The ability of organic matters in reducing nitrogen leaching and their effect on the cassava growth in Typic Hapludult

The study aimed to determine the ability of organic matters derived from legumes and non-legumes to nitrogen leaching and growth of cassava crops. The research was conducted in the ILETRI greenhouse at Malang. Randomized block design, two factors with three replications was used. The first factor was the use of soil which was differentiated by the duration of land cultivated by cassava: (1). less than 10 years, (2). more than 30 years. The second factor was sources of biomass: (1). Groundnut, (2). Maize, (3). Groundnut+maize (1:1), (4). Groundnut+maize (2:1), (5). Groundnut+maize (1:2), (6). Without biomass. The results showed that the duration of land cultivated by cassava affected the amount of NH4+ leaching. The cumulative amount of NH4+ leaching in the soil cultivated by cassava less than 10 and 30 years reached 24.02 mg.kg-1 and 40.02 mg.kg-1, respectively. The leaching of NO3- in the soil cultivated by cassava for more than 30 years was greater than it which was less than 10 years. The nitrogen leaching from the application of maize or groundnut+maize biomasses (1:2), is lower than other biomass sources. The application of groundnut+maize biomasses (2:1) resulted in the highest cassava weight.