Risk Of Lodging Research Articles

Progress in Agronomic Crops Lodging Resistance and Prevention: A Review

ABSTRACTCrop lodging is recognised as one of the yield‐limiting factors in agricultural production. Therefore, better understanding to improve lodging resistance and to prevent lodging‐induced losses in agronomic crops is necessary. Besides yield losses, lodging severely affects the crop harvesting process and increases the production cost. However, achieving the objective of higher crop yields and yield quality without increasing lodging risk is quite challenging. To this end, it is essential to interpret the underlying mechanism of plant stem buckling and failure of root anchorage and optimise the fundamental trade‐off between lodging resistance and yield performance in agronomic crops. In the present review, we made an effort to discuss recent and innovative research insights that guarantee greater lodging resistance along with advanced lodging prevention strategies while sustaining higher crop yield and yield quality.

Optimized Phosphorus Application Enhances Wheat Stem Lodging Resistance Under Spring Low-Temperature Stress.

Spring low-temperature stress (LTS) has become a major limiting factor for the development of high yield, quality and efficiency in wheat production. It not only affects the function of wheat leaves and the development of spikes but also impacts stem lodging resistance, and may experience elevated risk of stem lodging. This study conducted a field pot experiment to assess the effect of phosphorus fertilizer application mode on wheat stem lodging resistance under spring LTS. Two wheat varieties, Yannong19 (YN19, cold-tolerant variety) and Xinmai26 (XM26, cold-sensitive variety) used as the experiment material. Two phosphorus fertilizer application models including traditional phosphorus application (TPA) and optimized phosphorus application (OPA) were employed. Temperature treatment was conducted at 15 °C (CK) and -4 °C (LT) in a controlled phytotron. Our results showed that spring LTS decreased the stem wall thickness and internode fullness, and altered stem anatomical structure and chemical composition, resulting in a decrease in wheat stem mechanical strength and lodging resistant index. Compared with TPA, the OPA increased the stem wall thickness and internode fullness. The thickness of the stem mechanic tissue layer and parenchymatous tissue, and the area of the large vascular bundle and small vascular bundle were increased by the OPA, which alleviated the damage to stem cell walls caused by spring LTS. At the same time, the OPA also increased the contents of lignin, cellulose, and soluble sugar, improving the C/N ratio in wheat stem. Due to the improved stem morphological characteristics, anatomical structure, and chemical compositions, the wheat stem exhibited enhanced lodging resistance, which increased the lodging resistant index of the 2nd and 3rd internodes of YN19 and XM26 by 27.27%, 11.63% and 14.15%, 15.73% at the dough stage compared with TPA under spring LTS. Meanwhile, OPA could not only alleviate the yield loss caused by spring LTS, but also increase the grain yield without spring LTS. This study indicated that OPA enhances wheat stem lodging resistance under spring LTS, and would be meaningful and practical for improving wheat resistance to low-temperature stress.

Climate, altitude, yield, and varieties drive lodging in sugarcane: A random forest approach to predict risk levels on a tropical island

Lodging is a critical factor in reducing sugarcane yields worldwide, mainly due to the selection of highly productive varieties. Understanding the response of yield and lodging to the combined effects of climate, sugarcane traits, and varieties has become a priority under climate change. The aim of this study was to better understand the influence of plant characteristics, climate, and soil conditions on the trade-off between sugarcane yield and lodging on the tropical Reunion Island. Data from a 14-year experimental network run by the eRcane breeding institute were used to build random-forest models to predict sugarcane yield and lodging classes, i.e. <10 %, 10–50 %, >50 % of lodging. Yield and lodging probability were then predicted across the island using climate change projections from 2015 to 2035. Both yield and lodging were highly influenced by the variety and characteristics (height and tillering) and climatic conditions. Areas on the island at high altitudes were subject to high probability of lodging (>50 %), while in areas with high wind speed, the risk of moderate lodging (10–50 %) increased. Overall, conditions or plant characteristics that favor higher yields increased lodging probability. Nevertheless, the correlation between yield and lodging probability varied considerably depending on the variety, highlighting the importance of sugarcane characteristics in resistance to lodging. This study highlights the fact that promoting more productive varieties in recent decades has led to an increase in lodging and identified critical environments on the island prone to increased risk of lodging.

Nitrogen fertilization management and seeding density differently affect net blotch incidence and grain yield in one two-row and one six-row cultivar of barley

A two-year field experiment was carried out on barley (Hordeum vulgare L.) to test the effect of cultivar, N fertilization management and seeding density on crop growth, net blotch (NB) disease occurrence and yield. The three variables were factorially combined in a split-split-plot design as follows: 1) two barley cultivars, one two-row (H. v. distichum, cv Callas) and one six-row (H. v. hexastichum, cv Azzurro); 2) four N application schedules differing for rates and/or timing of N supply: unfertilized control; fertilized with 35kgha-1 of N at BBCH29 plus 30kgha-1 of N at BBCH31; fertilized with 70kgha-1 of N at BBCH29 plus 60kgha-1 of N at BBCH31; fertilized with 130kgha-1 of N simultaneously at BBCH31; 3) four seeding densities: 100, 200, 400 and 800 viable seeds m2.The three variables affected crop growth and NB occurrence resulting in different grain yield and quality. Results varied with the seasonal trend, in particular with rainfall regime and air temperature, for their possible effect on soil N dynamics and the presence of NB, which resulted in different source capacity, and for their effect on grain setting and filling, i.e., the sink capacity. Both N fertilization and seeding density increased NB pressure, with seeding density affecting the disease even under unfavourable weather conditions for NB development. At the maximum N fertilization rate, delaying N application helped limit plant height and the related risk of lodging, as well as NB symptoms, resulting in greater hectolitre weight and protein content together with no appreciable decrease of grain yield, provided seeding density was close to optimal (i.e., 400 seeds m-2) or higher.

Canopy coverage of wheat measured with high accuracy using the HSV colour model and relative depth estimation model, MiDaS

ABSTRACT Canopy coverage calculated from 2D images effectively estimates several parameters, such as dry weight above the ground, stem number, and risk of lodging, without destroying the crops. This study aimed to clarify how to accurately calculate canopy coverage, regardless of environmental conditions, using various colour models and a relative depth estimation model, MiDaS. For wheat cultivated in 2022/23, the canopy coverage at the initiation of the stem elongation stage (CC30), calculated using only the HSV colour model, was overestimated because of the presence of weeds. However, when the heatmap generated using MiDaS was combined with the results extracted from the HSV colour model, it showed a CC30 similar to the accurate CC30 calculated by hand drawing, regardless of the wheat variety, sowing pattern, and location of the image taken, with an RMSE as low as 3.48. The CC30 calculated by combining the HSV colour model and MiDaS was significantly positively correlated with the number of stems, dry weight above ground, and nitrogen content above ground at the initiation of the stem elongation stage of ‘Sanukinoyume 2009’ grown in 2021/22 and 2022/23 (n = 72, r > 0.798). The combination of the HSV colour model and MiDaS effectively and accurately calculates canopy coverage regardless of environmental conditions and can be used for growth diagnosis and variable nitrogen fertiliser application after the initiation of the stem elongation stage.

Modelling the impact of cabbage stem flea beetle larval feeding on oilseed rape lodging risk.

Cabbage stem flea beetle (CSFB, Psylliodes chrysocephala L.) is a major pest of oilseed rape (OSR, Brassica napus L.) in the UK and low availability of effective chemical control has increased the need for integrated pest management approaches. The risk of OSR to lodging is strongly related to stem strength, however, the impact of CSFB larval tunnelling on stem strength and subsequent risk to stem lodging is unknown. The study investigated this by applying the Generalised Crop Lodging Model to conventionally grown OSR crops scored for varying levels of CSFB larval tunnelling. Lodging risk mitigation strategies including plant growth regulators (PGR) and varying nitrogen regimes were tested under high CSFB larval pressure. Stems of OSR plants were categorised by the proportion of visual damage (< 5%; 5-25%; 26-50%; 51-75%; 75-100%). Stems of 26-50% damage had significantly lower breaking strengths and diameters compared to plants that scored < 5%, with the associated reduction in stem failure windspeed equivalent to an order of magnitude increase in the risk of a lodging event occurring in the UK. PGR use reduced plant height and subsequently lodging risk variably across the sites. Estimating the proportion of stem tunnelling alongside larval pressure may be a useful tool in considering the contribution of CSFB pressure to lodging risk. The research demonstrates that the use of canopy management principles to optimise canopy size through nitrogen management and PGR use may help offset increased lodging risk caused by CSFB tunnelling. © 2024 Society of Chemical Industry.

Utilizing auxin dwarf genes to optimize seed yield and lodging resistance in rapeseed

Direct-seeding rapeseed production at high plant density raises the risk of lodging. We investigated the use of dwarf genes to improve rapeseed plant architecture to balance yield and lodging. Three genotypes with different plant architectures (dwarf scaHS5, semi-dwarf +/scaHS5, and tall HS5) were evaluated under varying nitrogen rates (N1, N2, and N3: 120, 240, and 360 kg N/ha) and plant densities (D1, D2, and D3: 15, 45, and 75 plants m−2) from 2019 to 2022. The results showed that increasing N rate positively influenced yield while decreasing lodging resistance in all genotypes. Increasing plant density (D2–D3) enhanced lodging resistance and yield in scaHS5 and +/scaHS5, but reduced yield in HS5. Compared to the two parents, +/scaHS5 exhibited moderate expressions of IAA3, GH3.15, and SAUR30 in stems under N2D3, resulting in reduced plant height and increased compactness. Additionally, +/scaHS5 had a thicker silique layer than HS5 by 14.7 %, and it had a significant correlation between height/angle and yield. Increasing N rate led to increased lignin and pectin contents, while cellulose content decreased. Increasing plant density resulted in greater stem cellulose content and CSLA3/7 expression in scaHS5 and +/scaHS5, but decreased in HS5. Compared to HS5, +/scaHS5 exhibited higher expressions of ARAD1 and GAUT4, along with a 51.1 % increase in pectin content, leading to improved lodging resistance under N2D3. Consequently, +/scaHS5 showed a 46.4 % higher yield and 38.9 % lodging resistance than HS5 under N2D3, while scaHS5 demonstrated strong lodging resistance but lower yield potential. Overall, this study underscores the potential of utilizing auxin dwarf genes to optimize the trade-off between yield and lodging resistance in rapeseed and the possibility of maximizing yield potential by optimizing the plant architecture of +/scaHS5 through nitrogen reduction and dense planting

Effects of spraying cycocel and delaying nitrogen application on lodging resistance and yield formation of winter wheat.

We conducted a 3-year (2017-2020) field experiment in the wheat base of Jinzhong Agricultural Hi-tech Industries Demonstration Zone, aiming to determine the measures of nitrogen topdressing and the regulatory effect of cycocel in spring to increase wheat yield. Four nitrogen topdressing dates were set up under the condition of cycocel spraying and control (CK) during the rising period: 10 days (D10), 20 days (D20), 30 days (D30), and 40 days (D40) after regreening stage, to analyze the impact of different N topdressing dates on winter wheat yield and the regulation effect of cycocel on stem characteristics, lignin content and related synthetase activities. The results showed that compared to other nitrogen topdressing dates, D30 increased spike number by 1.4%-5.2%, grain number per spike by 0.4%-12.0%, 1000-grain weight by 1.7%-9.4% and yield 8.8%-22.1% respectively. Compared to D10 and D20, D30 significantly improved the activities of phenylalanine ammonia-lyase (PAL) at 0-21 days and 35-42 days after the formation of the second section and increased that of tyrosine ammonia-lyase (TAL) at 0-42 days after the formation of the second section, and increased the lignin content of stem, the internode quality, and the breaking resistance of stem, reduced plant height, and thereby improved the lodging resistance. However, D40 increased grain number per spike by 4.5%-10.1% and yield 0.04%-11.3%, but reduced the activities of PAL and TAL at 0-42 days after the formation of the second internode, reduced the lignin content, weakened the stem strength, and increased the risk of lodging. After spraying cycocel, plant height decreased significantly, the activities of PAL and TAL enhanced, the lignin content in internodes increased, the stem strength advanced, and reached a significant level under D30. Under the condition of nitrogen topdressing combined with cycocel spraying in spring, PAL and TAL activities were significantly positively correlated with lignin content. Lignin content was significantly positively correlated with stem breaking resistance. Stem breaking resistance was significantly positively correlated with lodging resistance index. Yield and its components were significantly posi-tively correlated with internode diameter, weight and breaking resistance, and significantly negatively correlated with plant height and internode length. Overall, nitrogen topdressing combined with spraying cycocel 30 days after regreening could promote the synthesis and accumulation of lignin, and improve stem plumpness, plant lodging resistance and yield.

Optimizing biomass allocation for optimum balance of seed yield and lodging resistance in rapeseed

ContextDense planting can boost achievable yields in rapeseed (Brassica napus L.). But it aggravates the lodging risk that is often associated with high–yielding cropping systems. ObjectivesThis research aimed to assess the agronomic performance of rapeseed in terms of yield and lodging related attributes under various planting densities. Meanwhile, the effectiveness of electrical measurements i.e., root capacitance (EC) and impedance (EI) for predicting root morphology and lodging resistance was also evaluated. MethodsThis study comprised two rapeseed varieties (Qinyou7: a lodging susceptible; Shanyou28: a lodging resistant) which were grown in four planting densities (15, 30, 45 and 60 plants m–2) across four site-year environments. Data on various agronomic parameters were recorded including seed yield, root and stem morphology and lodging resistance. Results and conclusionsWith an increase in planting density from 15 to 60 plants m–2, the seed yields of variety Qinyou7 and Shanyou28 were increased by 67 % and 56 %, respectively. However, a tradeoff of seed yield with lodging resistance was evidenced in lodging susceptible variety Qinyou7. It tended to invest more biomass in the siliques to maximize seed yield, which led to reduced stem bending strength (Ss) and weaker root anchorage strength (Sr), thus making plants more prone to lodging (in terms of lower safety factor, SF). Conversely, the lodging resistant Shanyou28 allocated a greater amount of photosynthates to the stems and roots to enhance its lodging resistance by maintaining higher Ss and Sr, thus compromising on a part of its seed yield. Large diameter of the root–soil cone and robust roots can be considered as critical traits for selecting lodging resistant varieties due to their strong correlation with Sr, and other lodging associated root morphological traits. Both EC and EI measurements were closely linked with seed yield, root–related traits, and SF. ImplicationsWe strongly recommend exploiting these electrical measurements as a quick, low–cost, non-destructive, and efficient technique for predicting seed yield and lodging susceptibility of rapeseed.

Effect of Ridge–Furrow with Plastic Film Mulching System and Different Nitrogen Fertilization Rates on Lodging Resistance of Spring Maize in Loess Plateau China

The ridge–furrow with plastic film mulching (RF) system has been widely adopted in rain-fed crop planting due to its potential to enhance crop yield and water use efficiency. However, the impact of the RF system on maize lodging resistance, particularly when nitrogen fertilizer is applied, remains uncertain. Therefore, a two-year field experiment was carried out with two planting systems (FP: flat planting and RF) and two nitrogen application rates (N180: 180 kg·N ha−1 and N300: 300 kg·N ha−1) to assess the risk of lodging in maize. The results showed that compared to FP, RF resulted in a significant increase of 78.7% in lodging rate. In addition, the lodging rate increased by 22.6% with increasing nitrogen fertilizer application. The lignin content increased by 43.4%, while the stalk bending strength rose by 42.5%, under RF compared to the FP system. These improvements in the mechanical properties of maize stalks contributed to the improved lodging resistance index of RF, which was found to be approximately 21.3% higher than that of FP. In addition, high nitrogen application rates increased the risk of lodging for different planting patterns over two years. In conclusion, fertilization of spring maize with 300 kg·N ha−1 under the RF system led to higher yields but increased lodging rates. The risk of lodging should be considered when planting maize under the RF system. The results of this study can provide scientific basis and technical support for the optimization of rain-fed maize cultivation measures in the Loess Plateau.

Optimizing canopy spacing configuration enhances foxtail millet grain yield and water productivity by improving stalk lodging resistance in the North China Plain

Optimizing canopy spacing configuration can enhance resources utilization, supporting robust growth and dry matter production, while mitigating the risk of lodging and improving crop yield and quality. However, research specifically addressing optimal canopy spacing configurations for foxtail millet remains limited. Over a two-year period, a field experiment in the North China Plain assessed the impacts of four-row spacing configurations (T0: 40 + 40 cm; T1: 30 + 50 cm; T2: 20 + 60 cm; T3: 10 + 70 cm), to investigate the effects of row spacing configuration on lodging resistance, canopy spatial configuration, stem characteristics, yield, and water productivity (WP) of foxtail millet, aiming to elucidate the underlying regulatory mechanisms. Row spacing configurations significantly influenced lodging resistance, yield, and WP. Under T1, improvements were observed in stem morphology and mechanical properties, particularly in the 2nd-6th basal internodes (I2-I6). The light interception rate in T1 at wide rows in the middle canopy (30–90 cm aboveground) increased by 97.89 %, compared to T0. Partial least squares-structural equation modeling revealed that improved light interception in wide rows in the middle canopy contributed to a rise in diameter and dry plumpness of I2. This, in turn, promoted greater breaking resistance of I2 and tensile resistance, ultimately reducing the lodging likelihood. Simultaneously, the decrease in lodging resulted in higher yield and WP at yield level of foxtail millet. Therefore, T1 demonstrated the lowest lodging rate (67.34 %–91.92 % lower than T0), and the highest yield and WP at yield level (4.10 %–8.03 % and 20.79 %–22.46 % higher than T0). Optimizing canopy spacing configuration is essential for cultivating high-yielding and water-efficient foxtail millet populations. The results indicated that the 30 + 50 cm row spacing configuration improves light distribution in the middle canopy, enhancing lodging resistance and consequently increasing both yield and WP. This research offers a theoretical foundation for foxtail millet breeding and agronomic practices to achieve lower lodging rate, higher yields, and enhanced WP in the North China Plain.

Sustainable controlled-release urea placement depth reduces lodging risk and enhances spring maize productivity

Sustainable controlled-release urea placement depth reduces lodging risk and enhances spring maize productivity

How do novel plant growth regulators and cultivation models strategies affect mechanical strength, lodging resistance and maize productivity in semi-arid regions?

Plant growth regulators are synthetic compounds that have become a significant and technical guarantee for agricultural productivity. In China, "Jindeli", which contains active elements of ethephon and cycocel (EC), has been proven to prevent maize stem elongation, improve maize stem thickness, stem morphology and mechanical strength, root growth, lodging resistance, and yield under various cultivation models. Diethyl aminoethyl hexanoate (DA-6) can promote cell division and growth. From 2020–2021, four growth regulators sprays were used to conduct a field experiment; G1: water spraying; G2: EC spraying; G3: DA-6 spraying; G4: EC+DA-6 spraying under two cultivation models; R: ridge covered with plastic film mulching and T: traditional flat planting without plastic mulching. The results indicated that RG4 treatment considerably decreased plant height, internode length, ear height, lodging rate, and center of gravity height, while improved the internode bending strength, cross-sectional area, cortical thickness, and stem vascular bundles as compared with rest of all other treatments. RG4 treatment considerably improved internode diameter, stem mechanical strength, filling degree, root growth, mean tilt angle, and lignin content, while significantly reducing LAI. In addition, RG4 considerably enhanced the quality of corn stems, such as increasing mechanical properties and enhancing the compressive strength of corn stalks that content of hemicellulose, cellulose, and lignin has been increased. Furthermore, RG4 treatment significantly improved grain yield by optimizing leaf layer structure and increasing bleeding saps levels, increasing the grains per row and ear. Thus, under the RG4 treatment maize lodging rate was decreased 72.1%, and increased WUE (52.8%), and grain yield (46.6%). In conclusion, the results clearly demonstrate that in the semi-arid regions risk of lodging can be avoided by spraying EC+DA-6 with ridge covered plastic film mulching to the enriched stalk quality, shaping plant morphological characteristics, and proving a stable cultivation model to improving maize productivity.

Management of Seeding Rate and Nitrogen Fertilization for Lodging Risk Reduction and High Grain Yield of Mechanically Direct-Seeded Rice under a Double-Cropping Regime in South China

Precision hill-drop direct seeding using mechanical drilling is a unique direct seeding technique employed in south China that offers advantages such as excellent grain yield and high lodging resistance. Improving yield and lodging-related traits is essential for efforts to improve mechanically direct-seeded rice (MDSR) production. Seeding rates (SR) and nitrogen (N) fertilization rate are two of the main factors affecting grain yield and lodging resistance under MDSR production. However, little information about double-season MDSR production in south China is available. Here, we evaluated yield and lodging risk for two rice cultivars Huanghuazhan, HHZ, lodging-resistant; Xiangyaxiangzhan, XYXZ, lodging-susceptible across two consecutive growing seasons under two under two seeding rates (LSR, 30 cm × 18 cm; HSR, 30 cm × 12 cm) and three N fertilization rates (N1 = 100 kg ha−1, reduced N; N2 = 150 kg ha−1, normal N; and N3 = 200 kg ha−1, enhanced N). We found that increased SR and N fertilization rate improved grain yield and increased lodging risk. SR and N were consistently and positively related to plant height (PH), gravity center height (GCH), the length from the broken basal internode to the panicle tip (SL), the fresh plant weight of the plant part above the broken point (FW), and the length of the two basal internodes. SR and N decreased breaking force (F) and breaking strength (BM), driving increased lodging risk as reflected by increases in lodging index (LI) values. Culm diameter (CD) and culm wall thickness (CWT) did not respond consistently to SR and N treatments. Correlation analysis revealed that PH, GCH, the length of first and second basal internodes, FW, and bending moment for the whole plant (WP) were positively correlated with LI, while F and BM were negatively associated with LI. These findings suggest that the increased lodging risk resulting from high SR could be mitigated by applying appropriate rates of N; that is, this work suggests that grain yield can be maximized and lodging risk minimized by increasing SR while decreasing N fertilization rate. Seasonal differences in the effects of SR and N fertilization should be considered to achieve a high grain yield and maintain high lodging resistance. Our study suggests that increasing SR and decreasing N fertilization can enhance rice grain yield while improving lodging resistance for both varieties. Optimizing grain yield by increasing SR while reducing lodging risk by lowering N application rates may maintain lodging resistance and improve grain yield.

Coupling GEDI LiDAR and Optical Satellite for Revealing Large‐Scale Maize Lodging in Northeast China

AbstractWind‐induced crop lodging can reduce agricultural production and impact food security. However, a systematic evaluation of large‐scale crop lodging and its drivers is lacking, mostly due to the limited observations available. Such knowledge gaps hinder the application of effective management practices to mitigate yield losses. Here, we quantify maize‐lodging induced by three consecutive typhoons in Northeast China in 2020 using direct crop canopy height observations from the Global Ecosystem Dynamics Investigations (GEDI) instrument and optical satellite imagery. We show that the canopy water‐related vegetation index provides a robust wall‐to‐wall mapping of crop lodging, supported by changes in GEDI canopy height. Our spatially contiguous lodging maps show that lodging intensity is mainly due to typhoon intensity (64.34%), with maize plantation fraction (11.94%) and phenology (7.94%) as secondary factors. The shelterbelt forest may partly alleviate the lodging risk, but its effect requires further investigation. Considering the recent expansion of maize cultivation and the poleward shift of landfalling typhoons alongside climate change, the lodging risk may increase for maize and further threaten China's food security.

Assessing PREDICTA®B as a Potential Disease Risk Management Decision Tool for Sorghum Charcoal Rot Based on Disease Levels, Lodging, and Associated Yield Loss

Charcoal rot, caused by Macrophomina phaseolina (Mp), is the most common and the most important root and stalk rot disease of sorghum. Survey data for sorghum charcoal rot disease and pathogen loads were analysed to assess the potential of PREDICTA®B as a disease risk management decision tool. The pathogen, at sowing and pre-harvest, was found to be strongly correlated. The results showed a strong quadratic relationship between the incidence of charcoal rot and the percent of lodging, supporting the notion that charcoal rot is one of the causative agents in sorghum lodging. An Mp load of 2.5 k copies per gram of soil on a log10 scale was established as an indicator of the high incidence of charcoal rot, and its associated risk of serious lodging can be used as a management decision tool. Rainfall and location were also shown to influence lodging rates. Some varieties of sorghum were found to be less susceptible to charcoal rot than others. This study found that disease incidence was a better predictor of damage than the disease rating index. As set by PREDICTA®B, at low or non-detectable levels of Mp, the risk of disease is low. With high levels of Mp, the incidence and severity of disease depend on the susceptibility of the variety and the conduciveness of the environment. High levels of Mp do not mean that disease will occur, but that there is a high risk if the conditions are favourable for disease development. While this study has provided much useful information, it has highlighted the need for further data collection to be able to develop reliable disease risk categories based on test results and its associated yield loss.

In-season prediction of maize stem lodging risk using an active canopy sensor

Lodging is a major problem in maize (Zea mays L.) production worldwide. An analytical lodging model has previously been established. However, some of the model inputs are time consuming to obtain and require destructive plant sampling. Efficient prediction of lodging risk early in the season would be beneficial for management decision-making to reduce lodging risks and ensure high yield potential. Remote sensing technology provides an alternative method for fast and nondestructive measurements with the potential for efficient prediction of lodging risks. The objective of this study was to explore the potential of using an active canopy sensor for the early prediction of maize stem lodging risk using simple regression and multiple linear regression (MLR) models. The results indicated that the MLR models using active canopy sensor data together with weather and management factors performed better than simple regression models using only sensor data for predicting maize stem lodging indicators. Similar results were achieved either using regression models to predict the maize stem lodging risk indicators directly or using the regression models to predict lodging related plant parameters as inputs to a process-based lodging model to predict lodging risk indicators indirectly, although the latter approach using MLR models performed slightly better. A medium planting density (7.0 plants m-2) and 240 kg ha-1 N rate would be suitable in the study region, and the recommendations may be adjusted according to different weather conditions. It is concluded that maize stem lodging risks can be predicted using active canopy sensor data together with weather and management information at V8 stage, which can be used to guide in-season management decisions. Additional research is needed to evaluate the potential of using unmanned aerial vehicles and satellite remote sensing technologies in conjunction with machine learning methods to improve the prediction of lodging risks for large scale applications.

Improving Stem Lodging Resistance, Yield, and Water Efficiency of Wheat by Adjusting Supplemental Irrigation Frequency

Optimizing supplemental irrigation (SI) measures and enhancing stem lodging resistance can be the keys to achieving a high and stable yield and high efficiency in wheat. The experiment was established as a two-factor field trial in 2018–2020. We used four SI combinations at different stages: rain-fed (T0), SI at jointing (T1), SI at jointing + anthesis (T2), and SI at regreening + jointing + anthesis (T3) with ‘Bainong4199’ (BN4199) and ‘Zhoumai18’ (ZM18) as experimental materials. We researched the effects of different SI combinations on the stem characteristics, stem vigor, grain filling, and yield of winter wheat. The results suggest that the basal internode at the anthesis stage grew with the increase in SI amount, but the stem fracture resistance of T1 and T2 was higher than that of T0 and T3. As grain filling continued, the lodging index increased and stem vigor decreased. In comparison with T3, the average stem lodging index of T2 decreased by 21.92% for ‘BN4199’ and 36.63% for ‘ZM18’, but the WUE increased by 29.76% and 14.92%, respectively. The grain yield increased with the increase in irrigation times during the growth period; there was no significant difference between T2 and T3 in 2018–2019. In a biennial comparison, the grain yield of all treatments in 2019–2020 was significantly lower than those in 2018–2019, and the grain yield of ‘ZM 18’ was lower than that of ‘BN 4199’. Correlation analysis displayed that there were significant positive correlations between post-anthesis stem vigor and the dry matter contribution rate of post-anthesis to grains and between the grain filling rate at 21–28 days after anthesis (DAA) and stem strength at 30 DAA. In summary, selecting a high-yield lodging-resistant wheat variety with SI at jointing and anthesis was beneficial for forming strong stems and maintaining higher stem vigor at the later growth stage for grain filling, which reduced lodging risk and ensured high yield and high WUE.

Predicting Rice Lodging Risk from the Distribution of Available Nitrogen in Soil Using UAS Images in a Paddy Field.

Rice lodging causes a loss of yield and leads to lower-quality rice. In Japan, Koshihikari is the most popular rice variety, and it has been widely cultivated for many years despite its susceptibility to lodging. Reducing basal fertilizer is recommended when the available nitrogen in soil (SAN) exceeds the optimum level (80-200 mg N kg-1). However, many commercial farmers prefer to simultaneously apply one-shot basal fertilizer at transplant time. This study investigated the relationship between the rice lodging and SAN content by assessing their spatial distributions from unmanned aircraft system (UAS) images in a Koshihikari paddy field where one-shot basal fertilizer was applied. We analyzed the severity of lodging using the canopy height model and spatially clarified a heavily lodged area and a non-lodged area. For the SAN assessment, we selected green and red band pixel digital numbers from multispectral images and developed a SAN estimating equation by regression analysis. The estimated SAN values were rasterized and compiled into a 1 m mesh to create a soil fertility map. The heavily lodged area roughly coincided with the higher SAN area. A negative correlation was observed between the rice inclination angle and the estimated SAN, and rice lodging occurred even within the optimum SAN level. These results show that the amount of one-shot basal fertilizer applied to Koshihikari should be reduced when absorbable nitrogen (SAN + fertilizer nitrogen) exceeds 200 mg N kg-1.

Prediction of Areal Soybean Lodging Using a Main Stem Elongation Model and a Soil-Adjusted Vegetation Index That Accounts for the Ratio of Vegetation Cover

In soybean, lodging is sometimes caused by strong winds and rains, resulting in a decrease in yield and quality. Technical measures against lodging include “pinching”, in which the main stem is pruned when excessive growth is expected. However, there can be a decrease in yield when pinching is undertaken when the risk of lodging is relatively low. Therefore, it is important that pinching is performed after the future risk of lodging has been determined. The lodging angle at the full maturity stage (R8) can be explained using a multiple regression model with main stem elongation from the sixth leaf stage (V6) to the blooming stage (R1) and main stem length at the full seed stage (R6) as the explanatory variables. The objective of this study was to develop an areal lodging prediction method by combining a main stem elongation model with areal main stem length estimation using UAV remote sensing. The main stem elongation model from emergence to R1 was a logistic regression formula with the temperature and daylight hours functions f (Ti, Di) as the explanatory variables. The main stem elongation model from R1 to the peak main stem length was a linear regression formula with the main stem length of R1 as the explanatory variable. The model that synthesized these two regression formulas were used as the main stem elongation model from emergence to R8. The accuracy of the main stem elongation model was tested on the test data, and the average RMSE was 5.3. For the areal main stem length estimation by UAV remote sensing, we proposed a soil-adjusted vegetation index (SAVIvc) that takes vegetation cover into account. SAVIvc was more accurate in estimating the main stem length than the previously reported vegetation index (R2 = 0.78, p &lt; 0.001). The main stem length estimated by the main stem elongation model combined with SAVIvc was substituted into a multiple regression model of lodging angle to test the accuracy of the areal lodging prediction method. The method was able to predict lodging angles with an accuracy of RMSE = 8.8. These results suggest that the risk of lodging can be estimated in an areal manner prior to pinching, even though the actual occurrence is affected by wind.