Swamp Rice Cultivation In South Sumatra, Indonesia

Introduction

Rice (Oryza sativa) is an important cereal in Indonesia since it is the staple food for nearly 90% of the population. The center of rice production area in Indonesia is essentially located in Java where rice has been intensively cultivated by the farmers. However, Java is also renowned as the most populated island in Indonesia that faces many limiting factors related to its massive population. Land competition between agricul-tural sector and other usages – especially for housing and industrial sectors – then has become a challenging concern. Furthermore, land conversion rate is reported has been increasing rapidly year by year. Over 63, 000 ha of agricultural land have been converted per year, particularly in Java that has reached about 50, 000 ha. Nasoetion (1994) estimated about 30, 000 to 50, 000 ha of rice field has been converted per year.

Therefore, the development of rice cultivation in swamp area outside Java has been targeted by Indone-sian government as one of the solutions for its food vs population problem. As one of provinces with largest swamp area coverage, South Sumatra has been consid-ered as new promising rice production area, especially during dry season where most of rice fields suffer from drought. However, unfortunately, not many references of swamp rice cultivation status in South Sumatra were found. Therefore, field surveys were conducted in both tidal swamp and non-tidal swamp areas in South Sumatra to investigate current situation of swamp rice cultivation and to identify main problems faced by the farmers. This study was expected to provide beneficial information for further studies in order to improve swamp rice cul-tivation and escalate the productions in South Sumatra, Indonesia.

Classification of Swamp

Swamp is a type of land that characteristically flooded for a long period of time and the soil is basically in mud form. Swamp area in Indonesia is classified into two main categories, tidal swamp and non-tidal swamp. These both types of swamp are dominantly distributed in Sumatra, Kalimantan, and Papua and small part in Su-lawesi. Total swamp area in Indonesia is estimated 33. 39 million ha, with 20. 09 million ha (60. 2 %) of tidal swamp and 13. 30 million ha (39. 8 %) of non-tidal swamp. There are about 1. 8 million ha of swamps that have been developed by the government. In addition, there are about 2. 4 million ha of swamp areas are reclaimed and developed by either private sector or local community resulting in total 4. 2 million ha of developed swamp area across Indonesia. This small number indicates a bigger potency of swamp that has not been exploited yet, especially for rice cultivation. Non-tidal swamp is also recognized as inland swamp, and specifically in South Sumatra it is called as lebak. Non-tidal swamp is a river flood plain that receives no effect from the sea tides. During rainy season, non-tidal swamp areas are flooded by the river and floodwater doesn’t recede until dry season. Water volume in non-tidal swamp significantly will depend on rainfall (deeper in rainy season and will gradually decrease during dry season). Therefore, planting usually will start at the end of rainy season or depend on water level in the field. Based on the depth and duration of flooding water, non tidal swamp can be divided into 3 typologies. They are: 1) shallow swamp; 2) medium swamp; and 3) deep swamp.

Tidal swamp or coastal swamp is a lowland area that influenced by the tidal fluctuations of sea. Rice cultivation in this area was initially started by early settlers – mostly Buginese and Banjarese descent – that first reclaimed and occupied the land years ago. The development of this area then has been intensified since early 1970s when Indonesian government first introduced transmigration program to balance the population from overpopulated Java to other potential areas outside Java, including to tidal swamp areas in South Sumatra. Surveys and studies were conducted, more areas were reclaimed and many infrastructures were built to support agricultural sectors that have become main specialties of the transmigrants.

Materials and Methods

Field surveys were conducted on both non-tidal and tidal swamp areas in South Sumatra to investigate rice farming systems cultivated by the farmers. Surveys were carried out by interviewing rice farmers and agricultural extension staffs directly. Yield components were also calculated by taking plant samples (three replications: 3 hills in a paddy field) from certain swamp areas as described below. a. Non-tidal swampSurvey sites in non-tidal swamp areas covered Rambutan Regency in Banyuasin District, Kayuagung Regency in Ogan Komering Ilir (OKI) District, and Ran-tau Panjang Regency in Ogan Ilir (OI) District, South Sumatra. Plant samples were collected from Kotadaro II Village in Rantau Panjang Regency on October 10, 2012 and from middle-swamp area in Sungai Dua Village in Rambutan Regency on October 14, 2012. b. Tidal swampSurvey in tidal swamp was carried out in Telang I and Telang II areas, Banyuasin District. While plant samples were collected from Banyu Urip Village in Telang II areas, Tanjung Lago Regency, Banyuasin District on February 20, 2013.

Results and Discussion

Farming Systems and Cultivation Practices

a. Non-tidal swamp

From the survey results, it was discovered that non-tidal swamp could only cultivated once a year, except for shallow swamp that could be cultivated twice a year. Planting season would start at the beginning of dry season or when water level in the field started to recede, while the second season (for shallow swamp) would start at the beginning of rainy season. Based on the interview, main problem faced by the farmers was due to unstable water level and unpredicted weather. Common situation in the field was high flooding prior to planting and extreme drought during reproductive stages. This had caused the farmers need to adjust their planting time and reconsider the use of proper cultivar combined with some improved cultivation techniques.

One of cultivation techniques carried out by the farmers to cope with deep flooding prior to planting was double or even triple transplanting method. Double transplanting is a planting method that used relatively older and taller rice seedlings to reduce flooding damage in rice cultivation. This method had also been used by rice farmers in Asian countries, such as in Bangladesh and in Vietnam. Double transplanting method in South Sumatra was usu-ally combined with rafting nursery system, as performed by farmers in Rambutan Regency. Seeds were first planted on a seedbed in a floating raft in the field tied on a stick to avoid the raft carried by the water flow. After 10 – 14 days, seedlings were then transplanted into rice field area which had relatively lower water level. Second transplanting then could be conducted after 18 – 20 days to the actual rice field. Triple transplant-ing would even be possibly performed by the farmers.

If water level in the field was still very high. However, rafting nursery was not applied by farmers in Kayua-gung and Rantau Panjang though they also used double transplanting system. Cultivars used by farmers in non-tidal swamp varied from Ciherang, Cibogo, Mekongga, INPARA, INPARI, IR 42, IR 64, and local cultivars such as Siam. Fertilizers used by the farmers were mainly urea and TSP (triple superphosphate) or SP 36 (Superphosphate 36%). Farmers in Rambutan Regency split fertilization into three application times. First was before transplanting to main field (SP 36, 150 kg/ha), second was about 7–15 days after transplanting (DAT) (urea, 75 kg/ha; compound fertilizer (N:P2O5:K2O=15:15:15), 50 kg/ha), and the third was 30–40 DAT (urea: 75 kg/ha; compound fertilizer (N:P2O5:K2O=15:15:15), 50 kg/ha). Farmers used compound NPK also to substitute potassium fertil-izer which was unavailable in the market. Even in some places, such as in Kotadaro II, farmers did not use any fertilizer to their paddy field due to farmers’ inability to afford fertilizer either because it was unavailable or the price was too high. Common pests found in non-tidal swamp were birds, rats, and also golden snail. Golden snail was even considered as one of the most harmful pests in Sungai Dua as it would come and attack rice field right after the flood water subdued. This would bring serious damage to the seedlings causing farmers had to re-transplant the new ones. If the seedlings were out of stock, farmers then would split existing rice hills into several new hills and re-transplant it to the field.

In both areas (Kotadaro II and Sungai Dua), Ciherang was used and resulted in 24. 7 and 25. 2 g yield/hill. Regarding planting space used by the farmers (20cm x 25cm), yield/m2 in both areas were about 494 g and 504 g respectively or ap-proximately equal to 5 ton/ha. This was 1 ton lower than 6. 0 ton of Ciherang average yield, and 3. 5 ton lower than 8. 5 ton of Ciherang yield potency. Lower yield in Kotadaro II was probably caused by lack of stem number indicating less tillering rate. Fewer tillers led to less panicle number per hill. Farmers in Rambutan Regency (middle-swamp area) transplanted rice seedlings from rafting nursery to the side of paddy field with lower water level (1st transplanting).

This occurred because sampled farmer did not use any fertilizer to his field, especially for nitrogen source which was beneficial for increasing tiller number in rice plant. While in Sungai Dua, spikelet number per panicle was indicated as the weakest component that led to lower yield. Sampled area in Sungai Dua was a middle swamp type area which was prone to drought that often occurred during reproductive stage of rice plant. This had been assumed as main factor of relatively small number of spikelet per panicle obtained in this sampled area.

b. Tidal swamp

In tidal swamp areas, canal systems were employed to manage water availability in the field which divided into primary, secondary, tertiary, and quaternary canals. As water could be controlled, the field then could be cul-tivated into three planting seasons. First season would start around November until February to cultivate rice. Second season was around March until May to cultivate rice and other upland food crop, such as corn and soy-bean. Third season, started from June until August, was usually used for cultivating upland food crop considering water availability in dry season. Farmers usually used broadcasting system to plant their rice in the first season, while in the second season most farmers would perform ratoon farming for rice cultivation. The use of broadcasting and ratoon farming system was more likely caused by labor shortage in this area. However, rice production in ratoon farming system would drastically decline which only could produce less than 1 ton per ha. This condition had made the farmers switch their option to cultivate other upland food crops to gain more benefits. There was no specific reason for the farmers to choose which cultivars planted on their field. It was based on their own preferences and seed availability. Ciherang was common cultivar used in tidal swamp as it could be easily obtained. Other cultivars, such as Cili-wung, INPARA, INPARI, Situbagendit and Kromojoyo were also cultivated by the farmers. Farmers used around 60 kg of seeds per ha, how-ever they would later control plant spacing by taking out some seedlings to gain favorable plant population estimated around 40-50 rice hills/m2. Farmers in Banyu Urip usually applied fertilizer to their field twice. First was about 40 days after sowing (DAS) by spreading 100 kg/ha urea and 100 kg/ha TSP to the rice field, and the second was about 70 DAS with same dosage as the first and also with the addition of 100 kg/ha compound fertil-izer (N:P2O5:K2O=15:15:15) as potassium source. Sampled cultivar was Situbagendit. Yield in tidal swamp area was lower than in non-tidal swamp since it was originated from broadcast-ed seed. High percentage of empty grains (± 40%) had initiated high yield loss resulted only in 9. 5 g yield/hill, approximately equal to 4. 75 ton/ha (maximum 50 rice hills/m2). This was 0. 75 ton lower than 5. 5 ton average yield and 1. 25 ton lower than 6 ton yield potency (Dept. of Agriculture, 2009). Besides high percentage of empty grains, spikelet number per panicle was also relatively low resulting in lower yield. Compared to Sungai Dua, drought probably was not the reason of decreasing yield.

Since rice cultivation in tidal swamp was during rainy season. Furthermore, Situbagendit was considered as a drought tolerant cultivar. Therefore, too densely plant population in the field was supposed as main factor of less number of spikelet per panicle due to high competition in light, space, and especially nutrient.

Constraints to Production

Farmers in tidal swamp area in Banyuasin District, South Sumatra were facing both on-farm and off-farm problems. On-farm problems were due to soil and water quality. Since tidal swamp was located on the coastal area and received direct impact of sea water, salinity intrusion would be the main problem during dry season, especially from July until September. However, this problem then would be naturally overcome when rainy season starts. During rainy season, soil water acidity would be another problem where pH will be around 4. While for off-farm problems, there were three main problems faced by tidal swamp farmers.

The first was labor shortage. Lack of infrastructures in tidal swamp areas, either for education and entertainment facilities, had forced young people to move to the city and most of them were not willing to come back to help their parents in the rice field. During harvest season, farmers even had to invite their friends and relatives from Java to help them in the field. Second was due to lack of local government support in provid-ing better transportation facilities, such as roads and bridges. Access to tidal swamp areas was mostly in poor condition which made them difficult to reach. Third was regarding grain quality. Harvest time in tidal swamp were mainly in rainy season, whereas the farmers still practiced traditional drying process using direct sunlight to dry rice grains. This unfavorable condition had led to degraded rice grain quality. Compared to tidal swamp with its controlled water system, as mentioned before, non-tidal swamp areas were facing problem due to its unstable water fluctua-tion: high flooding in rainy season and drought in dry season. Furthermore, non-tidal swamp development was mostly limited by socio-economic problem such as land ownership obscurity, local people characteristics and lack of government support regarding water canals facilities. Thus, integrated research and socio-economic approach were important to gain optimal result of non-tidal swamp development effort.

Conclusion

The development of swamp rice cultivation would be beneficial to support national rice sufficiency in Indo-nesia. However, many challenging constraints –both on-farm and off-farm– to the effort were found as presented by survey results in this study. Further field survey should be conducted since data of yield components reported in this study were only from limited category of swamp. The information gathered were hopefully would be a valuable consideration to improve rice production in swamp areas in South Sumatra, and particularly in Indonesia.