Processing Tomato Nitrogen Utilization and Soil Residual Nitrogen as Influenced by Nitrogen and Phosphorus Additions with Drip‐Fertigation

Abstract

Titnely sufficient water supply through drip irrigation or fertigation may increase nutrient demand of processing tomato {Lycopersicon esculentum Mill.) due to increases in yield production. However, excessive nutrient application could result in crop Itixury uptake and enrichment in soil profile, especially mineral N, with the latter potentially causing environmental concerns. A study was conducted to determine the responses of crop N utilization and post-harvest soil profile mineral N to fertilizer N and P additions under drip fertigated processing tomato in sandy loam soils from 2003 to 2005. Across the 3 yr, both fruit N removal and plant total N uptake were either linearly or quadratically related to fertilizer N rate, with 187 kg N ha" ' of fruit removal and 268 kg N ha" ' of plant total N uptake obtained at the maximum yield. Nitrogen uptake efficiency and apparent N recovery decreased linearly with increases in N rate. At the maximum fruit yield, N uptake efficiency was 0.71, and apparent N recovery was 51.7%. Post-harvest soil profile (0-100 cm) mineral N increased with increases in fertilizer N rate, and at greater rates with fertilizer N appHed at rates above those required for maximum fruit yield production. Of the soil residual N, 62% remained in the top 40-cm soil layer. Addition of fertilizer P had no effects on plant N uptake, N uptake efficiency and post-harvest mineral N in soil profile, presumably due to the high levels of soil test P. Beneficial management practices need to be developed to prevent soil N losses during the non-growing season following production of processing tomato with drip fertigation.

Crop and soil nitrogen responses to phosphorus and potassium fertilization and drip irrigation under processing tomato

“…However, plant total N uptake was not affected by fertilizer P input as evidenced by the opposite effects of P on N concentration and biomass. In a recent field study of fertilizer N and P effects on high yielding drip fertigated processing tomato, Zhang et al (2011) reported that fertilizer P rates, ranging from 0 to 87.3 kg P ha -1 , had no effects on plant N uptake, apparent N recovery, or post-harvest soil N. The soil P fertility in the current study ranged from medium to high levels for processing tomato according to provincial guidelines (OMAFRA 2008). The medium to high background soil P fertility might provide sufficient P required for healthy tomato growth, thus having no effects on tomato N uptake and soil N. Although soil N was not affected by fertilizer P input, post-harvest water extractable soil P and Olsen P increased linearly in response to P application (Liu et al 2011a), suggesting high fertilizer P input exacerbated the adverse P effects on surrounding water systems.…”

“…In a previous field study of drip fertigated processing tomato, Zhang et al (2011) found that plant total N uptake averaged 256 kg N ha -1 at an N rate of 240 kg N ha -1 . In the current study, plant total N uptake only averaged 185 kg N ha -1 in the DI treatment and 147 kg N ha -1 in the NI treatment using a higher N fertilizer rate of 270 kg N ha -1 .…”

“…Nitrogen application rates are known to affect plant and soil N in tomato production systems (Hebbar et al 2004;Vázquez et al 2006;Zotarelli et al 2009;Zhang et al 2011). A recent study recommended N fertilizer applications of 271 kg N ha -1 for drip fertigated processing tomatoes (Zhang et al 2010), approximately two times greater than previous N recommendations.…”

“…Numerous studies have demonstrated N leaching losses both during crop growing seasons and postharvest periods (Gehl et al 2006;Zotarelli et al 2007Zotarelli et al , 2009). In addition to measuring leaching losses of N from agricultural drainage tiles, N concentration in the soil profile are also used to evaluate potential leaching losses (Gehl et al 2006;Zhang et al 2011). Hence, evaluating spatial distribution of N in the soil profile at the end of a crop growing season, together with plant N responses, will enhance N management in processing tomatoes production systems.…”

Surface fertigation: a review, gaps and needs

“…However, plant fertilizer uptake plays a key role in the soil fertilizer cycle. This issue can only be analysed in fertigation experiments extending to the whole crop cycle (Janat, 2008;Zhang et al, 2011) or even to a whole hydrological year. In such experiments, fertilizer use efficiency (ratio of crop yield to total applied fertilizer) is an important indicator.…”