Optimizing the nitrogen (N) timings and rate can improve nutrient uptake, and nutrient-efficiencies, especially of N in wheat under the changing climate scenario. Climatic stress in the form of high temperature and drought resulted in the decreased crop physiology and, ultimately, grain yield. Taking the example of rainfed wheat, we quantified the impact of N application rates as full and split-dose at three variable sites of rainfed Pothwar, Pakistan by conducting field experiments for two years (2013-14 and 201-15). Treatments include, T₁ = Control (No fertilizer applied), full dose of N applied at the time of crop sowing, i.e. T₂ = 50 kg N ha^-1, T₃ = 100 kg N ha^-1 and T₄ = 150 kg N ha^-1 and split application of N at different timings during different stages of the crop called as split application of N, i.e. T₅: Application of 50 kg N ha^-1 (15 kg N ha^-1 (Sowing) : 20 kg N ha^-1 (Tillering) :15 kg N ha^-1 (Anthesis), T₆: Application of 100 kg N ha^-1 (30 kg N ha^-1 (Sowing): 40 kg N ha^-1 (Tillering) : 30 kg N ha^-1 (Anthesis) and T₇: Application of 150 kg N ha^-1(45 kg N ha^-1 (Sowing) : 60 kg N ha^-1 (Tillering) : 45 kg N ha^-1 (Anthesis). Three study sites include viz. Islamabad (High rainfall with optimum temperature), University Research Farm (URF)-Koont (Medium rainfall with moderate temperature), and Talagang (low rainfall with high temperature). Results showed that the highest stomatal conductance (0.80 mole m^-2 sec^-1), net photosynthetic rate (20.07 μmole m^-2s^-1), transpiration rate (9.58 mmole m^-2s^-1), intercellular CO₂ concentration (329.25 μmole CO₂ mol^-1 air), SPAD values (58.86 %) and proline contents (35.42 μg g^-1) were obtained for split application of N (T₆ = Split N₁₀₀) compared to control and full dose of N treatments. Among sites, these physiological traits remained highest at Islamabad and lowest at Talagang, while among years, maximum values of the measured parameters were obtained in 2013-14. A similar trend was observed for crop total N, N efficiencies, and agronomic traits of the crop. Our results suggest that optimum N application rate and its suitable timings can help to harvest real benefits of N as in our findings, split dose resulted in the maximum performance of the crop from physiological parameters to the agronomic traits of the rainfed wheat crop.

We studied the influence of lava meal, zeolite and top layer of sandy soil as bedding additives on gaseous C and N losses from a sloping-floor barn of naturally ventilated animal housing. We selected four barn units where eight young bulls’ group was reared in each barn. Chopped straw of wheat and barley applied daily at the rate of 5 kg per livestock unit (LU) in bedding areas where one LU consisted of 500 kg body mass of live bulls. Zeolite, lava meal and sandy soil (18% clay + silt) applied in barn at the rate of 10, 20 and 30% of straw dose, respectively. Static flux chamber was used to measure gases emissions from the barn unit and mass balance calculation was used to calculate straw manure total N (TN) losses during housing phase. On an average, all bedding additives decreased 85% of the NH₃ emission compared to control; however, they did not influence CH₄ emission. Zeolite decreased CO₂ (35%) and N₂O (37%) emission rates. Subsequently, lava meal, sandy soil and zeolite decreased 23, 37, and 50% of TN losses from barn manure, respectively. Overall, measured N emissions through NH₃-N and N₂O-N from the barns was 11% of calculated TN losses while remainder 89% was most probably attributed to di-nitrogen (N₂), a harmless gas. Hence, in straw-based cattle housings, zeolite could be a promising additive for reduction of CO₂, N₂O and NH₃ emissions and sandy soil can be considered as cheap and readily available resource for reducing NH₃ emission.