During 1980 – 1985 there was an acute scarcity for water in Madagascar (West Africa). Dr. Henri-de-Laulani a Ph.D. holder in Agricultural Sciences, who was working as a Baptist Bishop wanted to search an alternative cultivation practice to grow paddy with much less water. He started his research, by utilizing only 35% of water, 50% of manuring and 5% of seed material and was able to double the yield of paddy on his farm within 5 years by refining the practices. The neighbouring farmers were able to increase the yield four times. In some cases the yield level increased from 20 – 30 quintals per hectare to 150 to 200 quintals per hectare (even with very poor quality of soils with 3.8 to 4.2 PH). This system has become very popular in many paddy-growing countries especially in Cambodia and Sri Lanka. However, this system if popularised in India, can provide the much needed relief to the state governments and the farmers, who are fighting for non existing river waters.
This system of rice cultivation, popularly known as System of Rice Intensification (SRI) or Madagascar method of paddy cultivation was tried out on half an acre of land. This method involves managing plant, water and soil in a cordial relationship rather than as a mere technology. Probably the existing technology of paddy cultivation seems to ignore the capacity and the characters of paddy. A Japanese Agriculture Scientist Katayama had proved by his research earlier to Second World War that most of the seeds belonging to gramineae family (paddy is among them) could produce more than 100 tillers from one grain if they are provided with a conducive situation. Paddy has the capacity of doubling its tillers 13 times (Phyllochrons) during its vegetative growth.
Unfortunately, improper cultivation practices are being followed. For instance, raising paddy transplants in a thickly sown nursery between 4 to 8 weeks, transplanting densely in the main field in clumps (5 to 10 transplants in one clump) instead of single transplant at a spacing of 25 X 25 or 30 X 30 cms are being followed. Further, transplanting is done like “J” making the roots point upwards. This causes trauma as the roots need 12 to 14 days from transplanting to get the roots established to start growing. In such situations, 8 to 10 stages (Phyllochrons) of tillering is lost. Another practice is, submerging paddy field with 4 to 6 cms of water continuously from the date of planting till harvest. In fact, paddy is not an aquatic plant. It can survive and grow during stress compared to other crops belonging to gramineae family.
The practice of submerging the paddy field came to existence to check weed growth. Let us first understand the disadvantages caused by submerging.
- The microbial population will be affected due to absence of oxygen essential for their survival in the soil during submergence. This in turn affects the conversion of soil organic matter into humus, the ultimate source of plant nutrition.
- The nutrients, whether from organic or chemical source, percolate into the soil, much beyond the root zone (or rhizosphere) of paddy plant. Besides leading to wastage of plant nutrition, pollutes ground water source too.
- Since seedlings are densely planted in submerged conditions (55 to 60 clumps in a square meter), roots do not grow deeper and wider. Thus, cannot absorb nutrients from deeper zones.
- As roots do not get sufficient oxygen and about 78 % of the roots get degenerated by the time of panicle initiation. Some of the existing roots even form aerenchyama (or air pockets). Pores in the leaves (blades) and stem have to absorb and supply oxygen to the roots.
Dense planting does not provide enough light and air for the growing plants. They are increasingly susceptible to pests and diseases. Owing to prevalent practices, paddy plants do not grow healthily. They give very few tillers. The percentage of effective panicle eruption and grain filling in the conventional system is very little compared with paddy cultivated with wet and dry system of irrigation.
My method of SRI cultivation of paddy:
Looking at the advantages of SRI, one is regarding planting. As explained earlier a new way of transplanting was tried out. 10-12 days old seedlings were transplanted to avoid trauma and also save labour. These were planted at a distance of 30 X 30 cms to provide additional opportunities for tillering. Rat damage is also less, if planted at such a spacing,
Half-acre paddy field was ploughed twice. 5 tonnes of good compost manure was incorporated with the third ploughing. The mud clumps were broken and land was prepared to form fine tilth providing 1 % slope for effective irrigation. Narrow strips of about 2.6 meters wide with a height of 10 X 8 cms bunds were made on each plot of paddy field to speed up the flooding (as shown in the figure). The field was marked to dibble paddy at 30 X 30 cms spacing. Paddy soaked for 36 hours (24 hours in water and 12 hours in gunny bag without water) was dibbled. However, paddy need not be soaked if one is not sure of irrigating paddy field within 10 hours of dibbling. In such cases, paddy can be dibbled without soaking and irrigating even after 2 to 3 days.
The paddy field was irrigated every 5 days for 25 days without taking up any other work on that land. On 28th day from sowing, weeding was carried out. At this stage, the whole field may look almost vacant because of very few seedlings compared to the regular dense planting. But every week, the number gets doubled. The 6th irrigation was provided on 30th day from sowing. There after, every 3rd day of each irrigation, a rotary weeder was used to avoid cracking of the soil, which would create problem in future irrigation and also cuts off the roots with wide cracking. This operation also helps in checking weed growth and most importantly churns the land to form fine tilth and provides plenty of air for the roots. This activity was carried out 7 times. By 80th day of sowing, on an average, 94 tillers were formed and by 90 days 65% of panicles emerged. After 80 days from sowing provided irrigation every 2 days instead of 5 days as plants need more water for grain filling. Now you can stop using rotary weeder as the cracks do not develop because of excessive moisture. In most of the panicles there were 250 to 260 grains.
By conventional method, on an average, 9 to 10 quintals of paddy was produced from half acre land during the monsoon season. But, by SRI, the production was 18.5 quintals from the same area, utilizing only 50% manuring, 35% water and 5% seed material as compared to the conventional system of cultivation. Labour was saved to the extent of 20%.
The only problem faced with this system of cultivation is root grub menace, cutting away many clumps of paddy. Because of very conducive situation of wet and dry condition in the soil, about 840 white grubs were dug out, by which time they had spoiled at least 15 clumps each. However, these root grubs can be controlled by the following ways:
- Plant 10 or 12 neem branches (2 metres high and 1 metre wide) drenched with high dosage of pesticides for 4 days, soon after the first monsoon rain, so that most of the adult beetles can be killed before laying eggs in the soil.
- Submerge paddy field for 2 days with 5 cms of water either before sowing or within 25 days after sowing so that root grubs are killed or eliminated from the paddy field.
- Apply Bivaneria brangniyarti, a virus at the rate of 4 kilograms per acre during cooler period of the day. This virus is available with most of the sugar factories and is used to control root grubs in cane cultivation.
If this system of cultivation could be adopted by farmers wherever possible, we could save water, protect soil productivity, save environment by checking methane gas from water submerged paddy cultivation practices, bring down the input cost besides increasing the paddy production providing food for the growing population. Hence the Agriculture Universities, Governments, NGOs and Farmers in particular should give more importance in popularising this useful system as much as possible.
Shri. L. Narayana Reddy, Srinivasapura Via Maralenahalli, Hanabe P.O., Doddaballapur Taluk – 561 203,PH : 80 – 7651360.
