Effect of long-term application of farm yard manure and nitrogen on manganese fractions in soil

A long-term field experiment on compensation of fertilizer nitrogen (N) through use of farm yard manure (FYM) on pearl millet (B)-wheat (W) sequence since October 1967 was undertaken at Research Farm of the Department of Soil Science, CCS Haryana Agricultural University, Hisar. The present study was conducted to assess the effect of the experiment on the manganese (Mn) fractions in the soil after about 35 years of ^{experimentation. The treatments of the experiment consisting of three doses of FYM (15, 30 and 45 mg/ha/year) indicated as F₁₅, F₃₀ and F₄₅ applied in three different months i. e. in summer, in winter and in both the seasons (B+W). One control of FYM (F₀) was also included. These 10 treatments (three FYM levels x three modes of FYM+1 control) were assigned in main plots and each main plot was divided into three sub plots receiving nitrogen at the rate of 0, 60 and 120 kg/ha applied through urea. All the treatments were replicated four times. For the present study, soil samples were collected from only two out of three levels of nitrogen i. e. 0 and 120 kg N/ha and from two out of four replications. The FYM levels increased the readily soluble Mn in soil from 0.9 to 3.58 ppm. Similarly, the weakly and specifically adsorbed Mn increased from 6.42 to 12.74 ppm; carbonate bound Mn from 135.49 to 164.68 ppm; oxide Mn from 26.35 to 35.31 ppm and total Mn from 213 to 514 ppm from control of FYM to 45 mg FYM/ha year.}