<p>The need of nitrogen (N), phosphate (P) and potassium (K) nutrient in oil palm nursery are usually fulfilled with synthetic chemical fertilizers such as NPK fertilizer. The application of NPK fertilizer can cause the soil to become hard due to the accumulation of the residue left on the ground. Cow manure is able to substitute NPK fertilizer based on the chemical status of the soil. This study aimed at analyzing the effect of NPK fertilizer substitution with cow manure on the growth of oil palm seedlings in the pre-nurseries and main nurseries. The experiment was conducted from February to September 2018 in the Banguntapan research and experimental field, Faculty of Agriculture, Universitas Gadjah Mada. The experiment applied the Randomized Complete Block Design (RCBD) with one factor and six blocks as replications. The factors were subtitution using the replacement series method with five levels of doses, 100% NPK, 75% NPK + 25% cow manure, 50% NPK + 50% cow manure, 25% NPK + 75% cow manure and 100% cow manure. The observed parameter variables were root lenght, root area, hump diameter, leaf area, the number of leaves, plant height and plant dry matter. The use of 25% NPK substitute with 75% organic material was the best result in increasing the growth performance of oil palm seddlings in pre-nursery and main nursery.</p>

Twisted disease is one of the main diseases on shallot caused by <em>Fusarium </em>sp<em>.</em> One method to increase the resistance of shallot cultivars to the twisted disease can be performed by using True Seed Shallot (TSS) combining with a salicylic acid application. TSS is known as free pathogen. The objective of the research was to examine the effects of a salicylic acid application to the growth, yield and resistance responses of TSS on Tuktuk, Sanren and Lokananta cultivars to the twisted disease. The research was arranged in factorial Completely Randomized Design (CRD), consisting of two factors with three replications. The first factor included Tuktuk, Sanren and Lokananta cultivars and the second factor comprised salicylic acid applications (without salicylic acid and inoculation, without salicylic acid with inoculation, immersion treatment of salicylic acid with inoculation, spray treatment with inoculation as well as immersion and spray treatment with inoculation). The results showed that the application of salicylic acid in different treatments had the same effects on the growth, yield and resistance of TSS. An interesting result is found, in which the application of salicylic acid by immersing and spraying could reduce the incidence of twisted disease by 12.5% in TSS. Therefore, the application of salicylic acid by immersing and spraying can be one of the recommended twisted disease management.

<p>Salinity makes disorder to plant physiological causes decreasing in biomass production. Applying silica nutrients is expected to increase paddy (<em>Oryza sativa</em> L.) tolerance to salinity. The study aims to examine the effects of the application of silica nutrients under saline conditions regarding plant growth analysis and its correlation to paddy biomass production. The research was arranged in a factorial completely randomized design with two factors. The first factor was NaCl concentrations consisting of four levels, including non-saline, 4 dS m^-1, 8 dS m^-1 and 12 dS m^-1. The second factor was silica doses per kg soil with three levels including 300 mg, 450 mg and 600 mg. The treatments were repeated three times. The result showed that the NaCl concentration affected root shoot ratio at harvest. Silica dosage affected leaf area index 8 weeks after planting (WAP), root shoot ration at harvest and net assimilation rate. Interaction of NaCl concentration and silica dose affected root shoot ratio in 8 WAP and at harvest. Plant growth analysis illustrated on leaf area index, plant growth rate and root shoot ratio correlated positively with biomass production. However, the harvest index and net assimilation rate showed negative correlations to biomass production. The application of silica nutrients had the potential to improve paddy growth and yield under saline conditions.</p>