A Weed To Control Another Weed

LEAF MULCH OF MUGWDRT (ARTEMISIA DUBIA) TO CONTROL THE GROWTH OF BARNYARD GRASS ECHINOCLOA CRUS-GALLI IN RICE SEED BED 1 Parbakhar Poudel [email protected] Abstract Laboratory based pot experiment was carried to examine the effect of leaf mulch of Artemisia dubia wall ex. Besser (mugwort) on shoot elongation of Echinocloa crusgalli (L) and rice. Leaf mulch significantly retarded the growth of barnyardgrass. Inhibitory effect of leaf mulch to seedling growth of barnyardgrass can be used to control its problem on rice seedbed at the nursery level. This fact further supported the farmer conventional practice, mulching of mugwort leaf to control the barnyardgrass problem in their rice seedbed. Keywords: Leaf mulch, rice, barnyardgrass, traditional practices, weed control INTRODUCTION Rice is one of the most important food crops of the universe. The increasing population demand more food and the extent is increasing, in other hand the staple food crops, rice production is decreasing due to several agricultural problem. Weed infestation is the prime factor to reduce the rice yield. The losses caused by weed exceed the losses from any other categories of agricultural pest (Rao 1983). Among different weed, Echinocloa crusgalli (L) Beauvios (barnyardgrass, local name sama) is the world's principal weed of rice and is particularly serious problem in Asia (Holm et al. 1977). It a serious problem over 42 countries and is found in at least 27 more (Home et al. 1979). Heavy infestation reduces rice tillering by 50% and also reduces the number of panicles, height, number, size and weight of grain (Holm et al. 1977) Impure seed (mixed with weed seed) is one of the major sources of weed infestation (Moody, 1994). Barnyardgrass seedlings grow in nursery with rice seedlings and accidentally transplanted in field, and get chance to grow simultaneously in the same hill competing on common nutrients with rice. They have similar ecological preference to rice (Yabuno, 1966). Similar morphological appearance in young condition causes the rice mimicry (Barret, 1983) which make further complicated to remove by general person. A skilled person is needed even for handweeding practices. Control of barnyardgrass at nursery level is better than the removal from transplanted field. Conventionally people are using the leaf mulch of mugwort to check the barnyardgrass growth in rice seedbed. Present investigation tried to view the experimental proof beyond this farmer traditional belief. MATERIALS AND METHODS Fresh leaves of plant (Artemisia dubia) materials were collected on the day of experiment and mulched on earthen pots having similar types of sterilized soil. Test seeds (rice and weed) were sown alone as well as mixed form in both mulched and control (without mulch) condition. Weekly lengths of above ground part of seedlings were measured up to 4 weeks. The obtain data were statistically analyzed. RESULT AND DISCUSSION The promontory effect on rice seedlings elongation and inhibitory effect of barnyardgrass seedling elongation was obtained. The effect was varied base on age of seedling and cropping condition. The promotory effect was more prominent in mixed cropping sample as compared to the alone cropping sample in case of rice (pd significant at p = <0.001), however the

inhibitory effect on barnyard grass was more prominent or alone cropping sample. Such opposite trend of effect on rice and barnyard grass suggest the effectiveness of leaf mulch to check the barnyard grass seedling elongation. The paired difference in alone cropping sample, (significant p=<0.001) of rice and weed suggest such opposite effect of promotory to one and inhibitory to another. The high gap in paired difference between control-alone cropping and mulched-alone cropping is the further proof. In case of Barnyardgrass seedling growth there is not any alternation on effect of mulch on alone and mixed cropping sample. Table 1: Effect of mulch of leaves of Artemisia dubia on seedling growth of rice and barnyardgrass Age of seedlings

Length of Rice (cm) Control

Length of Barnyardgrass (cm) Mulched

Control

Mulched

Alone

Mixed

Alone

Mixed

Alone

Mixed

Alone

Mixed

1 Week

4.16±1.59

7.74±1.19

11.48±2.29

10.78±1.16

3.92±2.48

6.50±1.58

4.17±0.52

10.30±2.28

2 Weeks

14.22±1.21

12.42±2.97

18.00±3.08

15.34±3.97

5.72±1.47

17.66±2.33

6.88±1.84

15.99±4.65

3 Weeks

19.16±5.96

15.72±6.34

22.12±2.70

24.02±6.05

13.04±2.86

20.50±2.42

11.58±3.55

17.20±4.36

4 Weeks

19.58±1.40

19.84±2.28

22.20±3.11

25.14±1.27

17.16±4.21

21.50±2.50

13.48±1.23

19.34±1.71

Note: ± indicate the standard deviation from the mean value. Table 2: Paired sample test for seedling elongation of rice and barnyardgrass by the effect of leaf mulch on different condition. Paired sample RCA-RCM RCA-RMA RCM-RMM BCA-BMA BCM-BMM RCA-BCA RMA-BMA

Pd 0.35 -4.16 -4.89 0.93 0.83 4.32 9.42

T 0.36 -4.23 -4.82 1.21 0.86 3.65 13.83

d.f. 19 19 19 19 19 19 19

p 0.72 <0.001 <0.001 0.24 0.002 0.002 <0.001

** Correlation is significant at the 0.01 level (2 tailed) Note: pd = paired differences, d.f.= degree of freedom, p = probability In paired sample, First letter encodes plants name, R = Rice, B = Barnyardgrass Second letter encodes treatment, C = Control, M = Mulched Third letter encodes condition of cropping, M = Mixed, A = Alone

The problem brought by barnyardgrass due to the similar ecological preferences and similar morphology in young stage (Yabuno, 1966); and rice mimicry (Barret, 1983) in rice field can be solved by using leaf mulch. Significant promotory effect on rice and inhibitory effect on barnyardgrass supported this possibility. CONCLUSION Leaf mulch of Artemisia dubia retards the seedling elongation of barnyardgrass in nursery level but slightly promotory towards rice seedling growth. ACKNOWLEDGEMENT We are grateful to Executive Director of Research Center for Applied Science and Technology (RECAST), and Head, Central Department of Botany Tribhuvan University, Nepal for providing necessary Laboratory facilities. REFERENCES Barrett, S.C.H. 1983. Crop mimicry in weeds. Econ. Bot. 37: 255-282. Holm, L.G.; J.V. Pancho, J.P. Herberger and D.L. Pluknett 1977. The world's worst weeds. Universal Press of Hawaii, Honolulu. Holm, L.G.; J.V. Pancho, J.P. Herberger and D.L. Pluekneet 1979. A Geographical Atlas of the weeds. John Wiley and Sons, New York Moody, K. 1994, Weed Management in Rice, in R. Labradq, J.C. Caseley and C. Parker (eds.), Weed Management for Developing Countries. FAO Plant Production and Protection Paper 120:30 -308. Rao, V.S. 1983. Principles of Weed Science. Oxford and IBH Publication, New Delhi. 540 pp. Yabuno, T. 1966. Biosystematic study of the genus Echinocloa. Jon. Bot. 19: 277-323.