Energy Efficiency of Nitrogen Fertilization in Durum Wheat and Sorghum Grains

Abstract

The objective of this study was to assess the energy efficiency of nitrogen fertilization in durum wheat and sorghum grains in the period 2017-2019. Bulgarian durum wheat variety Predel was studied at a stationary fertilizer trial on soil type Pellic vertisols at the Institute of Field Crops in Chirpan, Bulgaria. Grain sorghum hybrid EC Alize was investigated on the experimental field of the Agricultural University of Plovdiv, Bulgaria, on soil type Mollic Fluvisols. The crops were grown under non-irrigated conditions. The studied nitrogen rates were 0, 60, 120, 180, and 240 kg N.ha-1. In durum wheat, nitrogen was applied two times: one third at sowing, and the rest - as top dressing in the tillering stage. In sorghum, the total nitrogen was applied as pre-sowing fertilization before sowing. The nitrogen fertilizer was applied as NH4NO3. The experimental design was a randomized, complete block design with four replications with a size of experimental plots of 20 m2 for both crops. The energy efficiency of nitrogen fertilization (h) was calculated as the ratio between the received energy from additional grain yield of wheat and sorghum, respectively, and the invested energy from fertilization. It was established that energy efficiency of nitrogen fertilization depended on the nitrogen rate and hydro-thermal conditions during the vegetation period of durum wheat and sorghum. The bioenergy coefficient of durum wheat widely varied from 0.79 (N240 in 2018) to 4.44 (N60 in 2017). The average for the period, the highest value of energy efficiency of nitrogen fertilization was obtained at the low rate N60 The higher nitrogen rate of 240 kg N.ha-1 was slightly effective. Under drought conditions during the vegetation period of sorghum, most effective was the application of rates N120 with the highest energy coefficient ​​of 1.23. The application of 180 kg N.ha-1 to sorghum was the most energy efficient under the favorable hydro-thermal conditions in 2018 and 2019, and the average for the period 2017-2019. A low N60 rate in grain sorghum was inefficient from an energy point of view. Durum wheat showed higher energy efficiency of nitrogen fertilization compared to grain sorghum.

Impact of Tillage and Phosphorus Application on Agronomic Efficiency of Maize (Zea mays L.) in the Eastern Part of DRC

“…This was due to the fact that P 60 generally produced a higher dry matter at both Walungu and Kabare, which translated into greater yields making P 60 produce a higher economic output relative to the control. These results are contrary to results obtained by Panayotova et al [43] that the agronomic efficiency of durum wheat decreased with increasing levels of triple superphosphate application in Bulgaria. They also reported that the soil application of P at rates exceeding 80 kg P 2 O 5 ha -1 was inefficient.…”

Effect of main agronomy factors on the productivity and physical characteristics of common winter wheat (Triticum aestivum L.) grown under conventional and transitional-organic production

“…This new reality is related to higher mean annual temperatures, amplitude anomalies and uneven distribution of rainfalls (Knight et al, 2004;Atanasova et al, 2009, Kostov & Cleemput, 2019. The quality of wheat grain can be improved by breeding and by proper agronomy practices (Panayotova & Kostadinova, 2004;Nankova et. al., 2020).…”