Notes on SRI work carried out at
National Wheat Research Program (NWRP)
Rupandehi, Nepal 

MR Bhatta, J Tripathi, RB Neupane and Scott Justice
National Wheat Research Program, Rupandehi, Nepal

Experiment 1

National Wheat Research Program, Bhairahawa conducted an initial study in SRI using two rice varieties (Sabitri and Radha-4), three spacings (20, 30, 40 cm, and farmers’ practice), four weeding practices (manual weeding, chemical weeding, hand rotary weeder, weedy check), and two seedling ages (10-days-old and farmers’ practice, 20-day- old seedlings) during 2001 rainy season. A plot size of 500 square meters per treatment was used with two replications. Except for chemical fertilizers no organic manures were applied to the SRI plots. The station represents a lower wet land with heavy soil - silty loam structure, poor drainage, and low organic content.

Heavy weed infestation just after 12 days of transplanting created some problems and we could not remove weeds from all plots on time. There were some losses in grain yields due to weeds. This is clearly indicated in weedy check plots in the Table 1.

If we see the outputs of the study, these are not discouraging if we compare them with our station’s long-term average yields of rice, which are 4000 kg/ha. We have not included the results obtained from a rice variety Radha-4 here. Radha-4 variety could not tiller well compared to Sabitri, and its SRI yields were essentially lower than what we obtained with farmers’ practice. 

If we exclude weeding cost, there is a 28 percent yield advantage with 20x20 cm spacing and 33 percent with 30x30 cm spacing over farmers’ practice with manual weeding treatment. Table 1 explains the yield and yield components as affected by spacing, weed control methods, and transplanting techniques. There is less weed population in farmers’ practice. 40x40 spacing did not give sufficient yield advantage compared to 20x20 and 30x30 spacing. The reason simply is that there is no profuse tillering as expected in wider spacing. There is less oxygenation in the study plots after transplanting as there was continuous water stagnation due to rains. And land area was not fully covered by crop canopy in wider spacing. 

This study was carried out in five farmer’s fields in Rupandehi district during 2002 rice season. The land and soil types were quite different from our station’s soil. The plots were relatively well drained, and farmers occasionally use organic manures in their fields. Chemical fertilizers were applied at 100:50:30 kg N, P₂0₅ and K₂0 per hectare. Plot size varied from 300 to 500 square meters. Manual weeding as well as hand rotary weeder was used by farmers.

One of the farmers could not control weeds on time and there were poor yields, so those data are not included here. Only grain yield data from four farmer’s fields are shown in Table 2. On-farm SRI yields are better than those obtained in the station. A maximum number of 80 initial tillers and maximum number of effective tillers up to 60 were observed in some hills. Again 20x20 spacing out-yielded the rest of the treatments in Table 2. There is 49 percent higher grain yields compared to farmers’ practice.

Maximum grain yield of 9.6 ton per hectare was obtained with 20x20 spacing. The national average rice yields are 2.7 ton per hectare. There is great potential of SRI to increase rice production in the country. The only problem is the management of weeds on time. This rice season many more farmers have adopted SRI in Rupandehi district. This season’s on-station SRI study includes 10-day single seedlings as well as two seedlings per hill to see the number of tillers per hill and final yield.

Table 1.  Rice Yield from Spacing x Weed Control Methods under SRI Techniques at NWRP Station, 2001-2002 Rice Season

Spacing (cm)	Weeding method	Effective tillers/m2	Grains/ panicle	TGW (g)	Grain yield (kg/ha)	% increase/decrease over farmers’ practice
20x20	MW	244	168	25	6577	28.1%
20x20	CU	267	179	25	5955	16.1
20x20	WC	160	135	25	3880	- 16.7
30x30	MW	181	177	28	6842	33.24
30x30	CU	200	184	26	5420	5.7
30x30	WC	86	204	24	2773	-40.5
30x30	RW	219	149	26	4975	-3.1
40x40	MW	179	194	25	5238	1.9-
40x40	CU	170	199	25	5005	-2.4
40x40	WC	63	218	25	1404	-69.8
40x40	RW	170	188	26	4602	-10.3
FP	MW	277	151	26	5135	---
FP	CU	279	143	26	5128	---
FP	WC	247	135	25	4657	--

NB: MW= Manual weeding, CU=Chemical use, WC=Weedy check, RW=Rotary weeder, FP= Farmers’ practice, TGW=1000 grain weight

Note: NWRP station’s long-term average rice yields using normal transplanting are 4000 kg/ha, there is additional yield advantage of 64 and 71% respectively with 20x20 and 30x30 spacing with manual weeding using SRI technique.

Table 2. SRI Yields Obtained from On-farm Sites of National Wheat Research Program, Rupandehi District, Village Tikuligarh, 2002 Rice Season

Spacing (cm.)		Rice grain yield (Kg/ha)   Average of four farms
	Farm 1		Farm 2	Farm 3	Farm 4	Mean (kg/ha)	Yield increase over FP
20 x 20	8795		9110	9675	7705	8821	49%
30 x 30	8855		6319	6845	8418	7627	28.8%
40 x 40	3191		4744	7903	7148	5747	-2.9%
FP	6756		5260	5260	6400	5919	---