Effect of Application Different Combinations of Phosphogypsum and Humic Acids Mixed With Saline Irrigation Water on Broccoli Yield and NPK Concentration

Abstract

Long-term irrigation with saline water causes detrimental effects on the soil-crop system. The study aimed to determine the best combination of Phosphogypsum and humic acid can mitigate the negative effects of saline water irrigation on broccoli growth. Therefore, two-factorial field experiment was conducted according to a randomized complete block design with three replications during autumn season of 2021 in Fallujah district /Anbar governorate in sandy loam soil. The first factor included three levels of saline water irrigation, namely 2.5, 5.0 and 7.0 dS.m-1. while the second factor involved three levels of humic acids i.e., 0.0, 0.25 and 0.50 g/l mixed with three levels of phosphogypsum that is 0.0, 0.25 and 0.50 g/l. Fruits weight, height, yield, plant nitrogen content, plant phosphorus, and plant potassium content were measured. The results showed that the combinations under study ( humic acids and phosphogypsum) had a crucial role in reducing the negative effects of irrigation salinity. Moreover, the macronutrients availability increased with increasing humic acids concentration in irrigation water. The observed results show a significant increase in the weight of broccoli fruit and yield at T8 by giving 325 g. plant-1and 8.66 t.h-1 respectively under effect of the combination under study. Also, the studied combinations led to increase the N,P,and K concentration in plant tissues. Where the highest observed averages of nitrogen and potassium were 3.96% and 2.56% at T8 treatment. While The highest concentration of phosphorus was observed at treatment T9 reached 0.47%.