This paper was presented at the first National Symposium on System of Rice Intensification (SRI) – Present Status and Future Prospects held in 2006. The parameters include thirteen soil properties which included six related to cultureable microorganisms, three root-related parameters and yield.
The authors begin with a brief history of SRI and discuss the differences between this system and the conventional method of rice cultivation. The authors point out that there are fundamental differences; these include low seed rate, wide spacing, single seed per hill, use of compost etc. In this part of the paper, the authors also discuss published findings on SRI.
The paper then goes on to explain the materials and methods used to conduct the experiment. The experiment was carried out over 4 seasons and the farmers were carefully vetted to ensure they were good practitioners of SRI. The participating farmer had plots of SRI and control, which was the conventional method of farming. Agronomic inputs were recorded through a questionnaire. Added to this, at the time of soil sampling at vegetative and harvest, observations on crop and soil status were recorded after discussions with farmers.
Soil samples were collected from SRI and conventional fields and the authors elaborate the method used to analyze them for chemical, microbiological and biological state. Also samples of roots were taken to determine root length density. The authors elaborate the methods used to study the roots.
From their analysis the authors find that Nitrogen fixing bacteria are higher in the SRI system, and the microbial biomass nitrogen (MBN) and dehydrogenase activity was significantly higher in SRI. Also SRI has better yields.
The authors also found more photosynthetic activity in plants of under SRI. The authors have tabulated these results for better understanding. One of the conclusions that the researchers draw, is that there is apparently more photosynthetic activity in the plants in SRI plots, which when associated with more roots and higher microbial activity in soil, play an important role in higher yields.
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