Method to evaluate the efficiency of manual overhead irrigation in citrus rootstock liner production

Abstract

Brazil produces grafted citrus seedlings in closed screen houses to reduce pest and disease incidence. Irrigation is usually performed by hand using either breaker nozzles or drilled polyvinyl chloride (PVC) pipe wands on garden hoses. Rootstocks are produced in cone-shaped containers filled with soilless potting mix. Since the containers have a small upper diameter, nutrient solution capture is reduced with the potential to cause environmental contamination from inefficient fertigation. This study provides a method to assess the efficiency of manual overhead irrigation systems used in liner production. The method consists of determining both the volume of water applied and volume lost (i.e., directly and by percolation) in order to obtain an estimate of the percentage of water loss, irrigation efficiency, and the drainage fraction. The method was tested in a commercial facility under standard production practices. The method's attributes included simplicity, quick sampling and data collection, and accuracy. The evaluated nursery was found to have low irrigation efficiency (27.14%) and excessive nutrient solution losses (72.86%). Considering an average production of 300,000 liners per year on 20,000 m 2 , we determined an annual solution loss of 221.8 m 3 with an average environmental release of 158.9 kg of fertilizer. Therefore, more efficient irrigation systems are necessary for sustainable citrus rootstock liners production.

Advances in citrus propagation in Brazil

“…Irrigation of rootstock liners in the seedbed: The irrigation systems traditionally used in the production of citrus liners include manual watering using shower heads, hose nozzles, rain wands, and perforated PVC pipes (Figures 4A and 4B) (SALVADOR et al, 2016), micro-sprinklers (Figure 4C), and spray bars (Figure 4D) .…”

Stock Plant and Tree Production: Irrigation and Fertilization

“…Citrus rootstock liners are traditionally watered using hose nozzles, rain wands, and perforated polyvinyl chloride (PVC) pipes (Figure 1A and 1B) (Salvador et al 2016) as well as overhead microsprinklers (Figure 1C) and spray bars (Figure 1D) (Testezlaf and Ferrarezi 2017). Those methods soak the plant canopy in order to guarantee that water reaches the substrate, because leaves block the substrate surface due to the umbrella effect.…”

“…Because the containers have a small volume, frequent irrigation and fertilization are required to meet crop water and nutrient requirements and accelerate tree growth. Welldesigned and properly managed irrigation systems provide uniform water and nutrient delivery and efficient water and nutrient distribution (Salvador et al 2016).…”

Sistema de indicadores aplicado à agricultura irrigada

“…Segundo Salvador et al (2016), esta estimativa pode ser realizada a partir da medição da condutividade elétrica e do volume da solução lixiviada após cada fertirrigação. No caso onde a fertirrigação é realizada via microaspersão, pode-se acrescentar ainda as perdas diretas de nutrientes, uma vez que a aplicação ocorre também nos corredores.…”

“…A estimativa de perda de sais foi realizada por Salvador et al (2016) em um viveiro de produção de mudas de citros. Os autores estimaram que, aproximadamente, 159 kg de sais 4 são perdidos anualmente para se produzir 300 mil mudas em uma área de 20 mil m², valor considerado significativo tanto em termos econômicos quanto ambientais.…”