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Herbicide Research on Groundnut and Sorghumunder Farmer Conditions in the Indian Semi-aridTropicsE. Li. P. Davies a & S. V. R. Shetty a ba International Crops Research Institute for the Semi-arid Tropics , Hyderabad, Indiab Service Malherbologie, ISRA , Box 29, Richard Toll, SenegalPublished online: 06 Jul 2009.

To cite this article: E. Li. P. Davies & S. V. R. Shetty (1981) Herbicide Research on Groundnut and Sorghumunder Farmer Conditions in the Indian Semi-arid Tropics, Tropical Pest Management, 27:4, 472-479, DOI:10.1080/09670878109413829

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Tropical Pest Management 27 (4): 472-479 @Crown copyright, 1981

Herbicide Research on Groundnut and Sorghum under Farmer Conditions in the Indian Semi-arid Tropics

E. LI. P. Davies and S. V. R. Shetty"

International Crops Research Institute for the

Semi-arid Tropics, Hyderabad, India.

Abstract. Plots 17 x 5 m were laid out in farmers' fields in three villages. Treatments (replicated thrice) included atrazine (0.5 or 1.0 kg a.i./ha) on sorghum and nitrofen (0.75 and 1.5 kg a i l ha ) on groundnuts with or without hand-weeding or farmers normal weed control. Groundnuts were unfertilized, sorghum received 20 or 80 kg Nlha. Cooperating farmers were allocated plots for traditional weed control, other operations were carried out by research staff. Some plots were discounted because farmers withdrew cooperation or did not participate correctly or because of flooding. In groundnuts nitrofen alone was inferior to nitrofen + one hand-weeding. In sorghum there were no differences between high and low fertilizer regimes. Atrazine gave superior yields to farmers' weed control. All treatments were better than the unweeded control. Generally farmers fields had low weed populations due to good, timely control and low soil fertility. Herbicides are not economic a t present. Pro- blems associated with research in farmers fields included: selection of farmers who would participate correctly, variability between different farmers' weeding practices and between different fields due to previous crops and cultural practices; lack of control of farmers weeding operations and the distance of experimental plots from the research station. The authors suggest that small experiments with only 4-6 treat- ments are easier for participating farmers to comprehend, selecting suitable size and shape of plots i s important and that i f many farmers are involved the number of replicates can be reduced.

Introduction

Sorghum (Sorghum bicolor L. Moench) and groundnut (Arachis hypogaea L.) are two important crops of the semi-arid tropics (SAT) of India. Sorghum is mainly grown as a food crop for basic subsistence whereas groundnut is normally sold for confectionary purposes and vegetable oil processing. The yields of the two crops in India are relatively very low, groundnut pod yields 7 1 9 kg/ha (Kumar and Rai, 1978) sorghum grain 500 kg/ha (Krantz et al., 1978). Several factors may contribute t o low yields, for example, poor agronomic practices, insufficient use of fertilizers, lack of suitable varieties, pests, diseases and weeds.

crops (Bhan etal., 1971; Chakravarty, 1963; Shetty, 1976) under the ecological and socio-economic conditions of the Indian SAT. Experiments conducted on research stations, in India, suggest that the use of herbicides may benefit farmers by giving more profitable yields (Mani and Gautum, 1977). In spite of the yield increase due to the use of herbicides there appears to be a reluctance by the farmers to adopt this method of weed control.

Poor weed control has been suggested to be one of the major factors contributing to low yields of the two

The investigation reported here was conducted on farmers' fields and involved their participation. The advantages of performing weed control experiments on the farmers' fields are that the weed flora is more natural than on the research station and the crop husbandry is the farmer's, and not simulated as on research stations. For these reasons the results can be regarded as more relevant and giving a more accurate indication of the likely success of the new technology.

The intended objectives of the investigation were essentially to establish i f : 1. farmers practised good weed control; 2. herbicides lead t o superior weed control compared with traditional practices; 3. herbicides could be incorporated into the farmers traditional practice; 4. herbicides were more effective under high fertility in contrast to low fertility.

'Present address: Service Malherbologie, ISRA, Box 29, Richard Toll, Senegal.

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Herbicide research on groundnut and sorghum - Davies and Shetty 473

Materials and methods

The Indian SAT climate is characterised by three distinct seasons, a humid season (monsoon), a cool dry season (post-monsoon) and a hot dry season. Crops are usually grown during the monsoon and post-monsoon seasons. The average annual rainfall i s approximately 600-800 mm and about 85% of the precipitation comes in the monsoon (Krantz eta/., 1978). Although there appears to be sufficient rain, the highly erratic and unpredictable rainfall pattern makes crop production hazardous. The land i s cultivated as soon as the rains start, usually in the month of June, but farmers delay planting until adequate moisture i s available in the soil for raising a successful crop.

TABLE 1. CHARACTERISTICS OF EACH VILLAGE WHERE WEED CONTROL EXPERIMENTS WERE CONDUCTED

Village Dokur Kanzara Pocharam

State Andra Pradesh Maharashtra

District Mahbubnagar Akola

Average rainfall (mm) 636 81 8

Andra Pradesh

Mahbubnagar -

Soil type Alfisols Vertisols Vertisols (depth) (shallow-medium) (medium-deep) (medium-deep)

Average farm size (ha) 4.4 6.0 -

The original intention was to select six farmers who were accustomed to raising crops of sorghum and ground- nuts, from each of the three villages listed in Table 1, and who were willing to cooperate and participate in the experiments se t up in their fields. Each sorghum experiment was intended to have a l l the treatments listed in Table 2, whereas the groundnut experiments only had the first seven treatments.

TABLE 2. TREATMENTS IMPOSED IN BOTH SORGHUM AND GROUNDNUT CROPS GROWN IN FARMERS' FIELDS

Treatment number*

Fertility Treatment

1 Low fertility Weed free 2 Low fertility Weedy control 3 Low fertility 4 Low fertility 5 Low fertility Herbicide (full rate) only 6 Low fertility Farmers' traditional weed control practice only 7 8 9 High fertility Herbicide (full rate) only

Herbicide (X rate) plus 1 hand-weeding 3 weeks after sowing Herbicide (full rate) plus 1 hand-weeding 3 weeks after sowing

Low fertility High fertility

Farmers' traditional weed control practice plus herbicide (full rate) Herbicide (full rate) plus 1 hand-weeding 3 weeks after sowing

10 High fertility Farmers' traditional weed control practice only 11

'Treatments 1-7 for groundnut and treatments 1-1 1 for sorghum crop.

High fertility Farmers' traditional weed control practice plus herbicides (full rate)

The land for the experiments was prepared in June 1978 by the farmers in the traditional manner using a simple wooden plough and/or a blade harrow drawn by oxen. The experiments were flat-planted by the farmer with row spacing of approximately 30-35 cm. The sorghum cultivar sown was CSH-6 and the groundnut cultivars were JII for Kanzara village and seed derived from TMV2 for Dokur village. The experiments were marked out with plot sizes of 17 x 5 rn and replicated three times in a randomised block design for both crops.

On the day of planting or the day after, the appropriate plots were sprayed with herbicide with a knapsack sprayer (CRP-50), carried by a skilled operator, fitted with twin cone nozzles with an approximate volume rate of

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474 Tropical Pest Management Vol. 27 No. 4, December 1981

800 Ilha. Atrazine was applied a t 0.5 or 1 .O kg a.i./ha to the appropriate sorghum plots and nitrofen a t 0.75 or 1.5 kg a.i./ha to the required groundnut plots. The groundnut crop did not receive any fertilizer as was the farmer's current practice. In the low fertility plots of sorghum 20 kg/ha of N was applied and 80 kg/ha for high fertility plots. Both rates were split, half a t the time of planting and half three weeks later.

Farmers were allocated their plots (treatments 6, 7, 10 and 1 1 ) and were instructed to carry out their usual weed control practice on them, whereas the other plots were our responsibility. The farmers generally practised two to three inter-row cultivations, with a simple blade harrow, within two to eight weeks after planting. Each inter-row cultivation was followed by a hand-weeding, within the rows, a t one to a few days after the inter-row cultivation. The weed-free plots (treatment 1) were hand-weeded approximately every ten days whilst the weedy control and treatments 5 and 9 were not weeded throughout the crop season. Other treatments (3,4 and 8) were given a single hand-weeding three weeks after planting.

Assessments were made of crop damage, crop density, weed flora, weed dry matter and yields of grain or pods and fodder.

Results

Many experiments were not set up because farmers withdrew their cooperation either by not providing any land or allocating insufficient area for a complete experiment, hence some experiments had incomplete sets of treatments. Further experiments were lost, by severe flooding or the farmers failure to participate correctly. Some aspects of this will be elaborated in the discussion. Only the results of the completed experiments will be reported.

TABLE 3. EFFECT OF SEVERAL WEED CONTROL TREATMENTS IN GROUNDNUT CROP ON POD YIELD, FODDER YIELD AND WEED DRY MATTER ATSEVEN FARMERS' FIELDS

Treatments Vi I lage Dokur Kanzara

Farmer 1 2 3 4 5 6 7

1. 2. 3. 4. 5. 6. 7.

1. 2. 3. 4. 5. 6. 7.

1. 2. 3. 4. 5. 6. 7.

Weed free Weedy control Herbicides (X rate) + 1 hand-weed Herbicide (full rate) + 1 hand-weed Herbicide only Farmers' control only Farmers' control + herbicide

LSD 5% CV%

Weed free Weedy control Herbicide (X rate) + 1 hand-weed Herbicide (full rate) + 1 hand-weed Herbicide only Farmers' control only Farmers' control + herbicide

LSD 5% CV%

Weed free Weedy control Herbicide (% rate) + 1 hand-weed Herbicide (full rate) + 1 hand-weed Herbicide only Farmers' control only Farmers' control + herbicide

LSD 5% CV%

Pod yield (100 kglha)

12.2 8.6 4.6 7.5 9.0

11.3 8.5 5.0 10.2 12.7 9.2 5.1 8.8 8.8 8.3 4.4 9.9

13.7 7.3 7.7 8.0 15.0 8.6 6.5 9.2

1.8 NS 1.9 NS 9.6 11.9 18.6 29.0

3.7 7.8 -

Fodder yield (1 00 kglha)

19.6 10.5 7.1 12.0 7.4 9.0 - 14.0

15.7 10.8 6.5 16.7 19.4 10.0 8.3 15.4 16.7 9.6 7.4 14.7 25.0 7.7 10.5 13.9 26.9 10.3 8.8 15.3

6.9 NS NS NS 22.2 19.1 19.2 23.3

Weed dry matter a t harvest (100 kglha)

- - - - 29.1 7.3 - 21.9 6.9 3.8 5.9 4.5 7.0 4.3 6.8 7.3

19.2 7.1 28.4 17.4 9.9 3.7 11.1 12.1 3.0 2.1 6.0 12.4

4.0 NS 10.6 .9.4 21.7 68.4 60.0 46.9

2.7 1.5 1.3 3.0 2.1 2.0 1.6

NS -

18.0 10.0 7.2

13.8 10.0 8.2 6.6

NS -

1.7 1.5 1.2 0.5 1.2 0.9 1.3 0.8 1.1 0.6 1.3 0.6 1.1 0.8

NS 0.3 - -

9.5 15.0 3.3 5.7 5.2 10.3 4.7 9.0 4.3 10.0 8.3 13.0 6.0 17.0

NS 2.4 - -

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Herbicide research on groundnut and scrghum - Davies and Shetty 475

Groundnut experiments

A few of the groundnut experiments gave significant results (Table 3). A large variation was observed between the farmers for pod and fodder yields. The pod yields a t Kanzara village (farmers 5, 6 and 7) are probably unreliable as not a l l the pods were recovered a t the time of harvest from the dry and very hard black vertisols. This i s reflected in a poor harvest index (20%), the ratio between fodder and pod yields.

The use of herbicide on i t s own (treatment 5) was inferior to herbicide treatments supplemented with hand- weeding. The latter gave comparable yields to farmer 1 plots (treatments 6 and 7) but not with farmer 3 plots (treatments 6 and 7) (Table 3). The application of half the quantity of herbicide gave comparable yields to the full rate.

The weed-free control did not give the highest yields, probably due to damage caused by continuous weeding.

The weedy control seriously decreased yields, and the use of herbicides reduced the quantity of weeds com- peting with the crop. The farmer plots supplemented with herbicides had the least amount of weeds, with the exception of the weed-free treatments.

A l i s t of weeds found in the groundnut experiments are shown in Table 4.

TABLE 4. WEED SPECIES FOUND IN GROUNDNUT EXPERIMENTS

Abelmoschus esculentus (L.) Moench Acanthospermum hispidum Dc. Alysicarpus monilifer Dc. Andrographia echiata L. Borreria articularis (L.) F. Will. Brachiaria eruciformis (Sm. ) G r ise b. Catharanthus pusillus G. Don Celosia agren tea L. Commelina benghalensis L. Convolvulus arvensis L. Cynodon dacfylon (L.) Pers Cyperus rotundus L. Dactyloctenium aegyptium (L.) Richt Digera muricata (L.) Mart. Digitaria ciliaris (Retz.) Koch Eclipta alba (L.) Hassk

Eragrostis hirta L. Evolvulus alsinoides (L.) L. Hedyotis corymbosa L. Justicia simplex D. Don Leucas aspera (Willd.) Link Phyllanthus niruri L. Polycarpea corymbosa L. Rhynchosia minima (L.) Dc. Sesbania bispinosa (Jacq) W.F. Wright Sonchus arvensis L. Trichodesma indicum R. Br Tridax procumbens L. Vernonia cinerea (L.) Less Voluterella divaricata Benth. and Hook Xanthium strumarium L.

Sorghum experiments

The sorghum experiments at Kanzara village gave no significant difference between the treatments except in the field of farmer D (Table 5). However, there are indications that farmer plots (treatments 7 and 11) treated with atrazine had higher yields of grain and fodder compared to the farmer’s own practice (treatments 6 and 10). The herbicide treatments tended to be superior to farmer’s control. No difference was observed between high fertility and low fertility plots. The weed-free treatments gave similar yields to the farmer’s plots and the weedy control gave substantially lower yields.

At Pocharam village only the comparison between the four farmer‘s treatments (6, 7, 10 and 11) were possible. The use of atrazine significantly increased yields (Table 5) and also decreased the quantity of weeds for both farmers. Unlike the experiments a t Kanzara a difference was observed between the two fertilizer levels and there was no differential response to atrazine a t the two rates.

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476 Tropical Pest Management Vol. 27 No. 4, December 1981

TABLE 5. EFFECT OF SEVERAL WEED CONTROL TREATMENTS IN SORGHUM ON GRAIN AND FODDER YIELDS OF SIX DIFFERENT FARMERS AT KANZARA AND POCHARAM VILLAGE

~

Treatments

~~~ ~ ~~ ~ ~~ ~

Village Kanzara Pocharam

Farmer A 0 C D E F

1. LF' 2. LF 3. LF 4. LF 5. LF 6. LF 7. LF 8 H F 9. H F

10. H F 11. H F

1. LF 2. LF 3. LF 4. LF 5. LF 6. LF 7. LF 8. H F 9. H F 10. H F 11. H F

Weed free Weedy control Herbicide (X rate) + hand-weed Herbicide (full rate) + hand-weed Herbicide only Farmers' control only Farmers' control + herbicide Herbicide (full rate) + hand-weed Herbicide (full rate) only Farmers' control only Farmers' control + herbicide

LSD 5% CV%

Grain yields (100 kglhal

10.1 20.6 11.0 14.1 18.7 18.1 16.5 17.8 16.5 16.2 15.4 12.5 13.5 14.8 14.2 15.4 16.9 18.9 14.3 15.9 15.7 17.9

NS NS 30.0 18.4

32.4 20.1 - 8.0 - - 30.0 -

27.3 15.9 31.8 21.3 30.3 -

27.4 16.1 28.8 17.7

NS 8.6 12.0 28.7

- -

- -

- - - - - - - - - - 12.4 2.7 18.9 4.4 - - - - 29.0 10.8 36.2 14.7

9.9 3.5 - -

Weed free Weed control Herbicide (X rate) + hand-weed Herbicide (full rate) + hand-weed Herbicide only Farmers' control only Farmers' control + herbicide Herbicide (full rate) + hand-weed Herbicide (full rate) only Farmers' control only Farmers' control + herbicide

LSD 5% CV%

Fodder yields (100 kglha)

36.0 45.7 33.3 29.2 43.3 34.8 31.7 41.0 30.0 28.5 27.5 30.5 22.5 32.0 30.8 29.2 31.0 30.8 23.3 30.0 25.0 33.7

NS 13.4 30.1 23.6

57.2 63.3 - 23.3 - - 44.8 -

43.0 36.3 48.5 56.7 43.7 -

48.8 48.3 49.5 58.3

NS 13.6 19.1 15.6

- -

- -

- - - - - - - - - - 92.0 40.0 116.0 56.0 - - - -

152.0 85.0 119.0 110.0

54.0 NS - -

'LF = Low fertility, HF = High fertility.

Discussion

Experimental results

Several of the experiments, both on groundnut and sorghum resulted in no significant differences between the various treatments including those with a weedy control. The results can probably be attributed to the low numbers of weeds in the farmers' fields. This can be related to three factors. 1. The farmers have practised excellent weed control in the past. They plough and harrow their fields a t the

beginning of the rains and continue until sufficient moisture is available for planting. 2. The farmers practised timely weed control in the crops. This reduces the amount of weed seeds returned to the

soil and, in combination with the first factor, the weed seed population in the soil, over a period of time, i s reduced.

3. The low fertility of the soil would tend to support weaker and relatively less aggressive weeds.

The groundnut experiments which produced significant results had generally greater crop yields and more weeds compared to experiments resulting in no significant difference, this suggesting that soil fertility i s an important factor. In sorghum, however, the two fertilizer rates failed to show any differential effect upon the weeds though in some experiments it i s probably that the nitrogen had either been leached out or denitrified by the heavy rains.

The farmers' effective and timely weed control practice, which consisted of 2-3 inter-row cultivations each followed by a hand-weeding in the rows, was probably the reason why the herbicide system was inferior. Herbicides may become of importance in the intensification of agriculture. The adoption of double cropping may create a

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Herbicide research on groundnut and sorghum - Davies and Shetty 477

TABLE 6. RELATIVE COSTS OF USING HERBICIDES OF SELECTED TREATMENTS COMPARED WITH FARMERS' TRADITIONAL PRACTICE IN SORGHUM AND GROUNDNUT CROPS

Mean yield Additional difference costs

Value of yieldC from farm relative to

Rupee (Re)

Net profit or

Relha Treatment difference loss

practice farm practice (treatment 6 + 10) (treatment 6 + 10)

Sorghum 7. Low fertility

Farm practice + +300 herbicide

11. High fertility Farm practice + +350 herbicide

Grou ndnut 4. Herbicide +

hand-weeding

7. Farm practice t herbicide

-107

+123

21 0

24 5

257

295

138 +72

138 +lo7

190

190

-447

+lo5

'Cost of sorghum grain Re70/100 kg; Cost of groundnut pods Re240/100 kg. Cost of herbicide and application: atrazine Re128/ha; nitrofen Rel80/ha; hire of labour and sprayer RelO/ha.

labour shortage at the start of the second crop season when timely weed control i s required. On heavy black clay soils a prolonged continuation of rain at the start of the crop season may prevent the farmer entering his field hence the use of pre-emergence herbicides may be advantageous. The use of fertilizer may increase the detrimental effects of weeds and thus herbicides may become more suitable for controlling weeds in conjunction with manual labour.

The relative costs of crop production for farmer 1 in groundnut and farmer E in sorghum (Table 6) indicate that herbicides were economically unsatisfactory. This however, does not include the labour cost of weeding which included bullock-drawn hoes and hand-weeding. The weeding cost between the two treatments does not differ greatly due to the relative cheapness of traditional weeding practice. The small net profit in the sorghum crop, was insufficient to justify the adoption of herbicides under the present traditional farming system. As was emphasised by Binswanger and Shetty (1977), herbicides may play a role provided they show a large incremental increase in yield which will offset the cost of the herbicide and its application and leave a sizeable profit margin.

Problems associated with research on farms

When performing experiments on farmers' fields many problems are encountered in the selection of farmers and their fields and in the management of the experiments. The following are some of the difficulties which were encountered in this investigation, and ways are suggested of avoiding or minimising them.

1. The selection of farmers

The need to find suitable farmers who are willing, interested and will continue their involvement until the termination of the experiment i s very difficult. In dealing with an illiterate peasant farmer, who has had no formal education or training, it is difficult to explain to him, and for him to comprehend, about his involvement in the experiment. The experiments, therefore, should be simple where the farmers' plots are clearly marked and possibly placed together although the latter may be a limitation experimentally. In selecting a farmer an educated person who resides in the village and has a knowledge of the ability and reliability of cooperation by each farmer would help.

2. The variability of farmers fields

crops in different parts of the field and hence heterogenous fertility occurs. The manuring of the fields, which is The variability which exists in the farmers' fields can be a real problem as farmers have often grown different

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478 TropicalPest Management Vol. 27 No. 4, December 1981

infrequently done, i s seldom uniform and contributes to a non-uniform crop. In addition the quantity and the type of weed flora present will be variable throughout the field. To overcome these problems the fields should probably be assessed for their suitability in the previous cropping season. Long narrow plots may have an advantage over square plots in reducing the variability.

3. Farmer differences

of weedings they performed. The investigation revealed that farmers differed in their methods of planting and also the timing and number

4. Lack of control over the experiment

where the farmer's participation is involved. In our investigations a few farmers were found to have weeded the wrong plots, or weeded the weedy control because they realised that low yields would otherwise occur even though they had been told that they would be compensated for any yield loss. In one experiment animals were found to be grazing the weeds. One major loss of control i s that the investigator has to rely on the farmers recording the dates and the number of weedings they performed in their plots. It may be necessary to employ a person to look after the experiments without interfering with the farmer so as to overcome this problem.

As reported by Plucknett et a/. (1977) it i s difficult to place weed control experiments in fields, particularly

5. Distance of experiment from research station

of the work load. The greater the distance between sites, the lower the number of variables which can be easily recorded. I t may be wiser to have al l the experiments in one particular location and investigated in greater detail than to have experiments dispersed over several locations with less information but this will depend on the objectives.

In multi-location investigations there i s a requirement for more man power, more time and good coordination

6. Number of treatments A small experiment with a few treatments, i s probably easier for the farmer to comprehend and i s less con-

fusing compared to a large experiment. The smaller experiments with a limited number of treatments were easier to manage and the farmers cooperation was much better. An experiment with no more than four to six treatments i s probably the most appropriate size to perform in the farmers' fields.

7. Size and shape of plots The size and shape of the plots should be carefully considered. To reduce variation it has been already

suggested that long narrow plots are appropriate. The size of the plots will be dependent on the crop and the varia- tion that i s likely to be met.

8. Number of replicates

the number of replicates per farmer can be reduced. Experiments with only a few treatments ought to have several replicates but i f many farmers are involved then

Conclusion

The results achieved indicate that herbicides are a t present impractical for peasant farmers but this could easily change once the farmers adopt more intensive forms of agriculture, e.g. double cropping and greater use of fertilizers. There i s a need to establish certain types of methodology for doing research in farmers' fields and with their participation.

Acknowledgement

The authors wish to thank Mr C. Parker, Tropical Weeds Specialist, Weed Research Organization, UK for his valuable comments in preparing this manuscript.

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Herbicide research on groundnut and sorghum - Davies and Shetty 479

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BINSWANGER, H. P. and SHETTY, S. V. R. (1977). Economic aspects of weed control in Semi Arid Tropical areas of India.

CHAKRAVARTY, S. (1963). Weed control in India; a review. lndian Agriculture 7: 23-28. KRANTZ, B. A., KAMPEN, J. and VIRMANI, S. M. (1978). Soil and water conservation and utilization for increased food produc-

KUMAR, A. and RAI, B. (1978). Challenges in groundnut production. /nd;Jn Farming 28(3): 3-5. MANI, V. S. and GAUTUM K. C. (1977). Economics of chemical weed control in crops. Proceedings of lndian Society of Weed

PLUCKNETT, D. L., RICE, E. J., BURRILL, L. C. and FISHER, H. H. (1976). Approaches to weed control in cropping systems.

SHETTY, S. V. R. (1976). Possible approaches to weed management in sorghum. Pesticides Information 2(3): 72-80.

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