Potato Yield Response and Seasonal Nitrate Leaching as Influenced by Nitrogen Management

Abstract

Nitrate leaching is of great environmental concern, particularly with potatoes grown on sandy soils. This 3-year study evaluated the effect of three N rates (100, 150, and 200 kg ha−1) of single applications of polymer-coated urea (PCU) and a 75% PCU + 25% urea mixture, plus a conventional split application of 200 kg N ha−1 of a 50% ammonium sulfate + 50% calcium ammonium nitrate mixture (CONV) on NO3−-N leaching, potato yield, and N uptake under irrigated and non-irrigated conditions on a sandy soil in Quebec (Canada). Fertilizer N application increased growing season NO3−-N leaching only under irrigation. On average, irrigation increased seasonal NO3−-N leaching by 52%. Under irrigated conditions, PCU reduced NO3−-N leaching compared to PCU + urea. However, both PCU and PCU + urea significantly increased NO3−-N leaching compared to the CONV at the equivalent N rate of 200 kg N ha−1. This was attributed to the timing of soil N availability and deep-water percolation. Total (TY) and marketable (MY) yields in the CONV were similar to those in the PCU applied at the equivalent N rate of 200 kg N ha−1. Despite lower plant N uptake, PCU resulted in greater TY and MY compared to PCU + urea. Residual soil inorganic N was greater for PCU and PCU + urea compared to the CONV, providing evidence that PCU products have the potential to increase NO3−-N leaching after the growing season. In this study, PCU was an agronomically and environmentally better choice than PCU + urea. The results also showed that the efficiency of PCU to reduce seasonal NO3−-N leaching may vary according to the timing of precipitation and irrigation.

Determination of Crop Coefficients and Evapotranspiration of Potato in a Semi-Arid Climate Using Canopy State Variables and Satellite-Based NDVI

“…As expected, fields where the total water inputs exceeded seasonal ETo recorded the highest drainage. It is well documented that drainage in sandy soils increases with greater total water input [36,37]. The risk of drainage in sandy soils with a lower water holding capacity is high after a major rain event.…”

Irrigation Water and Nitrogen Fertilizer Management in Potato (Solanum tuberosum L.): A Review

“…Potato growers can easily shift to polymer coated urea (PCU) instead of the conventional split N application without significantly reducing tuber yield [110]. Under irrigated conditions, the use of PCU and PCU + urea at the same N rate applied at planting led to a significant rise in seasonal NO 3 − leaching by 32% and 43%, respectively, when compared to the conventional split N treatment [105]. Clement et al [105] concluded that the use of PCU alone is more environmentally sound and profitable than a PCU + urea mixture for potato production in sandy soils.…”

“…Under irrigated conditions, the use of PCU and PCU + urea at the same N rate applied at planting led to a significant rise in seasonal NO 3 − leaching by 32% and 43%, respectively, when compared to the conventional split N treatment [105]. Clement et al [105] concluded that the use of PCU alone is more environmentally sound and profitable than a PCU + urea mixture for potato production in sandy soils. They also recorded a higher N uptake, dry matter content, and apparent N recovery under PCU + urea as compared to PCU alone and the conventional split N application method [105].…”

“…In red soil, the yield of tubers increased with increasing levels of N fertilizer, but the increase was not statistically significant when the N application rates exceeded 150 kg/ha [102]. Clement et al [105] also found no significant difference in the total yield and marketable yield among N application rates of 100, 150, and 200 kg N/ha with polymer coated urea (PCU) applied at planting under both irrigated and non-irrigated conditions. Bohman et al [98] found that slight reductions in the N rate (by 44 kg N/ha) and irrigation rates (by 15%) did not result in significant differences in tuber yield and economic return, compared to the application of the recommended rate of N (270 kg N/ha) and full irrigation (100% field capacity) under sandy soils and the humid climatic zone of Minnesota.…”

Effect of Irrigation and Nitrogen Management on Potato Growth, Yield, and Water and Nitrogen Use Efficiencies

“…Due to excessive irrigation water and chemical fertilizer inputs, the irrigated potato production systems could be a potential source of nitrate contamination in underground water [15]. Nitrate leaching beyond crop root zone increased with increasing nitrogen fertilizer rates under irrigated conditions as compared to non-irrigated potatoes [16]. A study by Vashisht et al [17] predicted that the current potato production level could not be achieved even with the increased water and nitrogen input levels, while there could be 41-67% anticipated increase in leaching losses by the years 2058-2067.…”