System of Rice Intensification

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Rice field, humid but not flooded according to the SRI method.
Rice seedlings, planted individually and at a distance according to the SRI method.

SRI (from English System of Rice Intensification , also SICA from Spanish Sistema Intensivo de Cultivo Arrocero , translated into German  rice intensification ) is a cultivation method for rice that was described in 1983 by the Jesuit Henri de Laulanie in Madagascar. The head of the International Institute for Food, Agriculture and Development at Cornell University , Norman Uphoff , contributed significantly to the establishment of the method in Asia from 1997. Because the principles of cultivating fields are partially transferable to other agricultural crops, the cultivation method is also referred to by some consultants at the Indian Agriculture Office as “root intensification”.

Basic idea

The central principles of the SRI method are:

  • Rice seedlings should be planted quickly, flat and carefully when young (less than 15 days old with only two leaves). This minimizes the root damage and the "plant shock".
  • Rice plants should be planted individually and at a distance. This improves root growth and increases the photosynthetically active leaf area.
  • The soil conditions should be improved through enrichment with organic substances. For the fertilization is preferably manure used, the use of artificial fertilizers can be reduced.
  • Rice fields should only be kept moist instead of saturating them with water (flooding). This improves root growth and supports the growth and diversity of aerobic soil organisms .

Supportive measures

Because the weed-inhibiting effect of the flooding is no longer applicable and the use of weed control agents should be avoided, the International Rice Research Institute (IRRI; German International Rice Research Institute) developed a simple weed hoe especially for the needs of the SRI. In the agricultural university of the Indian state of Andhra Pradesh , the device for so-called "Cono Weeder" was further improved. The "cone hoe" (German translation) can be pushed through the field on a handle. A stem reminiscent of the bow of a ship makes steering easier and prevents mud from clogging the blades behind. The sharp knives, which are arranged on rotating cones , cut the roots of unwanted herbs between the rows of plants, mulch them and also ensure better aeration of the soil. The device was designed in such a way that it can be produced or repaired on site with the simplest means. State agricultural advisors distributed the device in large numbers for free or for little money to the farmers. Since then, some inventive farmers have further simplified the operation or adapted it to different soil situations. Even motorized and multi-row machines are among the innovations .

Effects

By planting individual seedlings, the need for seeds is reduced to 20% to 10% compared to conventional cultivation. SRI can be used with well-adapted local rice varieties, as well as with hybrid seeds or other specialized seeds. Together with the increased yield, expanded possibilities for profitable generation can arise.

In irrigated rice fields it could be shown that SRI as a cultivation method could significantly reduce methane emissions compared to conventional cultivation methods, due to the adapted irrigation. In the case of lowland rice in rain-field cultivation, this effect is not so clear in the various cultivation methods, but it is still measurable. However, lower rice yields measured under SRI were measured in rain-field cultivation compared to conventional cultivation and the use of mineral fertilizers was recommended.

Compared to conventional rice cultivation with flooded fields, the SRI method increased yields by 20–40%, in some cases considerably more. This also means that despite the laborious manual weed control, the workforce employed per unit of yield is reduced by up to half. Whether this can be assessed positively or negatively depends primarily on social structures and future developments. Using the example of a large Indian farmer who works his fields with day laborers , the effort required to train them does not necessarily seem profitable, especially since the composition of the workforce is constantly changing. For the rich farmers there is a lack of incentives to introduce the new cultivation method, and for the very poor and landless the possibilities of the system are in any case inaccessible. For the time being there is only a chance for smallholders to increase the yield of their own agriculture and thus to bring about a structural change in the existing society in the long term.

rating

The reports of sometimes considerable increases in yield, especially on sterile soils, have been called into question for various reasons and are controversially discussed. As a result, extensive experiments and field research were undertaken, which was reflected in a large number of scientific papers. Nevertheless, according to a review from 2016 , SRI is not generally recognized in the international scientific community.

An extensive scientific evaluation of the available studies on SRI effects published in 2014 comes to a cautious assessment. In the course of the switch to SRI, the use of water, seeds, fertilizer and labor will typically change. In addition, the method would tend to be used more on highly productive areas and by socio-economically more advanced households. Very few studies would control for all influencing factors. Therefore, for the overall effect of the method there is "no firm evidence" ( "no reliable evidence" ); the results on land and labor productivity are mixed. The total yield would tend to increase, but production risks and labor intensity would also increase.

Criticism has also come from the agricultural scientist Yuan Longping from the People's Republic of China, who is considered the father of hybrid rice seeds. For the development of new rice varieties he received the World Food Prize in 2004 together with Monty Jones , the Minister for Agriculture, Forests and Food Security of Sierra Leone, and for a long time he was the world record holder for rice harvests. He doubts the high crop yields attributed to the cultivation method and continues to rely on biotechnology, as does the majority of agricultural researchers worldwide. He particularly emphasizes the importance of the work in the laboratory. Only after successful research could its results be used to increase production in the field.

According to Norman Uphoff, on the other hand, the method has [...] arrived in 54 countries (as of 2014). It is most widespread in the People's Republic of China , India , Indonesia , Cambodia and Vietnam . There they used around ten million smallholders on their fields - on a total area about the size of Baden-Württemberg . However, scientific studies on the spread of SRI are still lacking. Kurt Langbein has a similarly positive opinion in his book "Land theft: The global hunt for arable land": SRI is therefore considered by many to be the most important agricultural development of the last 50 years. Scientific studies, however, come to the conclusion that the rice intensification system (SRI) is presented as a new approach to rice cultivation that is said to be both more productive and more sustainable than conventional methods. However, such claims have been challenged or rejected by many rice researchers. ("The System of Rice Intensification (SRI) is claimed to be a novel approach to rice cultivation that is both more productive and more sustainable than conventional methods. Such claims have been challenged or dismissed by many rice scientists, however.") So there There are numerous reports such as the world record harvest of 22 tons of rice per hectare from autumn 2012, which are mostly not scientifically confirmed, but are based on self-reports from farmers. This is also the case with the report by the agricultural scientist Krishna Singh from the Indian Agriculture Council, who examined the average harvests on fields that were cultivated according to the rice intensification system. He reported a significant increase in the harvest. The harvests, which are 2.5 tonnes of rice per hectare with conventional cultivation methods, rose regularly to 8.6 to 10.5 tonnes per hectare with the SRI method. However, there is still no scientific evidence that takes all influencing factors into account.

Web links

Commons : System of Rice Intensification  - collection of images, videos and audio files

Individual evidence

  1. ↑ a b c d "Strong roots, proud harvests" , manuscript of a broadcast by Bettina Weiz on SWR2 Wissen
  2. ^ Cornell University, System of Rice Intensification
  3. ↑ a b c d e Amod K. Thakur, Norman T. Uphoff, Willem A. Stoop: Scientific Underpinnings of the System of Rice Intensification (SRI): What Is Known So Far? In: Advances in Agronomy . tape 135 , 2016, ISBN 978-0-12-804693-7 , ISSN  0065-2113 , pp. 150–151 , doi : 10.1016 / bs.agron.2015.09.004 .
  4. ↑ Amod K. Thakur, Norman T. Uphoff, Willem A. Stoop: Scientific Underpinnings of the System of Rice Intensification (SRI): What Is Known So Far? In: Advances in Agronomy . tape 135 , 2016, ISBN 978-0-12-804693-7 , ISSN  0065-2113 , pp. 167 , doi : 10.1016 / bs.agron.2015.09.004 .
  5. ↑ Weeders - A Reference Compendium, various designs (PDF, English)
  6. ↑ Amod K. Thakur, Norman T. Uphoff, Willem A. Stoop: Scientific Underpinnings of the System of Rice Intensification (SRI): What Is Known So Far? In: Advances in Agronomy . tape 135 , 2016, ISBN 978-0-12-804693-7 , ISSN  0065-2113 , pp. 170 , doi : 10.1016 / bs.agron.2015.09.004 .
  7. ↑ Amod K. Thakur, Norman T. Uphoff, Willem A. Stoop: Scientific Underpinnings of the System of Rice Intensification (SRI): What Is Known So Far? In: Advances in Agronomy . tape 135 , 2016, ISBN 978-0-12-804693-7 , ISSN  0065-2113 , pp. 168 , doi : 10.1016 / bs.agron.2015.09.004 .
  8. ↑ Pardis Fazli, Hasfalina Che Man: Comparison of Methane Emissions from Conventional and Modified Paddy Cultivation in Malaysia . Elsevier, 2014, doi : 10.1016 / j.aaspro.2014.11.039 .
  9. ↑ Proyuth Ly, Lars Stoumann Jensen, Thilde Bech Bruun, Andreas de Neergaard: Methane (CH4) and nitrous oxide (N2O) emissions from the system of rice intensification (SRI) under a rain-fed lowland rice ecosystem in Cambodia . 2013, doi : 10.1007 / s10705-013-9588-3 .
  10. ↑ Amod K. Thakur, Norman T. Uphoff, Willem A. Stoop: Scientific Underpinnings of the System of Rice Intensification (SRI): What Is Known So Far? In: Advances in Agronomy . tape 135 , 2016, ISBN 978-0-12-804693-7 , ISSN  0065-2113 , pp. 166 , doi : 10.1016 / bs.agron.2015.09.004 .
  11. ↑ Amod K. Thakur, Norman T. Uphoff, Willem A. Stoop: Scientific Underpinnings of the System of Rice Intensification (SRI): What Is Known So Far? In: Advances in Agronomy . tape 135 , 2016, ISBN 978-0-12-804693-7 , ISSN  0065-2113 , pp. 152 , doi : 10.1016 / bs.agron.2015.09.004 .
  12. ↑ a b Ezra Berkhout, Dominic Glover, Arie Kuyvenhoven: On-farm impact of the System of Rice Intensification (SRI): Evidence and knowledge gaps . In: Agricultural Systems . 132, 2015, ISSN  0308-521X , pp. 157-166. doi : 10.1016 / j.agsy.2014.10.001 .
  13. ↑ Kurt Langbein: Land Grab: The global hunt for farmland . Ecowin, Wals near Salzburg 2015, ISBN 978-3-7110-5132-5 , p. 192 , p. 177 ( limited preview in Google Book search).
  14. ^ Dominic Glover: Science, practice and the System of Rice Intensification in Indian agriculture . Elsevier, 2011, doi : 10.1016 / j.foodpol.2011.07.008 .