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ThesisItem Open Access Dynamics of soil phosphorus in relation to carbon under different cropping systems(Punjab Agricultural University, Ludhiana, 2016) Dhram Prakash; Benbi, D.K.Dynamics of phosphorus in soils were studied in relation to nutrient management and land-use practices. The nutrient management practices evaluated included source (rock phosphate and single superphosphate) and rates of P application in rice-wheat system; and integrated nutrient management (INM) and organic farming practices in basmati-wheat system in field experiments conducted at the research farm of Punjab Agricultural University, Ludhiana. The land-uses studied included ricewheat, maize-wheat, cotton-wheat and poplar based agroforestry systems at farmers’ fields in different districts of Punjab. After seven cycles of rice-wheat cropping, farmyard manure (FYM) and rock phosphate (RP) application increased available P and soil organic carbon (SOC) by 72% and 98%, respectively over control. Inorganic P constituted the largest proportion (88-92%) of total P in soil and relative abundance of different inorganic P fractions in soils followed the order Ca-Al associated > Fe associated > humic bound > water soluble P. In basmati-wheat system, application of recommended rates of NPK and adoption of INM improved available P in soil over unamended control by 75 and 100%, respectively. The comparison of three organic sources revealed that available P was the highest in soil receiving 400 kg N ha-1 through FYM followed by rice straw compost and the lowest in vermicompost-amended plots. Application of FYM significantly increased inorganic, organic and total P, SOC and labile C pools compared to INM treatments. The INM increased inorganic, organic and total P by 77, 82 and 78%, respectively over NPK. Humic-bound organic P constituted major proportion (39.5-49.5%) and water soluble organic P comprised the smallest proportion (0.83-2.5%) of organic P in soils under basmati-wheat system. Beneficial effects of different treatments on soil properties were higher in surface soil (0-7.5 cm), which decreased with soil depth. Generally, soil P fractions were positively correlated with soil C pools. Cumulative P released in 96 hours of equilibration increased with manure and fertilizer application either alone or in combination. Phosphorus release kinetics were best described by Elovich and power function equations (R2≥0.98). Results of land-use studies showed that agroforestry systems had relatively higher proportion of organic P (27%) compared to sole cropping (6-7.7%). Soil organic C was the highest (0.58%) under agroforestry and was significantly correlated with soil P fractions under sole cropping systems. Soil properties viz. clay, organic C, CaCO3 and available P content significantly influenced soil P sorption and release kinetics. Phosphorus release decreased with increase in clay and CaCO3 content. On the contrary, P release increased with increase in available P and organic C. The results suggested that P availability will be higher in coarse-textured, non-calcareous soils having higher levels of organic C and available P. Therefore, for efficient P management it is important to take into account soil texture, the existing soil P level, organic C content and calcareousness of soil. Practices that increase SOC content and ameliorate CaCO3 could lead to improved P use efficiency.ThesisItem Restricted Phosphorus Dynamics in Relation to Carbon Mineralization in Soils Under Different Moisture Regimes(College of Agriculture, Punjab Agricultural University, Ludhiana, 2005) Kaur, Harjinder; Saroa, GSThesisItem Restricted Impact of Continuous Cropping and Fertilization on Crop Yield and Soil Properties Under Maize-Wheat Sequenct(College of Agriculture, Punjab Agricultural University, Ludhiana, 2006) Kaur Brar, Kiranvir; Saroa, GSThesisItem Open Access CARBON AND PHOSPHORUS DYNAMICS IN SOIL IN RELATION TO NUTRIENT MANAGEMENT IN RICE-WHEAT SYSTEM(PAU Ludhiana, 2012) Seema Sharma; G. S., SaroaThe study comprised of two field and two laboratory experiments. In field experiment on organic and integrated nutrient management of basmati-wheat sequence, the effect of inorganic, organic and integrated nutrient management was studied on crop yield and soil properties. Water infiltration rate was highest and soil bulk density was lowest in recommended fertilizer + FYM (INM2) treatement. Total water stable aggregates (WSA) in the 0-15 cm soil depth ranged from 58.5 to 82.4 per cent; minimum WSA were observed in control and maximum in INM2 treatment. Among the aggregates 0.11-0.25 mm fraction constituted the greatest proportion and > 2 mm fraction constituted the least proportion. Maximum pH and EC were recorded in control plots and minimum in plots receiving 400 kg N ha-1 through FYM. Soil organic carbon (SOC), aggregate associated C, labile C and hot water soluble C was highest in FYM 400N treatment. Ammonical-N, nitrate-N, Olsen P, Bray I P, ammonium acetate extractable K, soil P fractions and total P in soil were highest in INM2 treatment and lowest in control. Grain yield, straw yield, NPK content and their uptake by basmati and wheat were maximum in INM2 treatment and minimum in control. Basmati and wheat grain yield were significantly correlated with soil P fractions and the highest correlation was observed with saloid-P. In the second experiment, effect of rock phosphate on crop yield and P fractions in soil under rice-wheat sequence was studied. Highest SOC, Olsen P, soil P fractions, ammonium extractable K and non-exchangeable K were recorded in rock phosphate (RP) and FYM treatment and lowest content of all these parameters was observed in control. Highest pH was observed in control P treatment and lowest in treatment where FYM was applied along with RP. Grain yield, straw yield, NPK content and uptake in grain and straw were also highest in plots recieving P from RP along with FYM. Grain and straw yield of both the crops were significantly correlated with all the soil P fractions (Sa-P, Al-P, Fe-P and Ca-P). Highest correlation of paddy grain yield was observed with Sa-P whereas wheat grain yield gave highest correlation with Al-P fraction and lowest with Ca-P. Rock phosphate gave almost similar crop yield and P availability in soil as that with SSP. In laboratory study I, P was extracted by different methods and the lowest amount of P was extracted with AB-DTPA and the highest with Bray-I method. Phosphorus extracted by Olsen, Bray-I, Morgan and AB-DTPA methods gave significant positive correlations with grain yield and nutrient uptake of paddy and wheat. In the soils from long-term experiments with different fertilization history, maximum P adsorption was observed in unammended soil and minimum in soils where FYM was applied alongwith chemical fertilizer. Contrarily, desorption was minimum in control plots and maximum in plots where organic sources along with inorganic fertilizers were applied. Adsorption data fitted well to both Freunlich and Lagmuir models. .ThesisItem Restricted Studies On Moisture Regime And Nitrogen Fertilizer Interaction In Winter Sunflower(Punjab Agricultural University ;Ludhiana, 2002) Satwinderjit Kaur; Hira, G SThesisItem Open Access Mobilization, Depleton And Influx Of Iron And Management In The Rihizosphere Of Different Crop Species(Punjab Agricultural University; Ludhiana, 2005) Moral, Gobinda; Sadana, U.S.ThesisItem Open Access Carbon and phosphorus dynamics in soil in relation to nutrient management in rice-wheat system.(PAU, 2012) Sharma, Seema; Saroa, G. S.The study comprised of two field and two laboratory experiments. In field experiment on organic and integrated nutrient management of basmati-wheat sequence, the effect of inorganic, organic and integrated nutrient management was studied on crop yield and soil properties. Water infiltration rate was highest and soil bulk density was lowest in recommended fertilizer + FYM (INM2) treatement. Total water stable aggregates (WSA) in the 0-15 cm soil depth ranged from 58.5 to 82.4 per cent; minimum WSA were observed in control and maximum in INM2 treatment. Among the aggregates 0.11-0.25 mm fraction constituted the greatest proportion and > 2 mm fraction constituted the least proportion. aximum pH and EC were recorded in control plots and minimum in plots receiving 400 kg N ha -1 through FYM. Soil organic carbon (SOC), aggregate associated C, labile C and hot water soluble C was highest in FYM 400N treatment. Ammonical -N, nitrate-N, Olsen P, Bray I P, ammonium acetate xtractable K, soil P fractions and total P in soil were highest in INM2 treatment and lowest in control. Grain yield, straw yield, NPK content and their uptake by basmati and wheat were maximum in INM2 treatment and minimum in control. Basmati and wheat grain yield were significantly correlated with soil P fractions and the highest correlation was observed with saloid-P. In the second xperiment, effect of rock phosphate on crop yield and P fractions in soil under rice-wheat sequence was studied. Highest SOC, Olsen P, soil P fractions, ammonium extractable K and non-exchangeable K were ecorded in rock phosphate (RP) and FYM treatment and lowest content of all these parameters was observed in control. Highest pH was observed in control P treatment and lowest in treatment where FYM was applied along with RP. Grain yield, straw yield, NPK content and uptake in grain and straw were also highest in plots recieving P from RP along with FYM. Grain and straw yield of both the crops were significantly correlated with all the soil P fractions (Sa-P, Al-P, Fe-P and Ca-P). Highest correlation of paddy grain yield was observed with Sa-P whereas wheat grain yield gave highest correlation with Al-P fraction and lowest with Ca-P. Rock phosphate gave almost similar crop yield and P availability in soil as that with SSP. In laboratory study I, P was extracted by different methods and the lowest amount of P was extracted with AB-DTPA and the highest with Bray-I method. Phosphorus extracted by Olsen, Bray-I, Morgan and AB-DTPA methods gave significant positive correlations with grain yield and nutrient uptake of paddy and wheat. In the soils from long-term experiments with different fertilization history, maximum P adsorption was observed in unammended soil and minimum in soils where FYM was applied alongwith chemical fertilizer. Contrarily, desorption was minimum in control plots and maximum in plots where organic sources along with inorganic fertilizers were applied. Adsorption data fitted well to both Freunlich and Lagmuir models.ThesisItem Restricted Effect Of Different Land Use Systems On Soil Quality In Kandi Region Of Punjab(Punjab Agricultural University ;Ludhiana, 2003) Dhaliwal , Salwinder Singh; Bijay SinghThesisItem Open Access Influence Of Soil Characteristics On Available Pb And Cd And Their Accumulation By Brassica Sp(Punjab Agricultural University ;Ludhiana, 2003) Sikka, Rajeev; Nayyar, V. K.
