Growth parameters
Growth parameters of maize were not significantly different between the alleys and across the various treatments. From the pooled data (Table 1),
Flemingia alley in T
3 (198.20 cm) exhibited the highest plant height, whereas T
5 (138.37 cm) from the
Senna alley had the shortest height. The highest number of leaves was recorded under the
Flemingia alley T
3 (12.60), whereas the lowest leaf count was observed in T
5 (9.25) from the
Senna alley. The height and number of leaves in both alleys had a pronounced effect on tilling treatments compared to other treatments. Similar results were obtained by
Kumari et al., (2024) on the growth and yield of sweet corn under conventional tillage compared with zero tillage.
Hakim et al., (2022) and
Sumitra et al., (2025) also found a positive effect of tillage on the growth and yield components of green gram and wheat respectively. Tilling might have created favorable environment for faster decomposition and release of nutrients from the applied plant biomass at initial stages of plant growth thereby resulting in taller height of maize in treatments T
3 of
Flemingia alley and T0 of
Senna alley. This finding is in line with the findings by
Ramadhan (2021), where deep tillage, conventional tillage and mulch treatments recorded taller plants.
da Costa Leite et al. (2019) also observed that the plant height, panicle diameter, panicle length of sorghum perform better in
Gliricidia sepium and
Leucaena leucocephala alleys than mono-cropping system of sorghum. Higher plant height and crop yield on maize and soybean was also reported by
Liu et al., (2023) under straw mulching and intercropping. The lower plant height in the treatments between
Flemingia and
Senna alleys in the present study could be due to zero tillage or minimum tillage which is also reported by
Anjum et al., (2014). Overall, the growth and germination of maize in all treatments of the
Flemingia alley were superior to those of
Senna alley. This could be due to higher shading effect of
Senna during the middle growth stages of maize. This effect was also reported by
Koyejo et al., (2023) where an increase in the space between the tree and maize resulted in better yield. The tallest plant height of maize was also obtained by
Taye and Kelil (2023) in alley cropping of
Sesbania sesban and
Cajanus cajan which was similar to the results obtained in the present study.
Yield parameters
The cob length and weight was found maximum in T
2 from the
Senna alley and minimum in
Flemingia alley at T4. The number of seed per cob and seed weight was also found highest in
Senna alley in T
2 and the lowest in T4 from
Flemingia alley (Table 2). The high yield parameters observed under
Senna alley (T
1 and T
2) and
Flemingia alley (T
0) may be attributed to tilling and application of pruned materials incorporated as mulch gives better yield in maize. Also crop residue used as mulch in T
2 had a residual advantage in sustaining the yield parameters of cob length and cob weight in the next cropping season.
Manu et al., (2018) in their study reported that application of thick mulch and hedgerow increases the yield of taro. The effect of crop residue retention on the growth and performance of maize was also reported by
Malgaya et al., (2023) and
Sahoo et al., (2024). Liu et al., (2023) recorded higher yield of maize and soybean under residue management in the form of mulching than the yield in mono-cropping system. Similarly,
Baier et al., (2023) and
Dey et al., (2023) also reported from their study that higher yield of maize and pulses due to addition of tree pruning and crop rotation.
Grain yield
The mean grain yield for the two cropping seasons (2021-2022) among treatments (p=0.01), between alleys (p=0.001) and the interaction between treatments and alleys was found to be significantly (p=0.02) different. From the pooled data in Table 2, the highest grain yield in
Senna alley was observed in T
1 (2306.22 kg/ha) compared to T6 (1044.35 kg/ha) which produced the lowest grain yield. Similarly, in
Flemingia alley, the highest grain yield was obtained from T3 (3713.33 kg/ha) and T
4 (1076.17 kg/ha) recorded the lowest grain yield. Similar level of grain yield was recorded by
Mupangwa et al., (2021) under maize-legume intercropping under conservation agriculture with grain yield of 3709 kg/ha. During the cropping years, fall armyworm (FAW) (
Spodoptera frugiperda JE Smith) infestations posed a significant challenge during the initial crop growth stages. These pest attacks threatened to reduce grain yields below the projected maximum potential yield of 4620 kg/ha under rainfed conditions in Aizawl district (
FAO, 2021). However, favourable rainfall patterns and effective agronomic practices helped mitigate the pest damage and ultimately supported an enhancement of the grain yield. A positive effect on yield was observed in the first year which might be due to the land not being used for intensive agriculture for a long period. The same observation was reported in a study on conservation agriculture by
Ngwira et al., (2012). The lower grain yield under no-till plots in the present study may be due to non-uniform seedling emergence from the compacted soil, resulting in a slower growth rate which was also reported by
Otieno et al., (2020). Yu et al., (2023) also recorded higher yield of maize in deep tilling when compared to no tillage experiment. Furthermore,
Gong et al., (2023) and
Menaie et al., (2024) mentioned that optimum tilling improves root growth, development and the yield of crops.
Neamatollahi et al., (2021), found a higher yield of melon when tillage was performed in combination with the incorporation of crop residue. Management practices like tilling; crop residue mulch and mulch from pruning materials have shown better growth and yield on maize
(Isaac et al., 2004; Hussain et al., 2020; Buttar et al., 2023). Akume et al., (2015) in their study also concluded that higher yield of maize was obtained in alley cropping due to soil improvement from the pruning materials. Between the alleys, maize grain yield was higher under
Flemingia alley. The lower yield of maize under
Senna alley could be due to the faster rate of decomposition of leaf litter, which allows the presence of nutrients for a shorter period while higher yield was obtained under
Flemingia alley which decomposed slower allowing nutrient retention for longer period in soil which is also in accordance with the findings by
Okogun et al., (2000) in
Albizzia lebbeck alley cropping.
Sharif et al., (2023) also reported that alley cropping system with
Sesbania grandiflora and
Leucaena leucocephala improved the yield performance of carrot due to increased soil fertility which is in consistent with the present findings.
Benefit cost analysis
In
Senna timoriensis alleys, T
1 showed the highest gross returns, net returns and benefit-cost (BC) ratio, while T
6 yielded negative net returns with lowest benefit-cost ratio. Similarly, in
Flemingia semialata alleys, T
3 showed maximum economic efficiency, whereas T
4 resulted in negative net returns with lowest benefit-cost ratio. Labor requirement was highest in the beginning of pruning and higher weeds density was observed in
Senna alley, as leaf litter decomposed faster. Similar findings were observed by
Ruhigwa et al., (1994), where more laborers were used in the initial pruning and the occurrence of weeds was higher in
Senna,
Gmelina and
Alchornea. In
Senna and
Flemingia alley, T
1 and T
3 showed the highest gross return, net return and BC ratio, respectively. The BC ratio in
Senna alley ranged from 0.63-1.42 and 0.56-1.89 for
Flemingia alley (Table 3). Similar findings was observed by
Choudhary et al., (2020), where the BC ratio of
S.
sesban +
C.
ciliaris + pearl millet was 1.98 when compared to the mono-cropping system.
Takawale et al., (2022) also found a BC ratio of 1.92 in maize and cowpea intercropping during the Kharif season. Additionally,
Rahman et al., (2017) opined that any agroforestry system had a higher NPV and BC ratio higher than other land use systems. Similarly,
Xu et al., (2019) also found that the Land Equivalent Ratio and BC ratio of alley cropping was higher than apple or crop monoculture.
