represented upland of Dhenkanal district, Orissa. The total geographical and cultivated areas ofthe district are 43.3 million ha and 2.56 million ha respectively, ...
Indian Journal o.fAgricultural Sciences 76 (1): 33-6, January 2006
Enhancing rainwater-use efficiency and stabilizing productivity of rainfed upland through rice (Oryza sativa)-based intercropping GOURANGA KARl, HN VERMA2 and R SINGH3
Water Technology Centrefor Eastern Region, Bhubaneswar, Orissa 751 023 Received: 3 July 2002
Key words: Crop productivity, Rainwater use efficiency, Rainfed upland, Intercropping, Rice, Net return
Rice (Oryza sativa L.) is the staple food of half of the contenlporary world. It occupies 44 mha ofcultivated land in India but produces hardly 42 million tonnes which is extremely low in comparison to the yields obtained in countries like Japan, Taiwan etc. Out of 44 million ha cultivated of rice, 7 ll1illion ha is under upland where rice cultivatio~nvolves high risk. The yield is very low and unstable due to erratic and uneven di~tribution of rainfall. In spite of getting low and unstable yield and less rainwater use-efficiency, traditional rice farmers grow rice in upland due to lack ofknowledge of improve cropping system. To enhance rainwater-use efficiency of rainfed upland, rice-based intercropping was practiced in represented upland of Dhenkanal district, Orissa. The total geographical and cultivated areas ofthe district are 43.3 million ha and 2.56 million ha respectively, out ofwhich 50% is under upland (1.37 million ha). The cropping intensity ofthe district is only 116%. During rainy season, 96% of the upland is dominated by paddy where' yield is very low and unstable. The rest 4% is under different crops like groundnut (Arachis hypogaea L.), maize (Zea mays L.), blackgram [Vigna mungo (L.) Hepper], greengram [Vigna radiata (L.) R Wilczek], sesamum [Vigna mungo (L.) Hepper], jute (Corchorus spp) etc. Thus, there is a need to increase cropping intensity, productivity and rainwater-use efficiency ofupland through adoption of better cropping system and crop Inanagement practices. In such a situation intercropping with rice by low water requiring or deep-rooted crops may prove as an effective lueans for ensuring stable yields and assured net econonlic return that will mitigate the effects of dry spell to some extent. IJ:?,tercropping of2 different crops gives higher yield advantage than the sole cropping through better use ofland, light, rainfall and nutrient. The complementarity, in combination may be due to better temporal and/or spatial use of these resources (Rao et aL 1982). When plants are grown in association (as intercropping or Inixedcropping) the interaction between cOlnponent species occurs which are essentially the response I Scientist, 2Head, Department of Agricultural Engineering, Himachal Pradesh Krishi Vishwavidyalaya, Palampur, 3Principal Scientist
of 1 species to the environment as modified by the presence of another species (MandaI et al. 1999). The efficiency of production in any intercrop systems can be improved by minimizing the inter species competition between the component crops for growth limiting factors through choosing appropriate crops depending upon their growth and resource utilization pattern. Increasing production oflegumes without sacrifice ofrice in rice area is possible through intercropping ofthese crops with rice (Sengupta et af. 1985 and Mahapatra 1987). Intercropping ofrice with legumes under rainfed upland condition improves rainwater-use efficiency and productivity due to better combined leafand root distribution systen1 (Patra et al. 1997). Many technologies on intercropping have been developed in the research farm but due to lack of proper dissemination the farmers have not got the benefits of the same. This necessitates concerted efforts to bridge the gap between research and extension. Hence the present investigation was taken up as on-farm trial to find suitable rice-based intercropping for yield stabilization and effective utilization ofrainwater in Iight textured upland. On-farm trials on rice-based intercropping were conducted in light textured upland during a deficit (rainy season 2000) and an excess rainfall year (rainy season 2001) at Arnapumapur village ofDhenkallal district, Orissa. This district belongs to mid-central tableland zone of Orissa where average annual rainfall is 1400 111m. The clinlate of the district is generally ho~ sub..humid and south-west nlonsoon normally breaks on 10 June. The soil was light textured and taxonomically belonging to the fine, loamy, nlixed iso-hypesthennic Typic Haplustalf. Texture ofthe soil varied from sandy to sandy loam.. Generally throughout the southwest tnonsoon season (JuneSeptember), the profile undergoes recharge from rainfall, soil profile becomes unsaturated during occurrence of dry spell in monsoon months. To study the feasibility of sowing period . utilizing monsoon rainwater, initial and conditional probabilities of receiving 10, 20 and 30 n1m weekly rainfall were analyzed using Markov chain model. To stabilize the productivity of rainfed upland rice ecosystem, 'Vandana' rice, 'T 9' blackgram (Phaseolus mungo
[Indian Journal ofAgricultural Sciences 76 (1)
KAR ET AL.
34
Table 1 Grain yield of component crops in upland rice based intercropping system Cropping systenl
Rice WI
Main crop (kg/ha) 2001 2000 1083 b b
W2
1215
W3
1395"
CD (p:= 0.05)
Rice-pigeonpea WI W2 W3 CD (p= 0.05) Rice + blackgran1 WI Vv'2 W3 CD (p= 0.05) Rice + groundnut WI W2
W3 CD (p:= 0.05)
270.3 833 b 1075;1 1 113a 260.2
812b 95011 1 l70 11 222.5 850h 1071 11 1 150a
258.6
Rice equivalent yield (kglha)
Intercrop (kglha)
2000
2001
2350 b 2575 b 2 750a 343.6
1 945 b 2250u 2365 a 374.6 2060 a 2210a
2380 a 462.6 2093 b 2364a
2495 a 364.9
2000
2001
2000
2001
I083 b I 215~' 1395" 270.3
2350 h
63 30
120
12
30
2575 a 2750il
5l0 b
4240 b
550a 668 a 122.0
540a
3350a
58 4680'1
608 a 119.3
4119 a
5
741.2
746.6
310a 360u 430"
360b 400a 470a
2052 b
136.2
98.1
738.2
3550 b 38Ioa 4260a 662.0
380b 325 a 455 a
475 h
2370b
a
a
69.1
L.), groundnut 'Smriti' [Arachis hypogaea (L.)] and 'UPAS 120'1 pigeonpea [Cajanas cajan (L.) Millps.] were sown with the ratio oftuain and inter-crop 4: I respectively. Markov chain probability model showed that the probability ofreceiving 10 rom rainfall exceeded dependable (70%) Iitnit in first week of June. I-Ience, an attenlpt was nlade to prepare the land and sow the seeds ofmain+ intercrops on 6 and 8 June in the year 2000 and 200 I respectively to ensure early and effective utilization of rainwater. The duration of rice (main crop), groundnut, blackgraln, pigeonpea (intercrops) was 90, 120, 105 and 140 days,respectively. Since in upland, weed infestation is the hindrance for direct seeded rice cultivation, treatInents on weed management practices were also imposed for optimunl growth and developnlent of crops. The weed management treatments consisted of (W), fanner's practice (manual weeding at 35 days after sowing; (W 2)' manual weeding at 20 and 45 days after sowing; (W3)' butachlor (1.5 kg ai/ha, pre-emergence) + interculture at 40 d~ys aftersowing.lntercropping experiments were laid out in sp~it plot design with crops in main plots and weedn1anagen1ent treatments in subplots. The size of the plot was 8 m >< 5 In. Herbicides were applied at pre-emergence stage after 2 days ofsQwing with the help ofknapsack sprayer. The major weeds infecting the plots were sawank (Echinochloa colonunz (L'.) Link), crowfoot grass (Eleusine indica Gaertn), goat weed (Ageratunconyzoides L.)~ nut grass (Cyperos rotundils (L.)Pers), dhubgrass (C~vnodoJt dactylon (L.) Pers.), pigeon gra.ss (Setaria glauca Beauv) etc. The intercepted photosynthetically active radiation
515 a 36.4
2390a 2890 a
2771 29701\ 175.2
44
343.6
545 b
498
Weed dry biomass at harvest (g/m2)
125
28
55
24
41
55 30
115
28
45
3939b
65
4356u 4555 a 552.3
45 30
135 65
lOl~
68
20
(IP AR) by different crops was also measured using light transmission rtleter (EMS 7), with the help offorrnula, IN=Ij-I rIt+Is' where IN' intercepted PAR; Ii' incoming PAR on the canopy; It' trans111itted PA'R through the canopy; Is, reflected PAR from the soil and It' reflected PAR from the canopy. Statistical analysis of tnains and subplots was made using Duncan Multiple Range 1'est. The weekly probability of rainfall. and wet-dry spell analysis revealed that initial probability ofgetting 10 rnm rainfall exceeded 75% (most dependable limit) in 7th, 14th, 16th, 17th, 19th weeks and continuously from 24th to 44th standard meteorological weeks. The probability ofreceiving 20 nlln or more rainfall exceeded most dependable linlit (75% probability) in the 24th and continues till 40th standard meteorological week. The 75% probability of receiving 30 111nl rainfhIl occurred in 24th, 27th, 32nd and 34th to 38th standard weeks. This indicated that, upland crops can be sown in 24rd standard weeks (11 to 17 June) in this region the south-west monsoon rainwater more effectively. The conditional probabilities (wet week followed by wet week) for receiving 10, 20 ~lld 30 mm or more rainfall were also computed. Result revealed that conditional probabUities (P, WIW) ofreceiving 10 ,nlm rainfall exceeded 75% probability level in 12th, 13th, 14th to 20th and 24th to 44th standard meteorological weeks. The conditional probability ofoccurring 20mm or more rainfall exceeded 75% probability after onset of full fledge southwest nl0nSOOTl, which occurred in 24th, 27th, 31stto33rd and 36th standard weeks. In general, from weekly probability analysis of rainfall, it can be inferred that (i) rainfall
January 2006]
RICE-BASED INTERCROPPING IN RAINFED UPLAND
35
Table 2 Rainwater use-efficiency and net return upland rice-based intercropping Cropping system
Rice WI W2 W3 CD (P = 0.05) Rice + pigeonpea' WI W2 W3 CD .(/l. =0.0-5-) Rice + blackgram WI W2 W3 CD (P = 0.05) Rice + groundnut WI W2 W3 CD (P =0.05)
Rice-equivalent yield (kglha) 2000 2001 1083 b 12I5a 1 395a 270.3
2350b 2575 a 2 750" 343.6
3285 b 3350a
4420 b 4680a 5 IOta 746.2
4119 a
741.2 2052 b
2390a 2890a 738.2 2370 b 2 771 2970a 175.2 8
3500 b 3810a 4260a
Total rain received (mm) 2000 2001
Rainwater use (kglhalnlnl) 2000 2001
631.1
1.71 h 1.92a
2.16 b 2.37
