Efforts to Improve Productivity of Paddy (Oryza sativa L.) Var. Inpari 30 by Settings of Planting and Different Cropping Patterns
Aris Ermanto1,2*, Agus Suryanto1and Didik Hariyono1
1Faculty of Agriculture, Brawijaya University, Veteran Street Malang City, 65145, East Java, Indonesia
2Department of Agriculture and Food Crops, Tebo Regency Government Office Complex, Jalan Sultan Thaha Street, 12th KM, Tebo Tengah, Tebo, 37571, Jambi, Indonesia.
Correspondence : aris.ermanto.tebo@gmail.com Submitted 27 November 2020 / Accepted: 21 August 2021
ABSTRACT
Solar radiation is an essential factor in the process of plant metabolism. Indonesia has a rainy season and the dry season, which causes differences in solar radiation intensity. The purpose of this study was to obtain information on suitable planting times and optimal cropping patterns for rice in the dry season in an effort to increase plant productivity. The study was conducted using a nested design, with two factors. The first factor is planting time. The second factor is cropping pattern, a nested factor in planting time that consists of 3 levels of cropping pattern (CP). These experiments have six combinations, and these experiments were repeated three times. Cropping pattern of jajar legowo 40 cm x 20 cm x 12.5 cm can give the best results on the parameters of leaf area index, plant growth rate, percentage of productive tillers, weight per square meter and rice productivity. Rice productivity is greatly influenced by planting time and cropping patterns. The planting time in September produced the highest productivity, reaching 6.99 t ha-1. While rice planted with jajar legowo cropping patterns (40 cm x 20 cm x 12.5 cm) had productivity up to 7.66 t ha-1.
Keyword : jajar legowo; productivity; solar radiation
INTRODUCTION
Rice production is an essential factor in world food security (Dass and Chandra, 2013). As a staple food for Indonesian people, rice's need continues to increase every year in line with population growth. The government continues to encourage all efforts to fulfill rice both with the application of a variety of cultivation technologies and the addition of raw paddy fields, especially outside Java island. Using the latest methods of Statistics Indonesia (BPS) has released data that national rice production in
2018 will reach 56.5 million tons. With a consumption level of 114.6 kg capita-1, assuming that Indonesia's population was 270 million in 2019, it will need around 31 million tons of rice. In reality, the government still imports rice every year to meet domestic needs, with 2.25 million tons of rice imported by the government in 2018 (Detikfinance, 2019).
On the other hand, climate change, which has an impact on increasing temperatures and rainfall patterns, can potentially reduce crop productivity. The average annual maximum and minimum average
temperatures have increased by 0.35°C and 1.13°C. There was a close relationship between grain yields and average minimum temperatures during the growing season (Peng et al., 2004). An increase in temperature increases evapotranspiration.
Changes in rainfall patterns will reduce the intensity of solar radiation due to cloud cover and increase humidity, which results in the potential for pests and plant diseases. Paddy is a plant that needs sunlight for metabolic processes. Each phase of the paddy growth requires a different intensity of solar radiation when the intensity of solar radiation is low due to clouds in the rainy season; the yield of rice plants will drop by up to 50% (Suryanto, 2018).
One of the physiological processes that affect plants' growth is photosynthesis and its distribution in all parts of the plant (Dass and Chandra., 2013). As an essential factor in metabolism in plants, sunlight has the primary function as a driving force in the process of photosynthesis to produce carbohydrates. The process of photosynthesis is vital for the plants themselves and for the survival of organisms that depend on organic matter.
Photosynthesis is a complex system that includes many biophysical and biochemical processes, such as light absorption and conversion of solar radiation to chemical radiation involved in metabolism (Yin et al., 2009).
Efforts to maximize the absorption of solar radiation in paddy were needed. The efforts were cultivation techniques and determining the right time so that radiation that falls on the canopy can be used efficiently for photosynthesis. The ideal planting distance will support the plants to grow optimally. It will effectively support rice plants' maximum growth because of getting nutrients, water, and solar radiation. Plant spacing affected the number of productive tillers (Hatta, 2012)
and flowering age (Hermawati, 2012). The distance of planting affects the number and area of leaves, indirectly. Tight spacing will suppress weed growth and vice versa. When the spacing is too wide, it will make it easier for weeds to grow between the plants, but the wide spacing or legowo row makes weeding easier.
Jajar legowo is a cropping pattern regulated by increasing plant population through adjusting distances and utilizing edge crop effects. This cropping pattern is made by reducing the distance of plants in sequence and widening the distance between plants. This cropping pattern aims to increase crop productivity. In the jajar jajar legowo 2:1 cropping pattern in this research, every two rows of paddy are interspersed with an empty row twice the range, and the distance in the row is narrowed to half of the original planting distance. This cropping pattern has better productivity than conventional cropping patterns (Adinuraniet al., 2019). A wide spacing of the jajar legowo cropping pattern makes it easy in weeding.
According to Yang et al. (2008), solar radiation is a determining factor, especially in the ripening phase of seeds, biomass accumulation, especially during grain filling, sink production capacity per unit of biomass, and at the time of flowering. These factors contribute to the difference in yield productivity between the dry season and the rainy season in irrigated rice fields.
According to Wassmann et al. (2009), temperature, solar radiation, and rainfall intensity are components that affect rice productivity. Those components also affect the vegetative phase, phenological development, source organ formation, and seed filling. The high daily temperature during the dry season seed maturation phase is thought to result in an accelerated ripening process so that the grain filling time is less than optimal. Long et al. (2006)
describe plants with a vertical leaf arrangement capable of capturing solar radiation in all leaf layers in the canopy.
The application of the jajar legowo planting pattern has several advantages compared to the tile planting pattern. These advantages are the use of more sunlight for the photosynthesis process, easier fertilization, and control of pests, and higher grain production than the tile planting method (Ikhwaniet al., 2013).
High intensity of solar radiation in the dry season has an impact on increasing rice productivity with sufficient watering requirements. During this time, the increase in productivity of rice more use of high external inputs. So, it will increase production costs while utilization of climate resources has not been fully considered. The efficient utilization of climate resources in increasing rice productivity can be done by selecting varieties of rice plants with upright leaves that are responsive to solar radiation, choosing the right planting time, and the right cropping pattern. This study aims to determine the effect of choosing planting time and cropping patterns on increasing rice productivity.
MATERIALS AND METHODS
The study was conducted at the Experimental Garden of the Faculty of Agriculture, Universitas Brawijaya, Jatimulyo, Malang, East Java. The altitude of 460 meters above sea level with temperatures of 14o - 32oC and Andosol soil types. This research was conducted in September 2019 until January 2020. The tools used were Handtractor, Leaf Area Meter type LI-3100, electric knapsack sprayer, scales Nict Voor type PS 1200, Memmert Oven type 21037 FNR, camera, and Lux meter. The materials used include varieties rice of Inpari 30, inorganic fertilizer Urea (46% N), SP-36 (36%
P2O5), KCL (60% K2O), and water.
The study was conducted using a nested design, with two factors: planting time and cropping patterns as a nested factor in planting time. Planting Time Factor (M) consists of planting in September (M1) and planting in October (M2). The second factor, a nested factor in planting time, consists of 3 levels (CP). Those levels are square cropping pattern (30x30) cm2 (CP1), square cropping pattern (20x20) cm2 (CP2), and cropping pattern of jajar legowo (40x20x12.5) cm2 (CP3). These experiments have six combinations, and these experiments were repeated three times. So, they were 18 units of trial plots, which are 9 m2each plot.
Observations were carried out with destructive and harvest methods.
Destructive observation methods consist of 30, 60, and 90 DAP. The parameters observed were the number of tillers per clump, leaf area per clump, total dry weight of plants, and leaf area index. Observation of harvest includes weight of 1000 seeds, number of seeds per panicle, number of panicles per clump, the weight of grain per square meter, and yeild. Data from observations were tested using Analysis of Variance (F test) at a 5% level to determine the effect of treatment. If the test results show that there is a significant effect, then it is continued with a comparison test between treatments with LSD (Least Significance Different) Test at the level of 5%.
RESULTS AND DISCUSSION Number of tillers
The formation of tillers starts from the beginning of growth and continues to form tillers until the plant enters the generative phase actively. The pattern of rice tillers is multiple tillers (Makarim and Suhartatik, 2009). When the rice plant enters the generative phase, the number of tillers tends to be constant and decreases due to
Table 1. Effect of planting time and cropping pattern on the number of tillers at 30, 60 and 90 days after planting (DAP)
Planting Time Number of Tillers at Plant Age (DAP)
30 60 90
September 7.83 b 19.11b 17.72 b
October 7.11 a 17.22 a 15.89 a
LSD 5% 0.68 0.72 0.68
Cropping Pattern
Square 30 cm X 30 cm 7.67 21.42 b 19.58 b
Square 20 cm X 20 cm 7.42 16.83 a 15.67 a
Jajar Legowo (40 cm x 20 cm x 12,5 cm 7.33 16.25 a 15.17 a
LSD 5 % ns 1.60 1.50
Note: The numbers in each column followed by the same letter are not significantly different at the LSD test level of 5%, DAP: Day After Planting, LSD: Least Significance Different, ns: not significant
competition between the tillers, which causes some tillers. This condition happened on the observation from the beginning of growth until the age of 60 DAP. Initially, the addition of tillers is quite significant, then decreases when the plant enters the generative phase.
Table 1 shows that the treatment of different planting times influenced the number of rice tillers. Planting time in September gives higher tillers than planting time in October. Wide cropping patterns or wide spacing with sufficient nutrient uptake, water, and solar radiation conditions allow plants to form tillers to the maximum. The number of tillers will be maximal if the plants have good genetic traits and environmental conditions suitable for plant growth and development (Husana, 2010). Rice productivity is strongly influenced by the number of tillers formed; the more number of tillers will increase crop yields (Mungara et al., 2013). Although planted firmly, the planting pattern of jajar legowo provides opportunities for plants to grow optimally.
That is because solar radiation reaching the lower canopy.
Furthermore, the planting pattern of jajar legowo can reduce competition between nutrients and water between rows. The
treatment of cropping patterns planted in September gave more number of tillers compared to other treatments (Table 1). This result proves that climatic conditions determine the number of tillers that come out on rice plants and the distance between plants.
Leaf area
The measurement of leaf area of paddy illustrates how much the plant can capture solar radiation to assist in the photosynthesis process. The more extensive plants can absorb the leaves of rice plants, the more solar radiation. In a wide leaf area, the effectiveness of solar radiation absorption is also significant. When the leaves of the plants cover each other, then what happens is that the leaves are inefficient in absorbing solar radiation for planting spacing, which gives the plant a chance to absorb the sun well, one of them is the Legowo jajar method.
The plants in September give a higher leaf area than those planted in October (Table 2).
The treatment of a 30 cm x 30 cm square cropping pattern gives the highest leaf area.
In line with research Kumalasariet al.(2018) stated that the wider plant spacing would increase the leaf area value of rice plants, as
Table 2. Effect of Planting Time and cropping pattern on Leaf Area at Age 30, 60 and 90 DAP Planting Time Leaf Area (cm2plant-1) at Plant Age (DAP)
30 60 90
September 478.87 b 1925.21 b 1696.76 b
October 439.40 a 1786.64 a 1552.06 a
LSD 5% 17.92 66.34 62.79
Cropping pattern
Square 30 cm X 30 cm 482.33 b 2080.35 b 1834.33 b
Square 20 cm X 20 cm 441.26 a 1720.42 a 1506.89 a
Jajar Legowo (40 cm x 20 cm x 12,5 cm 453.82 ab 1767.00 a 1532.00 a
LSD 5 % 39.48 146.20 138.37
Note: The numbers in each column followed by the same letter are not significantly different at the LSD test level of 5%, DAP: days after planting, LSD: Least Significance Different.
well as the narrower spacing plant spacing formed, which will be smaller.
According to the results of research Riantoet al. (2019), rice varieties influenced the changes in the percentage of canopy cover. Meanwhile, rice varieties and cropping patterns affect the light intensity and growing space between rows. However, the intensity of the light at the ground surface will decrease with the rice canopy growth.
The ability of plants to receive radiation depends on the shape of the canopy and the leaf (rate of formation, increase in leaf area, and age of the leaf) and its chlorophyll content (Sopandie, 2013). The increase in leaf area in the plant community is caused by the increase in the number of tillers and the increase in leaf area itself (Makarim and Suhartatik, 2009).
Total Dry Weight of Plants
The observation of whole plant dry weight showed that plants grew and developed as a characteristic of the organism. Plant biomass is the measure most often used in describing plant growth. Each level of observation shows that planting time affects the biomass that is produced by plants. Paddy planted in September, giving a higher biomass weight (Table 3). The treatment of a 30 cm x 30 cm square cropping pattern shows the highest
value compared to other treatments. The accumulation of biomass and total crop yield from plants depends on the plant's efficiency in converting solar radiation into dry matter (Shahidullahet al., 2010).
The wide cropping pattern allows the plant to be maximized in photosynthesis, which will be stored in the form of biomass.
However, the gap between plants is too wide, causing the reduction of plant population area. A large number of tillers will be in line with the addition of plants' total dry weight. At a wide spacing, plants provide space for plants to express their genetic traits maximally coupled with good climate support.
Sometimes, many saplings are not effective because most of the tillers will die due to competition between individual plants.
Leaf Area Index
Leaf area index (LAI) is one of the parameters used in plant growth analysis by comparing the leaf area formed by plants with the area covered. The LAI needed to absorb 95% of the light coming in the rice plant canopy ranges between 4 - 7 for the photosynthesis process or the optimum LAI value required by the plant (Yoshida, 1981).
In this study showed that paddy aged 60 DAP had a higher LAI compared to 90 DAP observations. This result was in line with the
study of San-oh et al.(2004) that LAI in the flowering phase will even reach a value of more than 6. In the early stages of growth, the LAI of plants is low because not many leaves are formed. The treatment pattern of planting shows the influence of different plant spacing on LAI values. Consistently, the highest LAI value in the treatment of cropping patterns is in the jajar legowo cropping pattern. The canopy can completely cover the area where the plants grow (Table 4). In the pattern of planting jajar legowo with sufficient space allows solar radiation to enter the lower leaves.
When planting in September gives a higher leaf area index value, this shows that
the plants planted in September can form better leaves because of the support of more solar radiation intensity. Tabbalet al. (2002) suggested that sunlight plays a very important role in plant physiology. Plant physiology processes such as photosynthesis, respiration, and transpiration. The photosynthesis process is very dependent on the received solar radiation, photosynthesis rate of leaf area per unit, leaf area index and leaf angle. LAI greatly affects the course of photosynthesis;
in other words, LAI will affect plant productivity (Fageria, 2007).
Table 3. Effect of Planting Time and Cropping Patterns on Total Dry Weight of Plants at 30, 60 and 90 DAP
Planting Time Dry Weights at Plant Age (g plant-1) (DAP)
30 60 90
September 12.83 b 39.81 b 68.32 b
October 12.01 a 36.72 a 63.82 a
LSD 5 % 0.70 0.78 1.28
Cropping pattern
Square 30 cm X 30 cm 12.48 42.68 b 77.27 b
Square 20 cm X 20 cm 12.41 35.43 a 59.30 a
Jajar Legowo (40 cm x 20 cm x 12,5 cm 12.36 36.69 a 61.64 a
LSD 5 % ns 1.72 2.81
Note: The numbers in each column followed by the same letter are not significantly different at the LSD test level of 5%, DAP: Days After Planting, LSD: Least Significance Different, ns: not significant
Table 4. Effect of Planting Time and cropping pattern on Leaf Area Index (LAI)
Planting Time Leaf Area Index at Plant Age (DAP)
30 60 90
September 0.98 b 3.92 b 3.45 b
October 0.90 a 3.63 a 3.14 a
LSD 5% 0.04 0.11 0.15
Cropping Pattern
Square 30 cm X 30 cm 0.54 a 2.31 a 2.04 a
Square 20 cm X 20 cm 1.07 b 4.30 b 3.77 b
Jajar Legowo (40 cm x 20 cm x 12,5 cm 1.21 c 4.71 c 4.09 c
LSD 5 % 0.09 0.24 0.33
Note: The numbers in each column followed by the same letter are not significantly different at the LSD test level of 5%, DAP: Days After Planting, LSD: Least Significance Different.
Table 5. Effect of Planting Time and Cropping pattern on the Number of Seeds Per Panicle, Number of Panicles Per Clump, Weight of Seeds Per Clump, Total Dry Weight of Plants, Seed Weight Per Square Meter and Yield
Planting Time NSP NTH GWC TDWH SWM2 Yield
(t ha-1)
September 125.32 b 15.44 b 41.35 b 106.04 b 822.93 b 6.99 b
October 117.57 a 13.67 a 37.68 a 97.98 a 738.03 a 6.27 a
LSD 5 % 7.65 0.50 1.04 2.43 31.10 0.26
Cropping Pattern
Square (30x30) cm 132.36 b 16.17 b 52.01 b 118.86 b 614.97 a 5.23 a Square (20x20) cm 114.64 a 13.42 a 33.05 a 92.06 a 825.87 b 7.02 b Jajar Legowo (2 :1) 117.33 ab 14.08 a 33.49 a 95.13 a 900.62 c 7.66 c
16.86 1.09 2.28 5.36 68.55 0.58
Note: Numbers in each column followed by the same letter are not significantly different at LSD test level 5%, DAP:
Days After Planting, LSD: Least Significance Different, NSP: Number of Seedlings per Panicle, NTH: Number of Panicles per Clump, GWC: Grain Weight per Clump, TDWH: total dry weight of harvest, SWM2: seed weight per square meter, ns: not significant
Harvest
Observation of yield components in this study included the number of panicles per clump, number of seeds per panicle, the weight of seeds per clump, the weight of seeds per square meter, total dry weight of plants, and yield. The analysis of variance's result on the component results showed the effect of treatment on the observed parameters.
The results showed that the plants planted in September had higher yields on observed harvest parameters. This research shows that climatic conditions and the environment of growing plants affect plant growth and development. According to Wassmann et al. (2009), several stages of paddy growth are affected by temperature, solar radiation, and rainfall intensity. Those several stages of paddy growth are vegetative phase, phenological development, source organ formation, and seed filling. The role of element N is also very influential on panicle formation, especially in female panicles (Makarim and Suhartatik, 2009).
According to Yang et al. (2008), solar radiation is a determining factor, especially in
the ripening phase, accumulation of biomass, especially when filling grain, sink production capacity per unit of biomass and when flowering is a critical factor causing differences in yield between the dry season and rainy season on land irrigated rice fields.
Furthermore, rice yields in the dry season are higher than in the rainy season.
In the parameters of the number of seedlings per panicle, the number of panicles per clump, seed weight per clump and total dry weight of plants at harvest treatment square 30 cm x 30 cm cropping pattern gives a higher yield whereas on seed weight per square meter and productivity of rice plants cropping patterns jajar legowo gives a higher value. In the maximum population of jajar legowo cropping pattern, plants can get full solar radiation. In the parameters of the weight of the square seed per meter and productivity of the cropping pattern of jajar legowo give a maximum population so that it helps in increasing the productivity of rice plants. The treatment of jajar legowo cropping patterns gives a more significant yield of 7.66 t ha-1. In line with the results of research Anggraeniet al. (2013)
Figura 1. Intensity of solar radiation and rainfall in the Malang region from September 2019 to January 2020 (BMKG, 2020)
showed the jajar legowo planting system on Inpari 13 variety, had panicle per clump, 1000 grain weight and grain weight per clump were the same as the square planting system but resulted in the production of yield 6.47 t ha-1 which is higher than the square planting system which only produces 5.67 t ha-1. A right growing environment, supported by sufficient nutrients and water, will make plants grow optimally. Wide cropping patterns allow plants to grow optimally individually, but in land use, it is not sufficient because of the large amount of unplanted land.
The application of jajar legowo planting system has several advantages. The advantages are that sunlight can be used more for photosynthesis, fertilization and control of plant pests organisms become easiest. It has the opportunity to produce higher grain compared to the way of planting tiles through more populations, more varieties Adaptive to dense cropping conditions, which is shown by the low decrease in yield due to dense plantings compared to the usual planting/tile (Ikhwani et al., 2013).
The intensity of solar radiation in September and October 2019, the daily average reached 536.31 cal cm-2 day-1 and 571.10 cal cm-2 day-1. In November, when the plants planted in September entered the reproductive phase, the average daily intensity was still high at 525.47 cal cm-2day-
1, this much helped the plant in maximizing the photosynthetic process. Different things were seen in rice plants that were planted in October when the plants entered the reproductive phase, at the age of 60 DAP the average intensity of solar radiation received an average of 418.42 cal cm-2day-1. Yoshida (1981) said that solar radiation had little effect on the growth of rice in the vegetative phase but in the reproductive and cooking phases of solar radiation was very instrumental in increasing crop productivity.
Solar radiation of 300 cal cm-2 day-1during the reproductive stage allows yields of 5 t ha-
1. To increase the productivity of rice plants need to pay attention to the right time to start planting, the dry season with high solar radiation would be suitable to start cultivating rice in irrigated land. Besides, the utilization of jajar legowo cropping patterns will be able
to increase plant efficiency in the utilization of solar radiation, land, and also the process of plant maintenance.
CONCLUSION
The planting time of September has better growth and development of paddy compared to planting in October. Individual plants with 30 cm x 30 cm square cropping pattern give better results especially on the parameters of the total dry weight of plants, number and area of leaves, number of panicles per clump, number of seedlings per panicles, the weight of grain per clump and total dry weight of harvest. However, on the parameters of leaf area index, plant growth rate, percentage of productive tillers, weight per square meter and rice productivity of cropping pattern of jajar legowo 40 cm x 20 cm x 12.5 cm can give the best results. Rice productivity is greatly influenced by planting time and cropping patterns. Rice plants planted in September produced higher productivity at 6.99 t ha-1. While rice planted with jajar legowo cropping patterns (40 cm x 20 cm x 12.5 cm) can increase yields up to 7.66 t ha-1.
ACKNOWLEDGMENT
The author would like to thank to all those who have helped in this study, especially to Faculty of Agriculture, Brawijaya University and also Department of Agriculture and Food Crops, Tebo Regency Government of Indonesia.
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