Effect of rates and sources of nitrogen on rice yield, nitrogen efficiency, and methane emission from irrigated rice cultivation

Abstrak. Unsur hara Silika (Si) memiliki peranan penting pada pertumbuhan dan produktivitas tanaman padi. Tanaman padi menyerap Si dalam jumlah yang besar yaitu sekitar 10 kali N, 20 kali P, 6 kali K dan 30 kali Ca. Budidaya padi di lahan rawa memiliki beberapa faktor pembatas yang mempengaruhi pertumbuhan dan produktivitas padi diantaranya keracunan unsur toksik seperti Fe dan Al. Kadar unsur toksik terutama Fe di lahan rawa menyebabkan tanah menjadi masam, sehingga banyak tanaman yang tidak dapat beradaptasi dengan kondisi tersebut. Kondisi ini dapat diatasi diantaranya dengan aplikasi Si, yang berperan menurunkan serapan Fe dan Al yang berada dalam kondisi toksik. Beberapa hasil penelitian menunjukkan bahwa Si berpengaruh dalam menurunkan tingkat toksisitas Al dan Fe di tanah. Aplikasi Si sebagai amelioran mengurangi kandungan Fe pada permukaan akar padi serta menurunkan serapan Fe pada tanaman padi sawah melalui peningkatan kekuatan oksidasi akar. Lebih lanjut, aplikasi Si pada budidaya tanaman padi dapat meningkatkan hasil gabah sebesar 50,8%. Abtract. Silicon (Si) has an important role on rice crops growth and productivity. Rice crops absorbs enormous amount of Si as much as ten times of N, twenty times of P, six times of K and thirty times of Ca. Rice cultivation in swampland has several limiting factors such as Fe and Al toxicity. Fe toxicity could increase soil acidity in swampland. However, most plants could not adapt to this condition. Si application as soil ameliorant could be an option to overcome this problem. Si could reduce the toxicity level of Fe and Mn in soil. Previous research proved that Si could decrease Fe and Al toxicity. Si application as ameliorant could reduce Fe concentration in root zone which lead to decreasing Fe uptake through increasing oxidation capability of the root. Moreover, Si application could increase rice yield up to 50.8%..

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WATER MANAGEMENT AND METHANE EMISSION FROM RICE CULTIVATION: A CASE STUDY IN AN GIANG PROVINCE, VIET NAM

Vietnam Journal of Science and Technology ◽

10.15625/2525-2518/54/2a/11916 ◽

2018 ◽

Vol 54 (2A) ◽

pp. 91

Author(s):

Duong Mai Linh

Keyword(s):

Water Management ◽

Global Warming ◽

Rice Yield ◽

Soil Surface ◽

Water Levels ◽

Rice Cultivation ◽

Viet Nam ◽

Ch4 Emission ◽

Wetting And Drying

Rice cultivation causes the emission of CH4 consequenced to the global warming. Reduction of irrigation in rice cultivation is not only saving water resources but also reducing greenhouse gases emission. The objectives of this study was to determine impacts of water management on the emission of CH4 and rice yield. Experiment was conducted in field conditions in An Giang province, Viet Nam with three treatments as continuous flooding (CF), An Giang Alternative Wetting and Drying (AAWD) which is mostly applied by farmers in An Giang province-Viet Nam, and Alternate Wetting and Drying (AWD). Water levels in the field +5 cm, ± 5 cm and -15 cm were controlled higher, fluctuated and lower than soil surface, respectively for CF, AAWD and AWD. CH4 emission determined every week during 13 weeks of the experiment. Rice yield was determined in 1 m2 at the end of the experiment. The results showed that AWD and AAWD, respectively decreased 78.7 % (p < 0.05) and 6.8 % (p > 0.05) CH4 emission compared to the CF 11.9 mg CH4/m2/h. The rice yield of CF was 6.32 ton/ha lower than AAWD 7.8 ton/ha (p < 0.05) but not different with AWD 6.67 ton/ha. AAWD had higher rice yield but same emission than the CF. Farmers in An Giang province should consider application of AWD in rice cultivation in term of saving water and reduction of CH4 emission.

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