Weed management in groundnut under organic farming

Introduction

Groundnut (Arachis hypogaea L.) is one of the important oilseed crops. India is world's second largest producer of groundnut and Gujarat is almost 40-50% contributions to the total groundnut production of groundnut in India. It is predominantly grown during kharif season. Groundnut production reaches 118.96 lakh tonnes from 17.73 lakh hectares in 2024-25 and in Gujarat in kharif season, it had been cultivated in 1.9 Mha area with 5.0 MT production with productivity of 2665 kg/ha [1] Heavy weed infestation appears to be the most serious menace in groundnut production causing extensive losses. Because of its short stature and initial slow growth in comparison to fast growing weeds, weeds smother this crop at every stage by sharing water, nutrients, space, solar radiation and other resources. Weeds problem is dominant in the rainy season as compared to summer due to constant moisture availability. It has been estimated that yield-loss may reach up to 80% due to weed infestation [2] It is also crucial to control weeds under organically cultivated groundnut due to non use of synthetic chemicals. So to find out the effective way to control weeds means of various crop mulch, stale seed bed and mechanical means this experiment is formulated.

Materials and Methods

The field experiment was conducted at Agricultural Research Station, S. D. Agricultural University, Aseda during kharif seasons of three consecutive years 2023 to 2025. The experimental soil was sandy loam with low water holding capacity, Low in available nitrogen (224 kg N/ha), high in available phosphorus (78 kg P 2 O 5 /ha) and high in available potash (294 kg K 2 O/ha). The variety used in this experiment was GG 37. Total eight treatment viz; T 1 :Weed free, T 2: Weedy check, T 3: Stale seed bed fb HW at 25 DAS T 4: Castor shell mulch @ 5t/ha fb HW at 25 DAS, T 5: Mustard straw mulch @ 5t/ha fb HW at 25 DAS, T 6: Fennel straw mulch @ 5t/ha fb HW at 25 DAS, T 7: Interculturing fb HW at 25 DAS, T 8: Interculturing at 25 DAS and two HW at 25 and 40 DAS are framed in randomized complete block design which replicated thrice. The weed free treatment was imposed by weeding carried out up to 45 days after sowing with weekly removal of all weeds. Rain fall and rainy days were recorded 1005.9 mm & 35 rainy days, 668.6 mm & 29 rainy days and 1179 mm & 45 rainy days respectively. The analysis of data was done using the Fisher's method of analysis of variance technique as described by Gomez and Gomez (1984) [3] . The differences of means were identified by Duncan's univariate test at p ≥ 0.05 [4] .

Results

Effect on weeds

Major weeds of the experimental field were Amaranthus spinosus L., Digera arvensis Forsk, Physalis minima, Tribulus terrestris L., Portulaca oleracea L., Trianthima portulacastrum, Cyperus rotundus L., Cenchrus biflorus L., Eleusine indica L., and Dactyloctenium aegypticum Effect on growth and yield parameters of groundnut Plant population: The results revealed that plant population per meter row length was found non-significant due to different weed control treatments at 20 DAS during individual years as well as in pooled analysis. However, at harvest, plant population per meter row length was found significantly higher under treatment T 1: weed free (8.64) which was at par with T 7 (Interculturing fb HW at 25 DAS) and T 8 (Interculturing at 25 DAS and two HW at 25 and 40 DAS). The reduction in plant population was due to heavy infestation of weeds in the plots which spreads collar rot and root rot disease to crop and plant going to die. The result indicated that plant height of 46.18 cm at 45 DAS and of 65.47 cm at harvest were found significantly higher under treatment T 1 (weedy check), However lowest plant height at 45 DAS of 30.58 cm and at harvest of 44.93 cm observed under treatment T 1 (weed free) which followed by treatment T 8 (Interculturing at 25 DAS and two HW at 25 and 40 DAS).The higher plant height of weedy plots due to vertical development of plant height without less branching only vertical stem like development observed and it indicated higher plant height. Among the different weed control treatments significantly higher number of branches per plant (7.40), no. of pods per plant (33.09), Pod yield per plant (32.49 g), 100 kernel weight (44.33 g) and shelling percentage (66.18%) were recorded under treatment T 1 (weed free) on pooled results and remained statistically at par with T 8 treatment, while lower values of branches per plant (3.73), no. of pods per plant (7.42), Pod yield per plant (8.69 g), 100 kernel weight (40.33 g) and shelling percentage (57.08%) were observed under un weeded check. This higher yield attributes of plant is might be due to very less crop completion of weeds for solar, nutrient and water which leads to healthy plant growth and development. Pod yield of groundnut significantly affected by different treatments of weed control during all three years and in pooled analysis. Significantly higher pod yield (4145, 2858, 3213 and 3405 kg/ha, respectively) recorded under treatment T 1 (weed free) and remained statistically at par with treatment T 8 (Interculturing at 25 DAS and two HW at 25 and 40 DAS) while the lower yield was observed under un weeded control of 230,157,226 and 204 kg/ha respectively. Among the different weed control treatments significantly higher haulm yield of 6895,4537,5552 and 5662 kg/ha were recorded under treatment T 1 (weed free) during 2023,2024,2025 and on pooled results respectively. The higher pod and haulm yield might be resulted due to higher no. of pods per plant pod yield per plant and shelling percentage [5][6][7][8][9][10][11][12][13][14] .

Effect on weed dynamics

The effect of different weed control treatments significantly affected on weed density per m 2 . Significantly higher weed density/m 2 15.17, 16.03 and 18.51 and weed dry weight of 19.96 g., 23.27 g. and 21.05 g. at 45, 60 DAS and at harvest were recorded under the treatment of un weeded control while lower weed density/m 2 and weed dry weight observed under treatment T 1 (weed free) which was consistently followed by treatment T 8 (Interculturing at 25 DAS and two HW at 25 and 40 DAS). The result revealed that among the different weed control treatments numerically lowest weed index (9.38, 8.54, 11.53 and 9.82%) were observed under treatment T 8 (Interculturing at 25 DAS and two HW at 25 and 40 DAS). The result indicated that weed control efficiency (%) recorded maximum under the treatment T 8 (Interculturing at 25 DAS and two HW at 25 and 40 DAS) as per compared to others treatment. During the kharif seasons there is ample availability of soil moisture which leads to weed plant to germinate and make completion to plant.

Economics

The gross return and net return were found maximum under treatment T 1 (weed free) (249592 ₹/ha and 173333 ₹/ha, respectively) which was followed by treatment T 8 (Interculturing at 25 DAS and two HW at 25 and 40 DAS)and T 7 (Interculturing fb HW at 25 DAS). However, maximun B: C ratio (3.11) was recorded under T 8 (Interculturing at 25 DAS and two HW at 25 and 40 DAS) which was followed by treatment T 7 (Interculturing fb HW at 25 DAS) and T 1 (weed free). Price of different inputs (₹/unit, kg) Biofertilizers@300, Ghanjeevamrut@8, Jeevamrut@2, Fennel straw @0.5, Castor shell@1, Mustard straw@ 0.5

Conclusion

It can be concluded that for effective weed control, securing higher yield and net return under the organically cultivated groundnut are advisable to carry out Interculturing at 25 DAS and two HW at 25 and 40 DAS.

References

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