The fate of fertilizer nitrogen in a high nitrate accumulated agricultural soil

Abstract

Well-acclimatized nitrifiers in high-nitrate agricultural soils can quickly nitrify NH4+ into NO3− subject to leaching and denitrifying loss. A 120-day incubation experiment was conducted using a greenhouse soil to explore the fates of applied fertilizer N entering into seven soil N pools and to examine if green manure (as ryegrass) co-application can increase immobilization of the applied N into relatively stable N pools and thereby reduce NO3− accumulation and loss. We found that 87–92% of the applied 15N-labelled NH4+ was rapidly recovered as NO3− since day 3 and only 2–4% as microbial biomass and soil organic matter (SOM), while ryegrass co-application significantly decreased its recovery as NO3− but enhanced its recovery as SOM (17%) at the end of incubation. The trade-off relationship between 15N recoveries in microbial biomass and SOM indicated that ryegrass co-application stabilized newly immobilized N via initial microbial uptake and later breakdown. Nevertheless, ryegrass application didn’t decrease soil total NO3− accumulation due to its own decay. Our results suggest that green manure co-application can increase immobilization of applied N into stable organic N via microbial turnover, but the quantity and quality of green manure should be well considered to reduce N release from itself.

Assessing the Response of Tomato Yield, Fruit Composition, Nitrogen Absorption, and Soil Nitrogen Fractions to Different Fertilization Management Strategies in the Greenhouse

“…However, in our study, no significant difference in the soil fixed ammonium content in response to the N rate was observed (Fig. 4), indicating that the proportions of urea-N entering the soil fixed ammonium pools were low, which was consistent with previous studies (Luce et al, 2014;Quan et al, 2016). The soil fixed ammonium content is known to depend on the degree of K saturation of the interlayers in 2:1 clay mineral.…”

Sustainability Matters: Consumer Acceptance of Different Vertical Farming Systems

“…Surprisingly, the environmental attitude toward agriculture does not influence the perceived usefulness, although the participants rated fertilizer use in conventional farming systems as excessively high [62,63]. This result might present an opportunity for vertical farming systems, as fertilizer does not contaminate the soil in the systems' controlled environment.…”

How Rainforest Conversion to Agricultural Systems in Sumatra (Indonesia) Affects Active Soil Bacterial Communities

“…We detected the nitrification-related genus Nitrospirales and two genera of the Nitrosomonadales exclusively in oil palm plantations as associated taxa ( Lücker et al, 2010 ; Ma et al, 2013 ). This indicates higher degrees of nitrification in oil palm soils compared to rainforest, probably caused by fertilizer application and correspondingly nitrogen input, leading to more favorable conditions for nitrifiers ( Ma et al, 2013 ; Quan et al, 2016 ).…”