Author : Nguyen Van Nguu

Summary : The efficiency of cultural energy inputs used in the traditional and the modern cultivating systems of lowland rice production, particularly those for nitrogen fertilization (VCEI-N) and weed control (VCEI-W), were pared during the 1975 dry and wet seasons.

Results demonstrated that, regardless of the cropping season, the traditional cultivating system (TCS) was more efficient than the modern cultivating system (MCS) in utilizing cultural energy but did not give a better rice yield. Greater energy consumption in sustain the MCS cultural activities arose from the employment power tiller for land preparation, use of chemicals for weed control, and application of insecticide according to strict schedule. Failure of the MCS to produce better rice yield was associated with its inability to induce better crop growth and to control weeds.

Regardless of the cultivating system, the efficiency of VCEI-W was found superior to that of VCEI-N. Quantitative analysis strongly indicated that VCEI-W could be considered as a prerequisite to VCEI-N in rice production.

The following conclusions may be drawn from the results of the investigation: (1) the efficiency of fixed cultural energy inputs in the MCS was lower that that of the TCS; (2) the efficiency of variable cultural energy for weed control (VCEI-W) in the TCS was about 2-3 times that in the MCS at all levels; (3) the efficiency of variable cultural energy input for nitrogen (VCEI-N) was similar in both systems; (4) ignoring the cultivating system, the efficiency of VCEI-W was always higher than that of VCEI-N.