Vol. 10, Issue 6 (2021)

Author(s):
M Yamini, V Munaswamy, KV Naga Madhuri and Y Reddi Ramu

Abstract:
The long-term field experiment which was started at the Regional Agricultural Research station, Tirupathi, Acharya N.G. ranga agricultural university during kharif – 2014. The soil of the experimental field was red sandy loam (Haplustalf). The soil was low in available nitrogen, medium in phosphorus and medium to high in potassium. Inorganic P fractions like Al-P, Fe-P,O-P, Ca-P, total-P and available P at 0-15 cm depth before sowing of the crop ranged from 20.43 to 37.62, 34.46 to 57.12, 16.97 to 31.31, 14.20 to 22.01, 27.25 to 54.50, 112.87 to 192.78, 27.00 to 45.00 mg kg^-1. At harvest 0-15 cm depth P fractions like Al-P, Fe-P,O-P, Ca-P, total-P and available P varied from 17.06 to 33.20, 31.872 to 53.31, 14.87 to 28.31, 10.62 to 20.25, 30.652 to 56.80, 105.40 to 180. 52, 21.002 to 45.00 mg kg^-1, similarly at 15-30 cm depth before sowing P fractions like Al-P, Fe-P,O-P, Ca-P, total-P and available P varied from 16.91to 31.90, 32.27 to 49.95, 15.92 to 27.02, 12.57 to 22.72, 25.25 to 51.25, 106.72 to 185.47, 27.00 to 41.00 mg kg^-1 and at harvest 15-30 cm depth these are ranged from 15.62 to 29.68, 30.00 to 47.50, 14.25 to 20.56, 26.30 to 52.42, 101.97 to 175.77, 23.00 to 36.00 00 mg kg^-1 respectively. It was observed that P fractions in soil 0-15 cm depth either increased or decreased from sowing to harvest of groundnut crop. At harvest Al-P decreased -15.17 to 29.90 per cent, Fe decreased from 4.35 to -25.25 per cent. O-p decreased -0.08 to 27.95 per cent. Ca-P decreased from -7.99 to -44.13. Organic P increased from 2.47 to 20.59 per cent. Decrease in total P was small -1.09 to -10.16. At harvest decrease in available P -2.72 to 25.00 per cent. However at 15-30 cm depth also the values are varying but influence was more or less similar. By the correlation and regression analysis, Al-P(0.450^***), Fe-P (0.505^**) were positively and significantly correlated with available P but not with any other fraction. A positive correlation between total P with the fractions like Al-P (0.354^*), Fe-P (0.551^***) and occluded P (0.423^**) was observed but not with other fractions. Available P at harvest significantly correlated with the Al-P (0.346^*), Fe-P (0.472^**), occluded P (0.362^*) and total P (0.540^**) but not with Ca-P (0.199) and organic P (0.220). Total P positively correlated with Al-P (0.383^*), Fe-P (0.683^**), occluded P (0.466^*), Ca-P (0.370) and organic P (0.302^*). By the multiple regression, analysis that value of Fe-P was significantly correlated with available P (0.095^***) and total P (0.001^*) Al-P and occluded P was significantly correlated with total P (0.094^*** and 0.062^***) respectively. At harvest the values of Al-P and occluded P correlated with total P (0.002^**, 0.008^***) positive correlation was also observed between total P and available P (0.067***).