Intercropping can be a suitable and viable agronomic practice for stepping up the production and yield stability from a unit of land during a cropping period. It increases the intensity, productivity and profitability under optimum utilization of soil, water, nutrients and sunlight in time and space. Scientific approach of intercropping increases the productivity per unit area per unit time under a situation where two crops are grown in a certain row proportions. It has gained interest because of potential advantages it offers in yield through improved utilization of resources by the crops and particularly when a legumes is grown in association with another crop in an intercropping system.

Initial slow growth of the crops and adequate soil moisture provide conducive conditions for profuse growth of weeds relatively in wide-spaced crops. This necessitates that a systematic study on weed dynamics in such crops is essential for strategic weed management planning. The traditional methods of weed controls very often back breaking, costly, time consuming and needs so much of human labour and resources that this work often gets neglected or is given up during the peak periods of labour shortage. Use of the herbicides is, thus, the only resort as it offers a good scope for timely and adequate control of weeds. Efficiency of weed control in crops can be further enhanced if herbicidal treatments are coupled with intercropping rather than their sole cropping, as intercropping also plays a very significant role in suppression of weeds through their smothering effect. The selection of compatible crops is one of the important considerations, in deciding economically viable and feasible intercropping system. Chickpea with mustard is a prominent intercropping system in Indian subcontinent. The majority of the farmers adopt this system under recourse constraint conditions. Since Chickpea is a poor competitor for weeds because of its slow growth and limited leaf area development at early stages of crops growth and establishment. Among the various pulse crops, chickpea is the most important winter pulse crop of Indi which is grown both under assured irrigation as well as on residual soil moisture of Kharif rains during winter (Rabi) season. Therefore, intercropping of mustard with chickpea coupled with effective weed control measures may help the farming community to realize the potential yield of chickpea to its maximum with an additional yield of mustard which is raised as an intercrop since, there is scarcity of information on the efficacy of herbicides for controlling weeds in chickpea with mustard intercropping, the present experiment was conducted to study the dynamics of intercrop situations through computation of various indices and to work out the relative economics of the treatments. 

Yield kg/ha
 
Chickpea and mustard was the highest in their sole stand with respect to yield. Among the intercropping systems chickpea + mustard gave the highest chickpea equivalent seed yield as compared to sole crop of chickpea. Among weed management practices, the highest seed yields of chickpea and mustard were obtained under weed free treatment. Application of pendimethali@ 1.0 kg/ha recorded significantly higher seed yield of chickpea and mustard as compared to weedy check. Fluchloralin @ 1 kg/ha and quizalofop-ethyl @ 50ml/ha were also effective in controlling weeds and registered higher seed yield of chickpea and mustard than rest of theherbicides used. Kour et al., (2015) reported that yield of chickpea and mustard was increased by 40.7 and 55% with the application of fluchloralin and 37.1 and 57.2 by pendimethalin in chickpea and mustard intercropping System. Arya (2004) in chickpea + mustard also reported similar results.
 
Land equivalent ratio (LER)
 
(Land equivalent ratio is relative land area under sole crops required to produce the same yield as were obtained under their intercropping and the land equivalent ratio of more than unity expresses that the biological efficiency of such system is higher). The LER of chickpea + mustard intercropping was found biologically more efficient and which is quite obvious from their LER values of 1.75 (Table 1).
 

Table 1: Effect of chickpea + mustard intercropping system on production land equivalent ratio, relative yield total land use efficiency, production efficiency and economics as influenced weed management practices (Pooled over two year).

As regards variations realized in gross return under different intercropping and weed management treatments, the possible reasons were differences in seed yield of chickpea and mustard crops attained in treatments 10 with their respective sale rates. The highest net return (Rs 25618) obtained under intercropping system  over sole chickpea and mustard treatment might be owing to the highest chickpea equivalent yields acquired in this treatment. Among the weed management practices, the highest and lowest net returns under different herbicidal treatments were because of dissimilarities in the cost as well as quantity of herbicides used herbicide-applied treatments and in weed free treatment. The highest net returns and B:C ratio (Rs 21618 and 1.81) were recorded with pre-emergence of pendimethalin @1 kg /ha followed by pre plant-incorporation of fluchloralin @ 1kg /ha (Rs 20316 and 1.75) Lowest net return and B:C Ratio were recorded by weedy check followed by weed free condition. It was mainly owing to extra labours engaged in manual removal of weeds, Tripathi et al., (2005) reported similar results in respectof net return and benefit: cost ratio in chickpea + mustard intercropping system. Arya (2004) reported similar findings with the application of pendimethalin for net returns and benefit: cost ratio in weed management treatments, Kour et al., (2015) confirms the similar findings with regard for economics of weed management treatment. Thus Chickpea + mustard intercropping system proved to be the most promising system which obtained more net returns and benefit: cost ratio. So for realizing higher net returns and benefit : cost ratio, chickpea + mustard may be recommended to farmers who are intrested in taking both the crops instead of their pure stands as it proved to be economically better and feasible in generating more monetary benefits by spending less amount for their better lively hood security as well as land use efficiency.