The Research Team of IPB Responds Lodging Phenomenon That Caused losses
Lodging is the bending over of the stems near the ground level in grain crops, which makes them very difficult to harvest and can dramatically reduce yield. Lodging in rice production often limits grain yield and quality by breaking or bending stems. Yield was reduced by reduction in the grain size and number or by reducing the amount of crop that can be recovered by the combine harvester. From earliest times, farmers believed the phenomenon that excessive nitrogen (N) fertilizer rates are the cause of poor lodging resistance in rice, but little is known about the effect of top-dressing N application rates on the mechanical strength of japonica rice plants, especially how the anatomical structure in culms is affected by N. Although it is partly true that the loss of rice production is due to extreme weather, but such phenomenon has not been widely studied.
Such hot issues encouraged the research team of the Department of Agronomy and Horticulture, Faculty of Agriculture of Bogor Agricultural Institute (FAPERTA IPB), namely Edi Santosa, Herdhata Agusta, Dwi Guntoro and Sofyan Zaman; and researchers of the Department of Food Crop Cultivation, Lampung State Polytechnic, Dulbari, implemented a research program on phenomenon of rice lodging. The research was carried out in February-March 2016, in four provinces, namely West Java (Bogor and Karawang), Lampung (Banra Lampung, Central Lampung, South Lampung, and Mesuji), West Nusa Tenggara (West Lombok, Central and East, and West Sumbawa, Bima), and Daerah Istimewa Yogyakarta (Bantul, Kulon Progo, Wonogiri, and Sleman).
Most studies of the influence of weather and climate on food production have examined the influence on crop yields. However, climate influences all components of crop production, includes cropping area (area planted or harvested) and cropping intensity (number of crops grown within a year). The purpose of this present study is to mitigate future agriculture loss of rice, due to strong winds and heavy rain. Rice lodging due to extreme weather are observed from the morphological and plant agroecological aspects. The most commonly cultivated rice varieties are IR 64, IR 32, Ciherang, Emerging, Sintanur, Mekongga, Impari, and Loka. All varieties cultivated by farmers are affected by strong winds and torrential rain. According to the farmers' confession, they follow al the advices of Field Extension Officer (PPL) regarding applying standard cultivation technique, the use of recommended varieties, appropriate fertilization and pest eradication. While the nitrogen fertilizer is given according to the recommended dosage.
Increase of planting density has been widely used to increase grain yield in crops. However, it may lead to higher risk of lodging hence causing significant yield loss of the crop. However, plant spacing and plant population do not increase resistance to plodl, although there is a tendency of tile spacing is more vulnerable than row legowo (Plant spacing). However, the plant spacing (20 x 20), row legowo 2, and row legowo 4 can’t prevent from lodging. Reback position is random, there are on the edge of galengan and in the middle of the expanse. The existence of wind-breaking plants such as teak, mahogany, coconut and so forth can not prevent from falling down. There is a tendency, the plant near the wind breaker, has a higher prevalence of falls.
Some farmers in Bantul-DIY with less than 0.2 hectares of paddy field reduce losses due to lodging (aged under 75 days) by binding four clumps of rice into one to erect. But other farmers, especially with a land area of more than 0.5 hectares let the plant bend for lodging. Similar methods are also practiced by farmers of Bogor due to labour and effectiveness reasons, they experienced to have lodged plants more than once. Direction and degree of bending type of lodging are usually determined by direction and strength of wind and rainfall. The directional wind produces bending direction that is parallel to one direction. While the whirlwind to cause a mini hurricane or twisted.
Farmers suspect wind velocity of 50-70 kilometers per hour accompanied by rain caused the bend of the lodge. The figure is by analogy of wind speed while riding a motor similar to the wind speed. Strong rain 21 millimeters per hour and winds speed at 31.6 meters per second (113.76 kilometers per hour) during the typhoon causes the bending of rice stems. BMKG (2010) defines heavy rain is an intensity of more than 20 millimeters per hour and extreme rain is 40 millimeters per hour. However, to clarify the mechanism of lodging due to wind speed need to be investigated further.
Wind pressure and rain are the main factors of the external forces related to the lodging of rice plant. Lodging may be accelerated by the resonance with fluctuation of wind speed. The stronger the wind, the plants other than fall also broken. The ability of a crop to withstand lodging also depends on the length of the stems particularly the length of the peduncle (the distance from the last node to the base of the head). Lodging usually occurs in grain crops when the plant is mature and with filled grain heads, in the days or weeks before harvest. A broken position can be anywhere near a panicle stalk. Breaking of culms started from 1 centimeter to 22 centimeterm. As many as 75 percent of the plants are broken at 0-9 centimeters above ground level, 15 percent at 10-19 centimeters, 7 percent about 20-29 centimeters and the remaining 3 percent at 30 centimeters or more. The broken part is the straw (internode), as the weaken part. Broken on the nose panicles by the wind is usually because the plant has also been attacked by blast disease (Pyricularia orizae).
Lodging begin to occur at age 65 days on IR 64 at Sendangsari Kab Kulon Progo. In other areas, the start of lodging occurs in 70 – 85 days after planting. Lodging at the age of more than 85 days or before harvest by farmers are considered cause no losses. But farmers in Sungai Buaya Village, Mesuji-Lampung District, who cultivated IR 64 and Ciherang varieties loss 10 -20 percent of harvest due to lodging. They were due that their rice fields are were inundated 10 to 12 centimeters before harvest time, in contrast to the generally dry rice farmers. This condition encourages farmers to speed up harvest even though the grain is not ready.
All farmer respondents in NTB, Lampung and DIY stated that the largest production losses occur if lodging of their rice occur when their rice were less than 75 days or the initial filling period. Yield loss comes from poor grain filling, and head loss. Yield losses are greatest when a crop lodges during the ten days following head emergence. Yield losses at this stage will range between 15% and 40%. The losses are greater if the rice field conditions are full of water. Soaked rice has moisture content above 35-40 percent so that the grain is getting black or muddy, and the rice grain quickly yellow if dried late.
The extreme weather losses occur in the field and are evenly distributed across all production centres. For the area affected by about 3-5 percent of the harvested area, the flooding is not due to excessive N granting but by the combination of high winds and high rainfall. The harvest losses are dependent on the age of the plants when they start to lodge. Theoretically, the lodge occurs because the clump of rice aerodynamically becomes a barrier of wind rate. Plants with low aerodynamics easily fall down because of the mass of the wind is greater. Coupled with the mass of rain water, the pressure on the rice stem is greater.
Several rice varieties were evaluated for each lodging treatment and planting date at each location. The selection of rice variety resistance or tolerance to major diseases, insects, and other stresses including aerodynamics is important. Several factors that are suspected to affect rice aerodynamics are number of tiller, number, length and width of leaves, plant height, length and number of panicles, and number of grains of rice. It is expected that the rice variety will Aerodynamic lodging resistance so that the angle to lodging will be less 90 degrees in order to minimize the loss. Varieties for aerodynamic rice assembly are available, for example, high-yielding varieties of about 115 centimeters resistant to IR-48, Cilamaya Emerging, Way Seputih and Cibodas, while short varieties of 90 centimeters are IR-36, IR-70 and Citanduy. (Wied)
