Indian J. Agric. Res., 50 (2) 2016 : *Corresponding author s

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1 Indian J. Agric. Res., 50 (2) 2016 : Print ISSN: / Online ISSN: X AGRICULTURAL RESEARCH COMMUNICATION CENTRE Study of physiological growth indices of mustard in chickpea (Cicer arietinum) + mustard (Brassica juncea) intercropping system under different weed management practices Ranjeet Kour* and B.C. Sharma Department of Agronomy, Sher-e-Kashmir University of Agriculture and Technology, Jammu , India. Received: Accepted: DOI: /ijare.v0iOF.8433 ABSTRACT A field experiment was carried out during rabi seasons of and at the Research Farm of Sher-e-Kashmir University of Agricultural Sciences and Technology at Chatha, Jammu to assess the physiological growth indices in chickpea+mustard intercropping system under different weed management practices. The significant superiority of replacement series treatment for leaf area index of mustard over additive series treatment was noticed. The sole crop of mustard was followed by replacement and additive series treatments in recording highest dry matter, crop growth rate and net assimilation rate values. Sole stand of mustard recorded numerically higher relative growth rate (RGR) followed by replacement and additive series treatments. Weed free treatment recorded numerically highest crop growth rate (CGR) and net assimilation rate (NAR) of mustard at all the stages of observation. As regards yield, sole stand recorded significantly higher values of grain and was followed by additive and replacement series which in turn were differed significantly from one another in chickpea+mustard intercropping system. Key words: Chickpea, Crop growth rate, Mustard-intercropping, Net assimilation rate, Relative growth rate,. INTRODUCTION Mustard is an important oilseed crop in India next to groundnut. In India mustard is also grown on sizeable area. Higher productivity of chickpea when intercropped with Indian mustard (Prasad et al.1997). This system not only stabilized chickpea is recorded production but also increased the cropping intensity. It has aroused interest because of potential advantages it offers in yield through improved utilization of resources by the crops and particularly when a legume is grown in association with another crop in an intercropping system, commonly a cereal or oilseed as the nitrogen nutrition of the associated crop may be improved by direct nitrogen transfer from the legume (Giller and Wilson, 1991). The selection of compatible crops is one of important consideration in deciding an economically viable and feasible intercropping system. Chickpea + mustard is a prominent intercropping system in Indian sub continent. The majority of the farmers adopt this system under resource constraint conditions.weed infestation is one of the major limiting factors in the productivity of the crops both under rainfed and irrigated situations. Weeds always pose a serious threat to the stability of crop yields. They adversely affect the growth of crop plants, reduce the quality of the produce and impair with soil fertility by competing with the crop plants for resources like soil moisture, nutrients, space and sunlight. However, yield loss by weeds in different crops varies from situation to situation. Initial slow growth of the crops and adequate soil moisture provide conducive conditions for profuse growth of weeds relatively in wide spaced crops like chickpea. This necessitates that a systematic study on weed dynamics in such crops is essential for strategic weed management planning. MATERIALS AND METHODS A field experiment was carried out during rabi seasons of and at Research Farm of Sher-e-Kashmir University of Agricultural Sciences and Technology at Chatha, Jammu. The soil of the experimental field was sandy loam in texture, slightly alkaline in reaction, medium in organic carbon, available nitrogen, phosphorus and potassium. The experiment comprising of twenty four treatment combinations comprising of four intercropping systems viz. chickpea (sole), mustard (sole), chickpea + mustard intercropping system as additive series (where chickpea crop was sown at the spacing of 30cm and one row of mustard was sandwitched between two rows of chickpea) and chickpea + mustard intercropping as replacement series (where chickpea was sown at the spacing of 30cm and every alternate row of chickpea was replaced with mustard) were taken as main plot treatments and six weed management practices viz; weedy check, weed free, 1kg *Corresponding author s ranjeet1661@yahoo.com.

2 140 INDIAN JOURNAL OF AGRICULTURAL RESEARCH a.i/ha (PPI), 1kg a.i/ha (Pre-Emergence.), 0.75 kg a.i/ha (Post-Emergence.) at 35 DAS and 50 gm a.i/ha (Post-Emergence.) at 35 days after sowing (DAS) as sub-plot treatments. The experiment was laid out in split-plot design with three replications. Furrows were opened manually with the help of liners at a specified row to row distance of 30 cm. The chickpea variety GNG-469 and mustard variety RSPR-01 was sown using a seed rate of 70 kg and 5 kg/ha for chickpea and mustard on 5 November, 2010 and 31 October, Whereas the seed rate of chickpea and mustard for replacement series was used 35 and 2.5 kg/ha respectively. The recommended nutrients of chickpea were applied uniformly through 100 kg/ha and the irrigation was given accordingly. Herbicides were sprayed by knapsack sprayer fitted with flat fan nozzle using a spray volume of 500 l/ha. Weedy check plots remained infested with native population of weeds till harvest. All the growth parameters viz. plant height, leaf area index, dry matter accumulation were recorded as per standard method at harvest. Leaf area index: The leaf area index of mustard was calculated by selecting five plants randomly in the border rows of mustard in each plot and were cut close to the ground. All the leaves were removed from these plants, counted and categorized into three groups of large, medium and small. A representative leaf from each category was chosen and its leaf area was measured with the help of leaf area meter (Model: LAMETRE-211, Systronic Make) and the leaf area/ plant was worked out by averaging the total leaf area of five plants obtained by multiplying the leaf area of specific category leaf with their respective leaf number. Further, the leaf area index was worked out by using the formula as given here under: Land area/plant = Row to Row distance x Plant to plant distance Leaf area/ plant Leaf area index = Land area/ plant Dry matter accumulation: All the above ground biomass of the five plants cut for calculating leaf area index was chopped, sundried and thereafter kept in the oven to dry at a temperature of 65 ± 5 0 C till a constant weight was achieved. The dry matter accumulation/plant was worked out by averaging the total dry matter recorded from five plants and expressed as dry weight in g/plant. Crop growth rate (CGR): The crop growth rate (g/plant/ day) for each specified stage was calculated using the standard formula was given by Radford (1967) below: W 1 CGR = T 2 - T1 Where, = Dry weight of crop plant at the time T 2 W 1 = Dry weight of crop plant at the time T 1 Relative growth rate (RGR) : The relative growth rate (g/g/day) for each observational stage was worked out by substituting the corresponding dry matter accumulation values of that very stage in the formula was given by Radford (1967) under : Log e log e W 1 RGR = T 2 T 1 Where, = Dry weight of crop plant at time T 2 W 1 = Dry weight of crop plant at time T 1 Net assimilation rate (NAR)-: NAR (g/g/dm 2 ) was measured by the formula as suggested by Enyi (1962) and given here under: (W2 W 1 ) (log e L 2 log e L 1 ) NAR = (T 2 - T l ) (L 2 L 1 ) Where, and W I are the dry matter of plants at the time of T 2 and T l respectively. L 2 and L I are the leaf area of the plant at the time of T 2 and T 1 respectively. Yield: The thrashed seed of mustard obtained from each net plot were weighed separately and finally converted into quintals per hectare by multiplying with conversion factor given below: Yield obtained from net plot (kg) Seed /Grain yield (q/ha)= x 10,000 Area of net plot x 100 And mustard yield was not converted into mustard equivalent yield. RESULTS AND DISCUSSION Growth parameters Leaf area index: Leaf area index (LAI) of mustard crop under different intercropping and weed management treatments at different crop growing periods increased with the advancement in age of the crop and was maximum at 60 and 90 DAS, thereafter a decline was noticed and significant differences among different treatments were observed from 60 DAS onwards up to 120 DAS (Table 1). This growth trend of LAI of mustard could also be attributed to the usual typical growth pattern of plants which signifies an increase in all the growth parameters of the plants including leaf area and thus the increase in LAI might have been the result of the cumulative effect of the increase in leaf number and leaf growth with the advancement in age of the mustard plants. Where-as, reduction in LAI of mustard at 120 DAS might have occurred due to drying and fall of leaves as a result of initiation of senescence phase. Further, significant changes in leaf area index at 60 DAS and onwards up to harvest might have happened due to induction of competitiveness among plants for various essentials with the increased growth of plants as well as their roots densities. As regards intercropping treatments, the replacement series was superior

3 Volume 50 Issue 2 (2016) 141 Table 1. Effect of chickpea+mustard intercropping and weed management treatments on the periodic leaf area index of mustard Treatments 30 DAS 60 DAS 90 DAS 120 DAS Sole mustard Chickpea + mustard (Additive series) Chickpea + mustard (Replacement series) SEm (±) LSD (p= 0.05) NS NS Weedy check Weed free kg a.i/ha (PPI) kg a.i/ha (Pre-Em ) kg a.i/ha (Post-Em) gm a.i /ha (Post-Em) SEm (±) LSD (p= 0.05) NS NS to additive series treatments. This significant superiority of replacement series treatment for leaf area index over additive series treatment might have resulted due to availability of wider space for these crops which have provided better physical environment and thus reduced the competition of plants for light, nutrients and other essentials which helped in better growth of the plants besides other factors. Singh (2005) also reported the similar findings for leaf area index of chickpea and mustard. As regards the effect of weed management practices on leaf area index of mustard, LAI increased upto 90 DAS and thereafter there was decline in LAI at 120 DAS except for leaf area index values recorded at harvest wherein a reduction was observed. As already explained for leaf area index under different intercropping treatments at 120 DAS, the reduction in LAI at this stage under different weed management treatments probably be due to initiation of senescence after 90 DAS. At different stages of crop growth from 60 DAS onwards, highest LAI was recorded under weed free check and lowest under weedy check plots. Among herbicidal treatments, pendimethalin gave maximum LAI, however the differences with other herbicidal treatments were not always significant. Differences in LAI values realized under different weed management practices were probably due to better growth of plants under these treatments. The interactional effects of intercropping with weed management treatments on LAI were non-sifnificant. Dry matter accumulation : There was a continuous increase in dry matter accumulation of these crops from 30 DAS onwards up to harvest as observed at different observational stages during crop growing period and it was found to be significantly different at 60 DAS and onwards and highest at harvest (Table 2). The expression of significant differences among different intercropping and weed management treatments at 60 DAS and onwards divulged that before it there might had been almost negligible competition of these crop plants for inputs due to their less growth which might have sufficed on the input supplies from existing space. Among the intercropping treatments, the sole crop of mustard accumulated highest dry matter at all the periods of observation and was found to be significantly superior to replacement and additive series treatments of intercropping which in turn also differed significantly from one another with replacement series being superior to additive seriesr. This can be ascribed to the fact that mustard plants under sole stands might have got optimum space which provided better physical environment and minimised the competition of plants for various essentials and ultimately led to establishment of better growth parameters which contributed for significantly higher dry matter in this crop under their sole stand as compared to replacement and additive series. The significant dry matter accumulation by mustard plants in replacement series over additive series can be ascribed to the optimum space available to mustard plants as compared to additive series. These findings corroborate the findings of Kumar et al. (2006) in respect of dry matter accumulation by chickpea and mustard in chickpea+mustard intercropping system. The crop of mustard recorded significantly higher dry matter accumulation under weed free treatment as compared to all other treatments and this might have happened due to almost negligible competition for this crop plants from weeds which led to better development of growth parameters and ultimately higher dry matter accumulation. Among herbicidal treatments, pendimethalin and fluchloralin were statistically at par and pendimethalin was significantly superior to quizalofop-ethyl and isoproturon which were also found to be at par with one another and fluchloralin as well. It can better be explained from their respective weed control efficacies which probably minimised the crop-weed competition and provided better physical environment that ultimately

4 142 INDIAN JOURNAL OF AGRICULTURAL RESEARCH Table 2. Effect of chickpea+mustard intercropping and weed management treatments on the periodic dry matter accumulation (g/plant) of mustard Treatments 30 DAS 60 DAS 90 DAS 120 DAS At harvest improved the plant growth parameters accordingly. The dry matter accumulation mustard plants under weedy check treatment was observed to be significantly lowest among all the herbicidal treatments which could be attributed to higher crop-weed competition that led to poor development of growth parameters. There was higher dry matter accumulation by mustard plants during second year in all the intercropping and weed management treatments which might have occurred due to less competition exerted for the availability of various inputs for the expression of growth parameters responsible for dry matter accumulation. The interactional effects of intercropping with weed management treatmen ts on dry matter accumulation by plants were non-significant Sole mustard Chickpea + mustard (Additive series) Chickpea + mustard (Replacement series) SEm (±) LSD (p= 0.05) NS NS Weedy check Weed free kg a.i/ha (PPI) kg a.i/ha (Pre-Em ) kg a.i/ha (Post-Em) gm a.i /ha (Post-Em) SEm (±) LSD (p= 0.05) NS NS Crop growth rate : There was a variable trend in values of crop growth rate of mustard at different periods of observation in all the treatments and significant changes with respect to intercropping treatments were observed at days stage only whereas for weed management practices at all the stages of 30-60, and days after sowing (Table 3). In all the intercropping treatments the periodic crop growth rate of this crop increased with the advancement in age of the crop and reached the peak at DAS stage followed by sharp decline at and DAS which was lowest among all the three stages. The increase in CGR may be due to accelerating the photosynthesis activity and the positive response of CGR to plant population. Similar Table 3 Effect of chickpea+mustard intercropping and weed management treatments on the crop growth rate (g/plant/day) of mustard Treatments DAS DAS DAS Sole mustard Chickpea + mustard (Additive series) Chickpea + mustard (Replacement series) SEm (±) LSD (p= 0.05) NS NS NS NS Weedy check Weed free kg a.i/ha (PPI) kg a.i/ha (Pre-Em ) kg a.i/ha (Post-Em) gm a.i /ha (Post-Em) SEm (±) LSD (p= 0.05)

5 results were also reported by Jeffrey et al. (2005) in maize. The decrease in CGR at the time of harvest is due to senescence of leaves and decrease of leaf area index. Similar results were reported by Egli and Guffy (1997) in soyabean. The crop of sole mustard was followed by replacement and additive series treatments in recording highest crop growth rate values at all the periods of observation except for days stage where these treatments even differed significantly from one another. As regards influence of weed management practices, weed free treatment recorded numerically highest crop growth rate (CGR) of this crops at all the stages of observation i.e , 60-90, and days and it was followed by pendimethalin, fluchloralin, quizalofopethyl, isoproturon and weedy check treatments in the descending order of CGR values of these crops. Weed free treatment at and days stages of mustard recorded significantly higher CGR values than all the other treatments except for pendimethalin at days stage which also recorded statistically similar CGR values with that of fluchloralin and this in turn was found statistically at par with quizalofop-ethyl and isoproturon. Further, weedy check treatment recorded significantly lower CGR values than all the treatments at these stages. The better CGR obtained in all the weed management treatments was by and large attributable to reduced crop weed competition due to less infestation of weeds and the proportionately less dry matter of these crops achieved under weedy check treatment over other treatments was probably due to enhanced crop weed competition for essentials created by higher relative weed density in weedy check treatment. Arya (2004) also observed that weed control techniques favourably influenced the growth parameters and regarded pendimethalin as better herbicide in controlling weeds in chickpea+mustard intercropping as compared to other herbicides where as Singh Volume 50 Issue 2 (2016) 143 and Singh (1997) reported that pre-plant incorporation of fluchloralin in soil improved the growth characters of both chickpea and mustard significantly. The interactional effects of intercropping with weed management treatments on dry matter accumulation by plants were non-significant. Relative growth rate : The results related to relative growth rate of mustard cleared that all the intercropping treatments failed to produce significant changes on relative growth rate of mustard at the all the stages of 30-60, 60-90, and days after sowing (Table 4). An increasing trend in RGR values of mustard was observed with advancement in crop age at all the stages of observation with respect to its just preceding stage up to DAS and thereafter a decrease was observed in all the subsequent stages. In the initial stages of the crop growth the ratio between alive and dead tissues is high and almost the entire cells of productive organs are activity engaged in vegetative matter production. RGR decreased during crop growth and reached to a minimum level. The reason of decreasing in RGR at the final stage can be related to increasing of the dead and woody tissues comparing to the alive and actives texture and decrease of leaf area index. Similar observations have been reported by Shukla et al. (2002) in Indian mustard and Jeffrey et al. (2005) in corn. Relative growth rate (RGR) of mustard was not seen to be significantly influenced by weed management practices also. The interactional effects of intercropping with weed management treatments on dry matter accumulation by plants were also non-significant. Net assimilation rate : The data presented in Table 5 exhibited that different intercropping treatments significantly influenced the net assimilation rate of mustard and days stages and weed management practices at 30-60, and days stage of mustard. An Table 4. Effect of chickpea+mustard intercropping and weed management treatments on the relative growth rate (g/g/day) of mustard Treatments DAS DAS DAS Sole mustard Chickpea + mustard (Additive series) Chickpea + mustard (Replacement series) SEm (±) LSD (p= 0.05) NS NS NS NS NS NS Weedy check Weed free kg a.i/ha (PPI) kg a.i/ha (Pre-Em ) kg a.i/ha (Post-Em) gm a.i /ha (Post-Em) SEm (±) LSD (p= 0.05) NS NS NS NS NS NS

6 144 INDIAN JOURNAL OF AGRICULTURAL RESEARCH increasing trend in NAR values of mustard was observed with advancement in crop age at all the stages of observation with respect to its just preceding stage up to days stage and thereafter a decrease was observed in all the subsequent stages. At and days stage of mustard significantly higher NAR was recorded under sole stand of this crop followed by replacement series and additive series which in turn also differed significantly from one another whereas at dats stage the numerical trend of all the intercropping treatments did remain the same with nonsignificant differences. NAR was high in the beginning of crop which might be due to high light penetration in the crop canopy and less shading and competition between plants for light and other resources. Thereafter it decreased considerably upto harvesting time. This might be related to competition between plants for light and other resources. Among the weed management practices, highest NAR was recorded with weed free treatment followed by pendimethalin, fluchloralin, quizalofop-ethyl and isoproturon in succession and weedy check treatment recorded lowest values of NAR at all the stages of mustard. At and days stages of mustard significantly higher NAR was recorded with weed free treatment followed by pendimethalin which in turn was found to be statistically at par with fluchloralin. Among the herbicidal treatments, lowest NAR was recorded with isoproturon followed by quizalofop-ethyl and fluchloralin however all the three herbicidal treatments were statistically at par during both the years. At days stage significantly higher NAR was recorded in weed free treatment followed by pendimethalin which in turn was found to be statistically similar with fluchloralin. Lowest NAR was recorded with isoproturon which was found to be statistically at par with quizalofop-ethyl, fluchloralin and pendimethalin during both the years. This could be attributed to better growth parameters under chickpea+mustard intercropping by pendimethalin Arya (2004). The interactional effects of intercropping with weed management treatments on dry matter accumulation by plants were non-significant. Yield : The data presented in Table 5 revealed that mustard in sole stand recorded significantly higher values of grain yield and was followed by additive and replacement series which in turn were differed significantly from one another in chickpea+mustard intercropping system. The optimum space as available for mustard plants under sole stand reduced the competition for moisture, nutrients and light among the mustard plants as compared to that as provided under other intercropping combinations might be responsible for the production of higher yield attributes of sole crop of mustard. These results are in agreement with the findings of Singh et al. (2008). The possible reason for higher yield of mustard in additive treatment rather than the replacement treatment might have been achieved due to the fact besides the single plant yield remaining inferior in additive treatment the overall yield per unit area improved due to cumulative effect of higher plant populations in additive treatment during first and second years of cropping. Among the weed management practices, higher grain yields of mustard were recorded where weed free environment was provided to the crop throughout its crop growing period. The grain yields of mustard as recorded with the application of pendimethalin followed by fluchloralin, however, found to be statistically at par to that of weed free treatment and fluchloralin. This also might be due to reduced crop-weed competition and enhancement in most of the crop-growth parameters under the favourable environmental situation probably provided by the application of pendimethalin in mustard thus resulting Table 5: Effect of chickpea+mustard intercropping and weed management treatments on the net assimilation rate (g/g/dm 2 ) and yield of mustard Treatments DAS DAS DAS Yield (q/ha) _ Sole mustard Chickpea + mustard (Additive series) Chickpea + mustard (Replacement series) SEm (±) LSD (p= 0.05) NS NS Weedy check Weed free kg a.i/ha (PPI) kg a.i/ha (Pre-Em ) kg a.i/ha (Post-Em) gm a.i /ha (Post-Em) SEm (±) LSD (p= 0.05)

7 in better plant growth. These results are in conformity with the findings of Sinha et al.(1999). Further, weeds were unable to compete with the crop plants and resulted in better expression of yield attributing characters and thus gave higher yield. Among the other herbicidal treatments, the lowest grain yields of mustard was recorded with isoproturon which in turn was observed to be statistically at par with quizalofop-ethyl and fluchloralin. This confirms the findings of Singh et al. (1986) and Yadav et al. (1983). Volume 50 Issue 2 (2016) 145 It is concluded that in the intercropping treatments, sole mustard recorded highest grain yield owing to relatively superior growth parameters like leaf area index, dry matter accumulation, crop growth rate and net assimilation rate compared to additive and replacement treatments. However, in additive treatment, significantly higher yield of component crops were recorded as compared to replacement treatment which can be ascribed to higher plant populations in additive treatment. REFERENCES Arya. R. L. (2004). Integrated weed management in chickpea (Cicer arietinum) + mustard (Brassica juncea) intercropping system under rainfed conditions. Indian Journal of Agronomy,. 49: Egli,D. B., Guffy, R. D. (1997). Factors associated with reduced yields of delayed planting of soybean.agronomy journal.159: Enyi, B. A. I. (1962). Ann. Bot., 26: Giller, K.E. and Wilson, K. J. (1991). Nitrogen Fixation and Tropical Cropping Systems. CAB International, Wallingford, pp Jeffrey.T.,Edwards, C.,Purcell, E., Earl, D. (2005). Light interception and yield potential of short season maize (Zee maysl.) hybrids in the midsouth. Agronomy Journal.97: Kumar, R., Ali, M., Arya, R. L. and Mishra, J.P.(2006). Enhancing productivity and profitability of Chickpea (Cicer arietinum) + Mustard (Brassica juncea) intercropping system. Indian Journal of Agronomy, 51: Prasad, S. N, Singh, R. and Chouhan, V. (1997). of gram (Cicer arietinum) with mustard (Brassica juncea) and linseed (Linum usiatissimum) on conserved moisture in South Eastern Rajasthan. Indian Journal of Agricultural Sciences, 67: Radford, P. J. (1967). Growth analysis formulae-their use and abuse. Crop Science, 3: Shukla, R. K., Arvind, K. B., Mahapatra, S., Basant, K. (2002). Integrated nutrient management practices in relation to morphological and physiological determination of seed yield Indian mustard(brassica junecia).journal Agricultural Science.72: Singh, B. D. and Singh, B. P. (1997). Effect of weed-control measures and phosphatic fertilization on growth and yield of chickpea (Cicer arietinum) +Indian mustard (Brassica juncea) intercropping under dryland conditions. Indian Journal of Agronomy, 42: Singh, A., Ahlawat, I. P. S. and Saraf, C. S. (1986). Studies, on weed control in chickpea. Indian Journal of Agronomy, 31: Singh, R., Singh, B. P., and Tripathi, K. P. (2008). Effect of inputs on moisture use efficiency and productivity in green gram under low rainfall situation. Journal of Agricultural Sciences, 78: Sinha, K. K., Mishra, S. S. and Singh, S. J. (1999). Yield and economics as influenced by winter maize based intercropping systems in North Bihar. Indian Journal of Agronomy, 44: Singh,T.(2005). Influence of moisture conservation practices and fertility levels on mustard and lentil intercropping systems under rainfed conditions. Ph.D. Thesis. Indian Agricultural Research Institute, New Delhi, India. Yadav, S. K., Singh, S. P. and Bhan,V. M. (1983).Weed control in chickpea. Tropical Pest Management 29: