Effect of adding chemical, organic fertilizers and spraying seaweed extracts on the availability of NPK and organic material in calcareous soil

Abstract

A field experiment was carried out in the agricultural season 2021-2022 in one of the farming fields in the region of Muqdadiya, Al-Harouniya district, located 40 km northeast of Baquba district of Diyala governorate. (Soil Survey Staff, 2006). It is located at a longitude of 53° 34' N and latitude of 56° 04° 45° S. The experiment aimed to study the effect of adding chemical and organic fertilizers and spraying seaweed extracts on NPKS concentrations and cauliflower yield. The investigation included three factors; the first factor was the addition of organic fertilizer (buffalo waste) at three levels (0, 5 and 10%) of the terrace size, which M1, M2 and M3 respectively symbolize. It was added at a depth of 0-30 cm a month before planting the seedlings in the field. The second factor was the addition of NPK compound chemical fertilizer (20:20:20) at two levels (0 and the full fertilizer recommendation is 300 kg H-1 when planted as a feed) and symbolized by C1 and C2, respectively. The third factor is spraying seaweed extract with three levels (0, 2 and 4) ml L-1 represented by A1, A2 and A3. The experiment results showed that adding chemical fertilizer significantly affected the availability of organic material in the soil. The 2C treatment (and the full fertilizer recommendation of 300 kg H-1) outperformed and reached 2.96 gm kg-1; nitrogen availability in the soil amounted to 2.96 %. As well as the availability of phosphorous in the soil, which amounted to 76.28 mg P kg 1-soil, and potassium availability in the soil amounted to 76.28 %. The addition of buffalo manure to calcareous soils significantly affected the readiness of the organic material. Also, treatments M2 and M3 outperformed in soil with a value of 3.34 and 23. 4 g/kg-1, and nitrogen availability in soil amounted to 29.88 and 31.25 mg N kg-1-. The M3 treatment also excelled in the availability of phosphorous in soils, which amounted to 86.98 mg P kg-1-soil mg M kg-1-soil. The availability of potassium in the soil amounted to 361.33 %. The triple interaction between the studied factors significantly affected the availability of organic material in soils. The M2×C2×A3 treatment also excelled in recording the highest value, which was 3.85 gm kg-1, nitrogen availability in soil amounted to 37.75 %, phosphorous availability in soil amounted to 94.16 mg P kg-1 and potassium availability in soil amounted to 436.42 mg kg1-soil. Keywords: chemical fertilization, organic fertilization, seaweed extracts.