SHARMA, UDAYDHINDSA, RAVNEET KAUR2019-01-012019-01-012018-10http://krishikosh.egranth.ac.in/handle/1/5810086892ABSTRACT Investigations entitled “Comparative efficiency of different nitrogen sources on soil properties and productivity in apple” were conducted at three different locations viz. Solan, pot culture (cv. Starking Delicious), Seobagh, Kullu (cv. Vance Delicious) and Rohru, Shimla (cv. Red Chief) during 2015-16 and 2016-17 with 14 treatments comprising different sources including urea (soil and foliar) and liming, calcium nitrate, calcium cyanamide, 12:32:16, 15:15:15 and their combinations replicated thrice in a RBD under field conditions and CRD under container grown experiment. The different sources were given on N equivalence basis depending upon the age of the plants. In Starking Delicious apple plants grown in containers the highest pH was recorded under no application of fertilizers (6.81 in 2016 and 6.79 in 2017) and lowest under urea application (6.48 in 2016 and 6.40 in 2017). The highest N and K contents were found in urea + liming (In March) treatment and P under 12:32:16 + calcium nitrate. Maximum leaf N was recorded in urea + liming (In March) (2.62% in 2016 and 2.67% in 2017, leaf P (0.221% in 2016 and 0.228% in 2017) and leaf K (1.76% in 2016 and 1.84% in 2017) in calcium nitrate + urea + liming. Maximum annual extension growth (98.61 cm in 2016 and 99.54 cm in 2017), increase in plant height (20.32% in 2016 and 21.51% in 2017) and increase in plant girth (8.69% in 2016 and 8.77% in 2017) were recorded in plants supplied with calcium nitrate+ urea+ liming. The treatments when superimposed on Vance Delicious and Red Chief grown at two different locationsrevealeda similar trendwith reference to soil and plant nutrient contents. At Seobagh pH was highest under the application of calcium cyanamide (5.84 in 2016 and 5.87 in 2017) and at Rohru under control (5.61 in 2016 and 5.55 in 2017). Urea application was found to decrease the soil pH to a small extent. Increase in tree height was highest in urea + liming (In March) at both the locations in both years. Annual extension growth was maximum under calcium nitrate + urea + liming with mean value of 73.27 and 73.33 cm at Seobagh and 45.33 and 48.67 cm at Rohru in 2016 and 2017, respectively. Fruit yield was also affected significantly and varied with the type of nitrogen source used. It was highest in trees supplied with calcium nitrate + urea + liming at both the locations and in both the years with the mean values of 74.39 and 78.33 kg tree-1 at Seobagh and 59.00 and 66.33 kg tree-1at Rohru in 2016 and 2017, respectively.ennullThesis