Cropping System and Type of Pig Manure Affect Nitrate‐Nitrogen Leaching in a Sandy Loam Soil

Abstract

The application of livestock manure can result in the loss of nitrate-nitrogen (NO-N) and degrade surface and groundwater. A 3-yr lysimeter study was set up to compare the effect of cropping system and nitrogen (N)- and phosphorus (P)-based pig manure application rates on the loss of water and NO-N below the root zone. The experiment was a split-plot design with annual and perennial cropping systems as the main factor. Five nutrient management treatments were the subplots: N-based liquid pig manure application; P-based liquid pig manure application, N-based solid pig manure application, P-based solid pig manure application, and a control without amendment. The results showed that 40 to 60 kg NO-N ha was lost from the annual plots in 2010 and 23 to 60 kg NO-N ha in 2011, whereas a negligible amount of NO-N was lost from the perennial (<1 kg ha) plots in both years. The application of solid pig manure on a P basis followed by urea in subsequent years reduced the risk of NO-N leaching over the course of the rotation, likely due to immobilization of N by the straw in the solid pig manure. Our study showed that a perennial cropping system consisting of a mixture of grasses has the capacity to receive and utilize significant amounts of nutrients with negligible amount of nutrient leakages to the adjacent environment. The inclusion of grasses in a crop rotation and their use to take up excess nutrients are sustainable practices that will benefit the environment.

Nitrate Leaching in a Loamy Sand Soil Receiving Two Rates of Liquid Hog Manure and Fertilizer

“…The total NO 3 − -N leached from the control plots was 21 and 19 kg ha −1 in 2010 and 2011, respectively, suggesting that although NO 3 − -N leaching can be reduced by withholding supplemental N, it may be unavoidable, particularly in sandy soils. Similarly, the lysimeter results of Karimi et al (2017) showed that the amount of NO 3 − -N lost below the root zone of an annual crop at Carman, MB, was 24 to 48 kg N ha −1 from unfertilized control plots.…”

“…One field core lysimeter was installed along the centerline of each plot, 2 m from the southern edge, to measure water and NO 3 − – N moving below the rooting zone (Nikièma et al, 2013). The lysimeters consisted of three parts (Karimi et al, 2017): the main column, a schedule 80 polyvinyl chloride (PVC) pipe (54‐cm i.d., 106‐cm length) representing the root zone of annual crops, a circular perforated plate, and a bottom cap for collection.…”

Nitrogen and phosphorus uptake from solid and liquid pig manure in perennial and annual cropping systems

“…Conversely, N removal from the solid-N plot was not statistically different from the control, again indicating low N availability in the solid manure. The leachate results obtained using field core lysimeters in these study plots also showed that this treatment reduced the risk of nitrate leaching, likely due to immobilization of N with the addition of straw in the manure (Karimi et al 2017). Previous studies have shown that the formula used in Manitoba to estimate available N in manure (available N in manure = 75% of NH + 4 -N + 25% of organic N) does not account for the effect of a relatively high C:N ratio (11-14, Loecke et al 2004) of the solid manure on N release and overestimates N availability for solid manures (Ige et al 2015).…”

“…It would take time for the mineralization of organic N to ammonium, and depending on the C:N ratio of the manure, immobilization of N may have also occurred. In addition, the leachate results obtained in these plots showed that solid manure reduced the risk of nitrate leaching (Karimi et al 2017). Therefore, it is likely that the method used to estimate available N from organic N in the solid manure overestimated the quantity of N mineralized.…”

“…One way of utilizing pig manure is by applying it to grassland in the vicinity of hog barns. Perennial grasses are known to efficiently use nutrients that may reduce nitrate leaching and reduce the potential for groundwater pollution (Karimi et al 2017). Comparing biomass yield and nutrient uptake of perennial grasses to that of annuals will provide us with information on the potential of these grasses to receive manure and be used to reduce nitrate leaching.…”