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SUMMARYIn search of a suitable resource conservation technology under pigeonpea (Cajanus cajan L.)–wheat (Triticum aestivum L.) system in the Indo-Gangetic Plains, the effects of conservation agriculture (CA) on crop productivity and water-use efficiency (WUE) were evaluated during a 3-year study. The treatments were: conventional tillage (CT), zero tillage (ZT) with planting on permanent narrow beds (PNB), PNB with residue (PNB + R), ZT with planting on permanent broad beds (PBB) and PBB + R. The PBB + R plots had higher pigeonpea grain yield than the CT plots in all 3 years. However, wheat grain yields under all plots were similar in all years except for PBB + R plots in the second year, which had higher wheat yield than CT plots. The contrast analysis showed that pigeonpea grain yield of CA plots was significantly higher than CT plots in the first year. However, both pigeonpea and wheat grain yields during the last 2 years under CA and CT plots were similar. The PBB + R plots had higher system WUE than the CT plots in the second and third years. Plots under CA had significantly higher WUE and significantly lower water use than CT plots in these years. The PBB + R plots had higher WUE than PNB + R and PNB plots. Also, the PBB plots had higher WUE than PNB in the second and third years, despite similar water use. The interactions of bed width and residue management for all parameters in the second and third years were not significant. Those positive impacts under PBB + R plots over CT plots were perceived to be due to no tillage and significantly higher amount of estimated residue retention. Thus, both PBB and PBB + R technologies would be very useful under a pigeonpea–wheat cropping system in this region.

A three-year study was conducted during 2006-2008 in India (Manipur) to study the response of soybean variety JS 335 to salicylic acid @ 50 ppm, Ethrel @ 200 ppm, Cycocel @ 500 ppm   and control (water spray) applied as foliar spray at different stages viz. flower-initiation (40 DAS),  pod-initiation (60 DAS) and flower-initiation + pod-initiation. The study revealed that application of Ethrel @ 200 ppm at both flower-initiation (40 DAS) + pod-initiation (60 DAS) gave higher vegetative growth, yield, net returns and B:C ratio as compare to salicylic acid  @ 50 ppm, Cycocel @ 500 ppm and control. However, maximum chlorophyll content and carotenoids were obtained from cycocel @ 500 ppm treated plants.

Aim : Methodology :Results : Interpretation :Increase in agricultural productivity with minimal energy utilization without any adverse impact on the environment is a pre-requisite of present agricultural practices through best agronomic management of crop production. The present investigation aimed to identify the most energy efficient cropping system and nutrient supply option which exert minimal impact on the environment.The experiment was carried out for two consecutive years at Indian Agricultural Research Institute, New Delhi for the evaluation of soybean-based cropping systems with five nutrient supply options with respect to energy parameters, as well as carbon emission equivalents. The different inputs used in raising the crops and output of crops were converted into energy and carbon equivalents using standard conversion factors and used for computation of different energy and carbon efficiency indices.The soybean-potato-mungbean system recorded significantly highest system productivity in terms of soybean seed-equivalent yield (7.68 t ha ), however soybean-chickpea-fodder sorghum system recorded highest net energy (333.9 ×10 MJ ha ), energy efficiency (9.56), energy productivity (179 gMJ ), energy profitability (8.6 MJ ha ), human energy profitability (105.2) and energy intensiveness (6.76). Soybean-chickpea-fodder sorghum system maintained higher carbon output and carbon efficiency which was 22.9 and 15.6% higher over soybean-wheat system, respectively. Among the nutrient supply options, application of 50% RDF + 50% RDN through FYM accounted for the highest energy output (286.1 MJ ha ), net energy (240.3 MJ ha ) and energy output efficiency (968 MJ ha day ) and also reduced the carbon flux to the atmosphere as compared to 100% RDF. The cropping system followed and sources of nutrient supply had considerable impact on utilization of energy, as well as carbon emission equivalents. Therefore, besides looking only upon productivity of a particular cropping system and management level, their relative energy efficiency and resultant impact on the environment should also be taken into consideration for ensuring judicious use of nonrenewable resources.