Effect of Panicle Nitrogen Fertilizer Management on Yield and Population Quality in Mechanical Transplanted Super Rice Ningjing 1 with Different Seedling Ages

Abstract

Adopting super high yield rice Ningjing 1 as material,the effect of panicle nitrogen fertilizer application time on yield and population quality of transplanted seedlings with different ages was studied.The results showed that,with the same panicle nitrogen fertilizer application time,rice yield,growth rate of rice population,dynamics of culm and tillers number,leaf area index and photosynthetic potential of right age seedlings were all better than those of overage seedlings in mechanical transplanted rice production.With the right age seedlings,when the panicle nitrogen fertilizer applied equally at the fourth leaf age from top and at the third leaf age from top(D4-3),rice yield,growth rate of population,percentage of productive tiller,leaf area index and photosynthetic potential after heading,leaf area of productive tillers at heading and its ratio,leaf area from flag leaf to the 3rd leaf from top of productive tillers at heading and its ratio,the drop angle of top three leaves were all higher than those when the panicle nitrogen fertilizer applied equally at the fifth leaf age from top and at the third leaf age from top(D5-3) or applied equally at the fifth leaf age from top and at the fourth leaf age from top(D5-4).With the overage seedlings,when the panicle fertilizer applied at D5-4,rice yield,growth rate of population from heading to maturing,dynamics of culm and tillers number and leaf area index after elongating,photosynthetic potential after the critical stage of productive tillers,leaf area of productive tillers and leaf area from flag leaf to 3rd leaf from top of productive tillers at heading,the length of basal three internodes of stem and its ratio to the whole stem were all higher than those when the panicle nitrogen fertilizer applied equally at the fifth leaf age from top and at the third leaf age from top D5-3 or applied at D4-3.The results indicated that seedling age is important for high yield of mechanical transplanted rice.Using right age seedlings is helpful for forming the high quality rice population and obtaining high yield when the panicle nitrogen fertilizer applied at D4-3.Instead,with the overage seedlings,the early applying of panicle nitrogen fertilizer,such as applying at D5-4,would promote some shaky tillers to be transformed into effective tillers and consequently form the ears,which provides a compensation for some insufficient growth due to transplanting with overage rice seedlings.However,the early applying of panicle nitrogen fertilizer would elongate the basal internodes of stem excessively and increase the risk of lodging.