Biostimulasi pertumbuhan vegetatif tanaman tebu (Saccharum officinarum L.) pada fase awal di lahan kering (Biostimulation of vegetative growth of sugarcane (Saccharum officinarum L.) in the initial phase on dry land)

AbstractThe expansion of sugarcane areas as a support to national sugar production has shifted to sub-optimal dry land. In drought stress conditions, early growth of sugarcane usually can inhibite and decrease its productivity. This study aimed to test the efficacy of organic biostimulant in increasing vegetative growth of sugarcane in the dry land. Firstly, seedlings were submerged with biostimulant of Citorin-Rfor overnight. Secondly, the biostimulant application of Citorin-S was carried out by foliar sprayat age1 and4 months old trees. Humicacid 0.5% (v/v) was applied in soil before planting while the application of mycorrhiza was carried out by direct pouring on soil during planting. The results showed that the initial vegetative growth of biostimulant-treated sugarcane stem diameter and length were 23% wider and 27% higher compared to that of control, respectively. In subsequent growth cycle, all observed vegetative parameters showed higher growth value in the biostimulant-treated sugarcanes than that of the control. Plant height, stem diameter and number of tillers of biostimulant-treated sugarcanes had significantly higher values than that of the control. P3 treatment (organic biostimulant plus humic acid and mycorrhiza) was the best treatment. The height and diameter of P3 sugarcane stems were 47% wider and 59% higher, respectively, compared to that of control at 107 DAP.[Keywords: biostimulant, plant height, stem diameter, number of tillers, number of leaves] Abstrak Penambahan areal tanaman tebu untuk mendukung peningkatan produksi gula nasional telah bergeser ke areal sub-optimal lahan kering. Pada kondisi cekaman kekeringan, pertumbuhan awal tebu biasanya terhambat dan dapat menurunkan produktivitas saat panen. Penelitian ini bertujuan menguji efikasi biostimulan organik untukmeningkatkan pertumbuhan vegetatif tanaman tebu pada fase awal di lahan kering. Perlakuan biostimulan Citorin-R diaplikasikan pada benih dengan cara perendaman semalam. Perlakuan kedua, biostimulan Citorin-S disemprotkanpada saat tanaman tebu berumur 1 dan 4 bulan secara foliar spray. Aplikasi asam humat 0,5 % (v/v) di tanah dilakukan sebelum tanam, sedangkan aplikasi mikoriza dilakukan dengan pemberian langsung pada tanah saat penanaman bagal tebu. Hasil penelitian menunjukkan bahwa nilai pertumbuhan vegetatif awal tanaman tebu perlakuan memiliki diameter batang sekitar 23% dan tinggi tanaman 27% lebih tinggi daripada tebu kontrol. Pada pertumbuhan selanjutnya, semua parameter vegetatif yang diamati menunjukkan nilai pertumbuhan yang lebih tinggi pada tanaman tebu perlakuan daripada kontrol. Tinggi tanaman, diameter batang dan jumlah anakan secara statistik berbeda nyata lebih tinggi pada tanaman tebu perlakuan daripada kontrol. Perlakuan P3 (biostimulan organik plus asam humat dan mikoriza) adalah perlakuan terbaik. Tinggi dan diameter batang tanaman tebu P3 masing-masing 47% dan 59% lebih besar daripada batang tanaman kontrol pada 107 hari setelah tanam (HST).  [Kata kunci :biostimulan, tinggi tanaman, diameter batang, jumlah anakan, jumlah daun]