Field experiments were conducted at Agricultural Experimental Farm, Giridih, Bihar during the winter seasons of 1992–93 and 1993–94 to compare 1 : 1 and 2 : 1 row‐replacement series intercropping of mustard (Brassica campestris Var. Toria) with pea (Pisum sativum), with lentil (Lens culinaris) and with gram (Cicer areitinum L.). Intercropping systems were assessed on the basis of new indices termed ‘actual yield loss’ (AYL) and ‘intercropping advantage’ (IA), as well as several existing intercropping indices such as LER, RCC and aggressivity. Intercropping reduced the yield of component crops, compared with respective pure stands. Mustard + pea in 1 : 1 row‐replacement series gave the highest mustard yield equivalent value (1.00 t/ha). When the actual sown proportion was considered, mustard + lentil (1 : 1) resulted in maximum AYL (+0.438) and IA (+2.889) values. We conclude that AYL and IA are more appropriate, particularly when per plant yield is considered.

The effect of organic sources of nutrients and inorganic fertilizers, was studied on grain yield of lowland rice and some aspect of soil quality parameters in a field experiment at Agricultural Experimental Farm of Indian Statistical Institute, Giridih, situated at eastern plateau region of India, during consecutive years 1997-2002. Chemical fertilizers and various organic matters were applied to two rice cultivars, Sabita and Subarna. The highest mean grain yield was 3.53 t ha )1 and maximum agronomic efficiency was 60.3 % with the application of inorganic fertilizer followed by cow dung, where 3.47 t ha )1 grain yield was recorded with an agronomic efficiency of 57.5 %. Grain yield of rice recorded under organic sources of nutrients was not significantly different from that of inorganic fertilization though there was improvement in soil quality parameters under organic sources. Soil organic carbon (0.72 %), microbial biomass-C (279.23 lg g )1 dry soil), urease activity with buffer (33.54 lg urea hydrolyzed g )1 oven-dry soil) and nonbuffer (21.97 lg urea hydrolyzed g )1 of oven-dry soil) methods and acid phosphatase activity (2.24 lg paranitrophenol released g )1 of oven-dry soil) analysed following the harvest of the crop were highest under cow dung manure treatment; the most efficient organic source under the experiment. Mean grain yield of rice was significantly higher in Sabita cultivar over Subarna. The regression analyses among the variables have shown that there was linear relationship among soil parameters and grain yield of rice.