1. Effect of Compaction of Soil Surface to Increase Herbicide Effect in Upland Rice Cultivation By THAN TOE DEPUTY SUPERVISOR MYANMAR AGRICULTURE SERVICE & MOHAMMED TAMIZ UDDIN KHAN AGRICULTURE EXTENSION OFFICER BANGLADISH

2. Introduction Weed infestation could be severe in upland rice cultivation and as a result yields may be drastically reduced. Weeds compete with rice plants for nutrition, sunshine and water. And causes serious loss of yield. Weeds also act as an alternate host to many pathogens and insects. Weeds are therefore a major constraint to upland rice cultivation. (Nemoto, 2000) ThereFore controlling weeds is important and this could be done in an economically good way.

3. MATERIALS AND METHODS This experiment was set up at the upland field of TBIC. Period of experiment was from 20 th April to 23 rd July. The variety tested was Yomenohatamochi

4. Four treatments were established in this experiment. (Tab.2) Tab.2 Treatments: T-1 No compaction + no herbicide -C-H T-2 Compaction + no herbicide +C-H T-3 No compaction + herbicide -C+H T-4 Compaction + herbicide +C+H

5. Field Layout Randomized block Design with 4 treatments and 2 replications. Two area of 15x14m each were demarcated as block 1 & Block 2 Respectively. Each block was made up of four plots measuring 12m 2, which had five lines each. Block 1was covered by net and block 2 was not covered.

6. Land Preparation Ploughing and harrowing was completed by the middle of April. After ploughing and harrowing dig a ditch which has 10 cm depth, alongside the cord by hoe.

7. Seeding preparation Seed selection was by a winnower machine. the seeds were disinfected with `Benlate – T (Benomial + Thiram) at the rate of 1kg of the chemical to 100kg of seed. Disinfection was done on the 20 th of April.

8. Fertilizer application N:P:K(50:!00:100) fertilizer was applied on the ditch uniformly as basal at the time of sowing by side dressing method. Cover the soil on the fertilizer and level. Press the soil by foot on the ditch. Fertilizer Application was done on the 20 th of April. Sulphate of Ammonia, Super phosphate and Potassium chloride were calculated separately,mixed and applied.

9. Method of sowing Direct hill sowing was employed & sow seeds along the trace uniformly. Seed rate was 50kg per hectare (5g/m 2 ); thus 36gramms per plot of 7.2m 2, equivalent of 1290 seeds. The distance between lines (ridge width) was 60 cm apart and sowing was done on the 20 th of April.

10. Compaction After sowing, cover the soil on the seeds for again. Soil surface of T-2 and T-4 plots were compacted by land roller( Weight-22 x 2 Kg, Wide-29.4cm, Diameter-35.4cm ) attached to hand tractor. Compaction was done on 20 th of April.

11. Herbicide Application Herbicide was applied on plots earmarked for herbicide application in the treatment plan. Herbicide application rate was 4l/ha. Herbicide spray solution was prepared by mixing 200 litres of the chemical to 100 litres of water per 500m 2 and it was on 23 rd of April.

12. Topdressing Application Top dressing was applied at 5.8-leaf stage on 29 th of May. LP40 fertilizer was used at the rate of 40 N kg per hectare by side dressing method..

13. Observation Plants establishment was investigated on the 17 th of May (28 Days) at leaf age 3~4. Dry matter weight of rice and weeds were taken and recorded on 4 th of June (45Days), 18 th of June (59Days), 2 nd July (73Days) and 16 th July (87Days).

14. Additionally rice plants suffered severely from drought damage that eventually made them to wither away. ( Total precipitation recorded between the period of June 22 nd ~ August 21 st was only 30mm. ) However we didn’t irrigate between crop season because we expected plants drought tolerance ability. Finally the rice plants produced only white panicles and therefore no further observations were done and so yield data was not taken.

15. Result Establishment Establishment percentages recorded ranges between 11.5 % ~ 33.6 %. (Tab.3,4) It was observed that seed emergence was three times higher on compacted plots. Compaction plots showed seed emergence of 30.2%,33.6% while plots without compaction recorded 11.5%, 12.8%.

16. Tab.3. Percentage of Germinated seeds in 170 grains seeded/m 2 Grains/m 2 % -C-HT121.712.8 +C-HT257.133.6 -C+HT319.611.5 +C+HT451.330.2

17. Tab. 4 Germination Percentage on differend concept of plots Avg Without Compaction 12.8(T1) 11.5 (T3) 12.2 With Compaction 33.6(T2) 30.2(T4) 31.9 Without Herbicide 12.8(T1) 33.6(T2) 23.2 With Herbicide 11.5(T3) 30.2(T4) 20.9

18. Weight Tables 3&4 shows that compaction is effective to seed establishment. It was also observed that combination of herbicide and compaction was not effective to weed control. This was indicated by the dry matter weight per meter square of both rice and weeds taken throughout the growing period. (Tab.5)

19. Tab. 5 Dry Matter Weight (g/m 2 ) of Rice plants and Weeds Days after Sowing 45 59 73 87 Rice-C-H1.33.74.93.2 +C-H4.713.716.113.5 -C+H0.57.338.3127.8 +C+H6.840.0103.3251.2 Weed-C-H46.3199.0479.4658.1 +C-H70.2233.9500.7782.5 -C+H0.17.015.8358.5 +C+H0.417.764.7204.9

20. Tab. 4 Germination Percentage on differend concept of plots Avg Without Compaction 12.8(T1) 11.5 (T3) 12.2 With Compaction 33.6(T2) 30.2(T4) 31.9 Without Herbicide 12.8(T1) 33.6(T2) 23.2 With Herbicide 11.5(T3) 30.2(T4) 20.9

21. Discussion In table 3,4 the number of seeds that germinated was highest in T-2 and T-4.T-1 and T-3 followed in that order. This table shows that where compaction was applied the effect was good but was better where it was without herbicide. T-1, which was without herbicide achieved higher germination than T-3.

22. Plots with compaction plus herbicide, it could be seen that rice growth in terms of dry matter weight/m 2 was higher than that of weeds. (Tab.5) It possible for the rice to grow faster. With compaction plus herbicide application was effective throughout the growing period but without compaction plus herbicide was only effective at the initial stages of growth. (0~73 DAS) At later stages (87 days and beyond), the weeds were able to compete favourably with the rice and over shadowed it. In other situation dry matter weight of weeds were higher than that of rice. Plots with compaction plus herbicide, it could be seen that rice growth in terms of dry matter weight/m 2 was higher than that of weeds. (Tab.5) It possible for the rice to grow faster. With compaction plus herbicide application was effective throughout the growing period but without compaction plus herbicide was only effective at the initial stages of growth. (0~73 DAS) At later stages (87 days and beyond), the weeds were able to compete favourably with the rice and over shadowed it. In other situation dry matter weight of weeds were higher than that of rice.

23. Conclusion In term of germination, compaction is very effective whiles herbicide application could reduce germination. Compaction is absolutely effective for germination in upland rice cultivation whereas herbicide applied before germination and establishment may reduce the emergence rate. Herbicide in upland rice cultivation should be applied after seedling emergence and establishment between 10-14 days after sowing.