Mitigating Climate-induced Lodging While Sustaining Fodder Supply Through Cutting Management in Dual-purpose Barley (Hordeum distichon L.)

Global temperatures have increased by around 0.4 °C since 1980, with significant variations in different areas. Warming increased the yield in some regions, decreased it in others and had a minor impact on others (Lobell et al., 2007). Barley is the 4^th most important cereal crop after rice, wheat and maize globally. Compared to the other crops, it has more regeneration capacity, less water requirements, requires fewer external inputs, is more resistant to pests and diseases and is comparatively capable of surviving harsh climatic conditions. It is mainly grown for grain, feed and fodder purposes. However, it is prone to lodging during critical growth stages, particularly in dense canopies with excessive vegetative growth.
       
Only 20-25 % of the grain is used in the malt industry, while the rest is used for fodder purposes in the dairy sector to fill the gap between the demand and supply of the green fodder during the lean period of the year (Kumar et al., 2013). Globally, it has grown over 123.55 million acres, with production of 150.9 million metric tons. India produced about 1.91 million metric tons of barley over 614.5 thousand hectares of land with an average productivity of 27.3 quintals per hectare in 2023 (Foreign  Agricultural Service, 2023).
       
Lodging is a complex process that is impacted by external factors like wind speed, rain, soil and plant characteristics. The plant lodging resistance can be assessed by the weight of the upper portion and the resistance of the lower parts, which shows the importance of interaction in plant stability (Mengistie et al., 2023). It also complicates the harvesting procedure and the quality of the grains is also reduced. Adopting proper lopping management before the jointing stage, i.e., taking one cutting during the active vegetative growth stage, can significantly reduce the chances of lodging in barley due to its shorter height, better stability and strong root anchorage (Dhillon et al., 2020) (Fig 1).


       
Fodder lopping is critical, as early lopping reduces fodder yield, while delayed lopping can hinder plant regeneration and grain yield (Neelam et al., 2022). Stump height during lopping impacts nutrient availability, regeneration and grain production, ensuring effective photosynthesis and productivity. Additionally, the number of leaves left on the stump affects sunlight capture and regrowth capacity, influencing both green fodder and grain yields (Atıs et al., 2018).
       
To address this issue, proper lopping time and stump height management are essential for enhancing both grain and fodder yield of dual-purpose barley in Punjab. This study aims to optimize these factors to achieve a balanced supply of fodder and grain by maximizing resource usage, enhancing food security and promoting agricultural sustainability while addressing challenges like lodging from changing weather patterns.

A field experiment was conducted at Lovely Professional University in Phagwara, Punjab, during the rabi seasons of 2022-23 and 2023-24. The site is located at 31.08810 N latitude and 75.51700 E longitude at 233 meters above sea level. The soil is sandy loam with a pH of 0.41 and 0.44 and low in available nitrogen (223, 231 kg/ha), high in available phosphorus (29.3, 32.5 kg/ha) and medium in available potassium (160, 184 kg/ha).
 
Meteorological data
 
Meteorological parameters from the cropping seasons of 2022-23 and 2023-24 are shown in Table 1. While overall seasons were normal, the second season had higher total rainfall and relative humidity. Increased wind speed in March raised the risk of lodging, leading to reduced grain filling, photosynthesis, quality and yield.


 
Preliminary information
 
The experiment was laid out in a Randomized Block Design with ten treatments and four replications. The treatments include- T₁: Control (No lopping), T₂: Lopping at 30 DAS + 1 inch stump height, T₃: Lopping at 30 DAS + 2 inches stump height, T₄: Lopping at 30 DAS + 3 inches stump height, T₅: Lopping at 45 DAS + 1-inch stump height, T₆: Lopping at 45 DAS + 2 inches stump height, T₇: Lopping at 45 DAS + 3 inches stump height, T₈: Lopping at 60 DAS + 1-inch stump height, T₉: Lopping at 60 DAS + 2 inches stump height, T₁₀: Lopping at 60 DAS + 3 inches stump height. DWRUB-52 barley was sown on November 19, 2022 and November 18, 2023, at a 5 cm depth and 22.5 cm row spacing, using 100 kg/ha seed. Fertilizer (75:30:20 NPK kg/ha) was applied, with P and K at sowing and N in three split doses. Necessary agronomic practices, like irrigation and weeding, were followed.
 
Observations recorded
 
Growth parameters
 
Dry matter accumulation is determined by oven drying plant samples at 60-70^oC until a constant weight is reached. For the leaf stem ratio, samples are collected at harvest, dried at 60^oC and separated into leaf and stem. The leaf stem ratio is calculated by dividing leaf dry weight by stem dry weight.
 
Phenological studies
 
For crop phenological studies, days were counted from sowing to tillering, booting, 50% spike initiation, 50% maturity and full maturity.
 
Crop yield
 
Fodder was lopped from plots, leaving stump heights of 1, 2 and 3 inches for regeneration. Green fodder yield was measured in q ha^-1.

The crop was harvested and threshed, with grain weights recorded. Straw yield was calculated by subtracting grain yield from total biological yield and the harvest index (HI) was the percentage of grain yield to biological yield.
 
Lodging and sustainability-related indices
 
Parameters to assess lodging’s impact on crop yield and treatment sustainability are detailed in Table 2.


 
Statistical analysis
 
The data of individual years was pooled and analysed using Excel software with ANOVA for Randomized Block Design. Two-way ANOVA was used to determine the statistical significance of the difference between mean treatment values. Treatment means are compared at a 5% level of significance using the least significant difference test to decode the significance of the treatment effect (Gomez and Gomez, 1984).

Phenological studies of dual-purpose barley in Table 3 showed significant effects from varying lopping times and stump heights at post-tillering stages. The time taken for tillering was consistent across treatments, ranging from 25 to 27 days, indicating that genetic and environmental factors influence tillering. Previous studies by Lal et al., (2017) and Singh et al., (2017) support these findings. Variations in booting times were significant, with T₁: Control (No lopping) booting first at 53 days, followed by T₄: Lopping at 30 DAS + 3 inches stump height at 61 days and T₈: Lopping at 60 DAS + 1-inch stump height at 71 days. The delays in T₈: Lopping at 60 DAS + 1-inch stump height and T₅: Lopping at 45 DAS + 1-inch stump height may be attributed to lower stump heights and prolonged vegetative growth, as higher stump heights are associated with increased photosynthesis and carbohydrate storage (Atıs et al., 2018).


       
The 50% spike initiation occurred first in T₄: Lopping at 30 DAS + 3 inches stump height at 81 days, followed by T₁: Control (No lopping) and T₃: Lopping at 30 DAS + 2 inches stump height at 84 days, likely due to lopping at early vegetative growth redirects assimilates and hormonal signals (like cytokinin flow) from shoot expansion to reproductive development. In contrast, T₈: Lopping at 60 DAS + 1-inch stump height took 108 days, possibly due to extended vegetative growth and greater residual biomass (Sharma et al., 2023).
       
T₄: Lopping at 30 DAS + 3 inches stump height reached 50% maturity in just 105 days, followed by T₁: Control (No lopping), while T₈: Lopping at 60 DAS + 1-inch stump height took longer at 134 days. Throughout the experiment, T₄: Lopping at 30 DAS + 3 inches stump height progressed through stages faster than other treatments, with T₈: Lopping at 60 DAS + 1-inch stump height showing slow growth after tillering. Delayed lopping increases residual biomass, extending grain-filling duration and lengthening the crop cycle. It significantly affects crop physiology and phenology, causing delays in booting and spike initiation. Early lopping leads to faster maturation due to reduced regeneration and photosynthesis, while delayed lopping lengthens the maturity period (Patel et al., 2024; Lal et al., 2017).
       
The data in Table 4 shows that T7: Lopping at 45 DAS + 3 inches stump height has the highest dry matter accumulation (75.3 g/m²), followed by T₆: Lopping at 45 DAS + 2 inches stump height (74.4 g/m²), while T₂: Lopping at 30 DAS + 1-inch stump height has the least (62.8 g/m²) during growth. T₅: Lopping at 45 DAS + 1-inch stump height has the maximum leaf stem ratio (2.37) and T₁: Control (No lopping) has the lowest (1.68). Lower stump height lopping resulted in the highest fodder yield, whereas grain yield was highest during 30 DAS lopping. Highest grain yields were noted in T₄: Lopping at 30 DAS + 3 inches stump height (40.8 q/ha) and T₃: Lopping at 30 DAS + 2 inches stump height (38.8 q/ha) from 30 DAS lopping, outperforming no lopping and other treatments. Heavy lodging with no cutting reduced yields compared to 30 DAS lopping. A delay in lopping decreases the grain yield but increases fodder yield. The lowest straw yield was in T₂: Lopping at 30 DAS + 1-inch stump height (69.44 q/ha), while T₇: Lopping at 45 DAS + 3 inches stump height had the maximum (74.56 q/ha).


       
The results revealed significant differences in grain and straw yield across treatments compared to the control group (T₁: No lopping). Treatment T₄, with lopping at 30 DAS and a 3-inch stump height, yielded a 6.25% increase in grain yield and a minor 2.0% decrease in straw yield. In contrast, T₈ (lopping at 60 DAS with a 1-inch stump height) experienced the largest grain yield drop of 26.0%. T₇ (Lopping at 45 DAS + 3 inches stump height 3-inch stump height) and T₆ (2-inch stump height) also showed declines in grain yield of 11.7% and 8.1%, respectively, but had modest increases in straw yield of 1.6% and 2.5%.
       
Slow initial vegetative growth and reduced stem biomass result in a better leaf-to-stem ratio. Delayed lopping increases stem biomass, leading to more dry matter in stems than leaves (Kumar et al., 2021). Lower stump heights capture less solar radiation due to greater leaf area removal. Early lopping at 30 DAS allows time for regeneration, enhancing grain production, with results showing 4.89 t/ha for grain and 5.91 t/ha for both grain and fodder at a 7.5 cm cutting height (Atıs et al., 2018). Delaying fodder lopping increases vegetative growth, yielding higher fodder at 60 DAS compared to 45 and 30 DAS, benefiting from additional growth (Dhillon et al., 2020). Early lopping improves the harvest index at 30 DAS, while delaying it favors taller stumps for better outcomes.
       
The performance of dual-purpose barley showcased in Fig 2, which displays the crop yield index and combined sustainability index. Treatment T₄, which involves lopping at 30 DAS with a stump height of 3 inches, stands out for its superior agronomic and environmental benefits in terms of both grain and fodder production.


       
Data in Table 5 shows that T₄: Lopping at 30 DAS + 3 inches stump height has a better grain fodder ratio (1.6) and T₁: Control (No lopping) had the highest lodging severity at 2.17%, while T₂: Lopping at 30 DAS + 1-inch stump height (0.04%), T₃: Lopping at 30 DAS + 2 inches stump height (0.35%) and T₄: Lopping at 30 DAS + 3 inches stump height (1.60%) had lower rates. No lopping increased vulnerability to wind and rain, while delayed cutting improved stem strength and reduced lodging. Early lopping weakened root anchorage and increased lodging risk during heavy rain. Barley cell walls consist of 30-31% cellulose, 27% hemicellulose, 16-19% lignin and 3.9% ash, with variations contributing to lodging. Plants sustain gravity along with strong opposing wind speeds by accumulating cell walls around each cell (Mengistie et al., 2023). The seasons were normal, but rainfall and humidity were higher in the second season compared to the first, as shown in Table 1. Increased wind speed in March raises the risk of lodging due to stem bending and breakage, leading to reduced grain filling, photosynthesis, grain quality and yield. The long-term impact of varying lopping time and stump heights on dual-purpose barley productivity is illustrated in Fig 3.




       
Tillering negatively correlated with all phenological stages but had a weak positive correlation with grain yield (r =0.3548) in Fig 4. The booting stage was strongly correlated with later stages (50% spike initiation r =0.7342; 50% maturity r =0.7529) but negatively impacted grain yield (r =-0.6699). The stages of 50% spike initiation, 50% maturity and full maturity had high correlations (r =0.99) while also being negatively correlated with yield (r =-0.98). Maintaining optimal phenological through proper lopping and stump height is essential for grain productivity (Lal et al., 2017).

Based on the above findings, it may be concluded that the impact of lopping time and stump height on crop physiological maturity was significant; a delay in lopping time and higher stump height will lead to delayed maturity. Lopping time and stump height significantly impact crop maturity; delays in lopping and higher stumps result in later maturity. Although late lopping can reduce lodging in barley, it may harm fodder and grain yields. Early lopping at 30 DAS with a 3-inch stump height is promising for improving stability and sustainability in Punjab’s grain and fodder production, also lowering lodging compared to no lopping. These practices align with SDG 2 (Zero Hunger) and SDG 13 (Climate Action).
               
This study has limitations, including a focus on a single variety and the absence of an economic analysis to evaluate the cost-benefit ratio of management practices, which is essential for farmer adoption. Future research should address these issues by studying long-term effects on nutrient cycling, soil health and crop resilience across various environments and cropping patterns, along with economic feasibility for farmers.

The authors acknowledge the Department of Agronomy, Lovely Professional University, for the research facilities provided.
 
Disclaimers
 
The views and conclusions expressed in this article are solely those of the authors and do not necessarily represent the views of their affiliated institutions. The authors are responsible for the accuracy and completeness of the information provided, but do not accept any liability for any direct or indirect losses resulting from the use of this content.
 
Informed consent
 
All animal procedures for experiments were approved by the Committee of Experimental Animal care and handling techniques were approved by the University of Animal Care Committee.

The authors declare that there are no conflicts of interest regarding the publication of this article. No funding or sponsorship influenced the design of the study, data collection, analysis, decision to publish, or preparation of the manuscript.