Ridge-furrow Mulching System Research Articles

Effects of mulching types on the yield and water utilization by broomcorn millet (Panicum miliaceum): Results of a study in the Loess Plateau, China

Mulching practices have been widely adopted to improve rainfed crop productivity. However, the major resources including water, heat, and light that influenced the yield of broomcorn millet in different dryland regions have rarely been explored. A three-season field experiment with three mulching practices i.e. traditional planting with non-mulching (TP), ridge-furrow mulching system (RF), and plastic film mulching (PFM) was conducted in three semi-arid regions in the Loess Plateau, China, i.e. Guyuan city (GY), Huining county (HN), and Yulin city (YL) between 2020 and 2022 to investigate the impacts of mulching regimes on soil hydrothermal conditions, agronomic characteristics, leaf photosynthetic properties, broomcorn millet yield, and water use efficiency (WUE). Results showed that both PFM and RF treatments increased soil temperature and moisture, and enhanced dry matter accumulation by promoting leaf photosynthetic capacity and chlorophyll content, thereby improving broomcorn millet yield and WUE. PFM and RF increased the average broomcorn millet yield by 15.08% and 24.86% at GY site, 20.86% and 25.61% at HN site, and 15.75% and 25.57% at YL site, respectively, and increased the average WUE by 16.31% and 27.48% at GY site, 23.21% and 28.80% at HN site, 15.55% and 28.57% at YL site, respectively. Partial least squares path modeling analysis revealed that soil moisture was an important environmental factor in determining broomcorn millet yield. Overall, RF practice can be taken to improve the management of agricultural climate factors and maximize yield, thereby promoting the sustainable development of dryland agriculture in the Loess Plateau.

Microbial carbon and nitrogen limitations with mulching of proso millet fields on the Loess Plateau: Evidence from soil ecoenzymatic stoichiometry

AbstractMulching measures can regulate soil properties; however, little is known about the effects metabolic limitations on farmland during the key growth stages of broomcorn millet in multiple regions of the Loess Plateau. We conducted field experiments to compare three techniques: flat planting with no mulching (TP), ridge–furrow mulching system (RF), and plastic film mulching (PFM). Soil extracellular enzymatic stoichiometry and physicochemical properties of three growth periods (jointing, flowering, and maturity) of proso millet (Panicum miliaceum L.) were measured to investigate microbial metabolic limitations and the relationship with soil moisture, temperature, and nutrients in the three regions of the Loess Plateau (Guyuan city, Huining County, and Yulin city). The results show that compared with TP, both PFM and RF techniques increased soil organic carbon (SOC), total nitrogen (TN), ammonium nitrogen (), and nitrate nitrogen () during the jointing period, but the levels decreased during the flowering period, and the activities of C‐, N‐, P‐acquiring enzymes were 29.02%, 33.68%, and 19.46% higher when using PFM, and 13.78%, 6.81%, and 6.52% higher when using RF. Meanwhile, RF treatment significantly increased the carbon metabolism limitation during the jointing, flowering, and maturity periods of proso millet in the three regions, and also improved the nitrogen metabolism limitation during the jointing and flowering periods of proso millet in the Huining and Yulin regions. Linear regression analysis showed that pH, SOC, and contents significantly affected carbon limitation, and nitrogen limitation was gradually alleviated with increases in SOC, TN, and contents in proso millet farmland soils. Partial least squares path modeling showed that soil moisture and nutrients differed significantly among the regions, and soil temperature positively regulated the soil nutrients. Mulching significantly improved the carbon limitation owing to increased soil temperature and moisture. These results provide important ideas for nutrient cycling and microbial metabolism of broomcorn millet farmland soil under mulching measures on the Loess Plateau.

Partitioning evapotranspiration using 18O abundance to understand water use efficiency in maize produced using ridge-furrow mulching system

The ridge-furrow mulching system (RFMS) is an efficient farming strategy that has been used widely for improving crop productivity in dryland agriculture. However, the physical mechanism that allows RFMS and its optimal ridge/furrow ratio to drive the efficient utilization of water in fields are unclear. Thus, we conducted a field research for two years with spring maize based on a long-term field experiment in a semiarid region of Northwestern China to quantify evaporation and transpiration, and their relationship with maize growth, yield and water use efficiency (WUE) under RFMS. Three planting patterns of ridge/furrow ratio were tested: (1) RF40, RFMS with 60 cm wide ridges and 40 cm wide furrows; (2) RF60, RFMS with 60 cm wide ridges and 60 cm wide furrows; (3) FP, traditional flat planting (control). Stable oxygen isotope (18O) analysis was used to partition the evapotranspiration (ET) into evaporation (E) and transpiration (T). The results showed that RFMS significantly increased the soil water content (SWC) in the early and late growing season, but not in the middle period (60–120 days after sowing, DAS) when dry matter accumulated rapidly and the highest transpiration occurred. RFMS significantly decreased the nonproductive evaporation, thereby increased the physiologically significant maize transpiration by 25.0–35.7% during the whole growing season. Therefore, the transpiration fraction of ET (T/ET) was 73% and 70% under RF40 and RF60 during the whole growing season, which were significantly higher than FP. Compared to FP, the maize yield and WUE increased significantly by 55.1% and 52.2% under RF40 and by 49.5% and 47.6% under RF60. We found RFMS drives optimization of ET fractions by increased transpiration but decreased evaporation and then improved WUE of maize, higher ridge/furrow ratio (RF40) create uneven line space and higher mulching area in the field, thus drives optimization of ET components and increased yield and WUE the most. Clarification of this physical mechanism improves our understanding of the optimization of maize production under RFMS, thereby helping to optimize the ridge/furrow ratio in semiarid regions.

Optimization of ridge–furrow mulching ratio enhances precipitation collection before silking to improve maize yield in a semi–arid region

Insufficient soil moisture and heat often limit crop productivity in semiarid regions. The effects of the ridge–furrow mulching system (RFMS) on improving the soil water and temperature conditions have been confirmed in many studies, but the effects of different ridge–furrow ratios on the changes in soil water, temperature, and the interception rate of canopy photosynthetically active radiation (PARIR), and thus crop productivity remain unclear. Therefore, we conducted a field experiment from 2015 to 2020 in the Loess Plateau region of northwest China by testing conventional tillage without mulch (CK) as a control treatment and three ridge–furrow ratios (60:60 cm, 80:40 cm, and 50:10 cm). We studied the changes in the soil hydrothermal characteristics and the response of maize canopy under continuous mulching with different ridge–furrow ratios. Compared with CK, RFMS increased the soil water storage in the 0–200 cm soil layer by 5.2–9.3% and the effective accumulated soil temperature by 10.4–29.1%. The hydrothermal properties affected the maize canopy under RFMS where compared with CK, PARIR increased by 6.3–11.7% at 61 to 90 days after planting (DAP) and the maize yield finally increased by 44.8–77.9%. Correlation analysis showed that the contribution of precipitation from 0 to 90 DAP to the maize yield was greater than that of the effective accumulated soil temperature, whereas the contribution of the effective accumulated soil temperature was greater at 91 to 150 DAP. The precipitation during 61 to 90 DAP was the most important factor that affected the yield during the whole growth period. Thus, increasing the ridge–furrow ratio can improve the soil hydrothermal properties and maize productivity to ensure food security and avoid resource shortages in the Loess Plateau region and similar areas.

Effect of a Ridge-Furrow Mulching System and Limited Supplementary Irrigation on N2O Emission Characteristics and Grain Yield of Winter Wheat (Triticum aestivum L.) Fields under Dryland Conditions

Knowledge of the characteristics of N2O emissions and the influential mechanism is of great significance to mitigate greenhouse gas emissions in semi-arid areas. In the present study, a three-year water-control study was conducted; three simulated rainfall amounts (heavy, normal, and light rainfall = 275, 200, and 125 mm, respectively), two wheat (Triticum aestivum L.) planting modes (RF (ridge–furrow mulching system) and TF (traditional flat planting)) and four supplementary irrigation amounts (150, 75, 37.5, and 0 mm) were set up. The effects of different cultivation methods and irrigation amounts on soil N2O emissions, the soil water content, available nitrogen content, and denitrifying enzyme activity were investigated to clarify the N2O emission mechanism in winter wheat fields (Triticum aestivum L.). The results obtained after three years showed that compared with TF, the N2O emissions under RF decreased by 21.62–30.72% (p < 0.001), whereas the soil water content increased by 6.26–8.82%, the available nitrogen content decreased by 1.71–16.24%, and the denitrifying enzyme activities increased by 0.2–24.16% under heavy rainfall conditions. Under conditions with normal and light rainfall, the N2O emission fluxes under RF increased by 3.66–12.46% and 6.08–15.57% (p > 0.05), while the soil water contents increased by 6.13–11.49% and 8.05–13.88%, the soil available nitrogen contents decreased by 11.0–21.42% and 19.93–34.44%, and the denitrifying enzyme activities increased by 0.01–24.08% and 0.03–20.79% compared with TF. Principal component analysis showed that the main factors related to N2O emissions under RF were the soil moisture content and available nitrogen content; these factors combined explained 94.37% the variation of the N2O emissions. However, the main factors under TF were the soil moisture content and denitrifying enzyme activity; these factors combined explained 85.81%. In the heavy and normal rainfall years, compared with TF, using RF and 75 mm irrigation achieved the goal of reducing water usage as well as decreasing the N2O emissions (or N2O increase was not significant). In light rainfall years, RF with 150 mm irrigation obtained significant reductions in water usage compared with TF but it also increased the N2O emission flux. Under different rainfall years, the yield of RF increased by 2.89–50.44% compared with the TF system, and the increase in wheat grain yield increased with decreasing rainfall.

Effects of organic amendments and ridge–furrow mulching system on soil properties and economic benefits of wolfberry orchards on the Tibetan Plateau

Water scarcity and low soil fertility severely constrain crop growth and sustainable agricultural productivity on the Tibetan Plateau. Organic amendments and ridge–furrow mulching system (RFMS) are widely used to improve soil moisture, soil structure, and crop production in arid and semi-arid areas. However, their combined effects on soil physicochemical properties and economic benefits of wolfberry (Lycium barbarum L.) on the Tibetan Plateau remain unclear. A two-year field experiment was undertaken to evaluate the combined effects of organic amendments and RFMS on soil water, soil structure, soil saturated hydraulic conductivity, soil organic carbon (SOC), total nitrogen (TN), and economic benefits on wolfberry. Four cultivation practices were established: traditional flat plot with mulching (FP), traditional flat plot with mulching and organic amendment (FPOA), ridge–furrow planting with mulching (RF), and ridge–furrow planting with mulching and organic amendment (RFOA). The organic amendment and RFMS treatments had higher soil water storage (SWS) and soil desiccation index (SDI) than the FP treatment in both growing seasons, especially at 20–60 cm soil depth. In addition, organic amendment significantly decreased soil bulk density by 6.4% and increased soil saturated hydraulic conductivity by 16.8% in the 0–60 cm soil layer, respectively, and improved the proportion of larger soil aggregates (0.02–2 mm) by 10.8% in the 0–40 cm soil layer. Furthermore, the RFOA treatment significantly improved SOC and TN contents at 0–60 cm soil depth by 47.7% and 19.4%, respectively, relative to FP. The measured soil properties were highly correlated with wolfberry yield and water use efficiency over 2 years. In particular, the RFOA treatment had higher crop yield and economic benefit than the other treatments due to the more favorable soil environment. Therefore, the RFOA treatment could be a sustainable and efficient cultivation practice for alleviating drought stress, improving soil properties, and increasing economic benefit on the Tibetan Plateau.

Optimizing the ridge–furrow ratio and nitrogen application rate can increase the grain yield and water use efficiency of rain-fed spring maize in the Loess Plateau region of China

Providing a suitable water environment and nitrogen (N) supply are essential for improving the crop productivity, especially in rain-fed areas affected by drought and nutrient deficiencies. The ridge–furrow mulching system (RFMS) is an efficient planting pattern in the rain-fed area of the Loess Plateau in China. Changing the ridge–furrow ratio in RFMS often modifies the hydrothermal environments. Few previous studies have investigated the combined effect of changing the ridge–furrow ratio and N application rate. Thus, we conducted a field experiment from 2020 to 2021 in the Loess Plateau region of China with two planting patterns (flat planting without film mulching and RFMS with three ridge–furrow ratios of 40:70 cm, 55:55 cm, and 70:40 cm) and three nitrogen application rates (N1, 180 kg ha–1; N2, 240 kg ha–1; and N3, 300 kg ha–1). We analyzed the effects of different N application rates and planting patterns on the soil hydrothermal environment, growth and development, grain yield, and water use efficiency (WUE) of spring maize. The results showed that the soil hydrothermal environment improved as the ridge–furrow ratio increased, but increasing the N application rate risked aggravating the soil water consumption. Compared with FP, the warming effect of RFPM accelerated senescence and shortened growth period (1–4 days) of spring maize under N1, and the negative effect could be effectively alleviated with the increase of N application rate. Increasing the ridge–furrow ratio and N application rate increased the photosynthetic capacity, leaf area, and accumulated dry matter. Compared with FP, RF40–70, RF55–55, and RF70–40 significantly increased the grain yield by 12.96%, 20.28%, and 28.98%, and significantly increased WUE by 16.01%, 22.35%, and 31.83%, respectively. Grain yield and WUE also increased with the increase of N application rate. Regression analysis further showed that, under RFMS at 70:40 cm, the highest spring maize grain yield and WUE were achieved with N application rates of 274.14 kg ha–1 and 268.56 kg ha–1, respectively. Therefore, we suggested that RFMS at 70:40 cm and N application at 268.56–274.14 kg ha–1 are most suitable for rain-fed spring maize production in the Loess Plateau region.

Simulation of Soil Water and Heat Flow under Plastic Mulching and Different Ridge Patterns

The ridge–furrow mulching system with plastic film (RFMS) has been widely used in semi-arid areas in order to improve soil water and heat conditions, crop yields and water use efficiency. It is of practical significance to study the effect of mulching and ridge types on soil water and heat in order to optimize mulching measures and improve the effectiveness of the ridge and furrow system. To clarify the combined effect of soil water and heat beneath the system and the influence of ridge morphology on it, field experiments were conducted with three treatments, including conventional planting in bare land (CK), a ridge–furrow (wide ridge with 70 cm width and 10 cm height, narrow ridge with 40 cm width and 15 cm height) mulching system with complete plastic film (RFWN) and a ridge–furrow (equal ridge with 55 cm width and 15 cm height) mulching system with complete plastic film (RFE). An insufficient irrigation system was adopted and the two-dimensional numerical software HYDRUS-2D was used to simulate the soil water and heat flow under the experimental conditions. The model was calibrated and verified according to test data for the period of 2018 to 2019, which showed good agreement between the simulated and measured values. The simulation results revealed that the ground temperatures of RFWN and RFE were much higher than that of CK, and the average value of 0–25 cm during the growth period could increase by 2.29–4.61%. Compared with CK, RFWN and RFE reduced soil evaporation (84.71–93.73%) and field evapotranspiration (12.02–21.75%), while they increased root water uptake (25.87–40.98%) and T/ET (48.85–80.15%). Plastic film mulching and ridge morphologies affected the infiltration range and the direction of soil water movement, increased soil moisture when there was no rainfall or irrigation and reduced soil water and heat fluctuations, which was more conducive to crop growth, especially under the RFWN system. The simulation method proposed in this paper is an effective technique for calculating the soil water and heat dynamics under different ridge and furrow sections under the condition of film mulching, and it can be used for the optimal management of soil water and heat in this area.

Matching fertilization with water availability enhances maize productivity and water use efficiency in a semi-arid area: Mechanisms and solutions

Unpredictable precipitation and frequent droughts often threaten crop productivity in semiarid areas, but this challenge can be alleviated by optimizing the nutrient supplies to match the water availability. In this study, a field experiment was conducted from 2014 to 2017 in the Loess Plateau of northwest China to determine the soil water balance and maize crop productivity in the ridge–furrow mulching system under five N + P2O5 fertilizer application rates: 0 + 0 (control); 117 + 59 kg ha−1; 173 + 87 kg ha−1; 229 + 115 kg ha−1; and 285 + 143 kg ha−1. Results showed that fertilization increased the evapotranspiration by 5.1–11.8 %, maize yield by 94.0–129.9 %, and water use efficiency by 89.3–116.7 %, compared with the control. However, increasing the fertilizer rate resulted in the evapotranspiration exceeding the precipitation, thereby leading to significant soil water depletion (44.9 mm – 159.6 mm), especially in the 80–200 cm soil layer., The average soil water increment during the fallow period was 49.3 mm, which was not balanced with the soil water depletion, and thus the annual soil water imbalance characterized by decreased soil water storage at sowing (SWSs) that became worse each year. During the course of the four-year study, SWSs decreased from an average of 575.5 mm in 2014 to 358.8–500.0 mm (average 398.6 mm) in 2017, and the decreases were 20.5–28.2 % greater in soils that received higher fertilizer rates compared with the control. Thus, huge fluctuations occurred in the maize yield between years, which were greater as the amount of fertilizer increased. Our results suggests that fertilizer application at a rate of N 180.9+P2O5 90.5 kg ha–1 is ideal to match with the water availability to facilitate sustainable water use and achieve high maize yields. In addition, ensuring that SWSs is at least 441.1 mm and the sum of SWSS plus precipitation within 90 days after sowing exceeds 624.3 mm can help to stabilize the maize grain yield in the study region.

Density-dependent maize (Zea mays L.) yield increase in trade-off in reproductive allocation and water use under ridge-furrow plastic-mulching

• Maize yield responses to increasing planting densities were studied in RFM system. • Individual yield declined while population one increased first and then decreased. • This difference resulted from improved soil water availability as affected by RFM. • Optimal density had better trade-off between reproductive and vegetative growth. • Allometric R–V relationship explained density-dependent yield formation under RFM. The law of constant final yield and allometric theory have been seldom used to explore density-dependent yield formation and water use in rainfed farming systems, particularly in ridge-furrow mulching (RFM) system of maize. A two-year RFM field experiment was conducted using maize variety Yuyuan7879 in semiarid Kenya from 2015 to 2016, with four planting densities: 5.2 × 10 4 (D52, conventional density), 6.0 × 10 4 (D60), 6.9 × 10 4 (D69) and 8.5 × 10 4 (D85) plants per hectare. The grain yield and aboveground biomass per plant were significantly decreased with increasing density across two growing seasons. However, the population grain yield significantly was increased from D52 to D60 (from 3395.1–4471.7 kg ha −1 ) but declined significantly from D60 to D69 and D85 (p < 0.05) in 2015 and 2016, respectively. Meanwhile, the population aboveground biomass was significantly promoted from D52 to D60 (p < 0.05) and then remained relatively stable in D69 and D85, achieving a state of constant final yield. Under the improved soil storage, the RFM system raised the rational planting density from conventional D52 to D60 with regard to population yield. Water use efficiency for population yield (WUE G ) was the highest at D52 and D60, followed by D69, and the lowest at D85. However, the WUE for the aboveground biomass (WUE A ) was significantly lower in D52 than D60 and D85. Principal component analysis suggested that the population grain yield and WUE G were significantly positively associated with the reproductive allocation and leaf growth. This result was further affirmed by the allometric relationship between leaf biomass and body size, since the allometric exponent (<1) was raised with density. Allometric relationship between reproductive and vegetative mass demonstrated that the D60 treatment achieved a relatively balanced allocation of photosynthetic products into reproductive organs in comparison with other treatments. The RFM application significantly improved the availability of soil water, and the rational planting density of maize for better yield and WUE G . Thus, this phenomenon mechanically resulted from relatively better trade-offs between reproductive and vegetative growth, together with moderately increased leaf growth.

Alternating wide ridges and narrow furrows with film mulching improves soil hydrothermal conditions and maize water use efficiency in dry sub-humid regions

The ridge-furrow mulching system (RFMS) is widely used to improve crop yields and water use efficiency in arid and semi-arid rainfed agricultural regions. However, the effects of RFMS on hydrothermal states and maize (Zea mays L.) yields in dry sub-humid regions remain unclear. The objective of this study was to determine the influence of ridge-furrow construction and plastic film mulching on soil moisture and temperature, evapotranspiration (ET), maize growth and yield, water use efficiency (WUE), and thermal time use efficiency (TUE) in dry sub-humid regions of the Loess Plateau. A three-year field study was conducted in which four different planting practices were evaluated: (1) alternating wide ridges and narrow furrows with film mulching (WRM), (2) alternating equal-width ridges and furrows with film mulching (ERM), (3) equal row spacing in flat plot with half film mulching (EFM), and (4) conventional flat plot without mulching (CK). The results demonstrated that at early maize growth stages, soil water storage within the 0–200 cm soil profile and soil temperatures were increased for mulching treatments compared with CK. RFMS utilized soil water efficiently by increasing rainwater harvesting efficiency and transpiration while decreasing soil evaporation. RFMS significantly increased soil temperature in the ridges by 4.0–4.4 °C and reduced diurnal soil temperature amplitude in the furrows, thereby increasing soil thermal time. These positive effects of RFMS compared with CK improved maize growth and crop yields because of adequate absorption and utilization of water and thermal resources. RFMS increased average maize yield by 24.9–32.8%, WUE by 34.1–45.7%, and TUE by 15.9–21.1%. The highest grain yield, WUE, and TUE were observed with WRM due to its favorable soil hydrothermal conditions. The WRM treatment is a promising water-saving and high-yielding maize cultivation practice to improve grain yields and resource use efficiency in dry sub-humid regions.

Effects of ridge-furrow mulching system with supplementary irrigation on soil respiration in winter wheat fields under different rainfall conditions

Developing an ecologically friendly supplementary irrigation method is vitally important for improving wheat productivity in terms of reduced water usage and high yields in semiarid areas. In this study, we explored the effects of the ridge-furrow mulching system (RF) with supplementary irrigation on soil respiration in winter wheat fields under different rainfall conditions. Three rainfall conditions were simulated (heavy rainfall =275 mm, normal rainfall =200 mm, and light rainfall =125 mm) and four irrigation treatments (150, 75, 37.5, and 0 mm) were examined during the growth period for winter wheat. A traditional flat (TF) planting was used as the control. The results obtained after three years (October 2015 to June 2018) showed that there was no significant difference in the soil respiration rate between RF and TF under 200 mm and 275 mm rainfall in the winter wheat growth period. Under rainfall at 125 mm, the respiration rate using RF with the same irrigation was significantly increased by 5.31–23.38% compared with that using TF, where the differences among treatments were significant, except for that with irrigation at 150 mm. Under rainfall at 275, 200, and 125 mm, the coefficients of determination for the effects of the soil temperature and water content on soil respiration were lower with RF than TF. The coefficients of determination also tended to increase as the amounts of rainfall and supplementary irrigation decreased. Therefore, to reduce the impact of supplementary irrigation under climate warming, we conclude that the P1R75, P2R150 and P3R150 treatments are suitable ecologically friendly supplementary irrigation method for reducing water usage in semiarid areas.

Ridge-furrow mulching system and supplementary irrigation can reduce the greenhouse gas emission intensity

In this study, in order to explore the greenhouse gas emissions and global warming potential (GWP) in winter wheat fields under the ridge-furrow mulching system (RF) with supplementary irrigation, three rainfall conditions (heavy rainfall = 275 mm, normal rainfall = 200 mm, and light rainfall = 125 mm) and four irrigation treatments (150, 75, 37.5, and 0 mm) were simulated during the growth period. Traditional flat planting (TF) was used as the control and we determined the emissions of N2O, CO2, and CH4, as well as the GWP and greenhouse gas emission intensity (GHGI). The results obtained after three years (October 2016 to June 2019) showed that when the amount of irrigation was the same during the winter wheat growth period, the N2O emission flux, CO2 emission flux, and GHGI under RF decreased by 3.30–23.78%, 5.93–6.45%, and 5.01–23.72% with rainfall at 275 mm, respectively, compared with those under TF. Under the same level of supplementary irrigation, the N2O emission flux, CO2 emission flux, and GHGI decreased by 0.8–4.18%, 5.05–13.53%, and 7.83–13.72%, respectively, with rainfall at 200 mm, and they decreased by 17.49–32.46%, 25.57–35.35%, and 6.22–30.20% with rainfall at 125 mm. Under the three rainfall conditions, the absorption of CH4 in the winter wheat field increased as the supplementary irrigation decreased. Our results showed that the RF system can satisfy the goal of achieving high yields and saving water, as well as reducing the GHGI to contribute less to global climate warming as an environmentally friendly irrigation method.

Ridge-furrow mulching system regulates hydrothermal conditions to promote maize yield and efficient water use in rainfed farming area

The ridge-furrow mulching system with plastic film (RFMS) is considered an effective strategy to improve grain yield and has been widely used in arid and semi-arid rainfed agricultural areas. However, the key mechanism by which RFMS increases yield and efficiency under different hydrothermal conditions remains unclear. Understanding this mechanism and the interaction between different RFMSs and hydrothermal conditions could provide a practical reference for optimizing cultivation. We aimed to investigate the yield increase potential of different planting systems under the same hydrothermal conditions and evaluate the effects of RFMS treatments on drought resistance and yield increase under different hydrothermal conditions. The following planting treatments were carried out in ridge–furrow prepared fields under seven different hydrothermal conditions in a representative rainfed agricultural area for four consecutive years: 1) ridge-furrow mulching system with complete coverage (RC); 2) ridge-furrow mulching system with ridge coverage (RR); and 3) planting without mulching (control treatment; CT). Compared with CT, RFMS improved field hydrothermal conditions and reduced evapotranspiration of crops. In more hydrothermally limited areas (precipitation, 196–320 mm; temperature, <18 °C), the grain yield and water-use efficiency (WUE) with RC significantly increased by 49.95 % and 57.12 % compared with that of CT, respectively. However, RR and RC had no significant difference in grain yield and WUE in areas less hydrothermally limited (precipitation, 320–460 mm; temperature, 18.6 °C–23.6 °C) but increased by 13.51 % and 22.19 % compared with that of CT. Additionally, RFMS improved economic benefits, especially in hydrothermally limited areas, with RC increasing benefits by 142.64 %–200.84 % compared with that of CT. Therefore, RC can be used as the optimal technique to overcome simultaneous drought and cold weather in rainfed agricultural areas under hydrothermally limited conditions.

Ridge-furrow mulching system drives the efficient utilization of key production resources and the improvement of maize productivity in the Loess Plateau of China

Utilizing ridge-furrow construction combined with plastic film mulching system (RFMS) is an effective strategy for improving crop productivity in semi-arid areas. However, the key mechanisms by which RFMS stimulates the integrated utilization of key production resources (thermal, water and radiation) to affect maize production is not well-defined. In the Loess Plateau of China, three treatments were applied in a two-year field experiment: 1) RFH with RFMS at a high coverage ratio (50 cm mulched ridge:10 cm unmulched furrow); 2) RFL with RFMS at a low coverage ratio (60 cm mulched ridge:60 cm unmulched furrow); and 3) FP as the control without mulching. RFMS significantly improved soil hydrothermal conditions, which enhanced photosynthesis and promoted canopy growth to intercept more radiation. With an increase of soil thermal time (TTsoil) by 199.1–415.1 °C d compared with FP, the thermal effect of RFMS improved maize crop phenology by shortening the duration of vegetative stage to prolonging reproductive stage by 1–3 days, thereby prioritizing the allocation of the captured radiation, thermal and water to reproductive growth. These alterations significantly increased maize grain yield by 38.0–59.6%, and enhanced the efficient use of resources by 13.7–21.9% in thermal, 34.6–59.8% in water and 30.0–50.0% in radiation, which enhanced when increasing coverage (RFH vs. RFL). Overall, these alterations of RFMS on hydrothermal, as an adaptive strategy, can positively mark the capture and allocation of resources and the conversion of resources into biological materials (especially grains) in semi-arid areas like the Loess Plateau.

Ridge-furrow mulching system regulates diurnal temperature amplitude and wetting-drying alternation behavior in soil to promote maize growth and water use in a semiarid region

Utilizing the ridge- furrow mulching system with plastic film (RFMS) is an effective strategy for improving crop productivity in semiarid areas. However, the key mechanism by which RFMS drives spatiotemporal hydrothermal variation of soil to positively affect crop production is not well-defined, and a better understanding of this mechanism could guide RFMS optimization. A two-year field experiment was conducted with three planting treatments: 1) the RFMS with high coverage ratio, 50 cm mulched ridge:10 cm bare furrow, RFH; 2) the RFMS with low coverage ratio, 60 cm mulched ridge:60 cm bare furrow, RFL; and 3) flat planting without mulching as the control treatment, CK. The results showed that RFMS increased topsoil temperature by 1.0–2.5 °C during the day (08:00–20:00) and 1.6–3.4 °C at night (20:00–08:00), respectively, compared with CK, which led to a decrease of 0.4–1.3 °C in diurnal temperature amplitude, but indicated a strong positive impact on maize growth in the thermally deficient study area. In addition, RFMS drove the spatio-temporal alternation of soil wetting and drying (alternation of high and low SWC) relative to CK, indicating an efficient water use strategy that significantly reduces soil evaporation but promotes the plant transpiration during water sensitive period. These effects in RFH were significantly greater than those in RFL due to its significantly enhanced water infiltration, suppressed evaporation and reduced heat loss, which stimulated vigorous crop growth. This study suggested that, compared to CK, RFH was more efficient than RFL to improve maize production, which increased these amplitudes from 43.1% to 59.2% in grain yield increase, from 38.5% to 57.4% in water use efficiency (WUE) increase and from 71.7% to 95.0% in economic benefit increase, respectively. Therefore RFH can be considered as a superior technique for overcoming simultaneous drought and cold stresses in northwestern China.

Effects of ridge–furrow mulching on soil CO2 efflux in a maize field in the Chinese Loess Plateau

Ridge–furrow mulching system (RFMS) is widely used in arid and semi–arid areas, but its effect on soil respiration (Rs) and its components, including heterotrophic (Rh) and autotrophic respiration (Ra) are still poorly understood. In this study, CO2 flux from the soil of furrows and ridges was measured across different RFMS practices (i.e., three different ridge/furrow ratios) and conventional flat planting (CK). A trenching method was used to estimate the contribution of Rh to Rs. Compared with CK, RFMS significantly increased soil temperature of the ridge, promoted soil moisture of the furrow, and enhanced microbial diversity at the early crop growth stage, resulting in increased Rs and its components. The ridge soils exhibited much higher Rs (3.43 μmol m–2 s–1) than the furrow soils (2.98 μmol m–2 s–1) under all three RFMS practices. The contribution ratios of Rh to Rs across the different practices ranged from 50.4% to 59.6%. Soil temperature rather than soil moisture explained the seasonal variation of Rs and its components for both CK and RFMS. Nonetheless, high Rs and Rh values in RFMS did not induce a decline of soil organic carbon during the two–year experimental period. Improved root growth in RFMS practices may provide more exudates to the soil, thus offsetting soil carbon decomposition. Compared with CK, RFMS with ridge/furrow ratios of 40:70 cm, 55:55 cm, and 70:40 cm, significantly increased soil CO2 emissions by 10.6%, 19.6%, and 20.4%, respectively, while increasing maize yield by 26.1%, 36.4%, and 50.3%, respectively. Carbon emission efficiency (CEE) was significantly higher in RFMS than in CK in both years. This study suggests that, due to its high CEE, RFMS with a ridge/furrow ratio of 70:40 cm could be a highly promising strategy for sustaining crop productivity while minimizing environmental impacts.

Environmental and economic benefits of micro–field rain–harvesting farming system at maize (Zea mays L.) field scale in semiarid east African Plateau

To explore low–cost, high–yielding and environment–friendly rainfed farming technology is critical for sustainable agricultural development in semiarid east African Plateau (EAP). An innovative ridge–furrow mulching system (RFMS) was first introduced to EAP, with a two–year field experiment using maize cultivar KDVI in a typical semiarid site of Kenya from 2012 to 2013. Nine treatments were designed including ridge–furrow cultivation with black plastic mulching (RFB), straw mulching (RFS) and without mulching (RF) under high (375 kg ha−1), conventional (225 kg ha−1) and zero fertilization rates. We found RFB and RFS significantly increased soil water storage (0–40 cm) by 10.2% and 4.8%, while lowered evapotranspiration rate and improved thermal status, compared to RF across two growing seasons. Importantly, RFB and RFS increased soil organic carbon and C/N ratio (soil organic carbon/soil total nitrogen) by 7.8% and 4.9%, 7.2% and 5.1% respectively, following two growing seasons of farming practice. As expected, grain yield and water use efficiency (WUE) were averagely increased by 63.3% and 63.8%, 27.5% and 35.9% in RFB and RFS than those of RF respectively. Additionally, net income and economic output–to–input ratio were significantly greater in RFB and RFS than those of RF. On the other hand, conventional fertilization rate achieved similar grain yield and WUE as high fertilization did. Considering environmental and economic benefits, the RFMS farming system with conventional fertilization may act as a promising option to upgrade local dryland agricultural system in EAP.

Optimum ridge-to-furrow ratio in ridge-furrow mulching systems for improving water conservation in maize (Zea may L.) production.

Water-saving cultivation techniques have been attracting increased attention worldwide. Ridge-furrow mulching system (RFMS), as a prospective rainwater harvesting system, has been widely adopted in arid and semi-arid areas. Field experiments were conducted in 2014 and 2015 to compare soil water storage, soil temperature, maize yield, and water use efficiency (WUE) among different ridge/furrow width arrangements in RFMS comprised of three different ridge/furrow ratios, i.e., 40:70cm (RFMS40), 55:55cm (RFMS55), and 70:40cm (RFMS70) and conventional flat planting (CK, without mulching). All these four planting patterns had the same planting density. The RFMS technique not only increased soil temperature of the ridge but also improved soil moisture of the furrow when compared with CK. These positive effects were intensified with increasing ridge/furrow ratio in RFMS. This improvement in RFMS resulted in more stable and earlier seedling establishment. Maize yields were increased by 26.1, 36.4, and 50.3% under RFMS40, RFMS55, and RFMS70 treatments, respectively, when compared with CK across both years. RFMS did not decrease the evapotranspiration significantly, compared with CK. Eventually, WUE were enhanced by 25.7, 38.7, and 53.9% in RFMS40, RFMS55, and RFMS70, respectively, compared with CK. Taken together, our results suggest that increasing ratio of ridge to furrow in the case of RFMS70, can be recommended as high-yielding cultivation pattern for promoting precipitation use efficiency in the rain-fed semi-arid areas.

Yield-phenology relations and water use efficiency of maize (Zea mays L.) in ridge-furrow mulching system in semiarid east African Plateau

Yield-phenology relation is a critical issue affecting rainfed maize field productivity in semiarid east African Plateau (EAP). We first introduced Chinese ridge-furrow mulching (RFM) system to EAP, using three maize cultivars with early-, mid- and late-maturing traits as test materials. A two-year field experiment was conducted in a semiarid farm of Kenya from 2012 to 2013. Three treatments were designed: alternative ridge and furrow with transparent plastic mulching (FT), with black plastic mulching (FB) and without mulching (CK). We found that FT and FB significantly increased soil moisture and accelerated crop maturity across two growing seasons. Leaf area and shoot biomass were increased by 30.2% and 67.5% in FT, 35.2% and 73.5% in FB, respectively, compared with CK. Grain yield, water use efficiency and economic output were increased by 55.6%, 57.5% and 26.7% in FT, and 50.8%, 53.3% and 19.8% in FB, respectively. Optimal yield and economic benefit were observed in late-maturing cultivar due to increased topsoil temperature in FT in 2012 (cool), and in early-maturing cultivar owing to cooling effect in FB in 2013 (warm). Our study suggested RFM system, combined with crop phenology selection, be a promising strategy to boost maize productivity and profitability in semiarid EAP.