Co-Authors:
Dasberg, S., Agricultural Research Organization, The Volcani Center, Bet-Dagan 50-250, Israel
Erner, Y., Agricultural Research Organization, The Volcani Center, Bet-Dagan 50-250, Israel
Bielorai, H., Agricultural Research Organization, The Volcani Center, Bet-Dagan 50-250, Israel
Abstract:
Differential fertillizer and irrigation applications were utilized to assess the N balance over a period of 4 yr in a typical mature 'Shamouti' orange (Citrus sinensis L.) grove located in the coastal plain of Israel. Nitrogen inputs in fertilizer and irrigation water were 100, 180, and 310 kg ha-1 annually for the three main treatments. The N removed by the crop was measured by yield and N content determinations in the fruits; the leached N was measured by sampling below the root zone. It was found that the amount of leached N was similar in the low and medium N applications (< 50 kg N ha-1). At the high N application, > 50 kg N ha-1 was leached and large amounts of N were unaccounted for (approximately 100 kg N ha-1). Analysis of published data on N losses from citrus orchards showed similar large amounts of N not found in the fruit or in the soil mineral N pool after large N applications. The possible pathways for these N losses were discussed. It was concluded that this excess N was either incorporated in the soil organic matter or stored in the tree rather than being denitrified.Differential fertilizer and irrigation applications were utilized to assess the N balance over a period of 4 yr in a typical mature 'Shamouti' orange grove located in the coastal plain of Israel. Nitrogen inputs in fertilizer and irrigation water were 100, 180, and 310 kg ha** minus **1 annually for the three main treatments. The N removed by the crop was measured by yield and N content determinations in the fruits; the leached N was measured by sampling below the root zone. It was found that the amount of leached N was similar in the low and medium N applications. At the high N application, greater than 50 kg N ha** minus **1 was leached and large amounts of N were unaccounted for. Analysis of published data on N losses from citrus orchards showed similar large amounts of N not found in the fruit or in the soil mineral N pool after large N applications. The possible pathways for these N losses were discussed.