall. This effect may be attributed to the substantial positive effect size observed when temperatures were below 11 °C, measuring 3037.55 with a 95

为了探寻我国黄土高原丘陵区坡地垄沟集雨种植控制水土流失和增产机理,本研究利用试验期2019年坡地微型集雨垄收集的19次降雨-径流资料,率定不同坡度(0°、5°和10°)微型集雨垄SCS-CN模型的径流曲线数CN值和初损系数λ值,利用5次降雨-径流资料检验模型的有效性.结果 表明:自然降雨条件下,坡地微型集雨垄径流量随坡度增大而增大,λ值随坡度增加而降低,CN值随坡度变化不明显;William坡度修正公式、Huang坡度修正公式和Huang优化坡度修正公式确定纳什效率平均值分别为0.83、0.96和0.98,平均相对误差分别为17.67％、8.51％和5.84％;Huang优化坡度修正公式考虑坡度因子,率定径流曲线CN和初损系数λ,模拟精度优于Huang坡度修正公式和William坡度修正公式,适合于我国黄土高原丘陵区坡地微型集雨垄径流预测,为坡地垄沟集雨种植控制水土流失和增产提供科学依据.

Drought and soil erosion are significant environmental challenges to agricultural production in the Loess Plateau of China. We hypothesized that ridge-furrow rainwater-harvesting, especially tied-ridge-furrow rainwater-harvesting, with biochar application would increase soil moisture, temperature, and alfalfa fodder yield, and reduce runoff and sediment yield. A split-plot design experiment was conducted to determine the effects of biochar application patterns (biochar application pattern and no biochar application pattern) and tillage practices (tied-ridging, open-ridging, and flat-planting) on soil temperature, moisture, runoff, sediment yield, fodder yield, and water use efficiency (WUE) of alfalfa during two consecutive alfalfa-growing years: 2019 and 2020. Biochar application decreased runoff, sediment yield, soil temperature, and increased soil water storage, compared to no biochar application. Open-ridging and tied-ridging significantly increased soil water storage, fodder yield, WUE of alfalfa, and decreased runoff and sediment yield, compared to flat-planting. Compared to no biochar application, soil water storage for biochar application increased by 34.51 mm during alfalfa growing season over two years. The mean runoff and sediment yield for no biochar application were 1.48–1.69 and 1.94–2.25 times greater than that for biochar application, respectively. Compared to flat-planting, the mean decrease of runoff and sediment yield was 27.4–31.9% and 60.1–64.7%, respectively, for open-ridging, while it was 37.1–55.2% and 71.8–82.4% for tied-ridging. The mean increase of soil water storage, fodder yield, and WUE of alfalfa for open-ridging was 39.5–52.1 mm, 26.2–31.7%, and 10.07–14.86 kg ha−1 mm−1, respectively, while it for tied-ridging was 31.2–60.5 mm, 26.5–35.2%, and 12.14–16.55 kg ha−1 mm−1 over two years. Tied-ridge-furrow rainwater-harvesting with biochar application is a potentially effective adaptation technology that could control soil erosion and increase alfalfa fodder yield in semiarid regions.

Ridge-furrow rainwater harvesting (RFRH) is known to be effective in controlling water loss and soil erosion, and increasing soil moisture and crop yield in semiarid regions. However, it can cause waterlogging, ridge overtopping, and harvest failure if not properly designed. A four consecutive-year field trial was carried out to assess the impacts of various slope gradients and tillage practices on soil moisture, runoff, sediment yield, associated soil nutrient losses, fodder yield, and water use efficiency (WUE) of alfalfa in the Loess Plateau, China. The trial adopted a split-plot design, taking slope gradient (5 degrees and 10 degrees) as main plot treatment and tillage practice (traditional tillage, open-ridging, and tied-ridging) as split plot treatment, from 2015 to 2018. There were greater variations in runoff, sediment yield, and associated soil nutrient losses than in fodder yield and WUE. Tied-ridging and open-ridging resulted in decreased runoff and reduced sediment transport and associated soil nutrient losses, and increased soil moisture, fodder yield, and WUE. Runoff, sediment transport, and associated soil nutrient losses inclined with increasing slope; while fodder yield and the WUE declined. For slopes of 5 degrees and 10 degrees, the average decrease in runoff, sediment yield, total nitrogen, total phosphorus, and organic matter losses for open ridging were 47.7-56.2%, 91.0-92.7%, 90.4-93.1%, 90.1-92.2%, and 88.9-90.2%, respectively, while these for tied-ridging were 62.4-68.4%, 94.5-96.4%, 93.6-95.5%, 93.9-95.9%, and 93.0-94.9%, over 4 years as compared with traditional tillage. The mean annual runoff, sediment, total nitrogen, total phosphorus, and organic matter losses for slopes of 10 degrees were 1.31, 1.96, 1.87, 1.99, and 1.64 times greater than the corresponding values for slopes of 5 degrees, respectively. The increase of fodder yield and WUE for open ridging and tied-ridging was 40.1-45.6% and 16.0-17.5%, and 3.66-5.99 and 1.35-2.50 kg ha(-1) mm(-1), respectively, for slopes of 5 degrees and 10 degrees. The average fodder yield and WUE for slopes of 5 degrees were 1.19 and 1.23 times greater than corresponding values for slopes of 10 degrees, respectively. The disparities in fodder yield and WUE of alfalfa between slopes of 5 degrees and 10 degrees were not clear in dry years, but were evident in wet years. Tied-ridging was recommended for water and soil conservation, while open-ridging was recommended for increase of fodder yield and WUE of alfalfa. The implementation of RFRH in crop production should be evaluated by the use of a model in accordance with climatic conditions, soil type, and plant species. (C) 2021 International Research and Training Center on Erosion and Sedimentation, China Water and Power Press, and China Institute of Water Resources and Hydropower Research. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co. Ltd.

Soil desiccation is a major challenge faced by subsistence farmers growing alfalfa (Medicago sativa L) in consecutive cultivation in semiarid regions. We hypothesized that alfalfa fodder yield would increase with the length of growing season, growing degree-days, and rainfall. A field experiment was conducted on alfalfa production from 2012 to 2016 to 1) determine the response of fodder yield to rainfall, the length of growing season, and accumulated growing degree day (AGDD) in different growing-cutting stage (GCS)s; 2) obtain the suitable mulching material and the optimum ridge width for ridges with manually compacted soil (MCS), mulched with bio-degradable film (BF), and plastic film (PF). There were 10 treatments (3 ridge widths x 3 ridge-mulching materials + flat planting (FP) as control) with three replications laid in a randomized block design. The ratio of the first GCS to the second GCS in fodder yield ranged from 1.10 to 4.55, which was similar to the ratio of the first GCS to the third GCS in fodder yield ranged from 1.14 to 4.59, although rainfall, the length of growing season, and AGDD were different during the two or three GCSs. The highest fodder yield was obtained from the first GCS in one year and reached the highest level in the second growing year, and maintained a similar level in the subsequent years, although rainfall, the length of growing season, and AGDD varied during the five year periods. Fodder yield was affected by both the rainfall in the GCS and the available soil moisture prior to the GCS. Compared to FP, the increase of evapotranspiration for MCS, BF, and PF was 11, 61, and 63 mm, respectively. Fodder yield for BF and PF increased by 28% and 33%, respectively. Fodder yield for MCS maintained the same level as that for FP. Evapotranspiration increased and fodder yield decreased as ridge width increased. The optimum ridge width for MCS, BF, and PF was 29, 39, and 37 cm, respectively, across five years. Future study should focus on alfalfa-crop rotation to mitigate soil desiccation after alfalfa consecutively production.

Ridge-furrow rainwater-harvesting (RFRH) has emerged as an effective technology to mitigate drought stress, control soil erosion, and increase crop yield in semiarid regions of China. However, the use of plastic film mulch in RFRH makes this technology impractical. A field experiment was conducted for three consecutive years in a randomized complete block design to determine 1) the runoff coefficient for ridges compacted with soil mixed with two types of biochar (rice straw biochar and cow dung biochar) at two application rates (single application rate i.e., 3 x 104 kg ha- 1; and double application rate i.e., 6 x 104 kg ha- 1; and 2) the effects of the ridges compacted with soil mixed with two types of biochar at two application rates on soil physico-chemical properties, economic benefit, fodder yield and water use efficiency (WUE) of alfalfa, and ridges compacted with soil (no biochar) as control. The average runoff coefficient for NB, SRSB, DRSB, SCDB, and DCDB (NB, SRSB, DRSB, SCDB, and DCDB were ridges compacted with soil, compacted with soil mixed with single rice straw biochar application, double rice straw biochar application, single cow dung biochar application, and double cow dung biochar application, respectively) over these three years was 31%, 28%, 27%, 22%, and 21%, respectively. Ridges compacted with soil-biochar crust had lower runoff coefficients, soil water storage, net income, and higher soil nutrients, when compared to ridges compacted with soil. The topsoil temperature at ridge tops was affected by the ridges compacted with soil-biochar crust, but the topsoil temperature at furrow bottoms was not affected. Compared to ridges compacted with soil mixed with cow dung biochar, ridges compacted with soil mixed with rice straw biochar had lower soil nutrients, and higher soil water storage resulting in higher fodder yield and WUE of alfalfa. With runoff, the nutrients in biochar flowed from ridges to furrows, becoming usable for plants. Ridges compacted with soil-biochar crust increased topsoil nutrients, especially soil organic matter ranging from 15% to 34%, resulting in high fodder yield and WUE of alfalfa. Compared to NB, annual fodder yield for SRSB, DRSB, SCDB, and DCDB increased by 9.0%, 5.9%, 4.4%, and 3.8%, respectively, over three years, while WUE for the same treatments increased by 2.81, 1.95, 0.65, and 0.45 kg ha- 1 mm-1. Rice straw biochar at an application rate of 3 x 104 kg ha- 1 was found to be suitable type of biochar for increase in fodder yield and WUE of alfalfa in RFRH. Future studies should be conducted in the form of long-term field study to determine economic benefits of biochar application.

Erratic climatic conditions and poor intrinsic soil properties are major challenges constraining agricultural sustainability, resilience, and food security in the Loess Plateau in China. Thus, it is necessary to explore ridge-furrow rainwater harvesting with organic mulches to improve soil physical properties and maintain sustainable agricultural production. A consecutive 5-year field experiment was conducted in a randomized block design with ten treatments (three biochar application rates (0, 30, and 60 t ha−1) × three ridge widths (30, 45, and 60 cm) + flat planting without biochar (FP) as a control). Ridges compacted with biochar-soil mixture reduced bulk density and soil solid-phase ratio and increased total and capillary porosity, soil gas-phase ratio, and aggregate stability. Compared to FP, available water content in ridges compacted with biochar-soil mixture increased by 0.5–9.0% at furrow bottoms and 1.4–22.9% at ridge tops. Annual alfalfa fodder yield for MCS30, MCS45, MCS60, SMB30, SMB45, SMB60, DMB30, DMB45, and DMB60 (MCS, SMB, and DMB were abbreviations for ridges compacted with biochar-soil mixture at biochar application rate of 0, 30, and 60 t ha−1, respectively, while subscript numbers 30, 45, and 60 referred to ridge widths) increased by 9.4%, 9.4%, 6.9%, 29.5%, 24.9%, 12.5%, 21.3%, 16.2%, and 6.1%, respectively, over 5 years. Ridges compacted with biochar-soil mixture improved soil physical properties. Suitable biochar application rate was 30 t ha−1 and optimum ridge width was 30 cm for alfalfa production in ridge-furrow rainwater harvesting with biochar application.

Agriculture production in study areas benefits from the use of ridge‐furrow rainwater harvesting (RFRH) to supplement rainfall in the absence of irrigation from imported sources. However, it is necessary to select suitable fodder plants for use with RFRH in this climate. In this paper, 10 treatments (3 ridge widths × 3 ridge‐mulching materials + flat planting [FP] as control) in a complete random design were applied in a 3‐yr field experiment for alfalfa (Medicago sativa L.) and oat (Avena sativa L.) production, respectively. Ridges mulched with plastic film (PF) and ridges mulched with biodegradable film (BF) had positive effects on fodder, grain yields, and water use efficiency (WUE), but ridges with manually compacted soil (MCS) had a negative effect on yield and WUE in the most cases. Fodder, grain yields, and WUE decreased as ridge width increased. For oats, the decrease of WUE of MCS was 1.31 kg ha−1 mm−1, but the increase of WUE of BF and PF was 0.83 and 1.25 kg ha−1 mm−1, respectively, compared with that of FP over 3 yr. For alfalfa, the increase of WUE of MCS, BF, and PF was, respectively, 0.22, 5.62, and 6.33 kg ha−1 mm−1. The RFRH systems, especially PF and BF, produced oat and alfalfa fodders with increased crude protein content and decreased acid and neutral detergent fiber content. The average alfalfa fodder yield was 1.37 times greater than that of oats, whereas the average WUE of alfalfa was 2.62 times greater than that of oats. Alfalfa fodder contained higher crude proteins and lower neutral detergent fiber content than oat fodder and had similar acid detergent fiber. It is more economic to harvest oat fodder than to harvest oat grain, and it is more economic to produce alfalfa than to produce oats.

为探索和解决半干旱黄土高原区垄沟集雨种植紫花苜蓿的可持续性,采用完全随机设计布置大田试验,以传统平作为对照,研究不同垄覆盖材料（土壤结皮、生物可降解地膜和塑料地膜）和不同沟垄比[沟宽（cm）∶垄宽（cm）分别为60∶30、60∶45和60∶60]对垄沟集雨种植土壤水热效应、紫花苜蓿产量和水分利用效率（WUE）的影响。结果表明,紫花苜蓿连续种植第4和5年,深度0～3.0 m土壤含水量随紫花苜蓿生育期和生育年限增加而降低,排列次序为塑料膜垄＞生物可降膜垄＞土垄＞传统平作,土壤含水量随集雨垄宽度的增加而增加。垄沟集雨连续种植第4和5年紫花苜蓿全生育期各处理表层（0～1.2 m）土壤处于干旱胁迫状态,随生育期和生育年限延伸,干旱胁迫程度加剧,尤其传统平作。不同处理之间沟中土壤温度差异不明显,垄上土壤温度差异明显,随集雨垄宽度增加而增加。与传统平作相比,MCS 30 、MCS 45 、MCS 60 、BF 30 、BF 45 、BF 60 、PF 30 、PF 45 和PF 60 （MCS、BF和PF分别代表土垄、生物可降解膜垄和塑料膜垄,下标分别表示垄宽为30、45和60 cm）的2年垄上平均土壤温度分别增加0.68、0.99、1.49、2.49、3.05、3.44、3.44、4.03和4.29℃。垄沟集雨种植具有调温保墒的作用,促进紫花苜蓿生长发育和产量形成,与传统平作相比,MCS 30 、MCS 45 、MCS 60 、BF 30 、BF 45 、BF 60 、PF 30 、PF 45 和PF 60 的2年紫花苜蓿全生育期平均实际干草产量分别增加7.77%、7.30%、2.11%、32.23%、29.95%、22.47%、40.88%、38.44%和28.37%,WUE分别增加17.94、26.16、29.57、17.35、19.47、17.85、20.99、22.66和20.63 kg·hm -2 ·mm -1 。多年生深根性豆科牧草紫花苜蓿的根系层土壤干燥化机理需要做进一步研究。

为揭示土壤水分动态对半干旱区垄沟集雨系统水文和生态过程的影响机理,基于Laio土壤水分动态随机模型（Laio模型）,利用中国气象局定西干旱气象与生态环境试验基地2012—2013年垄沟集雨燕麦生长季根系层土壤水分观测数据及2000—2015年日降水资料,分析不同覆盖材料（生物可降解膜、普通塑料膜和土壤结皮）和不同沟垄比（30∶60,45∶60和60∶60cm）对生长季燕麦根系层土壤水分动态的影响,研究点尺度土壤水分概率密度函数特征,并对模型涉及参数进行敏感性分析。结果表明:研究区年降水的季节分配极不均匀,主要集中在5—10月份,占总降雨次数的66.6%;年降雨量的85.32%来源于＞10 mm的降雨,以暴雨为主;近16年研究区降水量呈缓慢增长趋势。生物可降解膜垄（BMR）、普通地膜垄（CMR）和土垄（SR）临界产流降雨量分别为1.35、0.95 mm和5.31 mm,平均集水效率分别为87.892%、94.203%和27.488%;在燕麦生长季,BMR和CMR的土壤含水量显著大于SR,SR的土壤含水量显著大于传统平作,各处理土壤含水量均服从正态分布;通过Laio模型模拟得到的各处理土壤水分概率密度函数的曲线特征（峰值及其位置、90%置信区间）及数字特征（期望、方差）与观测结果基本一致,CM指数均大于0.5,且可将集雨垄径流量作为单次降水的随机事件处理,说明该模型可应用于垄沟集雨系统土壤水分概率密度函数的模拟,为半干旱区农田水分高效利用管理提供理论依据。

Ridge-furrow rainwater harvesting (RFRH) with mulch offers farmers means to address drought, water loss, and soil erosion in arid and semiarid regions. Plastic film is widely used as a mulching material for RFRH; however, contamination of arable lands by its residual is a serious concern. We compared various mulches, including a biodegradable film for RFRH planted with sainfoin (Onobrychis viciifolia). A field study was conducted to (1) estimate runoff efficiency from three ridge widths using three different mulching materials; and (2) assess the effects of ridge widths and mulching materials on topsoil temperature, soil water storage, fodder yield, fodder nutrition, and water use efficiency (WUE) of RFRH planted with sainfoin, during 2015 and 2016. The predicted runoff efficiency for MCS30, MCS45, MCS60, BF30, BF45, BF60, PF30, PF45, and PF60 [MCS, BF, and PF are abbreviations for ridges with manually compacted soil, mulched with biodegradable film and with plastic film, respectively, subscripts 30, 45, and 60 refer to ridge widths (cm) all with 60 cm furrow width] was 9.9%, 22.2%, 24.7%, 85.3%, 88.8%, 92.7%, 85.9%, 89.7%, and 93.3%, respectively. The practice of RFRH, especially BF and PF, resulted in increased topsoil temperature at ridge tops and increased soil water content at furrow bottoms but decreased topsoil temperature at furrow bottoms. MCS decreased actual fodder yield, but BF and PF increased actual fodder yield. Compared to flat planting (FP), the decrease of actual fodder yield for MCS30, MCS45, and MCS60 was 7%, 15%, and 18%, respectively, for 2015 and 2016, but the increase of actual fodder yield for BF30, BF45, BF60, PF30, PF45, and PF60 was 10%, 8%, 6%, 15%, 13%, and 8%, respectively. Mean WUE for MCS, BF, and PF was 1.58, 1.64, and 1.70 times greater than that for FP, respectively. High soil water content and high soil temperature in RFRH, especially for BF and PF, resulted in increased crude protein and phosphorus content of the fodder produced but resulted in decreased acid detergent fiber and neutral detergent fiber content of fodder. Mean crude protein content for BF and PF was 1.25 and 1.30 times greater than that for FP, respectively, whereas phosphorus content for BF and PF was 1.37 and 1.32 times greater than that for FP. The optimum ridge width for BF was 35-36 cm, whereas for PF, it was 36-42 cm. The RFRH design should conserve water and improve fodder yields and quality.

Sensitivity analysis of parameters, calibration and validation of eco-hydrological models are essential for model evaluation and application. It is important in model application to accurately estimate the values of model parameters and to further improve model prediction capacity. Based on eco-hydrological process, the Laio soil moisture dynamics stochastic model (Laio model) was used to describe daily water balance in active soil depth of ridge-furrow rainwater harvest system during growing season to analyze the effects of the interactions among plants, soil and environment under different climatic conditions on soil water balance and plant water conditions. The performance of the Laio model varied with climatic zone due to the heterogeneity of climate, vegetation and soil characteristics. In this study, in order to establish an effective system for parameter sensitivity analysis, calibration and validation of the Laio model in a ridge-furrow rainwater harvesting system in a semi-arid area, a field experiment with a randomized complete block design was conducted during the 2012 and 2013 oat growing seasons at Dingxi Arid Meteorology and Ecological Environment Experimental Station. The experiment was designed to investigate the parameter sensitivity and to determine the optimal mode of parameter optimization of the Laio model under various mulching materials (common plastic film, biodegradable film mulch and manually compacted soil) and various ridge-furrow ratios (60 cm:30 cm, 60 cm:45 cm and 60 cm:60 cm). The methods in-cluded multi-factor sensitivity analysis, simplex method (ISM), particle swarm optimization algorithm (PSO) and hybrid particle swarm optimization algorithm (HPSO). Also continuously monitored soil moisture, precipitation runoff and daily precipitation data for 2012–2013 were used to run the model. The results indicated that: (1) mean precipitation per rainfall event (α) and soil saturation degree at wilting point (sw) were the most sensitive parameters for probabilistic density function of soil moisture [p(s)] in different experimental treatments. While the sensitivity of p(s) to α was more obvious under low soil moisture content, that to swwas more obvious under high soil moisture content. (2) There were good agreements among the results of modelling using optimized parame-ters of the Laio model for the three optimization algorithms (ISM, PSO and HPSO) and the observation values, which were deter-mined from the p(s) curve. This included curve peak value (CPV), curve peak position (PP), 95% confidence interval (CI95%) and consistency measure (CM). All of these indicated that the optimized parameters of the Laio model using the ISM, PSO and HPSO methods correctly estimated p(s) of ridge-furrow rainwater harvesting. (3) The HPSO method not only improved global optimization performance, but also quickened convergence and gave robust results with good quality. It was an effective optimization method for the Laio model calibration and validation. The study improved the efficiency of model parameter calibration, upgraded the accuracy of model simulation results and provided guidance for application of the Laio model in ridge-furrow rainwater harvesting research.

Drought, water loss and soil erosion are the main factors restricting grain production and economic development in the semiarid hill areas of Loess Plateau, China. A field experiment was conducted to determine the effects of different tillage systems (open-ridging and tied-ridging) on soil water moisture, runoff, sediment yield, fodder yield and water use efficiency (WUE) on 2 slopes (5 degrees and 10 degrees), using traditional planting (without ridges and furrows) as a control, during 2 consecutive alfalfa growing years: 2015 and 2016. Results indicated that the benefits of fodder yield and WUE increase from tillage system were more effective than the benefits from slope gradient on slight sloping land. Open-ridging and tied-ridging decreased runoff and sediment transport and increased soil moisture, fodder yield and WUE of alfalfa. The decrease of sediment for open-ridging and tied ridging was 85.1% and 88.4%, respectively, for slopes of 5 degrees, while it was 83.9% and 89.0% for slopes of 10 degrees. Only 7-10% rainfall events produced runoff and 4-6% rainfall events produced sediment. The mean runoff efficiency for traditional planting, open-ridging and tied-ridging was 11.6%, 9.1% and 6.7%, respectively, for slopes of 5 degrees, while it was 13.4%, 10.0% and 7.8% for slopes of 10 degrees, over 2 years. Increase of fodder yields for open-ridging and tied-ridging was 34.6% and 19.8%, respectively, for slopes of 5 degrees, while it was 32.7% and 20.6% for slopes of 10 degrees, over 2 years. The average WUE for open-ridging and tied-ridging was respectively 1.96 and 1.85 times greater than that for traditional planting, for slopes of 5 degrees, while it was 1.88 and 1.77 times greater than that for traditional planting, for slopes of 10 degrees, over 2 years. The mean runoff and sediment for slopes of 10 degrees was 1.14-1.16 and L19-1.57 times that for slopes of 5 degrees, respectively. The differences of fodder yield and WUE between slopes of 5 degrees and slopes of 10 degrees were not significant. Tied-ridging rainwater harvesting offered particular effects on water and soil conservation, while open-ridging offered particular effects on fodder yields and WUE enhancement during the first and the second growing seasons.

地表径流是引起土壤侵蚀的主要动力,控制水土流失和提高降水资源利用效率是半干旱区农业可持续发展的关键因素.本研究利用沟垄微型集雨径流场实测径流资料,基于SCS-CN模型,结合下垫面、降雨量等信息,分析模型参数(径流曲线数CN和初损系数λ)的敏感性,测定不同沟垄比和不同覆盖材料对模型参数的影响,提出适合沟垄微型集雨系统产流计算的参数值,并对其进行模拟验证及有效性分析.结果表明,初损系数λ是影响模型模拟的主要因子,试验沟垄比对模型参数率定的影响较小;该模型所模拟的径流量与实测径流量具有较好的一致性,土垄、普通塑料膜垄和生物可降解膜垄的有效性系数分别为0.864、0.988和0.947,说明模型在参数的确定上较为合理,可应用于沟垄微型集雨系统降雨径流的预测,为半干旱区控制水土流失和提高降水资源利用效率提供科学方法.

A new planting pattern for potato production in semiarid areas was designed and tested for enhanced tuber yield and for the benefit of collecting rainwater. This pattern comprised two elements: the ridge mulched by plastic film that acts as the runoff area and the furrow as the infiltration basin or planting area. The conventional planting pattern for potato production in semiarid regions of northwestern China is the opposite with mulched ridges for planting and the furrow as an infiltration zone. The purpose of this study was to examine the effect of the ridge with or without mulching on rainwater harvesting and the response in potato yield and to determine the optimal cross-sectional area of the ridge and furrow. A ratio defined as the width of the ridge to the width of the furrow or the planting area was used to evaluate the cross-sectional area. Three ratios of 0.5, 0.75, and 1.0 were tested under the conditions of mulched ridge, bare earth ridge, and no ridge or flat planting, respectively. No matter what ratio used, the width of the planting belt was the same at 0.6m. The results showed that for tuber yield, the ridge with the plastic mulching was more effective than the bare earth ridge and that the bare earth ridge was better than flat planting. In the mulched ridges, a ridge width of 0.45m or a ratio of ridge to furrow of 0.75 led to higher yield than that of ridges with a width of 0.3 and 0.6m. For the bare earth ridges, the yield in the 0.6m ridge width was higher than that of the other two ridges. Besides improving potato yield, the mulched ridge and furrow planting had the added advantage of collecting considerable rainwater for soil moisture. In addition, the percentage of small-sized potatoes was low. Therefore, we recommend that the mulched ridge with a ridge width of 0.45m and a furrow width of 0.6m as a successful method to increase potato yield in semiarid areas where potato production relies totally on rainwater.