Amounts, forms, and management of nitrogen and phosphorus export from agricultural peatlands

Abstract

Peatlands provide a setting that is well suited for cranberry agriculture in the Northeastern United States. However, misconceptions exist about the amounts and forms of nitrogen (N) and phosphorus (P) export from cranberry farms. In this study, we report inorganic and organic forms of N and P export from five peatlands cultivated for cranberry production in southeastern, Massachusetts, United States. We then compare N loading rates among cranberry farms in southeastern Massachusetts, row crop farms in the Midwestern United States, and uncultivated peatlands in the United States and United Kingdom. Based on a fluvial mass balance analysis, we find that nonriparian cranberry farms export 2.56 kg of P ha −1 year −1 of total P and 12.1 kg of N ha −1 year −1 of total N. Total N export from riparian or "flow through" farms is two times higher than nonriparian farms due to less retention of N fertilizer in the vadose zone of riparian farms. Gross total N export from riparian and nonriparian cranberry farms consists of 35% particulate organic N, 26% dissolved organic N, 31% ammonium (NH 4 + ), and 8% nitrate (NO 3 − ). The low proportions of NO 3 − export (13% of total dissolved N [TDN]) for cranberry farms differ from NO 3 − export for row crop farms (75% of TDN; p < .001) but not for uncultivated peatlands (17% of TDN; p = .61). Despite being highly modified by fertilizers and artificial drainage, low NO 3 − export (2.2 kg of N ha −1 year −1 ) from cranberry farms is consistent with field measurements of rapid N turnover in uncultivated peatlands. This finding suggests that statefunded wetland restoration efforts to restore denitrification in retired cranberry farms may be limited by NO 3 − rather than soil moisture or organic matter. K E Y W O R D Sagriculture, cranberry, nitrogen, peatland, phosphorus, water quality

Advancements in spring frost protection to sustain cranberry production in Massachusetts

“…Kennedy et al. (2016) reported that frost cycling could result in 35% water use reduction relative to conventional sprinkler irrigation on a frost night. This is a significant water saving as it results in a multiplier effect on chemical leaching reduction, energy use reduction, and labor cost savings.…”

“…Water management is a key component of sustainable intensification of cranberry production in Massachusetts. Previous research has shown that water management directly affects (a) crop yield (Caron et al., 2016), (b) environmental effects (Kennedy et al., 2020), (c) production costs (Olszewski et al., 2017), and (d) regulatory scrutiny (Mattson et al., 2015). One challenge facing Massachusetts growers is that soil moisture conditions are generally too wet to achieve optimal crop production (Lampinen & DeMoranville, 2003).…”

Measuring and modeling nitrogen export from cranberry farms

“…x in N inputs of fertilizer (x = fert), floodwater (x = f), irrigation (x = i), surface water (x = sw-in), net groundwater (x = gw-net), and atmospheric deposition (x = atm) that is not retained at the surface (y = s) or in the vadose zone (y = vz) of the farm. This N transmission coefficient equals one minus the attenuation rate in other studies and was previously referred to as the nitrogen loss coefficient in Kennedy et al (2020). The net N export from the cranberry farm is calculated as the difference between N outputs and the fraction of N inputs that leaves the farm:…”

“…Once Q net is known, the average N concentration in groundwater is applied to calculate F gw-net (Neill et al 2017, Kennedy et al 2018. Kennedy et al (2020) empirically calculated N transmission coefficients (c s f c vz f = 0.65, c s i c vz i = 0.78).…”

“…2. Data from Howes and Teal (1995), site NB; Neill et al (2017), site WS, SB, RB; Kennedy et al (2018), site AT; Kennedy et al (2020), site FF.…”