Effect of Long-term Application of FYM and Fertilizer N on Available P, K and S Content of Soil.
Ram Phal Narwal and Manju Chaudhary. Dept of Soil Science, CCS Haryana Agricultural Univ, Hisar, India
The effect of long-term use of Farm Yard Manure (FYM) and fertilizer N on the nutrient status of soil was studied in a field experiment started in 1967 at the Research Farm of CCS Haryana Agricultural University, Hisar, India. The experimental treatment consisted of 3 levels of FYM (15, 30, 45 Mg ha-1) applied in 3 different modes i.e. application in summer (June), in winter (October) and in both summer and winter. One FYM control treatment was also included. These 10 treatments were applied in main plots and each main plot was divided in 3 sub-plots receiving urea fertilizer N at 0, 60 and 120 kg ha-1. All treatments were replicated four times. The cropping sequence was pearl-millet (Pennisetum typhoides) and wheat (Triticum aestivum) for all the years. The soil samples for this study were collected from three depths (0-15, 15-30 and 30-45 cm) after harvest of wheat crop in 2001. After 34 years of continuous cropping under various treatments, the differences in Organic Carbon (OC) and available P, K and S were significantly influenced. The OC contents of the soil declined in control plots and increased with the application of various levels of FYM under all modes of application. The OC content of the soil decreased from its original value when no FYM was applied. The highest OC content of the soil was approaching 1.95% in plots receiving 45 Mg FYM ha-1 in both seasons. The application of FYM increased the available P, K, and S content of the soil from its original values up to 88, 1156 and 81 mg kg-1 soil. The highest contents of available P, K, and S were also found in plots receiving the highest levels of FYM in both seasons, along with inorganic N. The FYM and N application also increased the OC and available P, K and S content of the soil at lower depths but the increase was not at the same rate as in surface soils. The relationship curves drawn between OC and available P, K and S content of the soil indicate that with increases in OC content of soil by the application of FYM nutrient content (P, K and S) of soil also increased. Thus these results indicate that the combined application of FYM and inorganic N increased the productivity of soil.