Farmer adoption of improved nitrogen management technologies in rice farming: technical constraints and opportunities for improvement

Generally, agricultural research is conducted under the controlled conditio ns of research stations which, in many cases, do not represent farmers' cir cumstances. Thus, several technologies do not perform well in farmers' fiel ds and so are not adopted by farmers. Many technical factors and management practices constrain the adoption of improved technologies including effici ent N management techniques: (a) poor water control; (b) low plant populati on; (c) partial nutrient application; (d) insufficient weed control; (e) un timely sowing, transplanting, weeding, and/or harvesting; and (f) poor post harvest processing. Unless farmers improve many, if not all, of these condi tions, they cannot reap the full benefits of modern rice varieties and rela ted production technologies. In addition, soil-related constraints such as high spatial and temporal variability in nutrient status, nutrient imbalanc e, poor drainage, soil degradation (salinity, alkalinity, acidity), and sub soil compaction lessen the effectiveness of nutrient management techniques. Similarly, climatic factors such as variable and unpredictable rainfall, d rought, flood, low radiation, and extremes in temperature affect crop growt h and nutrient use in rice systems. Most of these factors are beyond farmer s' control. Stress-tolerant rice varieties and improved management practice s are being developed and evaluated on rice farms to tackle soil and climat ic constraints, especially in rainfed lowland rice systems. Two of the mana gement strategies rely on better N placement techniques and use of controll ed-release fertilizers to improve nutrient use efficiency in rainfed lowlan ds. Some tools for site-specific N management in rice include chlorophyll m eter and leaf color chart which are being evaluated on farmers' fields. Ano ther strategy is the integrated nutrient management to enhance crop nutriti on and minimize fertilizer costs. Adequate farmer training is needed to rec eive, process, and effectively exploit improved rice varieties and related information, knowledge, and technologies.