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Climate change may affect wheat positively or negatively when global warming is likely to increase evapotranspiration (ET) and decrease crop physiological functions. More often droughts are being encountered in Pothwar because of high ET and low precipitation in the form of rainfall. The impact of climate change on physiological attributes [Net photosynthesis(An), stomatal conductance(gs) and transpiration (E)] of spring wheat in Pothwar was studied through field experiments conducted at National Agriculture Research Centre (NARC), Islamabad, Barani Agriculture Research Institute (BARI), Chakwal and at farmer's field Talagang over two years (2008-2009 & 2009-2010). The treatments consisted of five planting windows, three genotypes arranged in Randomized Complete Block Design (RCBD) factorial replicated four times. The results revealed that changing environment and sowing dates changed the adaptability pattern of wheat crop at three locations, because of change in the temperature and rainfall over the phenological stages of wheat. The reduction in net photosynthetic rate during 2009- 2010 was 21% compared to 2008-2009, while among locations 20% decrease in An was recorded at Talagang from maximum value at Islamabad. The gs dropped to 50% during 2009-2010 due to temperature and moisture stress, while 92% reduction in gs was recorded at Talagang compared to highest value. However, transpiration rate dropped to 71% during 2009-2010, while among locations crop showed minimum transpiration (79% less than maximum) at Talagang. At Chakwal significant decrease in crop physiological parameters declined the grain yield. Talagang being the low rainfall and relatively higher temperature area of Pothwar produced the lowest yield due to drop in physiological functions of crop and reduced LAD and LAI. Findings of the present study provided support for further physiological investigations and potential strategy for minimizing the climate risk especially in rainfed agriculture [ABSTRACT FROM AUTHOR]

Knowledge about different phosphorus pools in the soil and their relationship with different soil properties is of immense significance for increasing phosphorus use-efficiency in agricultural systems. Fifteen soil series from the relevant agricultural fields were analysed for their phosphorus pools. The average size of different P pools (% of total P) in the soils was in order of, dHCl-P (63.7%) > cHCl-P[sub i] (14.8%) > residual P (9.4%) > cHCl-P[sub o] (3.8%) > NaHCO3-P[sub i] (2.4%) > NaOH-P[sub i] (2.0%) > NaHCO[sub 3-] P[sub o] (1.4%) > resin-P (1.3%) > NaOH-P[sub o] (1.2%). Overall, the inorganic P pools comprised of 93.6% of total P in the soils and had highly significant positive correlation with soil pH and CaCO3 content. The organic P constituted a small proportion (6.4%) of the total P and was positively correlated with the clay and organic C contents of the soils. The data indicated that organic P pool represents an important source of P in subtropical alkaline soil ecosystems. [ABSTRACT FROM AUTHOR]

Sorghum is capable of sustaining under high temperature and minimal soil moisture. Hydrocyanic acid toxin production is a serious problem associated with sorghum forage in dry areas and could be lethal to animals if ingested in higher quantities. Hydrocyanic acid (HCN) contents in forage sorghum were studied through field experiment executed at National Agricultural Research Centre, Islamabad during 2008 and 2009. Three sorghum cultivars JS-2002, Chakwal sorghum and Local sorghum were sown in a randomized complete block design in split-split plot arrangement with three seeding rates (75, 100 & 125 kg ha-1) and three nitrogen levels (0, 60 & 120 kg N ha-1). Increased nitrogen application progressively increased HCN production irrespective of cultivar and growth stage of the crop. Application of 120 kg N ha-1 recorded about 64% higher HCN than control treatment indicating the risk of higher doses of nitrogen fertilizer to sorghum forage in dry areas. Seeding rates had variable influence on HCN production. Cultivar JS-2002 produced 23, 36 and 57% less HCN contents compared to local sorghum at pre-booting, booting and 50% heading stage, respectively. On the basis of two year's field study, it may be concluded that approved cultivar JS-2002 produced less HCN sown with higher seed rate and applied low doses of N fertilizer under dryland farming conditions of Pothwar is recommended for general cultivation. [ABSTRACT FROM AUTHOR]

A field experiment was conducted for two years to assess the impact of buctril super herbicide application on soil enzymes activity and microbial population. The hypothesis of the study was that the herbicide has negative effects on soil microbes and enzymes. The experiment was laid out in randomized complete block design using five herbicide treatments: 375 mL ha-1, 750 mL ha-1, 1500 mL ha-1, 2250 mL ha-1 and control with four replications. Wheat variety Chakwal-50 was sown as a test crop and the herbicide was applied seven days after sowing. The soil samples were taken at 0, 7, 15, 30 and 60 days after herbicide application. Results showed 30% decrease in bacterial population, 23.4% decline in actinomycetes population, 34% decrease in fungi population, 30% reduction in urease activity, 36% inhibition in dehydrogenase activity and 34% decline in alkaline phosphatase activity with bromoxynil herbicide application at 2250 mL ha-1 during the year 2011-2012. However, 36, 27.7, 38.6, 31, 36 and 31% decline in bacteria, actinomycetes, fungi population, urease, dehydrogenase and alkaline phosphatase activity was observed, respectively where the herbicide was applied at 2250 mL ha-1 during the year 2012-2013. Overall bacteria, actinomycetes and fungi populations showed decreasing trend with herbicide application up to the day-15 and then increasing trend was observed till day-60. Decrease in dehydrogenase and alkaline phosphatase activities was experienced with herbicide application upto day-7, thereafter the activities of these enzymes showed increasing tendency up to day-60 during both years. Buctril super herbicide had negative effects on soil microbes and enzymes activity showing significant reduction in these parameters up to two weeks after its application, which later on subsided. © 2015 Friends Science Publishers [ABSTRACT FROM AUTHOR]