SETTINGS FOR SUPPLYING NUTRITION SOLUTIONS TO OVERCOME BROWN ROOTS IN SPINACH PLANTS CULTIVATED AEROPONICALLY

Abstract

ABSTRACT

This study aims to determine the cause of the appearance of brown roots in spinach plants cultivated aeroponically and how to overcome it by adjusting the interval of nutrient solution administration. This study was conducted at Parung Hydroponic Farm, Parung, Bogor in June - July 2010. Microscopic observation of plant root tissue was conducted at the Microtechnic Laboratory of the Department of Agronomy and Horticulture, Bogor Agricultural University. Examination of plant pests and diseases was conducted at the IPB plant clinic. Phenolic compound testing was conducted at the Organic Laboratory of the Department of Chemistry, Bogor Agricultural University and plant tissue analysis was conducted at the Bogor Soil Research Center. This study was conducted with a one-factor Randomized Block Design, namely the time of nutrient solution administration with three treatments: nutrient solution spraying with an interval of one minute on and one minute off (P1), nutrient solution spraying with an interval of half a minute on and half a minute off (P2), and nonstop (continuous) nutrient solution spraying (P3). The study was conducted with three replications so that there were 9 experimental units. Observations were made on 15 jelly cup samples with three plants/jelly cup. The results of the study showed that brown roots in spinach plants occurred in plants given nutrients every one minute and did not occur in plants given nutrients every half a minute continuously. The brown roots in spinach plants are thought to occur because the roots experience drought, causing the plants to release phenolic compounds. This drought is caused by the application of nutrient solution at intervals that are too long, namely once a minute. Brown roots in spinach plants do not cause root tissue death, this is indicated by the roots continuing to elongate and the roots still actively carrying out their function in absorbing nutrients. This is evidenced by the results of testing the three treatments on the observed variables. All three treatments of nutrient solution administration intervals showed the same plant height growth. All three treatments also had similar results calculated from the weight per plant, plant crown weight, plant root weight, and plant weight per square meter. The treatment of nutrient solution administration settings showed differences in the number of leaves and plant root length. Brown roots in spinach plants in this study can be overcome by increasing the frequency of nutrient solution administration. Increasing the frequency of nutrient solution administration from once a minute to once a half a minute continuously can reduce the number of brown roots.