Turkish Journal of Field Crops

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2. Beyler İş Hanı, No: 313 Kat: 3 Konak-İzmir

IRRIGATION AND PHOSPHORUS MANAGEMENT OF ALFALFA (Medicago sativa L.) UNDER SEMI-ARID CONDITIONS

Sule ERKOVAN, Onur ILERI, Halil Ibrahim ERKOVAN, Ali KOC

Abstract

The frequency of irrigation and deficit irrigation management are drawing attention because water resources are becoming limited year by year, especially in the last decade. Besides, the rate and application time of P fertilization gained more importance just after the researchers found out it is more effective than N-fertilizing for alfalfa cultivation. This study aimed to determine the effects of different irrigation managements (seasonal deficit, intervals of 5, 7, and 9 days), phosphorus application season (autumn and spring), and the rate of P fertilizer (0, 30, 60, 90 kg ha-1 ) on the yield and forage quality of alfalfa. The experiment was conducted in the 2019-2020 years, which was the 3rd and the 4th years of alfalfa respectively, under semi-arid Mediterranean conditions. The stand height and fiber content (NDF) were higher in the autumn application. However, forage contained more nitrogen in the spring application. A higher amount of water (1600 mm) with higher irrigation frequency (5 days – I5d) caused a reduction in yield due to water excess. The yield was the highest (21.34 t ha-1 ) and the forage quality was better in 896 mm water application with 9 days intervals (I9d). Seasonal deficit water management caused a significant loss in yield and quality. Nevertheless, 18.04 t ha-1 dry matter yield with 24.05 % CP content was recorded at seasonal deficit water management. P fertilization increased the yield and forage quality. The yield was the highest (20.23 t ha-1 ) at the rate of 90 kg ha-1 P fertilizer, but yield and forage quality characteristics were similar between 30, 60, and 90 kg ha-1 P. The results showed that P fertilization could be done in both autumn and spring at the rate of 30 kg ha-1 and 896 mm water could be applied at 9 days intervals for fulfilling performance under semi-arid Mediterranean conditions. When water resources are very scarce, the seasonal water deficit should be applied, especially in late summer.

Keyword: Alfalfa, deficit irrigation, fertilization, phosphorus ,

Effects of Different Water Stress Levels on Biomass Yield and Agronomic Traits of Switchgrass (Panicum virgatum L.) Varieties under Semi-Arid Conditio

Erdal GONULAL, Suleyman SOYLU, Mehmet SAHIN

Abstract

A field experiment was conducted in the Wielkopolska region at the Gorzyń Research Station, Poland (52.34°N, 15.54°E) in Central Europe. The study was conducted over a 3-year period (2017, 2018, 2019) as a two-factorial design with four replications in the RCBD. The aim of the research was to determine the effect of the cultivar (‘Bolero’, ‘Tytan’) and the inoculation (Nitragina–seeds inoculation, Nitroflora I–seeds inoculation, Nitroflora II–soil inoculation, HiStick® Lupin–seeds inoculation) on plant development, seeds chemical composition and yielding of narrow-leaved lupin. The weather conditions and experimental factors significantly influenced on productivity of narrow-leaved lupin ‘Tytan’. Drought during the growing season reduced seeds and protein yields. After inoculation of HiStck the seeds yield was significantly greater by 12.4% (p < 0.01) and the protein yield after application of Nitroflora I or HiStick by 13.9% (p < 0.01) and 19.2% (p < 0.01), respectively. Correlation coefficients showed strong relations between number of pods and seeds per plant in both cultivars regardless of the inoculation variant, however the strongest relations in both cultivar were proved on HiStick treatment.
Keyword: Biological nitrogen fixation, chemical composition, legumes, protein efficiency, yielding