Biosolids Benefit Yield and Nitrogen Uptake in Winter Cereals without Excess Risk of N Leaching

Silvia Pampana,Iduna Arduini,Alessandro Rossi

doi:10.3390/agronomy11081482

Abstract

Winter cereals are excellent candidates for biosolid application because their nitrogen (N) requirement is high, they are broadly cultivated, and their deep root system efficiently takes up mineral N. However, potential N leaching from BS application can occur in Mediterranean soils. A two-year study was conducted to determine how biosolids affect biomass and grain yield as well as N uptake and N leaching in barley (Hordeum vulgare L.), common wheat (Triticum aestivum L.), durum wheat (Triticum turgidum L. var. durum), and oat (Avena byzantina C. Koch). Cereals were fertilized at rates of 5, 10, and 15 Mg ha−1 dry weight (called B5, B10, and B15, respectively) of biosolids (BS). Mineral-fertilized (MF) and unfertilized (C) controls were included. Overall, results highlight that BS are valuable fertilizers for winter cereals as these showed higher yields with BS as compared to control. Nevertheless, whether 5 Mg ha−1 of biosolids could replace mineral fertilization still depended on the particular cereal due to the different yield physiology of the crops. Moreover, nitrate leaching from B5 was comparable to MF, and B15 increased the risk by less than 30 N-NO3 kg ha−1. We therefore concluded that with specific rate settings, biosolid application can sustain yields of winter cereals without significant additional N leaching as compared to MF.

Highlights

The growing global population has concurrently increased food demand and organic waste production, with the former requiring increasing areas of arable land for crop production, and the latter subtracting it for waste disposal
This is because the organically bound N, which is the prevailing chemical form in BS, is more stable compared to the N forms in mineral fertilizers, and less soluble in water; likewise, it must be mineralized into plant available nitrogen (PAN) before it can be assimilated by crops [6]
Durum wheat, and oat, no differences were observed between biosolids and mineral fertilizer in regard to biomass production, both at flowering and maturity, as well as in grain yield; our results demonstrate that BS can be a reliable option for fertilization of these crops [3,11,15,29], and confirm the rapid mineralization of BS [6]

Summary

Introduction

The growing global population has concurrently increased food demand and organic waste production, with the former requiring increasing areas of arable land for crop production, and the latter subtracting it for waste disposal. The agricultural benefits of BS utilization in agriculture are well-documented and mainly attributed to low-cost access to nutrients and organic matter [3,4,5]. Their high nitrogen (N) and phosphorous (P) content makes BS attractive as a fertilizer source [6]. Biosolids may have some advantages over inorganic fertilizers, the most important being that they can better match the nitrogen demand of crops. This is because the organically bound N, which is the prevailing chemical form in BS, is more stable compared to the N forms in mineral fertilizers, and less soluble in water; likewise, it must be mineralized into plant available nitrogen (PAN) before it can be assimilated by crops [6]

Methods

Results

Discussion

Conclusion