Evaluation of Nitrogen and Phosphorus Responses on Yield, Quality and Economic Advantage of Winter Wheat (Triticum aestivum, L.) under Four Different Agro-Climatic Zones in Afghanistan

Abstract

The response of winter wheat (Triticum aestivum L.) to the application of different rates of nitrogen (N) and phosphorus (P) on different agro-climatic zones (ACZs) has not been well studied in Afghanistan. The objectives of this study were to (1) determine the impact of soil and climate on the responses of wheat to N and P fertilization, (2) quantify the specific N and P response of winter wheat for different ACZs, and (3) determine the economical application rates of N and P for farmers for each considered ACZs. This paper evaluates the effects of nitrogen levels (NL) at 35.28, 65, 95, and 120 kg N ha−1 and phosphorus levels (PL) at 0, 50, 70, and 90 kg P2O5 ha−1, respectively, in four locations (L) for two growing seasons (GS), on both yield and quality characteristics of winter wheat. Soil pH was the main environmental parameter affecting straw yield (SY), grain yield (GY), protein content (PC), and protein yield (PY). Winter wheat SY, GY, PC, and PY increased significantly (p < 0.05) with PL rates up to 50 kg P2O5 ha−1 and with NL rates up to 120 kg N ha−1. NL was the most important parameter in determining PC, thus showing potential for further improvement in N management. The highest marginal rate of return was used as an index for the farmers to accept site-specific N and P fertilizer recommendations.

Effects of Pedoclimate and Agronomical Management on Yield and Quality of Common Wheat Varieties (Triticum aestivum L.) in Afghanistan

“…As an alternative, using salt-tolerant wheat varieties, implementing the banded application of P, and incorporating organic amendments could be recommended to enhance soil fertility and achieve a good yield and quality of irrigated wheat in Afghanistan. These recommendations align with similar findings reported by others [8,21,38].…”

“…Daily precipitation and daily average temperature (Tavg; • C) data from the NASA database (https://power.larc.nasa.gov/data-access-viewer/, accessed on 2 March 2023) were used to calculate the average precipitation and temperature on a monthly basis for a long-term period (2001-2020) as well as for the 1st and 2nd GS. For each location and growing season (GS), the cumulative precipitation values from tillering to the grain filling period (P_TGf) were calculated as reported in [21]. Growing degree day (GDD) data [22] were used to describe the timing of biological processes [23,24].…”

“…The DLN7 is an improved wheat variety characterized by good resistance to yellow rust and a grain yield (GY) potential of 4 t ha −1 [25]. The KBL13 is considered the most promising variety for improving Afghan wheat production in the coming time due to its resistance to Ug99 and other rust varieties, as well as its capability of producing an average GY of over 4.4 t ha −1 [21]. Since the mid-1990s, ZDNA has been one of the most popular varieties of common wheat in the northern regions of Afghanistan, given the higher average yields than other local varieties [26,27].…”

“…The total N to be distributed in each plot was reduced by the amount of N in DAP, while the remaining N in the form of urea (N: 46%) was applied 50% at tillering and 50% at stem elongation. In all the experimental fields, furrow irrigation with riverine water was carried out to satisfy the crop's water requirements during the common wheat growing season, following the protocol reported in [21]. All field activities were manually performed (i.e., sowing, fertilizer distribution, weeding, irrigation, harvesting, and threshing).…”

“…Wholemeal flour samples were obtained for each treatment using a grinder with a 0.5 mm screen (Cytolec 1093 lab mill, FOSS Tecator, Hoganas, Sweden) [21,29]. A CHNS analyzer (CHN-S Flash E1112, Thermo-Finnigan LLC, San Jose, CA, USA) was used to determine the total N percentage in wholemeal flour samples (5 mg per sample).…”