M. S. Baloch

Growth and yield of rice as affected by transplanting dates and seedlings per hill under high temperature of Dera Ismail Khan, Pakistan

Studies were initiated for two consecutive years to find out the effect of time of transplanting and seedlings hill−1 on the productivity of rice in Dera Ismail Khan district of North West Frontier Province (NWFP), Pakistan. The experiment was laid out in a randomized complete block design with split plot arrangements. Main plots consisted of four transplanting dates viz. 20th and 27th of June and 4th and 11th of July while sub-plots contained 1, 2, 3 or 4 seedlings hill−1. Among transplanting dates, June 20th planted crop gave highest paddy yield and net return with 1 seedling hill−1. It explains that the use of more seedlings hill−1 not only adds to cost but is also a mere wastage of natural resources. Based on research findings, we conclude that the use of 1 seedling hill−1 is most appropriate for timely sowing otherwise 4 seedlings hill−1 should be used to compensate for the yield gap in late transplanted rice.

Studies on Plant Population and Stand Establishment Techniques for Increasing Productivity of Rice in Dera Ismail Khan, Pakistan

Rice production in Pakistan is constraint by many factors pertaining to prevalent planting techniques. A research on the feasibility of new planting techniques (direct seeding on flat, transplanting on flat, direct seeding on ridges, transplanting on ridges and parachute planting) in transplanted and direct wet-seeded rice was undertaken at Dera Ismail Khan region of Pakistans North West Frontier Province during 2002 and 2003. Among the planting techniques, the best performance for the yield formation and economic evaluation was noted for transplanting on flat during both years. Chinese parachute planting technology also showed very promising results in most of the parameters. Direct seeding on ridges could not excel transplanting on flat and parachute planting during both cropping seasons. The findings concluded the feasibility of parachute planting technology along with traditional rice transplanting on flat over all other planting techniques being practiced in the area.

DYNAMIC OPTIMIZATION OF WATERING FOR QUALITATIVE IMPROVEMENT OF SATSUMA MANDARIN USING INTELLIGENT CONTROL TECHNIQUES

Abstract To improve the quality of Satsuma mandarin during the developing and maturing stages, an optimal watering operation was investigated through identification and optimization using intelligent control techniques. Dynamic changes in the sugar content and the citric acid of Satsuma mandarin, as affected by rainfall and sunshine duration, was first identified using neural networks, and then an optimal operation for watering (rainfall management) that maximizes the sugar content and that minimizes the citric acid of Satsuma mandarin was sought through simulation of the identified neural-network model using genetic algorithms. An optimal solution obtained here was an operation that increases the amount of watering during the first stage and then markedly reduces it during the latter half stage of the maturing stage. From simulation, the maximization of the amount of watering during the first stage resulted in a significant decrease in the citric acid, and the minimization during the latter half stage led to a marked increase in the sugar content. A mulching technique with plastic film and a sprinkling operation allow controlling the amount of rainfall. This operation suggests a better way for supplying the water to Satsuma mandarin and improving the quality.