Row-ratio optimization and organic nutrient management in pearlmillet + mungbean intercropping: yield, land-use efficiency and competitive interactions in the semi-arid zone of Rajasthan, India

Introduction

Pearlmillet [Pennisetum glaucum (L.) R. Br.] is the principal cereal of the arid and semi-arid regions of India, and Rajasthan accounts for the largest share of its national area. Globally the crop occupies about 30 million hectares, mainly in Africa and Asia (Raheem et al., 2021) [1] , and is grown for both human food and livestock fodder in dryland areas (Victor et al., 2023) [2] . In India it is cultivated on 7.36 million ha with a production of 11.20 million tonnes and a productivity of 1523 kg ha -1 (Anonymous, 2024-25) [3] . Its tolerance of drought, low soil fertility and high temperature allows cultivation in environments where maize or wheat fail (Basavaraj et al., 2010) [4] , and its nutritional value has led to its recognition as a climate-resilient "nutri-cereal" (Satyavathi et al., 2021) [5] . The scarcity of additional cropland and declining soil fertility threaten the long-term sustainability of agricultural production in these regions. Productivity must therefore be raised through more efficient use of existing land and nutrient resources. One such approach is intercropping, in which an additional population of a second crop is accommodated by modifying the planting geometry of the main crop (Renu et al., 2018) [6] . Because sole cereal cultivation is increasingly less remunerative, integrating pulses into cereal-based systems can help meet the diverse nutritional needs of a growing population. Legumes improve soil fertility through biological nitrogen fixation and are therefore ideal companions for cereals (Victor et al., 2023) [2] . Intercropping advantages arise from complementary resource use and facilitation between species that differ in stature, rooting pattern and duration (Zhang et al., 2003; Brooker et al., 2015) [8,7] , and the spatial arrangement of the component crops strongly influences productivity, economics, soil fertility and energetics in a region-and crop-specific manner (Kumar et al., 2006) [9] .

Mungbean [Vigna radiata (L.) R. Wilczek] is an important short-duration (70-90 days) warm-season legume that is drought tolerant, requires few inputs and fixes atmospheric nitrogen (Pataczek et al., 2018; Hou et al., 2019) [11,10] . In India, it occupies about 5.54 million ha with a production of 3.67 million t and a productivity of 663 kg ha -1 (Anonymous, 2024-25) [3] . Its short stature and early maturity make it a suitable companion for the taller, longer-duration pearlmillet, and pearlmillet-mungbean intercrops have given yield advantages in arid Rajasthan (Ram et al., 2014) [12] and in the Sahel (Diatta et al., 2020) [13] . However, the optimum row ratio remains location-specific, and relatively few studies have quantified the competitive interactions underlying such advantages. Intensive use of chemical fertilizers and pesticides to maximize productivity has contributed to soil degradation, erosion, and groundwater and atmospheric pollution, and to a decline in the nutritional quality of food. Organic sources such as farmyard manure (FYM) supply nutrients to both plants and soil micro-organisms and improve the physical, chemical and biological properties of soil (Diacono et al., 2010) [14] . Vermiwash, the liquid collected from vermicomposting units, contains soluble nutrients, growth-promoting substances and beneficial microbes and can be applied as a foliar spray (Das et [15,16,17] . Whether foliar vermiwash can partly substitute for bulky FYM, which is often in short supply, has rarely been tested in cereal-legume intercrops.

Moreover, legume-integrated intercrops are known to reduce the requirement for external nitrogen (Jensen et al., 2020) [18] , which makes them a natural platform for organic nutrient management. Against this background, the present investigation was conducted during kharif 2023 with the objectives of (i) identifying the most productive and land-use-efficient row ratio of pearlmillet + mungbean intercropping, (ii) characterizing the competitive interactions between the component crops using a set of complementary indices, and (iii) determining whether vermiwash sprays can reduce the FYM-N requirement without yield penalty.

Materials and Methods

Experimental site, climate and soil

The experiment was conducted on plot No. 9 of the Agronomy Farm, S.K.N. College of Agriculture, Jobner, Rajasthan, India (26°05′ N, 75°28′ E; 427 m above mean sea level), about 45 km west of Jaipur. The site lies in agro-climatic zone III-A (semi-arid eastern plain zone) of Rajasthan. Summer temperatures may reach 48 °C and winter temperatures may fall to -1.5 °C. Total rainfall during the crop season was 403.8 mm, received from the south-west monsoon between July and September. The soil was loamy sand, low in organic carbon and available nitrogen, medium in available phosphorus and potassium, and alkaline in reaction (Table 1). Values are for a composite sample drawn before sowing.

Experimental design and treatments

The experiment was laid out in a split-plot design with three replications. Five planting patterns were assigned to main plots: I In intercropping situation second and third row of pearlmillet were replaced by one row of mungbean in the pearlmillet + mungbean (1:1) and pearlmillet + mungbean (2:1) intercropping system, respectively.

While in pearlmillet + mungbean (2:2) intercropping system third and fourth rows of pearlmillet are replaced by two rows of mungbean (figure 1). Gross plot size was 4.0 m X 3.6 m, and the net plot size was 3.0 m X 2.4 m. Nitrogen (N), Phosphorus (P 2 O 5 ), and Potash (K 2 O) content in FYM were 0.51, 0.25, and 0.52%, respectively. Vermiwash diluted with water were applied at 30 DAS, and at 45 DAS using a battery-operated knapsack sprayer.

Grain, stover and biological yield and harvest index

At maturity the border rows were harvested first, after which the net plot of each crop was harvested separately, bundled, sun-dried and threshed. Grain/seed was cleaned and weighed, and stover/straw weight was recorded after threshing; both were converted to kg ha -1 . Biological yield was the sum of grain/seed and stover/straw yields, and harvest index (HI) was calculated using below formula (Singh et al., 1971) [19] . HI (%) = ( economic yield/biological yield ) × 100

System productivity and competition indices

Pearlmillet equivalent yield (PEY) PEY =

where Y PM and Y MB are the grain and seed yields (kg ha -1 ) and P PM and P MB the prices (₹ kg -1 ) of pearlmillet and mungbean, respectively. Land equivalent ratio (LER) (Mead et al., 1980) [20]

where Y ab and Y ba are the intercrop yields of pearlmillet and mungbean and Y aa and Y bb their sole-crop yields; L PM and L MB are the partial LERs. To characterize the competitive relationship between the components, the following indices were calculated, Aggressivity (McGilchrist, 1965) [21] ,

where Z ab and Z ba are the sown proportions of pearlmillet and mungbean in the intercrop (0.50 and 0.50 for 1:1 and 2:2; 0.667 and 0.333 for 2:1). A = 0 denotes equal competitive ability and a positive value denotes dominance. Competitive ratio (Willey et al., 1980) [22] ,

CRPM = ( LPM/𝑍 𝑎𝑏 ) / ( LMB/𝑍 𝑏𝑎 )

CRMB = 1/CRPM

Relative crowding coefficient (de Wit, 1960) [23] ,

𝑘 (Willey, 1979; Ghosh, 2004) [26,25] MAI = PEY × ( LER -1 ) /LER system productivity index (Amanullah et al., 2020) [27] SPI = ( 𝑌 𝑎𝑎 /𝑌 𝑏𝑏 ) × 𝑌 𝑏𝑎 + 𝑌 𝑎𝑏 MAI and SPI were expressed in pearlmillet-equivalent units (kg ha -1 ).

Statistical analysis

Data were subjected to analysis of variance appropriate to a split-plot design (Gomez et al., 1984) [28] . The standard error of the mean (SEm±) and critical difference (CD) at P = 0.05 were computed for each factor, and treatment means were separated by the CD test; homogeneous groups are indicated by superscript letters. For yield variables specific to one crop, the main-plot factor comprised four levels (the respective sole crop and the three intercrops), giving 6 and 24 error degrees of freedom for main and sub-plots; PEY and LER were analysed over all five planting patterns (8 and 30 error df). The maineffect F-ratios in Table 3 were obtained as

], which, for a balanced design equals the ratio of treatment to error mean squares; the coefficients of variation implied by these error terms reproduced the reported CVs to within 0.2 percentage points. Competition and economic indices were derived from treatment-mean yields averaged over organic sources. To visualize multivariate treatment performance, variables were standardized to zscores within each factor and displayed as heatmaps. Computations and figures were produced in Python (NumPy, SciPy, Matplotlib). Planting pattern × organic source interaction was non-significant for all the parameters.

Results

Grain and seed yield

Sole pearlmillet produced the highest grain yield (1968 kg ha -1 ), significantly more than all intercrops, which did not differ from one another (1283-1415 kg ha -1 ; Table 2, Fig. 2a). Grain yield under sole cropping exceeded that under the 1:1, 2:2 and 2:1 row ratios by 53.4, 47.7 and 39.0%, respectively; equivalently, intercropping reduced pearlmillet grain yield by 28.1-34.8%, with the smallest reduction in the 2:1 ratio, which allocated the largest share of rows to pearlmillet. Sole mungbean likewise produced the highest seed yield (983 kg ha -1 ). Among intercrops, the 2:2 ratio (613 kg ha -1 ) gave significantly higher mungbean seed yield than the 2:1 ratio (505 kg ha -1 ) and was at par with the 1:1 ratio (582 kg ha -1 ). Sole mungbean outyielded the 2:1, 1:1 and 2:2 intercrops by 94.6, 68.9 and 60.3%, respectively (Fig. 2b).

Organic nutrient sources significantly affected the yield of both crops (Table 2, Fig. 3). Application of 75% RDN through FYM + vermiwash produced the highest pearlmillet grain yield (1670 kg ha -1 ), which was significantly greater than the control (1241 kg ha -1 ) and 50% RDN through FYM + vermiwash (1476 kg ha -1 ), by 34.6 and 13.1%, and at par with 100% RDN through FYM (1612 kg ha -1 ). Mungbean responded similarly: 75% RDN through FYM + vermiwash (754 kg ha -1 ) exceeded the control (547 kg ha -1 ) and 50% RDN through FYM + vermiwash (656 kg ha -1 ) by 37.8 and 14.9%, and was at par with 100% RDN through FYM (726 kg ha -1

). Within a column and factor, means followed by a common superscript letter do not differ significantly according to the critical difference (CD) at P = 0.05; letters are not shown for non-significant effects (NS). RDN, recommended dose of nitrogen; FYM, farmyard manure; VW, two foliar sprays of vermiwash at 10%. Sub-plot LER is not applicable (-) because LER was computed per planting pattern.

Stover, straw and biological yield

Sole pearlmillet produced significantly higher straw yield (4348 kg ha -1 ) than the intercrops, which did not differ among themselves; the advantage of sole cropping over the 1:1, 2:2 and 2:1 ratios was 54.8, 48.2 and 43.2%, respectively. Sole mungbean gave the highest stover yield (2733 kg ha -1 ), exceeding the 2:1, 1:1 and 2:2 ratios by 105.3, 81.0 and 75.2%. Among intercrops, the 2:2 ratio produced significantly more mungbean stover than the 2:1 ratio and was at par with the 1:1 ratio. Biological yield followed the same trend: sole pearlmillet (6317 kg ha -1 ) and sole mungbean (3717 kg ha -1 ) were significantly superior to all intercrops; intercropped pearlmillet did not differ among row ratios, whereas mungbean biological yield under the 2:2 ratio (2173 kg ha -1 ) was at par with 1:1 (2093 kg ha -1 ) and significantly higher than 2:1 (1836 kg ha -1 ). Application of 75% RDN through FYM + vermiwash increased pearlmillet stover yield by 29.8 and 12.9% and mungbean straw yield (1985 kg ha -1 ) by 33.0 and 13.4% over the control (1492 kg ha -1 ) and 50% RDN through FYM + vermiwash (1751 kg ha -1 ), respectively, and was at par with 100% RDN through FYM (1906 kg ha -1 ).

The same treatment gave the highest biological yield of pearlmillet (5298 kg ha -1 ) and mungbean (2739 kg ha -1 ), which exceeded the control (4037 and 2039 kg ha -1 ) by 31.2 and 34.3% and 50% RDN through FYM + vermiwash (4691 and 2408 kg ha -1 ) by 12.9 and 13.7%, respectively, while remaining at par with 100% RDN through FYM (5101 and 2633 kg ha -1 ).

Harvest index and biomass partitioning

Harvest index was not significantly affected by planting pattern or organic source in either crop (Table 2, Table 3). Pearlmillet HI remained within a narrow range of 30.8-31.8% and mungbean HI within 26.5-28.2% across all treatments (Fig. 4). Thus, the yield responses to both factors were driven by proportional changes in total biomass rather than by altered partitioning between grain and straw. The slightly higher HI of intercropped mungbean (27.5-28.2%) compared with sole mungbean (26.5%), although not significant, is consistent with reduced vegetative crowding in the wider inter-row spaces of the intercrops.

Pearlmillet equivalent yield

Sole mungbean recorded the highest PEY (3747 kg ha -1 ), significantly higher than sole pearlmillet and the 1:1 and 2:1 ratios, but at par with the 2:2 ratio (3672 kg ha -1 ; Fig. 5b). Among intercrops, the 2:2 ratio was significantly superior to the 2:1 ratio (3340 kg ha -1 ) and at par with the 1:1 ratio (3503 kg ha -1 ). All intercrops produced 70-87% more PEY than sole pearlmillet (1968 kg ha -1 ). Among organic sources, 75% RDN through FYM + vermiwash produced the highest PEY (3635 kg ha -1 ), 36.6 and 14.2% higher than the control and 50% RDN through FYM + vermiwash, and at par with 100% RDN through FYM (3505 kg ha -1 ; Fig. 5c).

Land equivalent ratio

All intercrops recorded LER > 1, indicating a 23-30% land-use advantage over sole cropping (Table 4, Fig. 5a). The 2:2 ratio gave the highest LER (1.302), which was significantly greater than that of the 2:1 ratio (1.230) and sole crops (1.000) and at par with the 1:1 ratio (1.259). Partitioning of LER showed that pearlmillet contributed 0.65-0.72 and mungbean 0.51-0.62 of the total. In every arrangement both partial LERs exceeded the corresponding sown proportions (0.50 or 0.667 for pearlmillet; 0.50 or 0.333 for mungbean), meaning that each species produced more per unit of allocated area in the intercrop than in the sole stand. The largest mungbean partial LER (0.624) and hence the highest total LER was obtained in the 2:2 arrangement, whereas the 2:1 arrangement favoured pearlmillet (0.719) at the expense of mungbean (0.514).

Competition indices

Aggressivity values were close to zero in the 1:1 (A PM = +0.12) and 2:2 (+0.11) arrangements, indicating that pearlmillet was only marginally more competitive than mungbean and that the two species exploited resources almost equally (Table 3, Fig. 6a). In the 2:1 arrangement, however, A PM was strongly negative (-0.46) and CR MB rose to 1.43, showing that on a per-row basis mungbean outperformed pearlmillet when a single mungbean row was flanked by paired pearlmillet rows (Fig. 6b). The relative crowding coefficients of both species exceeded unity in all arrangements, and the system K ranged from 2.70 (2:1) to 3.48 (2:2), confirming a yield advantage (Fig. 6c). Partial AYL values were positive for both crops in all row ratios, and system AYL ranged from 0.49 (1:1) to 0.62 (2:1) (Fig. 6d). In the 2:1 ratio the AYL gain was concentrated in mungbean (0.54 vs. 0.08 for pearlmillet), whereas in the 1:1 and 2:2 ratios it was shared more evenly between the components.

Economic advantage of intercropping

The monetary advantage index was positive in all intercrops, ranging from 625 (2:1) to 852 kg PEY ha -1 (2:2), and the system productivity index followed the same order (2:2, 2560 > 1:1, 2448 > 2:1, 2426 kg ha -1 ; Table 4). When LER and PEY were considered jointly (Fig. 7), the 2:2 arrangement occupied the upper-right position, combining the highest land-use efficiency with a PEY statistically equivalent to that of sole mungbean, whereas the 2:1 arrangement was the least efficient intercrop on both axes.

Nitrogen substitution by vermiwash

The yield response to organic sources ranked O 3 > O 2 > O 4 > O 1 for every yield variable (Table 4, Fig. 8a). Relative to the control, O 3 increased yields by 29.8-37.8%, O 2 by 24.8-32.7% and O 4 by 14.9-19.9%. Mungbean seed yield was the most responsive variable (37.8% under O 3 ) and pearlmillet stover the least (29.8%). When expressed relative to 100% RDN through FYM (Fig. 8b), O 3 attained 103.6-104.1% of O 2 for all variables (differences not significant), whereas O 4 attained only 90.4-92.1% (differences significant). Thus, two foliar sprays of 10% vermiwash fully compensated for a 25% reduction in FYM-N, but not for a 50% reduction.

Overview of treatment effects

Planting pattern and organic nutrient source both had highly significant (P < 0.001) effects on grain/seed, stover/straw and biological yield of the two crops and on PEY, while planting pattern also significantly affected LER (Table 5). Neither factor influenced the harvest index of either crop (P ≥ 0.47). The F-ratios for mungbean straw (135.7) and biological yield (140.6) under planting pattern were the largest in the dataset, reflecting the strong dependence of mungbean biomass on its share of the land area, whereas organic sources exerted the greatest relative effect on mungbean seed yield (F = 43.4) and PEY (F = 36.3). The standardized profiles in Figure 9 summarize these patterns: sole crops scored highest for component yields but lowest for LER, the 2:2 row ratio combined above-average LER, PEY and mungbean HI, and O 3 occupied the most favourable position across all yield variables among organic sources. PP, planting pattern (main plot); OS, organic nutrient source (subplot); df, numerator and error degrees of freedom. **, P* < 0.001; ns, not significant. F-ratios were derived from the treatment means and pooled SEm of the split-plot analysis (see Section 2.6); reconstructed coefficients of variation reproduced the reported CVs to within 0.2 percentage points. For pearlmillet-and mungbean-specific variables the main-plot factor has four levels (the respective sole crop plus three intercrops); for PEY and LER all five planting patterns are included. 5).

Discussion

Component yields and yield attributes under intercropping

Intercropping with mungbean significantly increased the number of tillers plant -1 of pearlmillet, particularly in the 2:2 and 1:1 row ratios, whereas ear-head length was unaffected. This response can be attrib uted to the more favourable micro-environment created by the shortstatured legume: reduced intraspecific competition among pearlmillet plants in the wider inter-row spaces and the transfer of part of the biologically fixed nitrogen from the legume rhizosphere to the cereal, which promoted growth and yield-attribute formation (Zhang et al., 2003; Duchene et al., 2017) [8,29] . Similar increases in tillering of intercropped pearlmillet were reported by Kuri et al. (2012) [30] and Yadav et al. (2015) [31] , and Amanullah et al. (2020) [27] observed more grains head -1 in pearlmillet grown with mungbean than in sole stands. Despite these per-plant gains, intercropping reduced pearlmillet grain, stover and biological yields per hectare, because the reduced plant population per unit area in the replacement arrangements could not be fully offset by the improvement in individual plant performance. Among row ratios, the 2:1 arrangement recorded the highest pearlmillet yields, followed by the 2:2 and 1:1 arrangements, in proportion to the share of land allocated to the cereal. Comparable reductions in component yields under intercropping have been documented by Yadav et al. (2015) [31] , Victor et al. (2023) [2] and Amanullah et al. (2020) [27] . Pearlmillet did not affect the yield attributes of mungbean (pods plant -1 and seeds pod -1

), but sole mungbean produced significantly higher seed and straw yields than the intercrops, again primarily because of its larger plant population. These findings agree with Tripathi et al. (2005) [32] , who reported substantial reductions in chickpea yield when intercropped with mustard, and with Yadav et al. (2014) [33] for moth bean-pearlmillet intercropping. The stability of harvest index across planting patterns (Fig. 3) indicates that neither crop altered its assimilate partitioning under intercropping, so yield differences reflected differences in biomass production per unit area.

Land-use advantage and complementarity

Although each component yielded less than its sole crop, the combined system used land 23-30% more efficiently than sole cropping. That the partial LERs of both species exceeded their sown proportions in every arrangement indicates genuine complementarity rather than a transfer of yield from one species to the other (Mead et al., 1980) [20] . Pearlmillet, a tall C 4 cereal of longer duration, and mungbean, a short C 3 legume that matures earlier, differ in canopy height, rooting depth, nitrogen source and phenology. Such temporal and spatial niche differentiation is the principal driver of LER gains in annual intercrops (Yu et al., 2015; Li et al., 2020) [35,34] , and the partial relief of the cereal from nitrogen competition by the legume adds a facilitative component (Brooker et al., 2015; Bedoussac et al., 2015) [7,36] . The LER values obtained here (1.23-1.30) are comparable to those reported for pearlmillet-mungbean systems in arid Rajasthan (Ram et al., 2014) [12] and in Senegal, where LER consistently exceeded unity across mungbean densities (Diatta et al., 2020) [13] . The superiority of the 2:2 arrangement arose mainly from the higher mungbean partial LER (0.62), suggesting that paired mungbean rows experienced less shading from the adjacent cereal than single mungbean rows did in the 1:1 arrangement, while paired pearlmillet rows retained a partial LER (0.68) close to that of the 2:1 arrangement. Paired-row arrangements also facilitate intercultural operations and harvesting of the two crops separately, which favours their adoption by farmers.

Competitive interactions

The competition indices provide a mechanistic explanation for the differences among row ratios. Near-zero aggressivity and competitive ratios close to unity in the 1:1 and 2:2 arrangements indicate a balanced interaction in which neither species strongly suppressed the other, which is the condition generally associated with maximum intercrop advantage (Dhima et al., 2007) [37] . Pearlmillet was slightly dominant in these arrangements, in agreement with Amanullah et al. (2020) [27] , who found the cereal to be the more aggressive component in pearlmillet-mungbean intercrops, and with Ram et al. (2014) [12] , who reported that mungbean offered little competition to pearlmillet. In contrast, the 2:1 arrangement produced a strongly negative A PM and a mungbean CR of 1.43. In this arrangement, each mungbean row had pearlmillet on both sides and no mungbean neighbour, so its intraspecific competition was minimal and its per-row yield was high relative to the small area allocated to it, whereas paired pearlmillet rows competed with each other for water and nutrients on the low-fertility loamy sand. The index therefore reflects a per-row advantage rather than an absolute suppression of pearlmillet, and it did not translate into a higher system LER. System K values between 2.70 and 3.48 and positive AYL for both components (Banik et al., 2006) [24] confirm that all three arrangements were advantageous, with the 2:2 ratio showing the strongest mutual benefit. Because these indices were calculated from treatment means under an assumed replacement series, their absolute values should be interpreted with caution; nevertheless, their ranking was consistent with the independently analysed LER and PEY.

Economic implications

Owing to the higher market price of mungbean (a price ratio of about 3.8 relative to pearlmillet), sole mungbean recorded the highest PEY. However, the 2:2 intercrop was statistically at par with sole mungbean in PEY while additionally producing about 1.3 t ha -1 of pearlmillet grain and 2.9 t ha -1 of stover, a critical fodder resource for livestock-based farming in western Rajasthan (Satyavathi et al., 2021) [5] . Intercropping also spreads the risk of crop failure under erratic monsoon rainfall, a benefit not captured by single-season PEY. The positive MAI of all intercrops, highest for the 2:2 ratio, confirms that the biological advantage was converted into an economic one (Willey, 1979; Ghosh, 2004) [26,25] . A full economic analysis including cost of cultivation, net returns and benefit:cost ratio is needed to confirm these conclusions.

Organic nutrient management and substitution of FYM by vermiwash

Both crops responded strongly to organic nutrient sources on this soil, which was low in organic carbon (0.19%) and available nitrogen (132.3 kg ha -1 ). FYM improves soil structure, water-holding capacity and microbial activity and releases nutrients gradually over the season (Diacono et al., 2010) [14] , which accounts for the large yield increase over the unfertilized control. The key finding is that 75% RDN through FYM supplemented with two sprays of 10% vermiwash was statistically equivalent to, and numerically 3.6-4.1% higher than, 100% RDN through FYM for all yield variables. Vermiwash supplies readily absorbable nutrients, plant-growth-regulating substances such as auxins and cytokinins, enzymes and beneficial micro-organisms (Das et al., 2014; Oyege et al., 2023) [15,17] , and foliar vermiwash has been shown to increase plant nitrogen supply and alter shoot nutrient stoichiometry (Khan et al., 2014) [16] . Applied at critical growth stages, these inputs appear to have bridged the nutrient gap created by the reduction in FYM, while the basal FYM maintained soil nutrient supply. When FYM was halved (O 4 ), however, yields fell significantly below O 2 (90-92%), indicating that foliar vermiwash cannot substitute for the soil-applied organic N beyond a threshold on such N-deficient soils. The consistently higher yield attributes under O 3 (tillers, ear-head length, pods plant -1 and seeds pod -1 ) explain its yield advantage, and the unchanged harvest index indicates that the organic sources increased total source-sink capacity rather than partitioning. The slightly greater relative response of mungbean (37.8%) than of pearlmillet (34.6%) may reflect the stimulation of nodulation and early vigour of the legume by the growth-promoting substances and microbes in FYM and vermiwash. Because legume-integrated intercrops reduce the requirement for external nitrogen (Jensen et al., 2020) [18] , combining an efficient row arrangement with partial substitution of FYM by vermiwash offers a practical route to lowering organic-input requirements in semi-arid systems where FYM is scarce.

Conclusions

Intercropping pearlmillet with mungbean reduced the yield of each component relative to its sole crop but increased land-use efficiency by 23-30%. The 2:2 row ratio was the most efficient arrangement, recording the highest LER (1.302), system relative crowding coefficient (3.48) and monetary advantage index, and a PEY at par with sole mungbean, while providing pearlmillet grain and fodder. Balanced competitive interactions in the 1:1 and 2:2 arrangements underpinned this advantage, whereas the 2:1 arrangement favoured mungbean on a per-row basis without improving system productivity. Application of 75% RDN through FYM with two sprays of 10% vermiwash gave the highest yields of both crops and PEY, equivalent to 100% RDN through FYM, thereby saving one-quarter of the FYM requirement. Pearlmillet + mungbean in a 2:2 row ratio with 75% RDN through FYM + vermiwash is therefore recommended as a promising low-input practice for the semi-arid eastern plain zone of Rajasthan, pending multi-season validation.

Acknowledgement

AcknowledgementsGunjan-Research methodology, field investigation, data analysis, writing & editing of the original manuscript; Dinesh Kumar Jajoria-Research methodology, Conceptualization, Supervision, Resources, Data & manuscript evaluation; Dade Cholavardan-Data analysis, visualization, writing & editing of the original manuscript; Gelot Sumersinh-Conceptualization, Data analysis, editing of the manuscript; Vipin Kumar-Conceptualization, editing of the manuscript; Geeta Gawariya-Conceptualization, editing of the manuscript; Pooja Prajapat-Conceptualization, editing of the manuscript. Tejas S-Editing of the manuscript

References

1. Raheem D, Dayoub M, Birech R, Nakiyemba A. The contribution of cereal grains to food security and sustainability in Africa: potential application of UAV in Ghana, Nigeria, Uganda, and Namibia. Urban Science. 2021;5(1):8.
2. Victor VP, Sharmili K, Kumar DP, Minithra R, Balaganesh B. Performance of pearlmillet and pulses based intercropping system under rainfed condition. International Journal of Environment and Climate Change. 2023;13(8):747-752.
3. Anonymous. Agricultural Statistics. Indiastat / Ministry of Agriculture and Farmers Welfare, Government of India, New Delhi. 2024-25.
4. Basavaraj G, Rao PP, Bhagavatula S, Ahmed W. Availability and utilization of pearlmillet in India. SAT eJournal. 2010;8:1-6.
5. Satyavathi CT, Ambawat S, Khandelwal V, Srivastava RK. Pearl millet: a climate-resilient nutricereal for mitigating hidden hunger and provide nutritional security. Frontiers in Plant Science. 2021;12:659938.
6. Renu, Kumar A, Kumar P. Performance of advance pearlmillet hybrids and mungbean under sole cropping and intercropping systems under semi-arid environment. Journal of Pharmacognosy and Phytochemistry. 2018;7(2):1671-1675.
7. Brooker RW, Bennett AE, Cong WF, Daniell TJ, George TS, Hallett PD et al. Improving intercropping: a synthesis of research in agronomy, plant physiology and ecology. New Phytologist. 2015;206(1):107-117.
8. Zhang F, Li L. Using competitive and facilitative interactions in intercropping systems enhances crop productivity and nutrientuse efficiency. Plant and Soil. 2003;248:305-312.
9. Kumar P, Hooda RS, Singh H, Nanwal RK. Economics of pearlmillet-legume association as influenced by intercropping and strip cropping systems in sandy loam soils. Haryana Agricultural University Journal of Research. 2006;36:101-104.
10. Hou D, Yousaf L, Xue Y, Hu J, Wu J, Hu X et al. Mung bean (Vigna radiata L.): bioactive polyphenols, polysaccharides, peptides, and health benefits. Nutrients. 2019;11(6):1238.
11. Pataczek L, Zahir ZA, Ahmad M, Rani S, Nair R, Schafleitner R et al. Beans with benefits-the role of mungbean (Vigna radiata) in a changing environment. American Journal of Plant Sciences. 2018;9(7):1577-1600.
12. Ram K, Meena R. Evaluation of pearl millet and mungbean intercropping systems in arid region of Rajasthan (India). Bangladesh Journal of Botany. 2014;43(3):367-370.
13. Diatta AA, Thomason WE, Abaye O, Thompson TL, Battaglia ML, Vaughan LJ et al. Evaluating pearl millet and mungbean intercropping in the semi-arid regions of Senegal. Agronomy Journal. 2020;112(5):4451-4466.
14. Diacono M, Montemurro F. Long-term effects of organic amendments on soil fertility. A review. Agronomy for Sustainable Development. 2010;30(2):401-422.
15. Das SK, Avasthe RK, Gopi R. Vermiwash: use in organic agriculture for improved crop production. Popular Kheti. 2014;2(4):4546.
16. Khan MH, Meghvansi MK, Gupta R, Veer V, Singh L, Kalita MC. Foliar spray with vermiwash modifies the arbuscular mycorrhizal dependency and nutrient stoichiometry of bhut jolokia (Capsicum assamicum). PLoS ONE. 2014;9(3):e92318.
17. Oyege I, Balaji Bhaskar MS. Effects of vermicompost on soil and plant health and promoting sustainable agriculture. Soil Systems. 2023;7(4):101.
18. Jensen ES, Carlsson G, Hauggaard-Nielsen H. Intercropping of grain legumes and cereals improves the use of soil N resources and reduces the requirement for synthetic fertilizer N: a globalscale analysis. Agronomy for Sustainable Development. 2020;40:5.
19. Singh ID, Stoskopf NC. Harvest index in cereals. Agronomy Journal. 1971;63(2):224-226.
20. Mead R, Willey RW. The concept of a 'land equivalent ratio' and advantages in yields from intercropping. Experimental Agriculture. 1980;16(3):217-228.
21. McGilchrist CA. Analysis of competition experiments. Biometrics. 1965;21(4):975-985.
22. Willey RW, Rao MR. A competitive ratio for quantifying competition between intercrops. Experimental Agriculture. 1980;16(2):117-125.
23. Banik P, Midya A, Sarkar BK, Ghose SS. Wheat and chickpea intercropping systems in an additive series experiment: advantages and weed smothering. European Journal of Agronomy. 2006;24(4):325-332.
24. Ghosh PK. Growth, yield, competition and economics of groundnut/cereal fodder intercropping systems in the semi-arid tropics of India. Field Crops Research. 2004;88(2-3):227-237.
25. Willey RW. Intercropping-its importance and research needs. Part 1. Competition and yield advantages. Field Crop Abstracts. 1979;32:1-10.
26. Amanullah, Khalid S, Khalil F, Imranuddin. Influence of irrigation regimes on competition indexes of winter and summer intercropping system under semi-arid regions of Pakistan. Scientific Reports. 2020;10:8129.
27. Gomez KA, Gomez AA. Statistical Procedures for Agricultural Research. Edn 2, John Wiley and Sons, New York; 1984.
28. Duchene O, Vian JF, Celette F. Intercropping with legume for agroecological cropping systems: complementarity and facilitation processes and the importance of soil microorganisms. A review. Agriculture, Ecosystems & Environment. 2017;240:148161. International Journal of Research in Agronomy https://www.agronomyjournals.com 26180618, 2026, 9(10), Downloaded from https://www.doi.org/10.33545/2618060X.2026.v9.i10e.6806 by International Journal of Research in Agronomy on [09/10/2026]. See the Terms and Conditions (https://www.agronomyjournals.com) for rules of use; OA articles are governed by the applicable Creative Commons License
29. Kuri BR, Yadav RS, Kumawat A. Evaluation of pearlmillet (Pennisetum glaucum) and moth bean (Vigna aconitifolia) intercropping systems in hyper arid partially irrigated north western plains zone. Indian Journal of Agricultural Sciences. 2012;82(11):993-996.
30. Yadav BL, Patel BS, Ali S, Yadav SK. Intercropping of legumes and oilseeds in summer pearlmillet [Pennisetum glaucum (L.) R. Br. emend. Stuntz]. Legume Research. 2015;38(4):503-508.
31. Yadav RK, Shivran AC, Jakhar P, Jagetiya A, Puniya MM. Performance of rainfed moth bean and pearlmillet as influenced by intercropping systems and sulphur fertilization. Annals of Arid Zone. 2014;53(2):87-90.
32. Li C, Hoffland E, Kuyper TW, Yu Y, Zhang C, Li H et al. Syndromes of production in intercropping impact yield gains. Nature Plants. 2020;6:653-660.
33. Yu Y, Stomph TJ, Makowski D, van der Werf W. Temporal niche differentiation increases the land equivalent ratio of annual intercrops: a meta-analysis. Field Crops Research. 2015;184:133-144.
34. Bedoussac L, Journet EP, Hauggaard-Nielsen H, Naudin C, Corre-Hellou G, Jensen ES et al. Ecological principles underlying the increase of productivity achieved by cereal-grain legume intercrops in organic farming. A review. Agronomy for Sustainable Development. 2015;35(3):911-935.
35. Dhima KV, Lithourgidis AS, Vasilakoglou IB, Dordas CA. Competition indices of common vetch and cereal intercrops in two seeding ratio. Field Crops Research. 2007;100(2-3):249-256.
36. Jackson ML. Soil Chemical Analysis. New Delhi: Prentice Hall of India Pvt. Ltd.; 1973.
37. Olsen SR, Cole CV, Watanabe FS, Dean LA. Estimation of Available Phosphorus in Soils by Extraction with Sodium Bicarbonate. Washington DC: USDA Circular No. 939, United States Department of Agriculture; 1954.
38. Soil Survey Staff. Soil Taxonomy: A Basic System of Soil Classification for Making and Interpreting Soil Surveys. Agriculture Handbook No. 436, USDA Soil Conservation Service, Washington DC; 1975.
39. Subbiah BV, Asija GL. A rapid procedure for the estimation of available nitrogen in soils. Current Science. 1956;25:259-260.
40. Walkley A, Black IA. An examination of the Degtjareff method for determining soil organic matter, and a proposed modification of the chromic acid titration method. Soil Science. 1934;37(1):2938. How to cite this article: Gunjan, Jajoria DK, Cholavardan D, Sumersinh G, kumar V, Gawariya G, et al. Row-ratio optimization and organic nutrient management in pearlmillet + mungbean intercropping: yield, land-use efficiency and competitive interactions in the semi-arid zone of Rajasthan, India. International Journal of Research in Agronomy. 2026;9(10):336-347. doi: http s://www.doi.org/10.33545/2618060X.2026.v9.i10e.6806
41. Scholar, Department of Agronomy, B. A. College of Agriculture, Anand Agricultural University, Anand, Gujarat, India Gelot Sumersinh M.Sc. Scholar, Department of Agronomy, S.K.N. College of Agriculture, Sri Karan Narendra Agriculture University, Jobner, Rajasthan, India Vipin kumar M.Sc. Scholar, Department of Agronomy, ICAR-National Dairy Research Institute, Karnal, Haryana, India Geeta Gawariya M.Sc. Scholar, Department of Agronomy, S.K.N. College of Agriculture, Sri Karan Narendra Agriculture University, Jobner, Rajasthan, India Pooja Prajapat M.Sc. Scholar, Department of Agronomy, S.K.N. College of Agriculture, Sri Karan Narendra Agriculture University, Jobner, Rajasthan, India Tejas S M.Sc. Scholar, Department of Agricultural Statistics, SDAU, Dantiwada, Gujarat, India International Journal of Research in Agronomy https://www.agronomyjournals.com 26180618, 2026, 9(10), Downloaded from https://www.doi.org/10.33545/2618060X.2026.v9.i10e.6806 by International Journal of Research in Agronomy on [09/10/2026]. See the Terms and Conditions (https://www.agronomyjournals.com) for rules of use; OA articles are governed by the applicable Creative Commons License