Muhammad Anwar-ul-Haq

Impact of nursery seeding density, nitrogen, and seedling age on yield and yield attributes of fine rice

Producing vigorous seedlings and transplanting them at the appropriate age are the most important factors for obtaining high yield in rice (Oryza sativa L.) paddy production. The impact of seeding densities, N, and seedling age was evaluated in this experiment after transplanting 10, 20, 30 and 40-d old seedlings raised by using different seeding rates (high and low) and N conditions (with and without) in the 2008 and 2009 rice growing seasons. The study revealed that 10-d-old nursery seedlings, irrespective of seeding densities and fertilizer application, showed higher yields and yield attributes (productive tillers, plant height, 1000-grain weight, and straw yield), while at later stages significant interaction was observed with nursery management. Transplanting of 20-d older fertile seedlings grown with low seeding density at nursery-bed, resulted in a higher number of productive tillers m-2 (233.3, 227.3), straw yield (11.1, 10.7 t ha-1), and final yield (3.6, 3.4 t ha-1) in both years, 2008 and 2009, respectively. Yield and yield attributes were significantly reduced by transplanting older seedlings grown at high seeding density and without N application at nursery-bed. Minimum productive tillers (165.7, 133), straw yield (8.7, 8.1 t ha-1) and paddy yield (2.0, 1.8 t ha-1) were recorded with transplanting 40-d older seedlings grown at high seeding density and without N application. These findings support the use of young seedling in a system of rice intensification and illustrate that by making a minor additional investment to raise healthy and vigorous seedlings in nursery seed-bed, farmers can improve yields.

Dry Matter Partitioning and Mineral Constitution Response of Sunflower (Helianthus annuus) to Integrated Nitrogen and Boron Nutrition in Calcareous Soils

Abundant plant growth and development prominently rely on adequate supply of macro and micro nutrients. Among various nutrients, nitrogen (N) and boron (B) holds great importance in sustaining and enhancing the productivity of sunflower. In calcareous soils of Pakistan, B deficiency is prevalent that affects the uptake of nutrients. The present field study aimed to assess the impact of B on biomass production and nutrient absorption in calcareous soils by considering different B doses (0‒6 kg ha -1 ) under variable N rates (50‒100% RN ‘recommended nitrogen’) for consecutive two years of 2011 and 2012. The growth traits as leaf area index, leaf area duration, crop growth rate, net assimilation rate and dry matter accumulation were significantly affected with B rate of 3.20‒3.50 kg ha -1 with 100% RN. In addition, B rate of 3.44 kg ha -1 with 100% RN produced maximum biological yield and harvest index in both years. Leaf and achene N contents were higher by 3.32 and 3.38 kg B ha -1 , respectively with 100% RN fertilization as compared to 75% RN and 50% RN. B fertilization at 3.50 kg ha -1 also had highest B contents in leaf and achenes under 100% RN. The lower B contents were found at reduced level of 50% RN in contrast to 100% RN. Chlorophyll pigments (chl a, b and total) were also affected positively with B rate of 3.46 kg ha -1 under highest level of N nutrition. However, higher biomass production and mineral uptake could be obtained at 3.0-3.50 kg ha -1 B rate with 100% RN compared to 75% RN and 50% RN nutrition.

Evaluating groundwater quality for irrigated agriculture: spatio-temporal investigations using GIS and geostatistics in Punjab, Pakistan

Groundwater is cornerstone of global food production, and its quality plays a vital role in crop development. Success of agriculture in Pakistan relies heavily on groundwater because of reduced surface water supplies and rainfalls. The current study was conducted to assess the spatio-temporal quality of groundwater in the Lower Chenab Canal (LCC) east area with emphasis on characterizing groundwater quality zones for irrigation applications. Groundwater samples from 289 observation wells were collected and chemically analyzed. A geostatistical approach using kriging interpolation was applied to express spatial variation and minimize estimation error in data. Three water quality parameters, electrical conductivity (EC), sodium absorption ratio (SAR), and residual sodium carbonate (RSC), were utilized to develop groundwater quality maps for two seasons including pre-monsoon and post-monsoon. To describe the spatial autocorrelation, suitable semivariogram models were identified and cross validated. The exponential model gave the best results for EC and RSC, whereas the spherical model was found to be the best fit for SAR. The overlay analysis was performed to create composite water quality maps according to which 40% LCC area is showing good groundwater quality for irrigation, 49% is exhibiting marginal quality, and 10% unsuitable during pre-monsoon and post-monsoon seasons. Groundwater quality is 100% good for Sultanpur irrigation subdivision, and only 3.75% is good for Paccadala subdivision. The results of the study may provide guidelines for the planners/policy makers to devise area-specific strategies for sustainable groundwater use.

Effectiveness of Potassium in Mitigating the Salt-Induced Oxidative Stress in Contrasting Tomato Genotypes

ABSTRACT To check the efficacy of potassium in alleviating oxidative stress under salt stress, salt-tolerant (Indent-1) and salt-sensitive (Red Ball) tomato (Lycopersicon esculentum Mill.) genotypes were exposed to three levels of sodium chloride (NaCl) (0, 75, 150 mM) and two levels of potassium (4.5 and 9 mM) in solution and foliar form. Thirty days of treatments revealed that increasing NaCl stress increased lipid peroxidation (malondialdehyde, MDA) and correspondingly the activity of antioxidant enzymes (superoxide dismutase, SOD; catalase, CAT; and glutathione reductase GR) in both genotypes. However, higher potassium (K) level in solution or foliar spray during the salt-induced stress decreased MDA and antioxidant activity and increased the growth in salt-tolerant genotype than in the salt-sensitive genotype. Decrease in MDA concentration, activity of antioxidant enzymes, and increase in the growth of tomato plants by the application of potassium under salt stress suggest that potassium is an effective ameliorating agent against salt-induced oxidative damage.

Zinc Application to Rice Genotypes Under Saline Conditions

Zinc (Zn) is an important micronutrient for plants, animals and human beings. In Pakistan most of the calcareous and alkaline soils are deficient in plant-available Zn because of arid and semi arid climate, high soil pH and calcareousness of soil. Zinc concentration in the soils of rice track in Pakistan is decreasing rapidly due to less addition of Zn in the soils. Environmental stresses are among the most limiting factors to plant productivity. Among these, salinity is one of the biggest problems of Pakistan due to its arid to semi-arid climate. Salinity stress significantly reduces growth and productivity of glycophytes, which are the majority of agricultural products. Among the glycophytes, rice is a zinc-sensitive as well as saline-sensitive crop. In this chapter we show that when a soil is exposed to salinity the nutrient imbalance is the main issue that effecting the plant growth. Decrease in water availability is the main problem due to increase in osmotic potential. Zn application improves the plant physiological process: photosynthesis and respiration and increase the CO2 fixation. Crop cultivation in saline soil can be possible by cultivation of salt tolerant genotypes, and application of mineral nutrition in higher dose.