Film-mulched Ridge Research Articles

Autumn Film Mulched Ridge Microfurrow Planting Improves Yield and Nutrient-Use Efficiency of Potatoes in Dryland Farming

Potatoes (Solanum tuberosum) are the most important noncereal crop in the world. Increasing potato production is critical for future global food security. China is the world’s largest potato producer, and potato productivity is constrained by water scarcity and poor fertilizer use efficiency (NUEF). Recently, autumn film mulched ridge microfurrow rainwater harvesting (ARF) tillage has been successfully applied in potato production in dryland farming in Northwest China. However, the effects of ARF on the use efficiency (NUEF) of applied nitrogen (N), phosphorus (P), and potassium (K) nutrients in potatoes have not been systematically studied. A 3-year, consecutive field trial with four treatments, including moldboard planting without fertilizer application (control, CK), spring and autumn film mulched ridge microfurrow rainwater harvesting planting (SRF and ARF), and standard film mulched ridge-furrow planting (FRF), was conducted during 2018–2020. ARF greatly increased the water levels in the 0–200 cm soil profile at potato harvest compared to SRF, FRF, and CK. ARF and SRF significantly increased the levels of soil organic carbon (SOC), total and available NPK (TN, TP, TK and AN, AP, AK) compared to FRF and CK, with ARF being the most efficient at increasing the levels of the AN, AP, and AK. ARF significantly improved the soil water and nutrient activity and contributed the most to potato tuber and biomass yield and hence the NUEF. Under ARF, significant and positive associations were observed between the soil fertility traits, soil water storage (SWS), potato tuber yield, biomass yield, and NUEF. Soil fertility traits and the SWS were positively correlated with potato tuber and biomass yield. The SWS, potato tuber, and biomass yield positively correlated with the partial factor productivity (PFP) and the recovery efficiency (RE) of the applied NPK nutrients. Increased nutrient levels and their combination increased the NUEF and NUEF’s components. The TN and AN contributed more significantly to the PEP and agronomic efficiency (AE) of the applied NPK nutrients; the TP was significantly positively correlated with the AE (AEN, AEP, and AEK), while the AP was correlated with PEP (PFPN, PFPP, and PFPK) and RE (REN, REP, and REK); the TK was significantly positively correlated with the PFP and RE of the applied PK nutrients, while the AK was significantly positively correlated with the PEP, AE, and RE of the applied K nutrients. Therefore, ARF results in a synchronous increase in yield and NUEF and is the most efficient planting system for potato production in dryland farming.

Plastic film-mulched ridges and straw-mulched furrows increase soil carbon sequestration and net ecosystem economic benefit in a wheat-maize rotation

The application of soil mulching has been widely used to increase crop production in arid, semi-arid, and sub-humid areas, with plastic film-mulched ridges and straw-mulched furrows (RFPS) proving to be more effective as compared with other soil mulching practices. However, few research studies have comprehensively assessed the impacts of RFPS on greenhouse gas (GHG) emissions, grain yield, net ecosystem carbon budget (NECB), and net ecosystem economic budget (NEEB) compared against the single practices of either plastic film mulching or straw mulching. A three-year field experiment was conducted on a wheat (Triticum aestivum L.)-maize (Zea mays L.) rotation field in the southern Loess Plateau, China. Four treatments were evaluated: (1) conventional flat planting without mulching (CK), (2) flat planting with plastic film mulching (PM), (3) flat planting with straw mulching (SM), and (4) RFPS. All mulching practices significantly increased wheat and maize yields as well as the seasonal cumulative carbon dioxide (CO2) emissions from soil respiration (Rs) and ecosystem respiration (Re) compared with CK. RFPS had the greatest annual grain yield and the greatest Rs for wheat seasons. The average annual NECB values for CK and PM were − 1.47 and − 1.05 Mg CO2-eq ha−1 yr−1, respectively, where the negative values indicated that the soil in CK and PM acted as a carbon (C) source. SM and RFPS acted as C sinks because of the straw C input, having average annual NECB values of 1.46 and 1.74 Mg CO2-eq ha−1 yr−1, respectively. PM, SM, and RFPS significantly increased the average annual NEEB by 31.4%, 70.5%, and 60.3%, respectively, compared with CK. Although RFPS had greater C input and grain yield income, it also had greater Rs, harvest removal C loss, and agricultural input costs, resulting in similar NECB and NEEB to what was observed with SM. Considering that the greatest grain yields were obtained with RFPS, this production practice should be a promising method for maintaining greater, more stable crop production, while increasing soil C sequestration and NEEB for the wheat-maize cropping system in dry semi-humid regions such as the southern Loess Plateau of China.

Limited irrigation and fertilization in sand-layered soil increases nitrogen use efficiency and economic benefits under film mulched ridge-furrow irrigation in arid areas

Hetao Irrigation District (HID) in the upper Yellow River Basin of China is vulnerable due to the scarcity of water resources and environmental pollution caused by nutrient leaching. Appropriate irrigation and fertilization management are essential for improving crop productivity and developing sustainable agriculture in the HID. A two-year field experiment investigated the effects of irrigation and fertilization regimes on soil water, nitrogen accumulation and distribution in the soil profile and plant organs, nitrogen use efficiency, and economic benefits of spring maize (Zea mays L.) under film mulched ridge–furrow system. Three irrigation levels—I1 (high, 400 mm), I2 (medium, 300 mm), and I3 (low, 200 mm)—and two fertilization levels—F1 (high, 300 kg N ha−1) and F2 (low, 150 kg N ha−1) were designed. Mean soil NO3−-N contents did not significantly differ between I2 and I3 and were significantly higher than I1. I1F1 and I1F2 remarkably increased soil NO3−-N accumulation in the 80 − 100 cm soil layer at harvest. High irrigation increased the risk of N leaching into the deep soil layer. I2F2 increased plant nitrogen accumulation and promoted nitrogen transport to grains, improved nitrogen harvest index, and internal use efficiency. Under 400 or 300 mm irrigation amount, soil moisture and plant growth had little difference. Grain yields among I1F1, I1F2, I2F1, and I2F2 did not significantly differ in 2017 and 2018. In the relatively poor rainfall year (2017), I2F2 had 13.1%, 211.8%, and 294.1% higher net income than I2F1, I3F1, and I3F2, respectively, but 24.5% and 33.0% lower net income than I1F1 and I1F2, respectively. In 2018 with normal rainfall, I2F2 had 38.5%, 4.8%, 29.5%, 114.3%, and 96.2% higher net income than I1F1, I1F2, I2F1, I3F1, and I3F2, respectively. Therefore, the film mulched ridge–furrow irrigation system with 300 mm irrigation and 150 kg N ha−1 fertilization is a promising approach for reducing water supply and nitrogen leaching, and obtaining acceptable grain yield and economic benefits for spring maize production in the upper Yellow River Basin of China.

Enhanced maize yield and water-use efficiency via film mulched ridge–furrow tillage with straw incorporation in semiarid regions

ABSTRACT Film mulched ridge-furrow tillage (FMRF) with straw incorporation (S) can efficiently improve rain-fed maize yield and water use efficiency (WUE). The key mechanisms were investigated via a 3-year consecutive FMRF and S interactive experiments [CP (conventional planting, Control), CPS, FMRF, FMRFS] from 2014 to 2016. In comparison with CP, FMRFS increased the temperature by 1.8°C to 4.8°C and the soil water content of 0–200 cm soil profile (W200 ) by 98.0 mm to 106.7 mm from the seedling to tasseling stage, and decreased the temperature by 1.1°C to 3.7°C from flowering to maturity. The concentrations of soil organic carbon (SOC), soil total and available nitrogen, phosphorus and potassium (TN, TP, TK and AN, AP, AK) were also remarkable increased by 5.9% to 55.1% (P < 0.05) for FMRFS, respectively. FMRFS considerably mitigated the effects of the frequent water and heat stress and fertility deficit and led to a higher maize yield (27.0% to 40.0%), improved WUE (1.4-folds to 2.0-folds). The W200 , SOC, TN, TP, AN and AP significant contribute to maize yield. Therefore, FMRFS not only enhanced the soil fertility but also maintained soil water balance, thus causing a significant increase in maize yield and WUE.

Long-term straw mulching with nitrogen fertilization increases nutrient and microbial determinants of soil quality in a maize–wheat rotation on China's Loess Plateau

Mulching and nitrogen (N) fertilization are essential to increase crop yields in semiarid drylands. However, their long-term effects on soil physicochemical properties, extracellular enzyme activities, microbial community structure, and therefore soil quality via developing a soil quality index (SQI) remain largely unexplored. Hence, we analyzed soils after 14 years of mulching (CT, no mulch; RF, plastic film-mulched ridges and straw mulched-furrows; SM, straw mulching) and N fertilization (0, 120 and 240 kg ha−1) treatments in a maize–wheat rotation on China's Loess Plateau. Compared with CT, RF and SM significantly increased soil moisture content (SMC), organic carbon (SOC), phosphatase, and total phospholipid fatty acids (PLFAs). Compared with RF, SM increased SOC, total N, available phosphorus (AP), available potassium (AK), β-glucosidase, N-acetyl-glucosaminidase (NAG), peroxidase, and cellobiohydrolase, gram-negative bacteria (G−), and fungi. Consequently, the SQI was highest in SM (0.698), followed by RF (0.642) and CT (0.620). Nitrogen fertilization significantly increased total N, NO3−, microbial biomass N, α-glucosidase, NAG, total PLFAs, and G−, but caused a significant decline in pH, AP, AK, and the G+:G− ratio. Averaged across N-fertilizations, the SQI was ranked N240 (0.680) > N120 (0.650) > N0 (0.630). Redundancy analysis showed that SOC was closely associated with enzyme activities, whereas NO3−, SOC, and SMC were the key variables regulating microbial community composition. Structural equation model indicated that mulching and N fertilization strongly and positively affected SQI by regulating soil available N, P, and K, enzyme activities, and microbial communities, and the total effect of mulching (0.62) on SQI was greater than that of N addition (0.34). Collectively, the highest SQI observed in the SM + N240 treatment suggested that straw mulch, rather than plastic-film mulch, combined with high N addition could be a sustainable land management practice that improves soil quality in semiarid dryland farming systems.

Mechanism analysis and performance improvement of mechanized ridge forming of whole plastic film mulched double ridges

In order to achieve high-performance and mechanization construction standard of whole plastic mulched double ridge seedbed, and to meet its forming process and corresponding agronomic requirements of the mechanized double ridge seedbed, the key working parameters such as the speed of rotary blade group, the thickness of upturned sod and the power consumption of rotary blade group under different parameters were analyzed based on related working performance in ridge forming. Also, the test factors and their range of values were finally determined in this study. Discrete element method (DEM) simulation was applied in the numerical simulation of the mechanized ridge forming process of whole plastic mulched double ridges, and the ridge forming effect and digging resistance variation characteristics of different types of shovels were compared. Taking the forward speed of the combined machine, the penetration angle of the arc-shaped shovel and the depth of rotary tillage as independent variables, and the qualified rate of seedbed tillage as the response value, the mathematical model between the test factors and the qualified rate of the seedbed tillage was established, to explore the influence sequence of the factors on the qualified rate of seedbed tillage, and obtained the following optimal working parameters of the ridge forming device: the advancing velocity of the combined machine of 0.50 m/s, penetration angle of the arc-shaped shovel of 31°, rotary tillage depth of 140 mm, and average qualified rate 95.20% of seedbed tillage in corresponding simulation verification test. Field test showed that the average qualified rate of seedbed tillage in ridge forming device was 93.60%, which was close to that of the simulation results. The actual working condition of the sample machine was basically in line with the simulation process and could relatively precisely reflect the mechanized ridge forming mechanism of whole plastic double ridges. The results showed that the established DEM model and its parameter setting were relatively accurate and reasonable. Keywords: whole plastic film mulched double ridges, mechanized ridge forming, DEM, numerical simulation, parameter optimization DOI: 10.25165/j.ijabe.20201305.5747 Citation: Dai F, Song X F, Zhao W Y, Shi R J, Zhang F W, Zhang X K. Mechanism analysis and performance improvement of mechanized ridge forming of whole plastic film mulched double ridges. Int J Agric & Biol Eng, 2020; 13(5): 107–116.

Effects of different film mulching methods on soil water productivity and maize yield in a semiarid area of China

Film mulching has been used widely to improve field productivity in rainfed agricultural ecosystems in semiarid areas of China. During 2013–2016, we evaluated the effects of different film mulching methods on soil water, water productivity, crop yield, and economic benefits in a semiarid area of southern Ningxia, China. Five treatments were tested: (i) a control method consisting of conventional flat planting without mulching (CK); (ii) alternate mulching and bare rows without ridges and planting in mulched rows (P); (iii) maize planted in furrows separated by consecutive plastic film-mulched ridges (S); (iv) maize planted in furrows separated by alternating large and small plastic film-mulched ridges (D); and (v) maize, planted in furrows with large plastic film-mulched ridges alternating with flat plastic film-mulched spaces (R). After four years of continuous treatment, the results indicated that D and S treatments significantly increased soil water content at depths of 0–200 cm during the early growth stage, but the increases in the soil water content were lower later in the maize growth process. The grain yield increases were affected by the different hydrothermal conditions in various years. On average, mulching increased grain yield by 31.33 %, and biomass accumulation by 22.48 %. Across four seasons, film mulching significantly (P < 0.05) increased water use efficiency and precipitation use efficiency, especially in D by 34.56 % and 43.09 %, and S by 35.25 % and 42.79 %, respectively. Mulching changed the crop water consumption characteristics, and resulted in higher crop water productivity due to an improved hydro-thermal balance, especially during the vegetative (30–90 days) and pre-reproductive (90–120 days) growth stages, which may account for yield increase effects in this system. In addition, the results suggested that the mulching system achieves higher economic returns than CK, especially the S treatment (7538 ¥ ha−1, representing an average of 29.19 % higher than CK.). The S treatment could serve as a promising adaptive management method for increasing maize productivity to cope with food security and climate change in this semi-arid area with limited and erratic precipitation.

Sowing Methods Influence Soil Bacterial Diversity and Community Composition in a Winter Wheat-Summer Maize Rotation System on the Loess Plateau.

Soil bacterial diversity and community composition are crucial for soil health and plant growth, and their dynamics in response to agronomic practices are poorly understood. The aim of this study was to investigate the response of soil bacterial community structure to the changes of sowing methods, soil depth and distance to roots in a winter wheat-summer maize crop rotation system on the Loess Plateau in china (35°17′38′′N, 111°40′24′′E). The experiment was laid out as completely randomized block design with three replications. Sowing methods trialed were: traditional sowing (TS), film-mulched ridge and furrow sowing (FMR&F), wide ridge and narrow furrow sowing (WR&NF) and unplanted control (CK). The result showed that the WR&NF sowing method treatment significantly decreased soil bacterial diversity (Chao 1 and Shannon indices) compared to the TS and FMR&F treatment, but increased abundance of beneficial bacteria such as genera Bacillus and Pseudomonas compared to the TS treatment. These genera showed a stronger correlation with soil properties and contributed to the soil nutrient cycling and crop productivity. Bacillus, Pseudomonas, Nevskia, and Lactococcus were the keystone genera in this winter wheat-summer maize rotation system on the Loess Plateau. Strong correlations between changes in soil properties and soil bacterial diversity and abundance were identified. In summary, we suggest that the WR&NF treatment, as a no-mulching film and no-deep tillage sowing method, would be the most suitable sowing technique in the winter wheat-summer maize rotation on Loess soil.

Stratification of soil organic C, N and the C:N ratio as affected by different plastic film mulching modes in a semiarid region of China

The soil degradation caused by plastic film mulching tillage in rain-fed areas of north-west China is known to affect sustainable and stable crop yields because of major losses of soil organic carbon (SOC) and nutrients. To evaluate the effects of different plastic film mulching modes on SOC and total nitrogen (STN) sequestration capacity in loessic soil, we investigated the effects of different plastic film mulching on SOC, STN, and the soil C:N ratio in semiarid areas of southern Ningxia for a 4-year period (2013–2016). Five treatments were tested: (i) the control, conventional flat planting without mulching (CK); (ii) alternating mulching and bare rows without ridges and planting in mulched rows (P); (iii) furrow planting of maize, separated by consecutive plastic film-mulched ridges (S); (iv) furrow planting of maize, separated by alternating large and small plastic film-mulched ridges (D); and (v) furrow-flat planting of maize with a large plastic film-mulched ridge alternating with a flat plastic film-mulched space (R). In the final experimental year (2016), the results showed that the mean soil bulk density at 0–60 cm depth had decreased with film mulching treatments by 2.82%, 5.90% (P &amp;lt; 0.05), 7.29% (P &amp;lt; 0.05), and 9.46% (P &amp;lt; 0.05) respectively, compared with CK. Film mulching increased the concentration of SOC and STN, which were ranked in order S &amp;gt; R/D &amp;gt; P &amp;gt; CK; however, there was no significant increase with the storage of SOC and STN. The mean soil C:N ratio was higher with mulching treatment, i.e. 2.91% (P &amp;gt; 0.05) higher than CK in 0–60 cm depth. Mulching treatments significantly (P &amp;lt; 0.05) increased the stratification ratio (SR) of SOC and soil C: N ratio from the surface (0–20 cm) to all depths compared with CK, i.e. the SR of SOC at the 0–20:20–40 cm depth significantly (P &amp;lt; 0.05) increased with D, R, S, and P by 14.81%, 9.47%, 14.18%, and 9.51% respectively, compared with CK.

Fate and transport of urea-N in a rain-fed ridge-furrow crop system with plastic mulch

A better understanding of the fate and transport of fertilizer nitrogen (N) is critical to maximize crop yields and minimize negative environmental impacts. Plastic film mulching is widely used in drylands to increase soil water use efficiency and crop yields, but the effects on fertilizer N use efficiency need to be evaluated. A field experiment with 15N-urea (260 kg N ha−1) was conducted to determine the fate and transport of fertilizer N in a ridge-furrow system with plastic film mulched ridge (Plastic), compared with a flat system without mulching (Open). In the Plastic, the 15N-urea was applied to the ridge only (Plastic-Ridge), or to the furrow only (Plastic-Furrow). Maize grain yield and net economic benefit for Plastic were significantly higher (by 9.7 and 8.5%, respectively) than those for Open. Total plant 15N uptake was 72.5% greater in Plastic compared with Open, and 15N was allocated mostly to the grain. Losses of the applied urea-N were 54.5% lower in Plastic and much more residual 15N was recovered in 0–120 cm soil compared with Open (42.7 and 26.8% of applied 15N, respectively). Lateral N movements from furrow to ridge and from ridge to furrow were observed and attributed to lateral movement of soil water due to microtopography of ridges and furrows and uneven soil water and heat conditions under mulching and plant water uptake. The ridges were the main N fertilizer source for plant uptake (96.5 and 3.5% of total N uptake in Plastic from ridge and furrow, respectively) and the furrow was the main source of N losses (78.6 and 21.4% of total N losses in Plastic from furrow and ridge, respectively). Gas emissions, especially ammonia volatilization was probably the main N loss in furrow. Thus, appropriately localized N application – into the ridges, and management strategies should be designed for Plastic to maximize N use efficiency by crops, decrease N gas losses and maintain sustainable agricultural systems in drylands.

Ridge-furrow with plastic film and straw mulch increases water availability and wheat production on the Loess Plateau

Mulching is critical for increasing water availability and hence winter wheat production in dryland farming systems. A two-year study was conducted to assess the effects of mulches on soil water storage (SWS), temperature, water use efficiency (WUE) and yields of winter wheat on the Loess Plateau. Four treatments were examined: conventional flat planting (CK), straw mulch (FPS), transparent plastic film mulch (FPP) and ridge-furrow with plastic film-mulched ridge and straw-mulched furrow (RFPS). Compared with CK, RFPS greatly increased SWS from 0–60 cm, FPP increased SWS from 0–40 cm, and FPS slightly increased SWS from 0–60 cm; however, FPP significantly (P < 0.05) decreased SWS from 61–100 cm. RFPS and FPP increased soil temperatures in cold seasons relative to CK, especially in RFPS (2.0–2.3 °C). Meanwhile, the rate of soil temperature increase was greater in RFPS and FPP than in CK but was lower in FPS. Mean yields were significantly increased in RFPS (56.78%), FPP (44.72%) and FPS (9.57%), and WUE was significantly increased in RFPS (44.04%) and in FPP (37.50%) compared with CK (P < 0.05). We conclude that ridge-furrow planting with plastic film-mulched ridge and straw-mulched furrow has a good potential for raising winter wheat production on the Loess Plateau.

Effects of long-term cultivation practices and nitrogen fertilization rates on carbon stock in a calcareous soil on the Chinese Loess Plateau

Soil organic carbon (SOC) and soil inorganic carbon (SIC) are important C pools in the Loess Plateau of Northwest China, however, variations of SOC and SIC stocks under different cultivation practices and nitrogen (N) fertilization rates are not clear in this area. A long-term field experiment started in June 2003 was conducted to investigate the SOC and SIC stocks in a calcareous soil of the Chinese Loess Plateau under four cultivation practices, i.e., fallow (FA), conventional cultivation (CC), straw mulch (SM), and plastic film-mulched ridge and straw-mulched furrow (RF), in combination with three N fertilization rates, i.e., 0 (N0), 120 (N120), and 240 (N240) kg N/hm2. Results indicate that the crop straw addition treatments (SM and RF) increased the contents of soil microbial biomass C (SMBC) and SOC, and the SOC stock increased by 10.1%–13.3% at the upper 20 cm soil depth in comparison to the 8-year fallow (FA) treatment. Meanwhile, SIC stock significantly increased by 19% at the entire tested soil depth range (0–100 cm) under all crop cultivation practices in comparison to that of soil exposed to the long-term fallow treatment, particularly at the upper 60 cm soil depth. Furthermore, moderate N fertilizer application (120 kg N/hm2) increased SOC stock at the upper 40 cm soil depth, whereas SIC stock decreased as the N fertilization rate increased. We conclude that the combined application of crop organic residues and moderate N fertilization rate could facilitate the sequestrations of SOC and SIC in the calcareous soil.

Effects of Ridge-Furrow System Combined with Different Degradable Mulching Materials on Soil Water Conservation and Crop Production in Semi-Humid Areas of China.

In China, the ridge-furrow water conservation planting (RC) system is advantageous for improving crop yields and rainwater use efficiency. In RC planting system, plastic film-mulched ridges are employed for water harvesting while the furrows serve as infiltration and planting belts. To optimize the RC system and to overcome problems due to the lack of water in semi-humid areas at risk of drought, we mulched the furrows with 8% biodegradable film (RCSB), liquid film (RCSL), or no mulching in the furrows (RCSN), while conventional flat planting (CF) was employed as the control. After 4 year (2007–2010) consecutive field study, the results showed that the soil water storage level in the 0–100 cm layer with four treatments was ranked as follow: RCSB > RCSL > RCSN > CF, while the RCSB and RCSL were 26.3 and 12.2 mm greater than RCSN, respectively. Compared with CF, the average soil temperature was significantly (P < 0.05) higher by 3.1, 1.7, and 1.5°C under the RC planting treatments (RCSB, RCSL, and RCSN) during each year, respectively. The average ET rate of RC treatments were all lower than CF in each experimental year, and the average decreased by 8.0% (P < 0.05). The average yields with RCSB, RCSL, and RCSN increased by 2,665, 1,444, and 1,235 kg ha−1, respectively, and the water use efficiency (WUE) increased by 51.6, 25.6, and 21.1%, compared with CF. RCSB obtained the highest economic benefit, the average net income was higher than CF by 4,020 Yuan ha−1. In conclusion, we found that RC planting with biodegradable film mulching in the furrows is the best cultivation pattern in the semi-humid areas of China in terms of both environmental and economic benefits.

Coupled effects of mulching and nitrogen fertilization on crop yield, residual soil nitrate, and water use efficiency of summer maize in the Chinese Loess Plateau.

Appropriate water-saving and nitrogen management strategies are critical for achieving sustainable agricultural development in dry sub-humid areas of the Chinese Loess Plateau. The present study was conducted in 2004, 2005, 2008, and 2012 based on a long-term field experiment and aimed to investigate the coupled impacts of mulching and N fertilization on maize yield, water use efficiency (WUE), and residual soil nitrate (RSN) accumulated in the soil profile (0-200cm). The results demonstrated that mulch is conducive to increasing summer maize yield. The plastic film-mulched ridge and straw-mulched furrow (RF) treatment significantly increased maize yield across the studied period, while the straw mulch (SM) treatment did not significantly increase maize yield until the third experimental year. Compared with SM, the RF treatment showed more significant and positive effects on maize yield, WUE, and RSN accumulated in the 0-200cm soil depth. N fertilization significantly increased maize yield and WUE, but no significant differences were observed when 120 and 240kg N ha-1 were applied. The N240 treatment was characterized by relatively high NO3--N accumulation in 0-200cm soil depth and low ratios of soil nitrate in the upper to the lower soil layers, indicating a considerable potential for NO3--N leaching. Averaged across years, economic optimum N fertilizer rates (Nops) were 154, 148, and 150kg N ha-1 for the no mulch, RF, and SM treatments, respectively. This suggested that 25.8-51.2% of N rate can be reduced while maintaining an acceptably high maize yield. Additionally, understanding NO3--N depth distribution in 0-100cm soil profile can adequately predict and represent the characteristics of NO3--N accumulated in the 100-200cm and 0-200cm soil layers because of their significant correlations, thus saving time and money. In conclusion, the practice of RF combined with properly reduced farmers' N rate (~150kg N ha-1) is the preferred option for maize production in the Chinese Loess Plateau, and further research is required to investigate the effects of mulching on summer maize under Nop conditions.

Effects of tillage, mulching and N management on yield, water productivity, N uptake and residual soil nitrate in a long-term wheat-summer maize cropping system

A thorough understanding of coupled effects of soil management (tillage), mulch and N rate on the wheat-maize system is crucial for achieving sustainable agriculture in the southern Loess Plateau of China. This study was based on a 12-year (2003–2015) field experiment and aimed to evaluate the impact of three wheat-maize systems (S) which varied in terms of tillage, mulch, wheat row spacing and irrigation management (CT, conventional tillage with no mulch; RFM, ridge-furrow with plastic film-mulched ridges and straw-mulched furrows; CTM, conventional tillage with straw mulch) combined with N fertilizer rates (0, 120 and 240kgNha−1) on crop yield, water productivity (WP, kg grain per kg of water input), N uptake, residual soil nitrate (RSN) and soil physicochemical properties. Results demonstrated that RFM significantly increased maize yield in comparison with CT in all 12 years, while CTM increased yield in comparison with CT from year 3 onwards. By contrast, wheat yield was not strongly influenced by RFM and CTM from 2004 to 2012 (except for 2008). Maize yields of RFM were significantly higher than those of CTM from the third year onwards. Compared with CT, the other two practices, and more so RFM, showed beneficial effects on crop yield, the amount of stored water, WP, N uptake and RSN. N fertilization significantly increased crop yield, WP and N uptake, while no significant difference was observed between the N120 and N240 treatments. Notably, considerable buildup of RSN to∼490kgNha−1 at maize harvest and ∼340kgNha−1 at wheat harvest were observed in 0–200cm soil depth when 240kgNha−1 was applied. These results suggest that the conventional N rate of 240kgNha−1 is excessive, and risks serious contamination of the groundwater as a result of NO3−-N leaching. The N120 treatment was characterized with considerably lower RSN accumulation after harvest, while maintaining crop yield. Thus, we concluded that the RFM practice with 120kgNha−1 application could reduce irrigation water and fertilizer inputs and increase crop land and water productivity, and is a promising strategy for developing sustainable agriculture in the southern Loess Plateau and other areas with similar climate and cropping systems.

Plastic-Film Mulching for Enhanced Water-Use Efficiency and Economic Returns from Maize Fields in Semiarid China.

Film mulch has gradually been popularized to increase water availability to crops for improving and stabilizing agricultural production in the semiarid areas of Northwest China. To find more sustainable and economic film mulch methods for alleviating drought stress in semiarid region, it is necessary to test optimum planting methods in same cultivation conditions. A field experiment was conducted during 2013 and 2014 to evaluate the effects of different plastic film mulch methods on soil water, soil temperature, water use efficiency (WUE), yield and revenue. The treatments included: (i) the control, conventional flat planting without plastic film mulch (CK); (ii) flat planting with maize rows (60 cm spacing) on plastic film mulch (70 cm wide); (iii) furrow planting of maize (60 cm spacing), separated by consecutive plastic film-mulched ridges (each 50 cm wide and 15 cm tall); (iv) furrow planting of maize (60 cm spacing), separated by alternating large and small plastic film-mulched ridges (large ridges: 70 cm wide and 15 cm tall, small ridges 50 cm wide and 10 cm tall); and (v) furrow-flat planting of maize (60 cm spacing) with a large plastic film-mulched ridge (60 cm wide and 15 cm tall) alternating with a flat without plastic film-mulched space (60 cm wide). Topsoil temperature (5–25 cm) was significantly (p < 0.05) higher in field plots with plastic film mulch than the control (CK), and resulted in greater soil water storage (0–200 cm) up to 40 days after planting. Maize grain yield and WUE were significantly (p < 0.05) higher with the furrow planting methods (consecutive film-mulched ridges and alternating film-mulched ridges) than the check in both years. Maize yield was, on average, 29% (p < 0.05) greater and 28% (p < 0.05) greater with these furrow planting methods, while the average WUE increased by 22.8% (p < 0.05) with consecutive film-mulched ridges and 21.1% (p < 0.05) with alternating film-mulched ridges. The 2-year average net income increased by 1559, 528, and 350 Chinese Yuan (CNY) ha−1 with the consecutive film-mulched ridges, furrow-flat planting and alternating film-mulched ridges, respectively, compared with the control (CK). We conclude that the consecutive film-mulched ridge method was the most productive and profitable for maize in this semi-arid area with limited and erratic precipitation.

Mulching affects photosynthetic and chlorophyll a fluorescence characteristics during stage III of peach fruit growth on the rain-fed semiarid Loess Plateau of China

In this study, we compared the soil water content of plastic film mulched ridge with furrows (PFM) and straw mulched (SM) and unmulched (clean tillage, CT) peach (Prunus persica L.) orchard soil on the rain-fed semiarid Loess Plateau of China during the final stage of rapid fruit growth (stage III) in 2011 and 2012. Analyses were focused on measurements of fast chlorophyll a fluorescence (ChlF), photosynthetic performance, fruit yield and quality. Compared with the CT water management method, PFM and SM significantly increased the soil water content (P<0.05) by 14.5% and 19.5% in stage III, respectively. Both mulching methods increased the fruit yield (∼28%) with no change in fruit quality compared to the CT method. This result was supported by the analysis of the daily average photosynthetic rate (PN) showed that PN was improved from 11.4 (CT) to 13.1 (PFM) and 12.2μmolm−2s−1 (SM); these daily average photosynthetic rates were confirmed by the response curve analysis. Furthermore, the ChlF analyses uncovered major functional differences between the mulched and unmulched leaves at midday: lower connectivity among the photosystem II decreased the number of electron carriers and facilitated the dissipation of excess excitation energy to minimize the potential damage caused by CT drought stress. Nevertheless, the structural integrity and stability of PSII were largely maintained, as reflected by the recovering of the photosynthetic activity after mid-day.

Mulching increases water-use efficiency of peach production on the rainfed semiarid Loess Plateau of China

We examine the water-use balance, fruit yield and water-use efficiency of five-year-old peach trees with two different mulching systems: plastic film mulched ridge, with furrows (PFM) and straw mulched (SM). Compared with the clean tillage (CT) water management method, PFM increased, and SM significantly decreased, the soil temperature (P<0.05). Both mulching systems increased the gravimetric soil water content (1.9–2.9%) with a reduction in the average annual evapotranspiration (ET) of 82.5mm and 49.3mm through SM and PFM, respectively. The water-use efficiency (WUE) was improved from 5.7 (CT) to 8.1 (PFM) and 9.0kgm−3 (SM), resulting in a reduction in ET and an increase in fruit yield from 25.2 (CT) to 32.2 (PFM) and 32.5tha−1 (SM). Thus, both mulching systems could serve as models for peach production in semiarid rainfed areas, due to the high soil water content during bloom and fruit expansion.

Effects of a ridge-furrow micro-field rainwater-harvesting system on potato yield in a semi-arid region

To evaluate the effects of mulching and ridge and furrow widths on soil temperature and moisture, crop growth and yield, and water use efficiency (WUE), a series of field experiments were conducted in a potato field in Inner Mongolia, China. In 2009 and 2010, four treatments (flat plot without mulching (CK), plastic film mulched ridge (MR), MRF (plastic film mulched ridge and furrow (MRF), and non-mulched (NM0.5)) were conducted on the same widths of ridge (0.5m) and furrow (0.5m), and two additional non-mulching treatments (1.0m ridge and furrow width (NM1.0), and 1.5m ridge and furrow width (NM1.5)) were tested in 2011 and 2012. The results indicated that mulching practices increased topsoil temperature compared to non-mulching treatments at the emergence stage. Compared to CK, the soil water storage in furrows was increased by 10.2mm on average in 2009 for the MRF treatment, 8.1mm and 15.1mm in 2011, and 14.0mm and 21.2mm in 2012 for NM1.0 and NM1.5, respectively, and plant leaf area index and dry biomass values during the potato growth stage were also increased. The MR treatment produced greater effects on crop productivity than NM0.5, and increased total yield and marketable yield by 21.4% and 36.3% compared to CK in 2010. Of three non-mulching treatments (i.e., NM0.5, NM1.0, and NM1.5), the NM1.0 treatment produced the highest total yield and marketable yield; compared to CK, the WUE, total yield, and marketable yield were increased by 12.7%, 8.2%, and 52.0% in 2011, and 23.4%, 16.4%, and 81.0% in 2012, respectively.

Effects of water management with plastic film in a semi-arid agricultural system on available soil carbon fractions

There is little information regarding the sustainability of the high yield agroecosystem with double ridges and furrows mulched with plastic film in semi-arid areas. In this study, we explored the sustainability of this agroecosystem with different mulching time during two growing seasons over 2006 and 2007. Three treatments were designed: (i) plastic film mulching applied at sowing and film removed at harvest (CK); (ii) mulching applied 30 days before sowing and removed at harvest (M1); and (iii) mulching applied at sowing and film left on field after harvest and used continually for mulching in the second season (M2). Microbial biomass C (MBC) and ratio of MBC to soil organic C (SOC) (MBC/SOC) were higher in M1 and M2 than in CK in 2007 growing season. The reduction rates of the ratios of light fraction of organic C (LFOC) to SOC (LFOC/SOC) with sampling dates were 0.0020, 0.0047 and 0.0045 for CK, M1 and M2, respectively. A larger value means a faster reduction rate of LFOC/SOC with sampling dates, and implying farming system would face a higher unsustainable risk. MBC correlated negative significantly with LFOC (R = −0.939, P = 0.0001) and mineral N (R = −0.835, P = 0.0007) due to low soil C pool. Accordingly, film mulched ridge and furrow system would threaten the sustainability of soil ecosystem via MBC increase a semi-arid agroecosystem. The practices of mulching applied 30 d before sowing (M1) and use of plastic film once every two years (M2) lead to increased environmental risk for the farming system.