Effect of long-term of nutrient management on productivity and soil fertility of maize (Zea mays)–wheat (Triticum aestivum) cropping system in Tungabhadra command area

Abstract

The long term experiment was conducted since 1987-88 on permanent site at Agricultural Research Station, Siruguppa, Karnataka to assess the effect of long-term nutrient management on productivity and soil fertility of maize (Zea mays)–wheat (Triticum aestivum) cropping system in Tungabhadra command area. The experimental treatments consisting 3 levels of nitrogen (40, 80 and 120 kg N/ha), 3 levels of phosphorus (0, 40 and 80 kg P2O5/ha) and 2 levels of potassium (0 and 40 kg K2O/ha) and with one absolute control, it was laid out in partially confounded design with 4 replications. The experiment was conducted in vertisols, which is slightly alkaline (8.12), low in soluble salts (0.36 dS/m), soil organic carbon (0.38), and available nitrogen (165 kg/ha) and medium in phosphorus (16.6 kg/ha) and rich in potassium (341 kg/ha). The maize was sown during kharif followed by wheat during rabi after harvest of the main crop in zero cultivation practice. The treatments were imposed as per the treatment combination. Maize hybrid NK 6240 and wheat variety DWR 162 were used in the trial. Experimental results revealed that maximum maize grain yield (4240 kg/ha), MEY (7291 kg/ha) and system productivity (19.97 kg/ha/day) were observed with application of 120 kg N/ha compared to 40 kg N/ha. Similarly, 80 kg P2O5/ha produced higher grain yield (4742 kg/ha), MEY (8420 kg/ha) and system productivity (23.07 kg/ha/day) and potassium application @ 40 kg/ha recorded higher grain yield (4244 kg/ha), MEY (6998/ha), system productivity (19.17 kg/ha/day) compared to lower levels of nutrients. In case of wheat, application of N @ 120 kg/ha, 80 kg P2O5/ha and 40 kg K2O/ha produced maximum yields (1861, 2243 and 1679 kg/ha, respectively) compared to their corresponding lower doses. Similar trend was also observed in 28 years mean data. Higher availability of N, P, K and S were observed in soil fertilized with higher level of N, P and K compared to lower doses.