Comparative efficiency of barnyard grass and rice to nitrogen under transplanted condition

I. Aamer and A.C. Zahid

Abstract

Barnyard grass [(Echinochloa crus-galli (L.) Beauv] is a major competitor of rice (Oryza sativa L.) in all growth factors, among which, nitrogen fertilizer uptake is an important one. To find out the relative efficiency of barnyard grass and rice against nitrogen fertilizer, a field experiment using fine rice Basmati-385 was conducted under irrigated transplanted condition in the semi-arid region of Punjab, Pakistan. Treatments consisted of different densities of barnyard grass at 0, 4, 8, 12 and 16 plants/m2 while nitrogen fertilizer was at rates of 0, 60, 120 and 180 kg/ha applied at the time of transplanting and tillering stage. Both the factors under study significantly affected the nitrogen uptake by barnyard grass and rice. Similarly, recovery efficiency of barnyard grass and rice, agronomic and physiological efficiencies and partial factor productivity of rice calculated at harvest of the crop were also significantly influenced by different barnyard grass densities and nitrogen levels. Barnyard grass performed better as compared to rice in absorbing nitrogen especially when the growing conditions were similar for both i.e. 16 plants of each in maximum nitrogen supply treatment (180 kg N/ha), showing better nitrogen uptake efficiency. Recovery efficiency of barnyard grass was maximum at 120 kg N/ha with 16 barnyard grass/m2, whereas the highest recovery efficiency of rice was observed at 60 kg N/ha and when there was no competition with barnyard grass. The highest physiological, agronomic and recovery efficiencies and partial factor productivity of rice were recorded at 60 kg N/ha with zero barnyard grass density.

Full Text (26 KB)