Mulched Drip Irrigation Research Articles

Optimizing nitrogen fertilizer for improved root growth, nitrogen utilization, and yield of cotton under mulched drip irrigation in southern Xinjiang, China

The root system plays a crucial role in water and nutrient absorption, making it a significant factor affected by nitrogen (N) availability in the soil. However, the intricate dynamics and distribution patterns of cotton (Gossypium hirsutum L.) root density and N nutrient under varying N supplies in Southern Xinjiang, China, have not been thoroughly understood. A two-year experiment (2021 and 2022) was conducted to determine the effects of five N rates (0, 150, 225, 300, and 450 kg N ha−1) on the root system, shoot growth, N uptake and distribution, and cotton yield. Compared to the N0 treatment (0 kg N ha−1), the application of N fertilizer at a rate of 300 kg N ha−1 resulted in consistent and higher seed cotton yields of 5875 kg ha−1 and 6815 kg ha−1 in 2021 and 2022, respectively. This N fertilization also led to a significant improvement in dry matter weight and N uptake by 32.4% and 53.7%, respectively. Furthermore, applying N fertilizer at a rate of 225 kg N ha−1 significantly increased root length density (RLD), root surface density (RSD), and root volume density (RVD) by 49.6–113.3%, 29.1–95.1%, and 42.2–64.4%, respectively, compared to the treatment without N fertilization (0 kg N ha−1). Notably, the roots in the 0–20 cm soil layers exhibited a stronger response to N fertilization compared to the roots distributed in the 20–40 cm soil layers. The root morphology parameters (RLD, RSD, and RVD) at specific soil depths (0–10 cm in the seedling stage, 10–25 cm in the bud stage, and 20–40 cm in the peak boll stage) were significantly associated with N uptake and seed cotton yield. Optimizing nitrogen fertilizer supply within the range of 225–300 kg N ha−1 can enhance root foraging, thereby promoting the interaction between roots and shoots and ultimately improving cotton production in arid areas.

Mulched drip irrigation: a promising practice for sustainable agriculture in China’s arid region

The long-term practice of mulched drip irrigation (MDI) has significantly advanced cotton production in China’s arid regions. In this study, we conducted an evaluation of the changes to key soil environmental factors within cotton fields under MDI, providing a holistic assessment of MDI sustainability. Specifically, long-term MDI demonstrated numerous benefits including improved soil salinity management, nutrient retention, soil structure, and microbial functions. Collectively, these changes contribute to enhanced overall soil quality. Our research also confirms MDI as an effective integrated water-saving technology approach. Affirming the sustainability of widespread MDI promotion, our findings firmly support its potential as a sustainable and viable solution for oasis agriculture in arid lands, conferring long-term benefits to agricultural production in these regions.

Effect of mulched drip irrigation on crop biomass and carbon fluxes in maize field

The agroecosystem, a critical component of the terrestrial carbon cycle, plays an indispensable role in maintaining the balance of carbon pools and ensuring global food security. Investigating the interplay between crop yield and carbon cycle is essential for the advancement of sustainable agricultural practices. In the quest for water-efficient agricultural solutions, mulched drip irrigation emerges as a promising technique to mitigate water scarcity in agriculture. In the arid regions of northwest China, where water is a precious resource, understanding the impact of irrigation methods on the productivity and carbon dynamics of crops like spring maize is critical. Our study aimed to evaluate the influence of two irrigation methods—mulched drip irrigation (DI) and mulched border irrigation (BI)—on the biomass accumulation and carbon fluxes of spring maize by field observation and DNDC model simulation for comparative analysis. The findings based on field and flux observation data, underscore the transformative potential of shifting from BI to DI. DI was found to significantly enhance the soil's hydrothermal environment, which is crucial for fostering optimal conditions for crop growth. This improvement is instrumental in promoting the allocation of photosynthetic products to the aboveground biomass, ultimately leading to a substantial increase in grain yield. Our results indicated that the DI treatment not only bolstered the gross primary productivity (GPP) but also elevated the ecosystem respiration (RE) compared to the BI treatment. Finally, DI can increase the net ecosystem productivity (NEP) of maize fields by 6.08 %. The Denitrification-Decomposition (DNDC) model, after calibration and validation, proved to be a reliable tool for estimating ecosystem respiration under the two irrigation systems. A thorough analysis of the simulated data revealed that DI's enhancement of the soil's hydrothermal environment also led to an increase in soil heterotrophic respiration. This insight is vital as it sheds light on the complex interactions between irrigation practices and soil microbial processes, which are integral to the carbon cycle. These findings contribute to the growing body of knowledge on sustainable agricultural practices and provide a theoretical foundation for strategies aimed at achieving carbon neutrality. By adopting data-driven approaches and leveraging advanced models, we can pave the way for a more sustainable and resilient agricultural future that harmoniously balances productivity and environmental stewardship.

Rational optimization of irrigation regimes for drip-irrigated cotton fields without mulch can alleviate the problem of residual film contamination in arid zones

The serious problem of residual film pollution in the arid region of northwestern China has a severe negative impact on both the farmland environment and the benefits of cotton planting. Drip irrigation without mulch (DIWM) has the potential to serve as an effective alternative to mulch drip irrigation and address the issue of residual film pollution. However, there are few studies on how to formulate a rational irrigation regime under DIWM conditions and achieve water savings and productivity gains. Consequently, from 2020 to 2021, we established three DIWM treatments: W4, W6, and W8. None of the treatments were irrigated at the seedling stage, and the irrigation regime was the same for all the treatments at the squaring stage (2 irrigations at an irrigation quota of 45 mm). From the initial flowering stage, the frequency of irrigation was once every 6 d, 8 d, and 12 d for W4, W6, and W8, respectively, and the corresponding total numbers of watering times were 8, 6, and 4, respectively. The irrigation amount was 69 mm at each time point during the flowering and boll-forming stages in all the treatments, and the final irrigation amount was 52.2 mm in W8. The total irrigation amounts were 366 mm, 504 mm and 625.2 mm for W4, W6 and W8, respectively. This study explored the spatiotemporal characteristics of soil moisture via sensors combined with the spatial grid method. Additionally, the growth indices, biomass accumulation, yield components, and water use efficiency (WUE) of cotton were assessed across various treatments. The results revealed that, in 2020 and 2021, the W8 treatment resulted in the highest soil water content (SWC) in the 70–110 cm soil layer and soil water consumption (WC) in the 10–110 cm layer, with the WC in the 10 cm layer being 20 % and 44 % greater than that in W6, respectively. The excessive total irrigation amount (IA) in the W8 treatment led to high vegetative growth of cotton, diminishing the positive impact on yield. Across both years, the WUE observed in the W6 treatment significantly exceeded that of W8, while the seed cotton yield demonstrated only marginal decreases of 5 % and 0.9 % compared with that of W8. The irrigation amount and average WC in the 10–40 cm soil layer were 19 % and 29 % lower in W6 than in W8, respectively, but the economic benefits were only 2 % lower than those in W8. There was a significant positive correlation between the SWC and WC in all the different soil layers, and the effect of the SWC on the WC gradually decreased with increasing soil depth. Overall, the irrigation regime employed in the W6 treatment within the arid zone, devoid of mulch cover, proves to be an effective water-saving strategy, ensuring a consistent cotton yield and enhancing WUE. This study serves as a reference for developing an efficient irrigation system tailored to the DIWM cotton industry in arid zones, contributing to the promotion of green and sustainable agricultural development in this region.

Long-term mulched drip irrigation facilitates soil organic carbon stabilization and the dominance of microbial stochastic assembly processes

Mulched drip irrigation (MDI) is generally accepted as a method to decrease soil salinization and improve crop yields in arid and semi-arid regions. However, there remain gaps in how MDI drives soil organic carbon (SOC) dynamic microbial assembly processes with time, and the mediating role of microorganisms remains unclear. In this study, we investigated the aforementioned issues across soil profiles in cotton fields with different years of MDI. The results showed that MDI did not cause the differences in SOC, particular organic carbon (POC), and mineral-associated organic carbon (MOC) in soil layers. The POC and MOC contents had a parabola relationship with time, and showed an opposite trend in soil. After 15 years of MDI, the ratio of MOC/SOC increased to a peak value of 50 % and 52 % in topsoil and subsoil, respectively; the ratio of POC/SOC decreased to valley values of 50 % and 48 %, respectively (P < 0.05). Long-term MDI reduced the differences in oxidase between soil layers but accelerated SOC loss by increasing polyphenol oxidase activity (P < 0.05). Compared with that of other years, with 10 years of MDI, bacterial Shannon diversity decreased to a valley value, and fungal Shannon diversity reached to a top value in subsoil (P < 0.05). In general, stochastic processes were mainly controlled by dispersal limitation, and undominated processes dominated microbial assembly; however, there was a close relationship between bacterial communities and organic carbon fractions. The high percentage of positive linkages among microorganisms indicated that long-term MDI was beneficial for carbon fixation. Additionally, a decrease of fungal oligotroph/copiotroph ratio, the relative abundance of Ascomycota and Basidiomycota was beneficial for the accumulation of SOC and POC in topsoil (P < 0.05). In conclusion, long-term MDI is useful for the fixation of organic carbon via improving soil POC content and strengthening linkages within community assemblies.

The Influence of the Distribution Law and Uniformity of a Threshed Mixture with the Working Parameters of a Soybean Threshing Device

Soybean plants cultivated using mulched drip irrigation planting technology have the following characteristics during the harvest period: green stems and leaves, and a high straw/grain ratio. Moreover, the threshing device of a soybean combine harvester is difficult to adapt to, resulting in an increase in the accumulation and unevenness of the threshed mixture. This leads to an increase in impurity content and the loss rate. We conducted a single-factor experiment on a self-developed longitudinal/axial-flow soybean threshing and separation test bench, employing drum speed, feeding rate, and threshing clearance as experimental factors. The influence of the soybean threshing and separation device’s working parameters on the distribution and uniformity of the threshed mixture in the axial and radial directions of the drum was explored through experiments. The results showed that the mass of the threshed mixture and soybean seeds showed a trend of first rapidly increasing and then slowly decreasing in the axial direction of the drum. Additionally, the mass showed a distribution feature of large values on both sides and small values in the middle in the radial direction. A lower drum speed, greater threshing clearance, and a smaller feeding rate make the radial distribution of a threshed mixture more uniform. Based on the combination of the crushing rate and unthreshed rate, the optimal working parameter combination was determined to be as follows: a drum speed of 500 r/min, a feeding rate of 6 kg/s, and a threshing clearance of 25 mm. The findings of this research offer valuable insights for the structural optimization and design enhancement of threshing and cleaning mechanisms within soybean combine harvesters.

Maize straw biochar improved soil nitrogen, but no effect on phosphorus in desert under mulched drip irrigation

Maize straw biochar improved soil nitrogen, but no effect on phosphorus in desert under mulched drip irrigation

Effects of Irrigation Approaches and Mulching on Greenhouse Melon Production and Water Use in Northern China

To explore the effects of different irrigation approaches, mulching, and their interaction on greenhouse melon (Cucumis melo L.) production and water use, a field experiment was conducted in Northern China using four treatments: mulching drip irrigation (MDI), mulching furrow irrigation (MFI), drip irrigation (DI), and furrow irrigation (FI; CK). The plant biomass, yield, water consumption, and water use efficiency (WUE) of melons were measured at different growth stages. The results showed that mulching has significant positive impacts on the growth as well as the fruit yield of melons. However, the water use characteristics of the plant were more greatly determined by the various irrigation approaches, and there was a significant interaction between the irrigation approach and mulching for both the total water consumption and WUE of the greenhouse melon. Of these treatments, MDI resulted in the highest yield of 38.49 t/hm2, which was significantly higher than the yields obtained with DI (32.36 t·hm−2) and FI (CK, 30.34 t·hm−2). In addition, the water consumption under MDI was 45.80% lower than FI (CK), which resulted in the promotion of WUE under MDI. The WUE range of the greenhouse melon is as follows: MDI (334.77 kg·mm−1·hm−2) &gt; DI (244.84 kg·mm−1·hm−2) &gt; MFI (189.78 kg·mm−1·hm−2) &gt; FI (CK; 142.94 kg·mm−1·hm−2). The findings of this study indicate that mulching can boost melon yield, and drip irrigation can limit water consumption. This study provides a reference point for policymakers, indicating that drip irrigation with plastic mulching could be a feasible adaptation strategy for increasing greenhouse melon production in Northern China, as well as other agriculture regions that suffer from water shortages.

Fertilizer application parameters for drip-irrigated peanut based on the fertilizer effect function established from a "3414" field trial.

Scientific fertilization is an important technical means of achieving high and stable peanut yields. Using soil testing and formula fertilization, the "3414" optimal regression design was used and included 14 nitrogen (N), phosphorus (P), and potassium (K) fertilization treatments. Ternary quadratic functions of the fertilizer effect were established according to three-season field experiments and the regression analysis of fertilizer-yield function was performed to explore the optimal fertilizer application mode and ratio for peanuts under mulched drip irrigation (MDI), and a suitable fertilizer application system was established. The ternary quadratic equation relating peanut yield (y) and the fertilizer application rates of N (N), P (P2O5), and K (K2O) was obtained after fitting, i.e., y = 2912.528 + 21.432N + 16.324P + 6.181K - 0.051N2 - 0.109P2 - 0.061K2 + 0.017NP + 0.023NK + 0.086PK, and significance analysis and typicality assessment were performed. The model R 2 was 0.9709, both values are extremely significant (p < 0.01), which indicates that the obtained ternary quadratic fertilizer effect function is typical and could be used for statistical purposes and fertilization recommendations. Three quadratic fertilizer effect functions were obtained. Among them, the equation for K is extremely significant, and the equations of N and P are significant. According to the assumption that the marginal yield is zero and the marginal profit is zero, the fertilizer application rate with the maximum yield, the fertilizer application rate with the best economic benefits, and the corresponding yields were obtained. The optimal fertilizer application rate predicted by the ternary quadratic fertilizer effect function was relatively high, so the three quadratic fertilizer effect functions were used for prediction. Under the test conditions, the recommended fertilizer application rates for peanuts under MDI are 256.6 kg N per ha, 164.2 kg P2O5 per ha, and 213.2 kg K2O per ha, the recommended fertilization ratio is 1:0.64:0.83, and the recommended ratio under formula fertilization is 23:15:19. The study has developed a data-based decision support system for Xinjiang drip-irrigated peanut, which assists farmers and agricultural managers in making more scientific and precise fertilization decisions based on the specific growth requirements of the crops and soil conditions. This evidence-based methodology enhances the precision of agricultural management, which is conducive to increasing crop yields while reducing resource wastage and environmental impact. However, multipoint and multiyear experiments are still needed to ensure that the findings are adaptable to the diverse soil conditions and fluctuating climate patterns that may be encountered in practice.

Dry Matter Accumulation, Water Productivity and Quality of Potato in Response to Regulated Deficit Irrigation in a Desert Oasis Region.

As one of the most important food crops, the potato is widely planted in the oasis agricultural region of Northwest China. To ascertain the impact of regulated deficit irrigation (RDI) on various facets including dry matter accumulation, tuber yield, quality and water use efficiency (WUE) of potato plants, a two-growth season field experiment under mulched drip irrigation was conducted in the desert oasis region of Northwest China. Water deficits, applied at the seedling, tuber formation, tuber expansion and starch accumulation stages, encompassed two distinctive levels: mild (55-65% of field capacity, FC) and moderate (45-55% FC) deficit, with full irrigation (65-75% FC) throughout the growing season as the control (CK). The results showed that water deficit significantly reduced (p < 0.05) above-ground dry matter, water consumption and tuber yield compared to CK, and the reduction increased with the increasing water deficit. A mild water deficit at the tuber formation stage, without significantly reducing (p > 0.05) yield, could significantly increase WUE and irrigation water use efficiency (IWUE), with two-year average increases of 25.55% and 32.33%, respectively, compared to CK. Water deficit at the tuber formation stage increased starch content, whereas water deficit at tuber expansion stage significantly reduced starch, protein and reducing sugar content. Additionally, a comprehensive evaluation showed that a mild water deficit at the tuber formation stage is the optimal RDI strategy for potato production, providing a good balance between yield, quality and WUE. The results of this study can provide theoretical support for efficient and sustainable potato production in the desert oasis regions of Northwest China.

Increasing dissolved oxygen concentration of irrigation water is beneficial to nitrogen uptake of cotton under mulched drip irrigation

ContextEnhancing crop nitrogen absorption is crucial for improving nitrogen fertilizer utilization efficiency. Soil oxygen conditions play a vital role in influencing crop nutrient uptake. However, the impact of dissolved oxygen concentration in irrigation water on cotton’s nitrogen absorption remains unknow under mulched drip irrigation conditions. RESEARCH QUESTION: This study aimed to investigate whether the dissolved oxygen concentration in irrigation water affects cotton’s nitrogen uptake. METHODS: Urea was utilized as the nitrogen fertilizer, and 5 dissolved oxygen concentration of irrigation water were set in the experiment by adding sodium percarbonate (CK: 3.9 mg L−1, CO1: 9.2 mg L−1, CO2: 13.3 mg L−1, CO3: 17.3 mg L−1, CO4: 25.5 mg L−1). RESULTS: The results showed that increasing the dissolved oxygen concentration in irrigation water could increase the soil urease activity and bacterial operational taxonomic units (OTU), which may be beneficial to the urea decomposition and nitrogen cycling function. Towards the end of the cotton growth period, oxygenation irrigation led to an increase in nitrate nitrogen and ammonium nitrogen content in the soil. The average nitrate nitrogen content in the 0–60 cm soil layer of CO1, CO2, CO3 and CO4 increased by 12.4 %, 14.7 %, 15.9 % and 17.3 % respectively compared with CK. Similarly, the average ammonium nitrogen content of CO1, CO2, CO3 and CO4 in the 0–40 cm soil layer increased by 8.9 %, 11.7 %, 12.0 % and 11.6 % respectively compared with CK. Increasing the dissolved oxygen concentration in irrigation water resulted in elevated dry matter accumulation in cotton. The total dry matter of CO1, CO2, CO3 and CO4 increased by 9.5 %, 12.6 %, 14.6 % and 16.8 % respectively compared with CK. Additionally, the nitrogen concentration in each cotton organ also exhibited an increase. The total nitrogen accumulation of CO1, CO2, CO3 and CO4 increased by 26.1 %, 36.2 %, 48.2 % and 53.1 % respectively compared with CK. Furthermore, increasing the dissolved oxygen concentration in irrigation water also facilitated nitrogen migration to cotton bolls (boll shell + seed + fiber). The cotton boll nitrogen accumulation of CO1, CO2, CO3 and CO4 increased by 1.8 %, 3.4 %, 4.2 % and 4.2 % (absolute value) compared with CK (reached significant level). Finally, the lint yield and fiber quality parameters (micronaire, fiber elongation, fiber breaking strength) exhibited further improvement with the increase in dissolved oxygen concentration in irrigation water. CONCLUSIONS: Increasing the dissolved oxygen concentration in irrigation water promotes nitrogen absorption in cotton, facilitates nitrogen accumulation in cotton bolls, and enhances nitrogen fertilizer utilization efficiency. Moreover, it positively impacts cotton lint yield and fiber quality.

Influence of Long-Term Mulched Drip Irrigation on Upward Capillary Water Movement Characteristics in the Saline–Sodic Region of Northwest China

Capillary water, serving as a crucial intermediary between groundwater and crop root layer moisture, is important for both soil retention and crop utilization. To investigate the effect of mulched drip irrigation (MDI) on upward capillary water in cotton fields with different application years (0, 10, 14, 18, 20, and 24 years) in the saline–sodic region of Northwest China, an indoor soil column test (one-dimensional capillary water rise experiment) was conducted. The results showed that the wetting front transport law, capillary water recharge, and wetting front transport rate over time exhibited an increasing trend in the early stages of MDI application (10 and 14 years), peaking at 18 years of application, followed by a decreasing trend. The relationship between the capillary water recharge and rising height was fitted based on the Green–Ampt model, and their slopes reveal that 14 and 18 years of MDI application required the largest amount of water per unit distance, indicating an excellent water-holding capacity beneficial for plant growth. Conversely, 0 years required the smallest amount of water per unit distance. Based on the movement characteristics of upper capillary water, we confirmed that the MDI application years (0–18 years) improves soil infiltration capacity, while the long-term application years (18–24 years) reduces groundwater replenishment to the soil. Furthermore, the HYDRUS-1D model was employed to simulate the capillary water rise process and soil moisture distribution under different MDl application years. The results showed an excellent consistency with the soil column experiments, confirming the accuracy of HYDRUS-1D in simulating the capillary water dynamics in saline–sodic areas. The results would provide suggestions to achieve the sustainable development of long-term drip-irrigated cotton fields.

Effects of Different Film Types on Cotton Growth and Yield under Drip Irrigation

To address residual plastic film in fields in which mulched drip irrigation technology is applied, a sprayable degradable film (consisting of 1–5% clay, 5–20% humic acid, 0.5–5% crosslinker, and 0.5–5% auxiliary and water) can be used as a superior alternative to the plastic film applied in drip-irrigated fields. A field experiment was conducted in Xinjiang, Northwest China, to test the impacts of five different mulching treatments (SF1, sprayable degradable film applied at 1900 kg ha−1; SF2, sprayable degradable film applied at 1900 kg ha−1; SF3, sprayable degradable film applied at 2500 kg ha−1; PF, plastic film; and NF, no film mulching) on cotton growth and development, yield, and water use efficiency. The results showed that, compared to the NF treatment, sprayable degradable film mulching (SF1, SF2, and SF3) positively impacted the soil hydrothermal environment, promoted root growth, significantly increased plant height and leaf area, and enhanced physiological characteristics, which, in turn, increased yield and water use efficiency by 11.79–15.00% and 21.88–30.21%, respectively. The maximum yield and water use efficiency were observed in the PF treatment, amounting to 5345 kg ha−1 and 1.28 kg m−3, respectively, and they had no significant differences from those in the SF3 treatment. In general, applying moderate amounts of sprayable degradable film at a rate of 2500 kg ha−1 represents an effective agronomic strategy for managing residual film contamination while maintaining stable cotton yields.

The different responses of AOA and AOB communities to irrigation systems in the semi-arid region of Northeast China.

Ammonia oxidation is the rate-limiting step in nitrification and the key step in the nitrogen (N) cycle. Most soil nutrients and biological indicators are extremely sensitive to irrigation systems, from the perspective of improving soil fertility and soil ecological environment, the evaluation of different irrigation systems and suitability of selection, promote crop production and soil quality, study the influence of the soil microenvironment contribute to accurate evaluation of irrigation farmland soil health. Based on the amoA gene, the abundance and community diversity of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) and their responses to soil physicochemical factors and enzyme activities were studied in semi-arid areas of Northeast China. The study consisted of three irrigation systems: flood irrigation (FP), shallow buried drip irrigation (DI), and mulched drip irrigation (MF). The results showed that DI and MF significantly increased the contents of alkaline hydrolyzed nitrogen (AN), nitrate nitrogen (NO3--N), soil moisture, and the activities of ammonia monooxygenase (AMO) and hydroxylamine oxidase (HAO). Compared with FP, DI significantly increased the abundance of soil AOA and AOB, while MF significantly increased the abundance of soil AOB. Irrigation systems significantly affected the community composition of ammonia-oxidizing microorganisms (AOM). Also, AN and soil moisture had the greatest influence on the community composition of AOA and AOB, respectively. The AOB community had better stability and stress resistance. Moreover, the symbiotic network of AOB in the three irrigation systems was more complex than that of AOA. Compared with FP, the AOA community under treatment DI had higher complexity and stability, maintaining the versatility and sustainability of the ecosystem, while the AOB community under treatment MF had higher transfer efficiency in terms of matter and energy. In conclusion, DI and MF were more conducive to the propagation of soil AOM in the semi-arid area of Northeast China, which can provide a scientific basis for rational irrigation and N regulation from the perspective of microbiology.

Zeolite application coupled with film mulched drip irrigation enhances crop yield with less N2O emissions in peanut field

Zeolite has been previously reported to increase nitrogen (N) use efficiency in lowland paddy fields. However, few results are available regarding its effect on N2O emissions from upland field, especially with mulched drip irrigation. In present study, two-year peanut field experiments were conducted utilizing a split-plot design to assess the impact of zeolite application and irrigation regimes on plant dry weight and N accumulation, soil inorganic N content, peanut yield, N2O emissions, and soil physicochemical properties. Different irrigation regimes (MD, mulched drip irrigation; RF, rain-fed) as well as zeolite application rates (0 t ha−1 (Z0, control), 5 t ha−1 (Z5), and 10 t ha−1 (Z10)) were applied. Results showed that the MD treatment increased plant dry weight, N accumulation, soil NH4+-N, NO3−-N content and mean soil temperature compared to the RF control. Furthermore, cumulative N2O emissions and peanut yield were raised by 24.3% and 15.8%, respectively, with the MD treatment. The increased peanut yield by mulched drip irrigation might be resulted from the promoted soil inorganic N, soil temperature, and plant N accumulation. Regardless of irrigation, zeolite addition increased dry weight and N accumulation during all measured stages except seedling, mean soil NH4+-N, NO3−-N content, mean soil pH, and peanut yield. In contrast, cumulative N2O emissions were decreased compared to the non-zeolite control. Moreover, findings showed that Z10 performed better in increasing peanut yield by 12.7% and decreasing N2O emissions by 35.7% than Z5. Increasing soil inorganic N content with zeolite addition contributed to improve plant N accumulation and promote dry weight and peanut yield. Furthermore, the reduction of N2O emissions by zeolite was related to improved soil inorganic N and pH. Though MD increased N2O emissions, the MDZ10 treatment had 20.6% of cumulative N2O emissions lower than the conventional practice (RFZ0), indicating that zeolite application alleviated the adverse effect of mulched drip irrigation on N2O emissions. It was concluded that zeolite dose at 10 t ha−1 coupled with mulched drip irrigation gave a high peanut yield with less N2O emissions. Our findings could be adopted in arid areas to enhance peanut production and mitigate environmental risk induced by N2O emissions.

The Impact of Long-Term Mulched Drip Irrigation on Soil Particle Composition and Salinity in Arid Northwest China

The evaluation of soil particle composition and salt dynamics is essential for promoting the sustainable development of oasis agriculture in arid regions under long-term mulched drip irrigation (MDI). In this study, we employed the space-for-time substitution method to investigate the long-term effects of MDI on soil particle composition and salinity. Additionally, seven fields, with MDI durations ranging from 0 to 16 years, were selected to represent the primary successional sequence though time in Northwest China. Soil samples were collected from three soil depths (0–30 cm, 30–60 cm, and 60–100 cm) and then analyzed in the laboratory for soil particle composition and salt content. Our findings demonstrated that influenced by the depth of mechanical cultivation and the maximum wetting front depth, the long-term application of MDI significantly altered both the structure of soil layers and the composition of soil particles after 8 years. Soil sand content and soil salinity gradually decreased, whereas the content of soil silt and clay increased with increasing MDI duration throughout 0–100 cm soil depth. Furthermore, the rates of soil desalination stabilized after 10 years of MDI application, with desalination levels exceeding 90% in the 0–100 cm soil layer. Additionally, the soil mass fractal dimension (Dm) exhibited an upward trend across 0–100 cm soil depth. The changes in soil particle composition indirectly influenced the variations in Dm and salt content. Our study demonstrated that long-term application of MDI effectively mitigated soil salinity, changed soil structure, and ultimately enhanced soil quality and cotton yield.

Response of Soil Nitrogen Components and nirK- and nirS-Type Denitrifying Bacterial Community Structures to Drip Irrigation Systems in the Semi-Arid Area of Northeast China

Denitrification is a key process in soil available nitrogen (N) loss. However, the effects of different water-saving irrigation systems on soil N components and denitrifying bacterial communities are still unclear. In this study, quantitative fluorescence PCR and Illumina MiSeq sequencing were used to investigate the effects of three main irrigation systems, conventional flooding irrigation (FP), shallow buried drip irrigation (DI), and mulched drip irrigation (MF), on the abundance, community composition, and diversity of soil nirK- and nirS-type denitrifying bacteria in the semi-arid area of Northeast China, and to clarify the driving factors of nirK- and nirS-type denitrifying bacterial community variations. The results showed that, compared with FP, MF significantly increased soil moisture, alkaline hydrolyzed nitrogen (AHN), nitrate nitrogen (NO3−-N), non-acid hydrolyzed nitrogen (AIN), and amino sugar nitrogen (ASN), but significantly decreased the contents of ammonium nitrogen (NH4+-N) and acid hydrolyzed ammonium nitrogen (AN). The irrigation system changed the relative abundance of the dominant genera of denitrifying bacteria, DI and MF significantly increased nitrate reductase (NR) and nitrite reductase (NiR) activities, and MF significantly increased the diversity of nirK- and nirS-type denitrifying bacteria but significantly decreased the richness. The community structure of nirK- and nirS-type denitrifying bacteria was significantly different among the three irrigation systems. NO3−-N was the main driving factor affecting the community structure of nirS-type denitrifying bacteria, and moisture significantly affected the community structure of nirK-type denitrifying bacteria. DI and MF significantly increased the abundance of nirK- and nirS-type denitrifying bacteria and also increased the abundance ratio of nirS/nirK genes. Therefore, although DI and MF significantly increased the abundance of denitrifying microorganisms, they did not lead to an increase in the N2O emission potential.

Optimizing cotton yield through appropriate irrigation water salinity: Coordinating above- and below-ground growth and enhancing photosynthetic capacity

The employment of brackish water for irrigation holds considerable potential for addressing the shortfall of freshwater resources in arid regions. It is crucial to discern the impact of salinity on agricultural output and its mechanisms when irrigating with brackish water. Here, a two-year field experiment (2021–2022) was undertaken in Xinjiang, China to assess the effects of water salinity (0.85 g L−1, CK; 3 g L−1, S1; 5 g L−1, S2; and 8 g L−1, S3) on the growth, photosynthesis, carbon accumulation, and cotton yield under mulched drip irrigation. Results showed that, compared to CK, the S1 treatment led to increased biomass, the boll capacity of the root system (BCR), and a reduced root-to-shoot ratio (R/S). In addition, the S1 treatment enhanced the net photosynthetic rate (Pn) and chlorophyll content (Chl) of cotton, enhancing the total carbon accumulation of boll (Cboll) and consequently, the seed cotton yield. However, the higher salinity treatments, S2 and S3, demonstrated a detrimental impact on these indicators. In comparison to CK, the S1 treatment showed a yield increase of 5.92% and 4.76% in the respective two years, yet the S2 and S3 treatments showed a yield decrease of 5.55–15.77% and 5.06–16.74%. The application of a structural equation model (SEM) elucidated a direct effect of photosynthetic parameters (Pn and Chl) and biomass characteristics (total biomass, R/S, and BCR) on yield. These factors also indirectly modulated seed cotton yield through the Cboll/Croot ratio. These results suggest that irrigation with brackish water of 3 g L−1 optimizes cotton production by coordinating crop growth of aboveground and underground parts. This study offers practical strategies for the cotton industry to enhance yields under brackish water irrigation.

Irrigation and Fertilization Scheduling for Peanut Cultivation under Mulched Drip Irrigation in a Desert-Oasis Area.

The aim of this study was to investigate the impact of water and nitrogen regulation on the characteristics of water and fertilizer demands and the yield, quality, and efficiencies of the water and nitrogen utilization of peanuts cultivated under mulched drip irrigation in a desert-oasis region. The experiment, conducted in Urumqi, Xinjiang, centered on elucidating the response mechanisms governing peanut growth, yield, quality, water consumption patterns, and fertilizer characteristics during the reproductive period under the influence of water and nitrogen regulation. In the field experiments, three irrigation levels were implemented, denoted as W1 (irrigation water quota of 22.5 mm), W2 (irrigation water quota of 30 mm), and W3 (irrigation water quota of 37.5 mm). Additionally, two nitrogen application levels, labeled N1 (nitrogen application rate of 77.5 kg·ha-1) and N2 (a nitrogen application rate of 110 kg·ha-1), were applied, resulting in seven treatments. A control treatment (CK), which involved no nitrogen application, was also included in the experimental design. The results indicate a direct correlation between the increment in the irrigation quota and increases in farmland water-related parameters, including water consumption, daily water consumption intensity, and water consumption percentage. The nitrogen harvest index (NHI) demonstrated a higher value in the absence of nitrogen application compared to the treatment with elevated nitrogen levels. The application of nitrogen resulted in an elevation in both nitrogen accumulation and nitrogen absorption efficiency within pods and plants. When subjected to identical nitrogen application conditions, irrigation proved to be advantageous in enhancing water-use efficiency (WUE), nitrogen partial factor productivity (NPFP), and the yield of peanut pods. The contribution rate of water to pod yield and WUE exceeded that of nitrogen, while the contribution rate of nitrogen to nitrogen-use efficiency (NUE) was higher. The total water consumption for achieving a high yield and enhanced water- and nitrogen-use efficiencies in peanuts cultivated under drip irrigation with film mulching was approximately 402.57 mm. Taking into account yield, quality, and water- and nitrogen-used efficiencies, the use of an irrigation quota of 37.5 mm, an irrigation cycle of 10-15 days, and a nitrogen application rate of 110 kg·ha-1 can be regarded as an appropriate water and nitrogen management approach for peanut cultivation under mulched drip irrigation in Xinjiang.

Effect of unsaturated soil water transport function linearization for mulched drip irrigation

Water flow in the unsaturated zone is an important component of the water cycle. Linearized methods have been widely adopted to solve unsaturated flow problems described with Richards’ equation, which is nonlinear. To better understand the effect of unsaturated soil water transport function linearization, this article presents an analytical study of a two-dimensional soil water flow system. Analytical solutions, experimental observations and numerical simulations were compared, and the results indicated that the soil water content variation trends were the same, but the values were a little different. The analytical solutions have a certain reference value for researching unsaturated water flow. However, the soil volumetric water content (SWC) results were sensitive to linearized water flow parameter variations in soil water diffusivity (D). The D changes with the SWC. The results showed that unsaturated water flow function linearization affected the analytical solution results essentially. As the nonlinear math problem was not solved, we recommend the numerical solution when more precise values are needed and complex conditions are considered.