The Fertility Assessment of some Citrus Orchards in the District of Baquba

Abstract

Abstract A study was conducted on three citrus orchards in the regions of Bahraz, Khan al-Lawala, and Al-Hawidr in the city of Baqubah, the center of Diyala province. This province is known for its cultivation of citrus fruits and its superiority in quantity and quality of production across Iraq. On July 3, 2022, soil samples were taken at three depths: 0-30 cm, 30-60 cm, and 60-90 cm, with three replicates for each orchard. The samples were dried, sieved, and prepared for laboratory analysis. Five soil properties were selected (readily available nitrogen, phosphorus, potassium, organic carbon, and electrical conductivity) to determine soil fertility through laboratory analysis. After the analysis, the data were processed and statistically analyzed to determine the fertility of the orchard soil and its ability to supply plants with nutrients, identify deficiencies in elements, high salinity levels, and the quantity of organic matter. Soil fertility assessment for orchards provides a clear idea for estimating fertilizer recommendations, reducing fertilizer additions, minimizing fertilizer waste, and consequently lowering fertilization costs for farmers, thus saving financial resources. Additionally, excessive fertilizer application leads to groundwater pollution and affects the physical and chemical properties of the soil. Estimating electrical conductivity (salinity) is of great importance in citrus orchards, as salinity directly affects citrus trees. Monitoring salinity levels is necessary to maintain low levels because citrus trees cannot tolerate high salinity levels. Organic matter is important for improving the physical and chemical properties of soil. The decrease in organic matter in these orchards is attributed to the dry climate in most days of the year, prevailing in these areas, this study provides a general idea about the fertility of these orchards to identify production problems, determinants, and successful solutions to improve their fertility. Therefore, the results revealed the superiority of the soil in Bahraz area orchards over the other areas in terms of N, reaching the highest value of 25.13 at the first depth (0-30) cm, while the lowest value for N was 15.13 in Bahraz area at the depth of (60-90) cm. Khan al-Lawala area orchards excelled over the other areas in terms of P, with the highest value of P reaching 19.39 at the depth of (60-90) cm, while the lowest value for P was 13.20 in Bahraz area at the depth of (60-90) cm. The soil in Al-Hawidr area orchards surpassed the other areas in terms of K, with the highest value of K reaching 334.67 at the depth of (0-30) cm, while the lowest value for K was 165.12 in Bahraz area at the depth of (60-90) cm. The results also showed the superiority of the soil in Bahraz area orchards over the other areas in terms of EC, with the highest value of EC reaching 3.42 at the depth of (0-30) cm, while the lowest value for EC was 0.75 in Khan al-Lawala area orchards at the depth of (60-90) cm. Khan al-Lawala area orchards excelled over the other areas in terms of O.C, with the highest value reaching 2.24 at the depth of (0-30) cm, while the lowest value for O.C was 0.71 in Al-Hawidr area orchards at the depth of (60-90) cm from the soil surface.