System of rice intensification (SRI) as a method of stand establishment in rice.

摘要

System of rice intensification (SRI) is promoted as a system of rice cultivation, by which extraordinarily high grain yields could be very easily obtained even in the tropics. To confirm this and to identify the proper position of SRI as a method of stand establishment in the range of stand establishment methods in rice, a study was undertaken at the Rice Research and Development Institute, Batalagoda, Sri Lanka under the tropical environment. When the grain yield was expressed in area basis as t/ha, grain yields of SRI, standard broadcasting and standard transplanting were found to be the same indicating that SRI was not able to give extraordinary yields as reported. However, SRI gave five and ten times higher yields than that of standard transplanting and broadcasting, respectively, when the grain yield was expressed in seed basis as t/50 kg of seeds used for cultivation. This appeared extraordinary but was obvious because SRI used almost five and ten times less seeds than that of standard transplanting and broadcasting, respectively per unit land area. SRI was identified as one of the two extreme ends with the lowest seed requirement and highest sensitivity in yielding ability to changing environment in the range of establishment methods in rice. All the stand establishment methods tested including SRI ultimately ended up with the same grain yield through autonomous adjustments among yield components under proper management.