Water balance analysis on water management of organic System of Rice Intensification (organic-SRI) in West Java, Indonesia

Abstract

ABSTRAKPenelitian ini dilakukan untuk menganalisa efektifitas irigasi berselang dengan neraca air pada lahan SRI dengan penerapan pupuk organik. Eksperimen dilakukan di Desa Gabus Wetan, Kab. Indramayu, Jawa Barat dari 17 November 2016 sampai 1 Maret 2017. Sensor parameter cuaca dan tanah dipasang di lahan untuk mendapatkan data harian kondisi lapang termasuk pertumbuhan tanaman. Data cuaca seperti hujan, suhu udara, kelembaban udara relatif, dan kecepatan angin dan kedalaman muka air diukur secara otomatis setiap 60 menit. Analisis neraca air dilakukan dengan kesalahan (error) yang rendah (1,00%) dimana jumlah air masuk melalui hujan dan irigasi sebesar 560 mm dan 865 mm, sedangkan jumlah air keluar melalui evapotranspirasi tanaman, perkolasi, dan limpasan berturut turut sebanyak 430, 306 dan 675 mm. Perbandingan dengan sistem pertanian konvensional dengan irigasi tergenang, menunjukkan bahwa produktivitas air dari SRI organik berturut turut 30% dan 27% lebih tinggi untuk produktivitas air berdasarkan jumlah air masuk dan evapotranspirasi. SRI organik juga memproduksi 33% produksi lebih tinggi dari sistem pertanian konvensional di lokasi yang sama. Kunci keberhasilan irigasi berselang adalah dengan menjaga tinggi muka air dipermukaan tanah (macak-macak) pada fase vegetatif dan generatif. Oleh sebab itu, cara ini merupakan alternatif pilihan bagi petani ketika sumber daya air berkurang karena perubahan iklim. Diseminasi hasil direkomendasikan melalui program pelatihan dan pendampingan bagi petani.Kata Kunci: SRI organik, pengelolaan air, neraca air, produktivitas, sistem monitoring ABSTRACTThe current study was carried out to analyze effectiveness of intermittent irrigation by water balance components in SRI paddy fields with organic fertilizer. The experiment was conducted in Gabus Wetan Village, Indramayu District, West Java, Indonesia from 17 November 2016 to 1 March 2017. Weather and soil sensors were set up in the fields to acquire data on daily field conditions as well as on plant growth. Data on weathers such as precipitation, air temperature, relative humidity, and wind speed were collected automatically during the season every 60 min, as well as the soil water depth. Analyzing the data collected, water balance analysis was well performed with low error (1.00%) in which the water inflows through precipitation and irrigation were 560 mm and 865 mm, respectively, while the outflows by crop evapotranspiration, percolation, and runoff were 430, 306 and 675 mm, respectively. Compared to conventional rice farming as commonly practices by applying continous flooding irrigation, water productivities of organic SRI were 30% and 27% higher with respect to total water input (WPIR) and with respect to the amount of evapotranspiration (WPET, respectively. Organic SRI produced 33% higher yield than the average of conventional methods in the same subdistrict. The key was intermittent irrigation by maintaining shallow water depth (nearly soil surface) in the vegetative and generative stages. Therefore, it is an attractiv...

Evaluation of Growth, Yield, and Water Productivity of Paddy Rice with Water-Saving Irrigation and Optimization of Nitrogen Fertilization

“…However, reduction in rice yield was also reported by [4,38]. Arif et al [4] summarized 31 published research studies on AWD and concluded that 92% of AWD treatments led to yield decreases compared with continuously flooded treatments. The differences in frequency and threshold of the drying cycles of the AWD, soil types, groundwater table depths, and rice varieties used may contribute to the contrasting results.…”

“…Water is essential for growth and development of rice plants. However, continuous flooding irrigation results in a large amount of unproductive water outflows through evaporation, seepage through bunds, runoff, and deep percolation [4][5][6][7]. This causes loss of nutrients from the field and pollution of groundwater supplies.…”

“…The selection of water-saving methods and the optimum thresholds for obtaining maximum benefits of these regimes are largely site-specific, depending mainly on soil type, management, and the environment [24]. Examples of water-saving methods includes saturated soil culture [25], aerobic rice [26], system of rice intensification [27], non-flooded mulching cultivation [28], safe alternate wetting and drying irrigation (AWD) [4,29], among others. Among these methods, safe AWD is a practice in which water is applied to the field in a number of days after the disappearance of ponded water.…”

“…Water productivity and the response of rice under AWD irrigation is highly variable. Studies have demonstrated that AWD can save irrigation water and improve productivity compared with traditional flood irrigation [4,31,33], but the effect of AWD on rice yield is still in debate in most of African countries where few studies have been conducted. Several studies have shown that the adoption of AWD can maintain [33] or increase rice yield from 9% to 15% [33][34][35][36][37].…”

“…Several studies have shown that the adoption of AWD can maintain [33] or increase rice yield from 9% to 15% [33][34][35][36][37]. However, reduction in rice yield was also reported by [4,38]. Arif et al [4] summarized 31 published research studies on AWD and concluded that 92% of AWD treatments led to yield decreases compared with continuously flooded treatments.…”