PENGARUH CARA PENGAIRAN DENGAN AIR SALIN TERHADAP PERTUMBUHAN DAN HASIL PADI (Oryza sativa L.)

ADLIAN, Ir.Budiastuti Kurniasih, M.Sc.Ph.D.;Prof.Dr.Ir.Didik Indradewa,Dip.Agr.St.

2017 | Tesis | S2 Agronomi

Penelitian ini bertujuan untuk mengetahui pengaruh irigasi salin genangan, berselang, dan macak-macak terhadap pertumbuhan dan hasil tanaman padi. Penelitian dilakukan di kebun penelitian Tri Dharma Fakultas Pertanian, Universitas Gadjah Mada, yang berlokasi di Bantengan, Banguntapan, Bantul, DI. Yogyakarta pada bulan Agustus – November 2015. Penelitian menggunakan percobaan lapangan faktorial Split-plot dengan empat kali ulangan. Petak utama (main plot) yaitu irigasi yang terdiri dari tiga aras yaitu irigasi genangan, irigasi berselang, dan irigasi macak-macak. Anak petak (sub plot) adalah tingkat salinitas yang terdiri dari dua aras yaitu tanpa perlakuan salin (EC ̴ 0,3 dS/m) dan salin (EC ̴ 4,9 dS/m). Salinitas menghambat pembentukan asimilat tanaman dan translokasi asimilat yang ditunjukkan pada penurunan tinggi tanaman, jumlah anakan, luas daun, bobot kering tanaman, laju asimilasi bersih, dan laju pertumbuhan nisbi, yang berdampak pada penurunan hasil tanaman antara lain indeks panen, jumlah gabah per rumpun, bobot gabah per rumpun, serta persentase gabah isi. Irigasi cara genangan dan berselang mampu meningkatkan luas daun, laju fotosintesis, kerapatan stomata, panjang stomata, jumlah anakan, bobot kering toal tanaman, umur panen, nisbah akar tajuk, dan jumlah gabah per rumpun dibandingkan dengan cara macak-macak. Irigasi dengan cara macak-macak pada kondisi salin menurunkan pertumbuhan dan hasil tanaman dibandingkan dengan cara genangan dan berselang yang ditunjukkan pada penurunan kandungan prolin, kandungan klorofil total daun, bobot kering akar, dan jumlah malai.

This present field experiment aimed to study the growth and yield of rice under three irrigation methods which were in permanently flooded, wet/dry, and saturated soil condition. The experiment was performed at field station of Faculty of Agriculture, Universitas Gadjah Mada located on Bantengan, Banguntapan, Bantul, DIY, started from August to November 2015. The treatments were arranged in a four replicate split-plot with three irrigation methods occupying the main plot and two levels of salinity on the subplot. Three irrigation methods were permanent irrigation (flooded soil), intermittent irrigation (wet/dry soil), and irrigation above field capacity (saturated soil). Two levels of salinity were fresh water as a control (EC ï‚» 0.3 dS/m) and saline water (EC ï‚» 4.9 dS/m). The experimental results showed that salinity inhibited the assimilate production and translocation indicated by the decrease of plant height, number of tillers, leaf area, plant dry weight, net assimilation rate, and relative growth rate. Those all led to the decrease of plant yield, including harvest index, number of grain per hill, and percentage of filled grain. The permanent and intermittent irrigation were more effective than the irrigation above-field capacity as they were able to increase leaf area, photosynthetic rate, stomatal density, stomatal length, and number of tillers as well as to improve total plant dry weight, harvest time, root to shoot ratio, and number of grain per hill. Meanwhile, the irrigation above field capacity under saline condition reduced the growth and yield of rice compared to the permanent and intermittent irrigation as denoted by the decrease of proline content, leaf total chlorophyll content, root dry weight, and number of panicle.

Kata Kunci : Padi (Oryza sativa L.), Salinitas, Irigasi, Genangan, Berselang, Macak- macak