The Growth and productivity enhancement of rice by jajar legowo (double row) planting method in freshwater swampland

One of the technological innovations to increase rice productivity is the Jajar Legowo (double row) planting method. The research aimed to examine the technology of planting Jajar Legowo rice in two ways: manual and transplanter machines in freshwater rice fields. The research was conducted on 6 ha of freshwater rice fields in Martapura Barat, Banjar Regency and involved six cooperator farmers. The superior varieties used were Inpari-30 and Inpari-32. The results show that the average grain yield was higher with transplanter (8.10 t ha−1 GKP), compared to manual planting (6.90 t ha−1). Grain yields planted with transplanter + manure increased grain yields by 1.2 t ha−1 (increased by 17.4%). The transplanter treatment provided an income of IDR20,401,500.- and R C−1 = 2.70 higher than manual row planting (income IDR16,959,500.- R C−1 = 2.59). Transplanters also reduce labour costs for planting (IDR750, 000.- per hectare), and reduce planting times.


Introduction
Rice is the staple food of the Indonesian people. The need for rice is increasing, along with population growth. Increased production can be done by increasing productivity and increasing the planted area. The increase in planting area leads to sub-optimal land (such as freshwater swamps), due to the narrowing of arable land. Freshwater swamps in Indonesia, covering an area of around 25.21 million ha (73.9% of the total swampland of 34.12 million ha), are scattered in Sumatra, Papua, Kalimantan, Sulawesi and Maluku, which have the potential as an alternative source of rice production [1]. Even though freshwater land has the potential for rice development, it has several limiting factors that can affect rice productivity.
The limiting factor for freshwater swamps is the fluctuation of the water regime which is quite high, namely floods in the rainy season and drought in the dry season, especially in shallow freshwater swamps, and the physicochemical characteristics and soil fertility and micro-hydro topography of the land, which are diverse and generally not well ordered [2,3]. If the freshwater land can be engineered with the application of appropriate cultivation technology innovation, balanced development and management following the characteristics and behaviour of the swampland, it can make the swampland a productive, sustainable and environmentally friendly agricultural land [3,4,5]. Increasing rice productivity can be done by applying the Jajar legowo technology innovation. It is an integrated lowland rice crop management based on Jajar Legowo 2:1. The important parts are 1) New Superior Varieties (VUB) with high yield potential; 2) Biodecomposers, given during soil processing; 3) Bio-fertilizers as seed treatment and balanced fertilization based on the Rice Field Test Kit (PUTS); 4) Pest and disease control with vegetable pesticides (if possible); and 5) Agricultural tools and machinery, such as planting

Soil characteristics
The research location was a freshwater swampland. Freshwater swampland is a land that is submerged for more than or the same as three months, in the form of a basin with the characteristics of the rainy season being completely inundated by water. In the dry season, the water gradually dries up or even becomes completely dry in a relatively short period (1-2 months) [9]. Technically, freshwater swamps experience quite high-water regime fluctuations, namely floods in the rainy season and drought in the dry season, especially in shallow freshwater swamps [2]. Based on its topography, freshwater swamps are divided into three categories, namely shallow freshwater swamp, middle freshwater swamp and deep freshwater swamp. Inundation height in the shallow freshwater swamp is less than 50 cm, the middle freshwater swamp is 50-100 cm, and the deep freshwater swamp is more than 100 cm [10,11].
Assessment of soil fertility is limited to the root area of overlay plants (0-20 cm). Based on the results of laboratory analysis, soil characteristics tested were texture, soil acidity (pH), Organic C, Total N, C / N ratio, available P, exchanged K, CEC, and cations (Ca, Mg, K, and Na ) and several microelements in each freshwater swamp soil typology (table 1). The soil reaction was acidic with a pH of 4.62, which is still within the limits that rice plants can tolerate. The soil is quite fertile. It can be seen from the macronutrient content, which ranges from medium to high and C-organic 2.28% [12].
The micronutrient content of Iron (Fe) is 16.46 ppm, which is still low. The availability of Fe microelement is influenced by waterlogging conditions, ion balance, organic matter and soil pH. If the nutrient availability is at a low concentration of Fe 2+ 30 ppm, it is capable of poisoning plants. According to Hanafiah [13], the range of Fe in leaves is 10-100 ppm with a sufficiency level of only 50-75 ppm; however, according to Jones et al. [14], the range for iron adequacy for rice is 70-200 mg kg -1 in young leaves.
Dusty clay texture is classified as a suitable soil texture for food crops. The soil cation exchange capacity (CEC), which is classified as medium indicates that the soil can hold nutrients so that plants can absorb it.

Rice growth and yield
Observations on rice plant growth showed that Inpari-30 plant height ranged from 101.88-110.88 with the number of tillers per hill 13.63-18.00, and the plant height Inpari-32 ranged from 74.50-103.38 cm. The number of tillers 18-22. Statistical tests on plant height and number of tillers showed an interaction between planting method and variety on plant height. The use of transplanters increased plant height in the Inpari-32 variety, but there was no difference in the Inpari-30 variety. Cultivation methods and varieties increased the number of tillers (table 2).  The method of planting using a transplanter increased the number of fill per panicles compared to planting manually, but the varieties showed no difference. There was no effect of planting method or variety on the amount of empty grain (table 4). The method of planting using the Transplanter increased the yield (harvested dry grain), but the yield between varieties was not different (table 5). The yield of dry grain due to the use of transplanters is higher than manual planting. The two varieties of Inpari-30 and Inpari-32 gave the same grain yield. The difference in grain yield between manual planting and transplantation is thought to be due to the age of the seedlings and different populations. Planting with a transplanter requires that young seedlings are less than 18 days old, cannot use seeds that are more than 20 days old. At the age of young seedlings, the roots of the plants are still easy to separate with clamps on the Transplanter. When transplanting, young seedlings will experience less stress, resulting in more seedling growth. Manually planting using human labour (planting wages). The seeds used are 21 to 25 days old. Younger seedlings (10 to 15 DAS=day after sowing) will provide a higher number of tillers and panicles and productivity than older seedlings (more than 20 DAS). Transplanter planting made spacing more regular and row spacing of about 12.5 cm, the plant population was 213,333. Manual planting, spacing in irregular rows, averaging about 15 cm, plant population is 177,777. The results show that the Jajar Legowo planting method was an effort to increase the plant population per hectare so that productivity increased. In Jajar Legowo planting, all the hills become fringe plants. The effect of fringe plants is to get more sunlight and better air circulation, as well as to facilitate plant maintenance [15]. Several other research results also show that the 2: 1 Jajar Legowo planting system is profitable both in increasing productivity and farmers'  [16], the application of the Jajar Legowo 2: 1 planting system technology can increase the plant population by 33.33%, and according to Ishaq [17], this technology increases production by 18.7% in irrigated land. According to Suratmini and Suryawan [18], this technology produces milled dry grain 19.7% higher than the tile planting system. The results of the study by Suratmini and Sukraeni [19] showed that the number of productive tillers was higher in Jajar Legowo than in the tile planting method (the farmer's method) [20,21].
The results of the Jajar Legowo super dem-area activity in Indramayu shows that the productivity of the Inpari-30 Ciherang Sub-1 variety was 13.9 t ha -1 ; Inpari-32 HDB of 14.4 t ha -1 ; and Inpari-33 amounted to 12.4 t ha -1 , while the average productivity of farmers outside the dem-area with the Ciherang variety was 7.0 t ha -1 [22]. Planting the Jajar Legowo system can increase farmers' income compared to non-Jajar Legowo planting. The magnitude of the difference in yield between the Jajar Legowo 2: 1 planting system model with the non-Jajar Legowo system is 1,483 kg ha -1 , with the difference in profit from the non-Jajar Legowo system of IDR6,463,750.-ha -1 [23].

Farming analysis
The use of a transplanter provides an income of IDR20,401,500.-with R C -1 = 2.70 higher than manual planting, and an income of IDR16,959,500.-, R C -1 = 2.59. A higher R C -1 value indicates that the use of a transplanter is feasible, reducing labour costs for planting by IDR750,000.-per hectare, and the planting time is shorter (table 6).
The use of transplanters requires additional costs for seeding media because the media for seedlings in the tray requires loose media to facilitate the removal of young seedlings. The media for the seedling is a mixture of soil, manure and husk ash so that it is crumbed and loose.

Conclusion
Plant growth (height, number of tillers, number of panicles, panicle length, number of filled grains) using a transplanter is better than manual. The average yield of jajar legowo using a transplanter was higher (8.10 t ha -1 ) than manually. Increase in yield of 17.4% (equal to 1.2 t ha -1 ). The advantages of transplanting are higher grain yield (8.10 t ha -1 GKP) compared to manual planting (6.90 t ha -1 ); providing more profit (IDR20,401,500.-) with R C -1 = 2.70 than manual planting which is only IDR16,959,500.-with R C -1 = 2.59; reducing labour costs for planting (IDR750,000.-per hectare), and shorter planting times.