No abstract

The poultry manure and vertisols matter have potency for reclaiming a soil. The research objectives was to study the effect of poultry manure (PM) and vertisols matter (VM) on availability and leaching of macro nutrient in coastal sandy soil treated by rainfall simulation. A laboratory experiment was conducted with lesymeters to measure nutrient leaching. The factorial 4 × 4 treatment applied was arranged by randomized completely block design with three replications. The first factor was level of PM consisted of 0, 20, 40, and 60 Mg ha-1. The second one wasthe level of VM consisted of 0, 5, 10, and 15%. Variables observed were soil physical and chemical properties such as bulk density (BD), particle density (PD), porosity, pF 2.54, pF 4.2, available water capacity (AWC), permeability, cation exchange capacity (CEC), available macro nutrients (N, P, K, Ca, Mg, and S) by Morgan Wolf extraction, and the rate of macro nutrient leaching measuared by Spectrophotometry and Atomic Absorption Spectrophotometry. Result of the research showed that application of PM and VM in the sandy soil decreased soil PD and BD, increased soil porosity and AWC, decreased soil permeability, and slightly increased soil CEC. Application of PM and VM increased soil available nutrient in the sandy soil. Up to 60 Mg ha-1 dose PM increased soil available nutrient, while 10 to 15% dose, VM did not increased it. The rank of nutrient leaching from high to low by rain simulation was N-NO3 -> SO4 = > K+ > Ca2+. Leaching of K and N-NH4+ could be reduced by soil amendment. Combination of PM 60 Mg ha-1 and VM 10% was the best soil amendment for increasing nutrient availability and decreasing nutrient leaching in the sandy soil.Keywords: available nutrient, coastal sandy soil, leaching, poultry manure, vertisols matter

There are some changes in the rewatered citrus trees, among others are the content of nutrients and hormones. An experiment was conducted to study the effects of pruning and fertilization on the macronutrients and hormones contents in leaves of rewatered citrus trees. The research was conducted in a citrus orchard in Purbalingga, Central Java, Indonesia from June until October 2018. There were two observed factors, namely pruning intensity (0, 5, 10, and 15% of total number of branches each tree) and doses of fertilization (0, 2, and 4 % of weight of harvested fruits at previous season). The research used Randomized Completely Block Design and three replications. Observed variables were content of N, P, K, IAA, GA3, and C/N ratio. The result of research showed that pruning intensity of 5% gave the highest content of K and IAA, and highest C/N ratio but the lowest content of GA3. Doses of 2 % fertilization gave the highest content of IAA and the highest C/N ratio but the lowest content of GA3. High content of K and IAA, and high C/N ratio but lower content of GA3 were required to induce the flowering of citrus trees.

Pruning and fertilization are factors that can determine the production and quality of citrus. The objective of this study was to determine the effect of pruning intensity and fertilizer doses of N (nitrogen), P (phosporus), and K (potassium) on citrus production and quality. The study was carried out in a citrus orchard in Central Java, Indonesia, over the course of two seasons, 2016-17 and 2017-18.The experiment was conducted as a two-factorial, completely randomized block design where the first factor was pruning intensity, namely 0, 5, 10, and 15 % of the total number of branches per tree while the second factor was doses of N, P, and K fertilizers, namely 0, 2, and 4 % of the weight of harvested citrus fruit in the previous season. The result showed that increasing doses of N, P, K fertilizers from 0 to 4 % increased fruit set, harvested fruits, fruit size, content of vitamin C, sugar, and soluble solid. The highest fruit set, weight of harvested fruits, and content of vitamin C were achieved by pruning intensity of 10 %.