Pengaruh Tutupan Lahan Terhadap Sifat Kimia Serta Fluks CO2 Di Lahan Jagung Dan Lapangan Rumput Pada Inceptisol Dramaga

Abstract

Perubahan iklim yang saat ini dihadapi sebagian besar dipicu oleh melonjaknya kadar gas rumah kaca di atmosfer, terutama karbon dioksida (CO2). Aktivitas manusia seperti pertanian menjadi salah satu kegiatan yang aktif dalam meningkatkan konsentrasi atmosfer dari gas rumah kaca dan pemancaran radiasi. Penelitian ini bertujuan menganalisis distribusi sifat kimia dan total mikrob tanah, dinamika fluks CO2 pada pertanaman jagung, serta hubungannya dengan pemupukan dan faktor suhu, serta membandingkannya dengan lahan lapangan rumput. Penelitian dilaksanakan pada Inceptisol Dramaga, Kebun Percobaan Cikabayan dan Lapangan Rumput Kampus IPB Dramaga. Pengukuran fluks CO2 menggunakan metode sungkup dinamis dan Li-Cor 830 dengan prinsip Infrared Gas Analyzer (IRGA). Hasil penelitian berdasarkan analisis ragam (ANOVA) menunjukkan bahwa kandungan K-potensial, P-tersedia dan Fe-tersedia meningkat nyata setelah masa tanam (10 MST). Nilai pH tanah, P-tersedia, P-potensial, Fe dan Mn tersedia berbeda nyata antar tutupan lahan, sedangkan kandungan C-organik, dan total mikrob tidak berbeda nyata secara statistik. Pemberian berbagai dosis pupuk NPK (0; 0,5; 0,75; dan 1 STD) serta perbedaan posisi lereng tidak memberikan Perbedaan nyata (p > 0.05) terhadap fluks CO2 pada seluruh fase pretumbuhan jagung. Meskipun demikian, terdapat peningkatan emisi dari fase lahan bera (0,36–0,51 Mg ha-1 minggu-1) hingga fase pascapanen (1,05–1,31 Mg ha-1 minggu-1). Analisis regresi menunjukkan bahwa suhu tanah dan udara memiliki kontribusi terhadap nilai fluks CO2 walaupun pengaruhnya relatif kecil. Nilai kumulatif emisi CO2 tertinggi selama masa penelitian berasal pada lahan pertanaman jagung (16,42 Mg CO2 ha-1) dibandingkan lapangan rumput (2,46 Mg CO2 ha-1). Nilai fluks CO2 sangat dipengaruhi oleh jenis tutupan lahan dan faktor-faktor lingkungan lainnya yang dapat mempengaruhi (suhu udara, suhu tanah, pengelolaan lahan dan kemiringan lereng).

The climate change we are currently facing is largely driven by soaring levels of greenhouse gases in the atmosphere, particularly carbon dioxide (CO2). Human activities such as agriculture are among the main contributors to the increase in atmospheric concentrations of greenhouse gases and radiative forcing. This study aims to analyse the distribution of soil chemical properties and total soil microorganisms, the dynamics of CO2 fluxes in maize crops, and their relationship with fertilisation and temperature factors, whilst comparing these with grassland plots. The research was conducted on Inceptisol in Dramaga, at the Cikabayan Experimental Farm and on the grassland at the IPB Dramaga Campus. CO2 flux measurements were taken using the dynamic hood method and a Li-Cor 830 instrument based on the Infrared Gas Analyser (IRGA) principle. The results of the study, based on analysis of variance (ANOVA), showed that the levels of potential K, available P and available Fe increased significantly after the growing season (10 MST). Soil pH, available P, potential P, available Fe and available Mn differed significantly between land cover types; however, the levels of organic C and total microbes did not differ significantly statistically. The application of various doses of NPK fertiliser (0; 0.5; 0.75; and 1 STD) and differences in slope position did not result in any significant differences (p > 0.05) in CO2 flux across all phases of maize growth. Nevertheless, there was a trend of increasing emissions from the fallow phase (0.36–0.51 Mg ha?¹ week?¹) through to the post-harvest phase (1.05–1.31 Mg ha?¹ week?¹). Regression analysis indicated that soil and air temperature contributed to CO2 flux values, although their effects were relatively small. The highest cumulative CO2 flux was recorded in maize-cultivated fields, reaching 16.4 Mg CO2 ha?¹, compared with just 2 Mg CO2 ha?¹ in grassland fields. CO2 flux values are strongly influenced by land cover type and other environmental factors that may have an impact (air temperature, soil temperature, land management and slope).