Performance of Red gram [Cajanus cajan (L.) Millsp] +Groundnut (Arachis hypogaea L.) system in southern laterites

Abstract

The study entitled "Performance of red gram [Cajanus cajan (L.) Millsp] + groundnut (Arachis hypogaea L.) system in Southern Laterites" was conducted at the Department of Agronomy, College of Agriculture, Vellayani, from 2022 to 2024. The main objectives of the experiment were to evaluate the red gram based intercropping system with groundnut and to study the effect of crop geometry on growth, yield, and biological efficiency, and economics of the intercropping system. The field study comprised 7 treatments, laid out in randomized complete block design with three replications. The treatments were T1- red gram + groundnut in 1:4 ratio, T2- red gram + groundnut in 1:6 ratio, T3- red gram + groundnut in 1:8 ratio, T4- red gram + groundnut in 2:4 ratio, T5- red gram + groundnut in 4:5 ratio, T6- sole crop of red gram, and T7- sole crop of groundnut. The varieties used in the study were APK 1 (red gram) and TCGS 1694 (groundnut). The results indicated that crop geometry of red gram + groundnut intercropping significantly influenced the growth and yield of red gram. Among intercropping treatments, T2 resulted in the highest total leaf area of 2952.33±124 cm2 per plant and 2168.66±101cm2 per plant at 60 DAE (days after emergence) and 90 DAE respectively. The T2 was on par with T6 (sole crop) at 60 DAE and also comparable with T5 and T6 at 90 DAE. Among different crop geometries tried, T2 recorded the highest LAI at 60 DAE (3.24±0.15) and 90 DAE (2.71±0.12). Though the sole crop of red gram (T6) registered higher value of LAI at 60 DAE (3.50±0.17) and at 90 DAE (2.86±0.14), it was comparable with T2 at both these growth stages meanwhile T2 was also comparable with T5 at 90 DAE. Among different intercropping treatments, T5 (red gram + groundnut in 4:5 ratio) recorded significantly higher dry matter yield of red gram at harvest (4868 ±167 kg ha-1); meanwhile the dry matter production under sole cropping (T6) was significantly higher (6057±418 kg ha-1) than that under intercropping. Significantly higher root depth (28.89±1.81cm per plant) and root volume (13.16±0.27 cm3 per plant) of red gram were recorded in T3 which was on par with T2. Among different crop geometries, T5 (red gram + groundnut in 4:5 ratio) recorded significantly the highest red gram seed yield (1113.49±34 kg ha-1) and haulm yield (3722±77kg ha-1) compared to other intercropping treatments. However, the sole crop of red gram (T6) produced significantly higher seed yield (1305.44±84 kg ha-1) and haulm yield (4566±151 kg ha-1) than all other treatments. Higher chlorophyll content in red gram was observed in with T2 (1.42±0.13 mg g-1) which was comparable with T3. The T3 resulted in higher seed crude protein content (24.13±3.27 %) of red gram and was on par with T6. The T5 registered higher N uptake (87.89±3.40 kg ha-1), P uptake (16.31±0.89 kg ha-1) and K uptake (39.42±2.31kg ha-1) among intercropping ratios, whereas, significantly higher N uptake (108.32±6.30 kg ha-1), P uptake (19.53±1 kg ha-1) and K uptake (49.39±3.55 kg ha-1) were recorded in sole crop of red gram (T6) than the crop under intercropping situation. Among intercropping treatments, T3 produced significantly taller plants of groundnut at 60 DAE (47.60±3.34 cm) and at harvest (59.10±6.12 cm) which was comparable with T1, T2, and T4 at 60 DAE and also comparable with T2 at harvest stage. Sole crop of groundnut (T7) however produced significantly taller plants at 60 DAE (53.16±3.010 cm) and at harvest (62.82±2.27 cm), and it was comparable with T3 at harvest. Among intercropping treatments, T2 produced significantly higher total dry matter yield of groundnut (3490±88 kg ha-1) which was on par with T3 and T1. Sole crop of groundnut (T7) however recorded significantly higher total dry matter production (94210±392 kg ha-1) compared to intercropping situation. Under intercropping, T2 resulted in significantly higher kernel yield (1050.11±51.48 kg ha-1) and haulm yield (92579±143 kg ha-1) of groundnut which was comparable with T3. Sole cropping of groundnut (T7) however recorded significantly higher kernel yield (1186.36±70.64 kg ha-1) and haulm yield (3363±34 kg ha-1) than the yield under intercropping. Higher chlorophyll content of groundnut was recorded with T3 (0.79±0.06 mg g-1) which was comparable with T2. Higher crude protein content of groundnut kernel was registered with T2 (26.46±1.4 %) which was on par with T3. Among different intercropping geometries, T2 had higher N uptake (69.04±8.47 kg ha-1), P uptake (16.38±1.83 kg ha-1) and K uptake (41.64±2.01 kg ha-1), wherein T2 was comparable with T3 and T1 in case of N and P uptake while it was comparable with T3 only in case of K uptake. The sole crop of groundnut (T7) recorded significantly higher N uptake (92.96±6.08 kg ha-1), P uptake (22.95±0.60 kg ha 1 ) and K uptake (57.90±1.71 kg ha-1) than all other treatments. Analysis of competitive indices of intercropping system revealed that the land equivalent ratio (LER), relative crowding coefficient (RCC), aggressivity and red gram equivalent yield (RGEY) were the highest in T2. The positive aggressivity value (Arg) and higher relative crowding coefficient of red gram (Kr) indicated its competitive nature and dominance over groundnut. The monetary advantage index was the highest (54468) with T2 indicating the monetary advantage of this crop geometry over others. Sole crop of red gram (T6) had the lowest cost of cultivation of (₹ 65201 ha-1) while T2 resulted in the highest net returns (₹ 126414 ha-1) and benefit: cost ratio (2.74). The results of the study indicated that red gram + groundnut in a 1:6 ratio was the best intercropping geometry in terms of the land equivalent ratio, red gram equivalent yield, monetary advantage index, net income, and benefit: cost ratio. Hence intercropping red gram with groundnut in 1:6 row ratio could be recommended as a biologically efficient and financially viable option for intercropping in the Southern Laterites.