Pengaruh Sistem Tanam dan Pemberian Jerami Padi Terhadap Emisi Metana dan Hasil Padi Ciherang di Ekosistem Sawah Tadah Hujan

Abstract

Lahan sawah tadah hujan umumnya mempunyai produktivitas tanah dan tanaman rendah akibat rendahnya tingkat kesuburan tanah dan curah hujan tidak menentu. Perbaikan sifat fisik, kimia, dan hayati tanah sawah tadah hujan dapat dilakukan dengan pemberian pembenah oganik seperti jerami padi. Sedangkan peningkatan produktivitas sawah tadah hujan dapat ditempuh melalui pemberian pembenah organik dan pengelolaan tanaman. Namun pemberian pembenah organik dan pengelolaan tanaman padi dapat
berpengaruh terhadap emisi gas rumah kaca, terutama emisi gas metana (CH4). Penelitian lapang yang dilaksanakan di lahan sawah tadah hujan bertujuan untuk mengetahui pengaruh pemberian jerami padi dan sistem tanam padi terhadap emisi metana dan hasil padi. Percobaan dilakukan menggunakan rancangan acak kelompok, tiga ulangan, dan enam perlakuan kombinasi sistem tanam dan pemberian jerami padi. Padi yang ditanam dengan sistem tanam benih langsung memberikan pertumbuhan lebih baik, hasil gabah lebih tinggi, dan mengemisi CH4 lebih rendah dibandingkan dengan sistem tanam pindah. Sistem tanam benih langsung mampu menurunkan emisi metana ratarata 33,3 persen dan meningkatkan hasil gabah padi Ciherang rata-rata 76 persen
dibandingkan pada sistem tanam pindah. Pemberian jerami padi pada sistem tanam benih langsung nyata mengemisi metana lebih rendah dan menghasilkan gabah lebih tinggi daripada pada sistem tanam pindah. Jerami padi yang diberikan dalam bentuk melapuk cenderung mengemisi CH4 lebih rendah daripada dalam bentuk jerami segar. Hasil gabah tinggi dan emisi CH4 relatif rendah tercapai bilamana jerami padi diberikan dalam bentuk lapuk dan padi ditanam dengan sistem tanam benih langsung.

Rain-fed rice field generally has low productivity due to poor soil fertility and erratic rainfall. Physical, chemical, and biological properties of the soil can be improved by applying organic amendment such as rice straw. Moreover the productivity of rein-fed rice field can be improved by crop establishment. However, organic amendment application and crop establishment affect the greenhouse gases emission, especially methane (CH4). The field experiment was conducted in rain-fed rice field to evaluate the effect of rice straw application and crop establishment on methane emission and grain yield of rainfed rice crop.The experiment used randomized block design with three replications and six treatments of combination of crop establishment and rice straw application. Rice crop with direct seeding system gave better growth, higher grain yield as well as lower methane emission than that of with transplanting system. Direct seeding system could decrease average methane emission by 33.3 percent and increase average grain yield by 76 percent compared with transplanting system. Rice straw application in direct seeding system significantly reduced methane emission and increased yield of the grain than that of transplanting system. The composted straw application emitted less CH4 than that of fresh straw. The improved yield and the relatively low CH4 emission were reached when composted rice straw was incorporated and combined with direct seeding systems.