Status salinitas, varietas padi (Oryza Sativa L.) dan macam pembenah tanah untuk lahan sawah terdampak intrusi air laut di pantai utara Demak

Rina Kartikawati, Ir. Budiastuti Kurniasih, PhD; Eka Tarwaca Susila Putra, SP, MP, PhD; Dr. Ir. Eko Hanudin, MP

2025 | Disertasi | S3 Ilmu Pertanian

Tantangan budidaya di pesisir pantai adalah salinitas yang menyebabkan hasil padi lebih rendah dibandingkan dengan sawah normal. Selain itu adanya peluang menyumbangkan emisi metana karena pengairan terus-menerus. Penelitian bertujuan untuk menentukan status salinitas; memilih varietas padi toleran salinitas, hasil tinggi, dan rendah emisi metana; mengkaji mekanisme ketahanan salinitas dan mendapatkan bahan amelioran yang dapat menurunkan salinitas, meningkatkan hasil padi dan rendah emisi gas metana pada lahan terdampak intrusi air laut. Penelitian dilaksanakan melalui empat tahap. Penelitian tahap 1 dilaksanakan dengan pengambilan sampel tanah di Kecamatan Wedung, Demak. Penelitian tahap 2 dilaksanakan di Desa Berahan Kulon (lahan salin) dan Desa Kenduren (lahan non salin) menggunakan varietas Ciherang, Inpari 32, Inpari 34, Inpari 35, Biosalin 1, Biosalin 2, Unsoed 79, dan Inpari 30. Penelitian disusun secara acak kelompok dengan empat ulangan. Penelitian tahap 3 dilaksanakan di rumah kasa dengan menggunakan gipsum (17 t ha-1) dengan aras 8,5; 12,75; 17; dan 21,25 t ha-1; kompos enceng gondok, kompos jerami padi, dan biochar sekam padi (10 t ha-1) dengan aras 5; 7,5; 10; dan 12,5 t ha-1. Penelitian tahap 4 dilaksanakan di Desa Berahan Kulon (lahan salin) menggunakan varietas Ciherang, Inpari 32, Biosalin 1, dan Inpari 30 dengan bahan pembenah biochar 7,5 t ha-1. Hasil penelitian menunjukkan nilai DHL lahan sawah pesisir Kec. Wedung berkisar antara 0,35 – 4,96 dSm-1. Semakin dekat lokasi sawah dengan pantai, nilai salinitas juga semakin meningkat. Varietas padi Ciherang, Inpari 32, Biosalin 1, dan Inpari 30 dipilih sebagai varietas toleran salinitas, hasil tinggi, dan rendah emisi metana. Varietas padi yang toleran terhadap cekaman salinitas mempunyai multi-mekanisme ketahanan yang berbeda-beda dengan metode produksi SOD, escape, dan sintesis prolin. Penggunaan biochar sekam padi, 7,5 t ha-1 mampu menurunkan nilai DHL sampai dengan 2,35 dSm-1, meningkatkan hasil padi sebesar 6,3?n signifikan menurunkan emisi metana sebesar 33% dibandingkan dengan tanpa penggunaan biochar.

The challenge of cultivation in coastal areas is salinity, which causes lower rice yields compared to normal rice fields.  Additionally, continuous irrigation also has the potential to contribute to methane emissions. The research aims to determine salinity status; select salinity-tolerant, high-yielding, and low in methane emissions rice varieties; examine the mechanisms of salinity resistance and obtain ameliorative materials that can reduce salinity, increase rice yields, and lower methane emissions in areas affected by seawater intrusion. The research was conducted in four stages. In the first stage of the study, soil samples were collected from Demak's Wedung District. Second stage was conducted in Berahan Kulon Village (saline soil) and Kenduren Village (non-saline soil) using the Ciherang, Inpari 32, Inpari 34, Inpari 35, Biosalin 1, Biosalin 2, Unsoed 79, and Inpari 30 varieties.  The research was arranged in a randomized block design with four replications. Third stage of the research was carried out in a greenhouse using gypsum (17 t ha-1) at levels of 8,5; 12,75; 17; dan 21,25 t ha-1; water hyacinth compost, rice straw compost, and rice husk biochar (10 t ha-1) at levels of 5; 7,5; 10; dan 12,5 t ha-1.  Fourth stage was conducted in Berahan Kulon Village (saline soil) using the varieties of Ciherang, Inpari 32, Biosalin 1, and Inpari 30 with a biochar amendment of 7.5 t ha-1. According to the study's findings, the EC value of coastal rice fields in Wedung District ranges from 0.35 to 4.96 dSm-1. The salinity value increases with the distance between the rice field and the coastline. Ciherang, Inpari 32, Biosalin 1, and Inpari 30 were chosen as low-methane-emission, high-yielding, and salt-tolerant rice cultivars. Multiple resistance mechanisms are present in rice varieties during salt stress, in a unique way through SOD production, escape, and proline synthesis. The use of rice husk biochar, 7.5 t ha-1, can reduce the EC value to 2.35 dSm-1, increase rice yield by 6.3%, and significantly reduce methane emissions by 33% compared to without the use of biochar.  

Kata Kunci : intrusi, salinitas, varietas, biochar, kompos, emisi metana/ intrusion, salinity, rice variety, biochar, compost, methane emission