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The precision monitoring of film-mulched winter wheat growth facilitates field management optimization and further improves yield. Unmanned aerial vehicle (UAV) is an effective tool for crop monitoring at the field scale. However, due to the interference of background effects caused by soil and mulch, achieving accurate monitoring of crop growth in complex backgrounds for UAV remains a challenge. Additionally, the simultaneous inversion of multiple growth parameters helped us to comprehensively monitor the overall crop growth status. This study conducted field experiments including three winter wheat mulching treatments: ridge mulching, ridge–furrow full-mulching, and flat cropping full-mulching. Three machine learning algorithms (partial least squares, ridge regression, and support vector machines) and deep neural network were employed to process the vegetation indices (VIs) feature data, and the residual neural network 50 (ResNet 50) was used to process the image data. Then the two modalities (VI feature data and image data) were fused to obtain a multi-modal fusion (MMF) model. Meanwhile, a film-mulched winter wheat growth monitoring model that simultaneously predicted leaf area index (LAI), aboveground biomass (AGB), plant height (PH), and leaf chlorophyll content (LCC) was constructed by coupling multi-task learning techniques. The results showed that the image-based ResNet 50 outperformed the VI feature-based model. The MMF improved prediction accuracy for LAI, AGB, PH, and LCC with coefficients of determination of 0.73–0.92, mean absolute errors of 0.29–3.89 and relative root mean square errors of 9.48–12.99%. A multi-task MMF model with the same loss weight distribution ([1/4, 1/4, 1/4, 1/4]) achieved comparable accuracy to the single-task MMF model, improving training efficiency and providing excellent generalization to different film-mulched sample areas. The novel technique of the multi-task MMF model proposed in this study provides an accurate and comprehensive method for monitoring the growth status of film-mulched winter wheat. [ABSTRACT FROM AUTHOR]

Soil preparation and mulching practices in combination with slow-release urea application are important measures for agricultural yield enhancement. However, slow-release urea may cause a yield reduction due to insufficient fertility in early crop growth. We considered whether the ridge-furrow plastic-mulching (RFP) system using different mulch colors could offset this disadvantage. An experiment was conducted using a randomized split-plot design with three soil preparation and mulching practices as the main-plot treatments in combination with three different urea applications as sub-plot treatments. The three soil preparation and mulching practices were flat cropping without mulch (F), the RFP system with white plastic mulch over the ridge (W), and the RFP system with black plastic mulch over the ridge (B); the three urea applications were no urea (N0), slow-release urea (NS), and ordinary urea (NU). The results showed that compared to F, the RFP system (especially B) could increase the use of precipitation and reduce soil water depletion, which ultimately increased the water productivity (WP) of winter wheat. In addition, the nitrogen use efficiency of NS was further improved under the RFP system, while there was essentially no difference between the two different urea types under F. In summary, B could take full advantage of NS to coordinate the relationship between effective spikes per unit area, grains per spike, and 1000-grain weight, maximizing the WP, nitrogen use efficiency, and grain yield. Between 2016 and 2019, the WP and grain yield of B-NS increased by 79.2–107.0% and 75.7–87.0%, respectively, compared to the lowest value (F-N0). The nitrogen agronomic efficiency (NAE), nitrogen physiological efficiency (NPE), nitrogen recovery efficiency (NRE), and nitrogen partial factor productivity (NPFP) of B-NS increased by 116.1–123.3%, 28.5–34.8%, 66.1–71.9%, and 44.1–53.2%, respectively, compared with the lowest value (F-NU). • Ridge-furrow plastic-mulching used white (W) or black (B) mulching to cover ridges. • The urea applied to winter wheat was either slow-release (NS) urea or ordinary urea. • W and B enlarged differences in urea types compared with traditional flat cropping. • B made full use of NS to increase yield, water productivity, and N use efficiency. [ABSTRACT FROM AUTHOR]

• RF boosted yield, WUE and NUE of wheat than FP with same irrigation (I) and N input. • RF maintained yield with 180 mm and 70 kg ha−1 less I and N in wet and normal years. • RF maintained yield with 90 mm and 70 kg ha−1 less I and N in dry years. • RF with 90 mm more I further boosted yield, WUE and NUE in wet and normal years. Ridge–furrow film mulching (RF) is an effective planting pattern to harvest rainwater, reduce evaporation, increase root-zone soil moisture and improve crop yield in arid regions of northwest China. Compared to flat planting without film mulching (FP), RF significantly enhances the yield and water and nitrogen (N) use efficiencies of winter wheat under the same irrigation and N inputs. However, whether RF can boost or maintain yield, water use efficiency (WUE) and N use efficiency (NUE) of winter wheat with less irrigation and N supply remains unclear. Moreover, the irrigation-saving and N reduction potential for RF under different climatic (wet, normal and drought) years is unknown. From 2013–2016, field experiments with treatments of different planting patterns (RF and FP), irrigation (0, 90 and 180 mm; represented as I0, I1 and I2, respectively) and N (0, 140 and 210 kg ha−1; represented as N0, N1 and N2, respectively) application amounts were conducted to analyze the growth and physiological characteristics, yield, WUE and NUE of winter wheat. The results showed that the leaf area index, aboveground dry matter, leaf chlorophyll content and net photosynthetic rate were greatest for RFI2N2 (RF with 180 mm irrigation and 210 kg N ha−1) during the whole winter-wheat growing seasons. Eventually, RFI2N2 obtained 9.3–74.1 %, 19.5–81.1 % and 23.8–92.2 % significantly greater yield than other treatments in wet and cool, normal rainfall and temperature, and drought and heat years, respectively. Relative to FPI2N2 (FP with 180 mm irrigation and 210 kg N ha−1, and FPI2N2 is local conventional agricultural management for winter wheat), the irrigation and N reduction potential for RF differed for the three levels of annual rainfall. Treatment RFI0N1 (RF with no irrigation and 140 kg N ha−1) in wet and cool, and normal rainfall and temperature years, and RFI1N1 (RF with 90 mm irrigation and 140 kg N ha−1) in drought and heat years, had almost equal winter wheat yield, and achieved significantly greater WUE and NUE than FPI2N2. In addition, in wet and cool, and normal rainfall and temperature years, RFI1N1 had 14.6–17.7 %, 5.0–10.0 % and 16.2–30.5 % significantly greater yield, WUE and NUE than RFI0N1. Therefore, RFI1N1 could be considered as a favorable management for sustainable intensification of winter wheat production in northwest China, especially in drought and heat years and in areas where water resources are relatively abundant. [ABSTRACT FROM AUTHOR]

Ridge-furrow with plastic film mulching and nitrogen fertilization has been shown to improve soil conditions and plant growth, but it is still unclear how the above-mentioned agronomic practices regulate carbon assimilating (source) and carbon reservoir (sink) to increase winter wheat yield and water use. A field trial was conducted with planting patterns (flat planting with non-mulching (FP) and ridge-furrow with plastic film mulch (RP)) as main plots and N rates (0, 90, 180, and 270 kg N ha–1, marked as N0, N1, N2, and N3, respectively) as sub-plots. The results showed that RP significantly increased soil water storage (SWS), soil temperature (except that at the milk and dough stages of the 2019–2020 season), net content of soil mineral N, and consumption of soil mineral N by 3.8%− 13.5%, 1.4–5 ℃, 7.2%− 197.9%, and 15.1%− 595.7%, respectively, but significantly decreased evapotranspiration during the growth stages (ET i), total ET (ET Total) of 2019–2020, and WUE by 9.90%, 7.28%, and 11.52%, respectively, compared with FP. Nitrogen application significantly decreased SWS and soil temperature by 9.3%− 22.9% and 5.1%− 21.1%, but increased net content of soil mineral N, consumption of soil mineral N, ET i , ET Total , and WUE by 45.9%− 512.4%, 15.0%− 22.0%, 6.0%− 50.3%, 8.98%− 25.32%, and 38.50–145.75%, respectively, compared with N0. Soil water storage at the anthesis, milk, and dough stages and soil temperature at the milk stage mainly increased the source and establishment of the initial reservoir, while the soil mineral N mainly optimized the source-sink balance in the middle and late period. However, leaf area and dry matter at anthesis, chlorophyll content at 18 days post-anthesis, and grain number, especially spike number, played decisive roles in increasing yield, while leaf area and dry matter at the milk stage, grain volume at 30 days post-anthesis, and especially the post-anthesis contribution rate for dry matter accumulation in grains, were the main limiting factors. Therefore, ridge-furrow with plastic film mulching combined with 180 kg N ha−1 could balance the source-sink, but it is necessary to study the ratio of ridge-furrow and sowing rate to achieve a high yield and WUE. [Display omitted] • Soil water and temperature mainly increased the source and establishment of the initial reservoir. • Soil mineral N mainly optimized the source-sink balance in the middle and late period. • The path of RP and N from soil properties to increasing crop yield was found. • The decisive factors and main limiting factors for yield were obtained. [ABSTRACT FROM AUTHOR]

Ridge-furrow mulching patterns are beneficial to improve crop yields and rainwater use efficiency, but it is not clear whether they can improve productivity and simultaneously maintain soil fertility on the Loess Plateau of China. A three-year (2013–2016) field trial was conducted during the rotation of wheat (Triticum aestivum L.) – maize (Zea mays L.) to investigate the effects of ridge-furrow mulching patterns on soil moisture, soil fertility, grain yield, and water use efficiency (WUE). Four ridge-furrow planting patterns included: (1) white plastic film mulch over the ridge (RW), (2) straw mulch over the furrow (RS), (3) white plastic film mulch over the ridge and straw mulch over the furrow (RWS), and (4) black plastic film mulch over the ridge and straw mulch over the furrow (RBS). Flat planting without mulch was CK. The results showed that RW, RS, RWS, and RBS significantly improved soil water storage and aboveground biomass throughout each winter wheat and summer maize growing season compared with CK. Finally, winter wheat grain yield and WUE in the four mulching treatments markedly increased by 13.0–32.9% and 22.5–41.5% in a wet and cool season, 15.5–35.2% and 19.3–41.9% in a season with normal rainfall and temperatures, and 27.2–58.9% and 15.3–33.4% in a dry and warm season, respectively. Maize grain yield and WUE increased by 12.8–35.0% and 19.5–46.2% in a season with normal rainfall and temperature, 15.0–38.5% and 18.0–39.9% in a dry and cool season, and 17.4–50.5% and 13.0–42.5% in a dry and warm season, respectively. Among the four mulching treatments, RWS and RBS significantly improved the yield and WUE of wheat and maize relative to RW and RS over the three years. After three years, soil total nitrogen content in RWS and RBS was significantly greater than in RS. Besides, soil microbial biomass carbon and nitrogen, and soil dissolved organic carbon and nitrogen contents in RWS and RBS were all markedly higher than in RW and RS. Our results indicated that RWS and RBS were a promising agricultural practice that improved crop production and simultaneously maintained soil fertility in a rain-fed semi-arid region of China. • Four ridge-furrow planting patterns were adopted in crop rotation. • RWS and RBS achieved higher soil moisture, yield, WUE, and suitable soil temperature. • After three years, RWS and RBS remained significantly higher soil fertility. [ABSTRACT FROM AUTHOR]

A theoretical basis for optimizing mitigation and adaptation to future climate change can be obtained by determining the carbon balance and their control mechanism in agroecosystems. To better understand summer maize (Zea mays L.)/winter wheat (Triticum aestivum L.) agroecosystems in dry semi-humid carbon balance mechanism, we conducted an in-depth analysis of three-year (2019.6–2022.6) seasonal dynamics of carbon fluxes and their driving factors in summer maize/winter wheat cropland in the Guanzhong Plain combined with path analysis. The results showed that net radiation (R n) was the main direct controlling factor of the net ecosystem exchange (NEE) in the summer maize growing season, followed by leaf area index (LAI). However, LAI was the main factor controlling the seasonal variation of NEE in the winter wheat growing season, followed by R n. Furthermore, LAI was the dominant direct driving factor for the gross primary productivity (GPP) in the summer maize and winter wheat growing seasons. In addition, LAI was the dominant driving factor for the total ecosystem respiration (TER) in the summer maize season, while R n (indirect effect) and LAI (direct effect) were the main controlling factors of TER in the winter wheat season. The NEE values of the summer maize system, winter wheat system, and summer maize/winter wheat system in the study area were from 119 to 221, − 601 to − 595, and − 433 to − 291 g C m − 2 , respectively (the net biological production (NBP) were − 709 to − 437, 220–303, and − 496 and − 260 g C m − 2 , respectively). Notably, the average carbon emission rate of the summer maize/winter wheat agroecosystem in the Guanzhong Plain, considering the carbon output at harvest is 386.2 g C m − 2 year − 1 . Therefore, this study may guide assessment of carbon balance of agroecosystems in dry sub-humid regions, and provide a strong reference for achieving carbon neutrality in local agroecosystems. • Winter wheat dominates net carbon exchange in rotation agroecosystem. • Net radiation and LAI are the dominant controlling factors of carbon balance. • Carbon was exported at an average rate of 386.2 gC m − 2 year − 1 owing to grain removal. [ABSTRACT FROM AUTHOR]