Background: This study aimed to determine the pattern of N mineralization of tithonia (Tithonia diversifolia) and sugarcane (Saccharum officinarum) leaves and assess the uptake of N nutrients in maize by giving T. diversifolia and S. officinarum leaves with different qualities on sandy loam soil. Methods: The research used a completely randomized design (CRD) with following treatment: T1 (100% T. diversifolia), T2 (100% S. officinarum), T3 (75% T. diversifolia: 25% S. officinarum), T4 (50% S. officinarum: 50% T. diversifolia), T5 (25% T. diversifolia leaves: 75% S. officinarum), T6 (without T. diversifolia and S. officinarum or control). Result: The results showed that the N mineralization pattern of the organic matter combination was significantly higher than the control for all observations. The amount of N mineral released in each treatment was T1 (54.58-529.7 mg/kg), T2 (41.80-381 mg/kg), T3 (47.69-473.6 mg/kg), T4 (46.70-424.0 mg/kg), T5 (70.69-378.9 mg/kg) and T6 (47.14-303.6 9 mg/kg). The sequence of cumulative N release during 12 weeks of incubation was T1 (529 mg/kg) greater than T3 (573.6 mg/kg) greater than T4 (424.0 mg/kg) greater than T2 (381 mg/kg) greater than T5 (378.9 mg/kg) greater than T6 (303.6 mg/kg). These results suggested that T. diversifolia and S. officinarum leaves significantly increased N nutrient uptake in maize by 125% to 144.54%.

The yield of irrigated paddy rice in Sri Agung Village has decreased. In the last four years, the increase in the addition of input units (fertilizers) has not been followed by an increase in economic yields. This study aims to analyze the effect of organic fertilizers on soil fertility, such as pH, total N, organic C, available P and available K. The research was conducted in the rice fields of Sri Agung Village. Batang Asam area, West Tanjung Jabung Regency - Jambi. The research was conducted from April to September 2020. The study used a randomized block design with six treatments and five replications. The treatments tried were: Recommended Fertilizer (R), five types of organic fertilizer with a dose of 10 t ha-1 each, namely, Petroganik+R ( P1), Compost Solid Decanter + R (P2), Chicken Manure + R (P3 ), Cow Manure +R (P4) and Industrial Waste Compost + R (P5). The results showed that organic fertilizers significantly increased available K content of paddy soil but they did not significantly increase soil pH, total N, organic C and available P. The highest yield of dry milled grain (7.52 t ha-1) was obtained at +R (P1) Petroganic treatment.

A study on the addition of organic matter of different qualities was carried out to improve plant growth on a degraded sandy soil of Bambang Village, Wajak Malang, East Java. Two potential sources of organic matter in Bambang Village are Tithonia diversifolia and sugarcane leaves. This study aimed at elucidating the changes in some chemical properties of a degraded sandy soil of Malang, East Java, and nutrient uptake and growth of maize plants by applying mixtures of Tithonia diversifolia and sugarcane leaves of different quality. Treatments tested in this study were mixtures of Tithonia diversifolia leaves and sugarcane leaves at various proportions (%w/w), i.e. 100% Tithonia diversifolia leaves (T1), 100% sugarcane leaves (T2), 75% Tithonia diversifolia leaves + 25% sugarcane leaves (T3), 50% Tithonia diversifolia leaves + 50% sugarcane leaves (T4); without organic matters (T6), and control, without organic matter and inorganic fertilizers (T7). The results showed that the application of Tithonia diversifolia and sugarcane leaves affected soil pH, soil exchangeable bases, maize growth, and nutrients uptake. Nutrients taken up by maize plants significantly increased with the addition of Tithonia diversifolia leaves, either alone or in combination with sugarcane leaves. The application of 100% sugarcane leaves did not significantly affect maize growth and nutrient uptake.

<p>Ultisols have considerable potential in developing agricultural cultivation, but in their management, they face several obstacles, including physical properties that do not adequately support plant growth. The low content of soil organic matter causes poor soil physical properties. Low organic matter content leads to low soil aggregate stability, obstructing pore distribution and infiltration so the soil can easily become compacted. This study aimed to observe the changes in some physical properties of the soil due to the application of cow manure and <em>Gliricidia sepium</em> pruning compost and its effect on the yield of soybean plants. This study used a randomized block design with five treatments, namely, K0 (without cow manure-Gliricidia compost), K1 (5 t ha^-1cow manure-Gliricidia compost), K2 (10 t ha^-1cow manure-Gliricidia compost), K3 (15 t ha^-1cow manure-Gliricidia compost), and K4 (20 t ha^-1cow manure-Gliricidia compost). The results showed that the 15 t ha^-1 cow manure-Gliricidia compost was the best dose in improving the total pore space and penetration resistance of the soil studied. The application of 15 t ha^-1cow manure-Gliricidia compost significantly increased soybean yield, reaching 2.97 t ha^-1.</p>