Abdul Khaliq

Effect of Plant Growth-Promoting Rhizobacteria on Growth, Nodulation and Nutrient Accumulation of Lentil Under Controlled Conditions

Abstract Application of plant growth-promoting rhizobacteria (PGPR) has been shown to increase legume growth and development under field and controlled environmental conditions. The present study was conducted to isolate plant growth-promoting rhizobacteria (PGPR) from the root nodules of lentil ( Lens culinaris Medik.) grown in arid/semi-arid region of Punjab, Pakistan and examined their plant growth-promoting abilities. Five bacterial isolates were isolated, screened in vitro for plant growth-promoting (PGP) characteristics and their effects on the growth of lentil were assessed under in vitro, hydroponic and greenhouse (pot experiment) conditions. All the isolates were Gram negative, rod-shaped and circular in form and exhibited the plant growth-promoting attributes of phosphate solubilization and auxin (indole acetic acid, IAA) production. The IAA production capacity ranged in 0.5–11.0 μg mL −1 and P solubilization ranged in 3–16 mg L −1 . When tested for their effects on plant growth, the isolated strains had a stimulatory effect on growth, nodulation and nitrogen (N) and phosphorus (P) uptake in plants on nutrient-deficient soil. In the greenhouse pot experiment, application of PGPR significantly increased shoot length, fresh weight and dry weight by 65%, 43% and 63% and the increases in root length, fresh weight and dry weight were 74%, 54% and 92%, respectively, as compared with the uninoculated control. The relative increases in growth characteristics under in vitro and hydroponic conditions were even higher. PGPR also increased the number of pods per plant, 1 000-grain weight, dry matter yield and grain yield by 50%, 13%, 28% and 29%, respectively, over the control. The number of nodules and nodule dry mass increased by 170% and 136%, respectively. After inoculation with effective bacterial strains, the shoot, root and seed N and P contents increased, thereby increasing both N and P uptake in plants. The root elongation showed a positive correlation ( R 2 = 0.67) with the IAA production and seed yield exhibited a positive correlation ( R 2 = 0.82) with root nodulation. These indicated that the isolated PGPR rhizobial strains can be best utilized as potential agents or biofertilizers for stimulating the growth and nutrient accumulation of lentil.

COMPARATIVE EFFECTIVENESS OF UREA N, POULTRY MANURE AND THEIR COMBINATION IN CHANGING SOIL PROPERTIES AND MAIZE PRODUCTIVITY UNDER RAINFED CONDITIONS IN NORTHEAST PAKISTAN

A field experiment was conducted to evaluate the comparative effectiveness of poultry manure, urea N and the integrated use of both in changing soil properties, nutrient uptake, yield and yield attributes of maize grown at Rawalakot, Azad Jammu and Kashmir, Pakistan. Treatments include control without any amendment (N(0)); urea N (UN) = 120 kg N ha−1 (N120U); UN = 150 kg N ha−1(N150U); poultry manure (PM) = 120 kg N ha−1(N120PM); PM = 150 kg N ha−1(N150PM); UN = 90 kg N ha−1+ PM = 30 kg N ha−1(N90U+30PM); UN = 60 kg N ha−1+ PM = 60 kg N ha−1(N60U+60PM); UN = 30 kg N ha−1+ PM = 90 kg N ha−1(N30U+90PM). N fertilization from different sources and combinations increased dry matter yield from 5206 kg ha−1 in the control to 5605–5783 kg ha−1 and grain yield increased from 1911 kg ha−1 to 2065–3763 kg ha−1. Application of the highest rate of urea N recorded the highest grain yields of 3763 kg ha−1, double the control. The proportional increase for N90U+30PM and N60U+60PM was 85 and 83% while PM alone gave lower yields (41 and 44%) than the respective urea N treatments. Integrated use of urea + PM proved superior to other treatments in enhancing the uptake of N, P and K in plants. Averaged across two years, uptake of N, P and K in N90U+30PM and N60U+60PM was 88 and 85, 16.5 and 17.5, and 48.5 and 53.5 kg ha−1, respectively compared to 52.5, 11.5 and 33.5 kg ha−1 in the control. Nitrogen use efficiency (NUE) varied from 29% in PM treatments to 30–39% in combined treatments while NUE of 40% was recorded for urea N treatments. Application of PM lowered soil bulk density from 1.19 t m−3 in the control to 1.10 and 1.05 t m−3 in N120PM and N150U, enhanced pH from 7.39 to 7.65 and 7.78 and increased soil organic matter (22 and 32%), total N (21 and 26%), available P (44 and 55%) and available K (10 and 15%) compared with the control. Economic analysis suggested the use of 50% recommended mineral N (60 kg N ha−1) with PM saves the mineral N fertilizer by almost 50% compared to a system with only mineral N application. In addition, increase in N efficiency, plant nutrition and soil fertility associated with combined treatment would help to minimize the use of high cost synthetic mineral fertilizers and represents an environmentally and agronomically sound management strategy.

Influence of integrated phosphorus supply and plant growth promoting rhizobacteria on growth, nodulation, yield and nutrient uptake in Phaseolus vulgaris

To guarantee a sufficient phosphorus supply for plants, a rapid and permanent mobilization of phosphorus from the labile phosphorus fractions is necessary, because phosphorus concentrations in soil solution are generally low. Several plant growth-promoting rhizobacteria (PGPR) have shown potential to enhance phosphorus solublization and nodulation of legumes when co-inoculated with Rhizobium . This investigation was undertaken to assess the feasibility and compatibility of two mineral phosphorus fertilizers; diammonium phosphate (DAP), triple super phosphate (TSP), poultry manure (PM) and two PGPR strains on the growth, nodulation, yield, nutrient uptake and protein content of common bean ( Phaseolus vulgaris ) under deficient phosphorus supply. Integrated application of mineral phosphorus (P), PM and PGPR significantly increased shoot height, shoot fresh weight, shoot dry weight and leaf chlorophyll content by 67, 160, 51 and 106%, respectively, while increase in root length, root fresh weight and root dry weight was 79, 161, and 187%, respectively, over unfertilized control without PGPR application. Integrated use of different P sources and PGPR also increased number of nodules per plant, nodule fresh weight and nodule dry weight by 158, 107 and 168% over the control. Treatment with PGPR significantly increased number of pods per plant and grain yield by 224 and 96%, respectively over the control. Co-inoculation with Bradyrhizobium sp. strain MN-S and Agrobacterium sp. strain Ca-18 demonstrated two-fold increase in the proportion of nitrogen (N) and P uptake as well as protein content of the common bean grain was increases by 48%. Therefore, application of PGPR with low P fertilizer rates and PM could be a viable supplementary strategy for maximum benefits in terms of cost of production and sustaining productivity. Key words: Phaseolus vulgaris L., plant growth promoting rhizobacteria (PGPR), nodulation, yield, phosphorus deficiency, protein.

Effect of wheat cultivars on aphids and their predator populations

th week of February was found to be very favourable for aphids in wheat fields in the study area. The highest and lowest populations of coccinellid predators (all species) were recorded on TW0135 and 99T007 cultivars, respectively. The highest population of coccinellid predators was recorded during the 3 rd week of February. We observed a significant synchronization between aphids and coccinellids populations. It is concluded from the study that as INQLAB-91 is resistant to the attack of aphid’s population, this cultivar should be promoted in the areas of high aphid infestation. The populations of coccinellids follow the aphid’s population and coccinellids can be important biological control agents of aphids and can be imported tool for IPM programme in the study area.

Yield Losses in Chickpea with Varying Densities of Dragon Spurge (Euphorbia dracunculoides)

Abstract Knowledge of economic threshold level and growth habits of weeds in chickpea is essential to implement timely, effective, and economical weed control treatments. The effect of weed density on growth and yield performance in chickpea using dragon spurge as a test weed was investigated for 2 consecutive yr. Dragon spurge density levels of 5, 10, 15, 20, 25, 30, 35, and 40 plants m−2 were compared with weed-free plots. Each increment in densities of dragon spurge from 5 to 40 plants m−2 reduced plant height, number of fruits, seeds, and dry weight per plant. Chickpea grain yield losses varied between 1 to 63% with dragon spurge density ranging from 5 to 40 plants m−2. The seed protein content of chickpea was found to be significantly reduced above a weed density of 25 plants m−2. Maximum N, P and K uptake by dragon spurge was 1,520, 1,020, and 7,350 mg m−2, respectively. Thus, dragon spurge should be controlled at densities above 5 plants m−2 to achieve optimum chickpea yield. Nomenclature: Chickpea, Cicer arietinum L.; Euphorbia dracunculoides Lam.

EFFECT OF DIFFERENT PHOSPHORUS SOURCES ON THE GROWTH, YIELD, ENERGY CONTENT AND PHOSPHORUS UTILIZATION EFFICIENCY IN MAIZE AT RAWALAKOT AZAD JAMMU AND KASHMIR, PAKISTAN

Effect of poultry manure (PM) and four inorganic phosphorus (P) fertilizers sources, i.e., diammonium phosphate (DAP), single super phosphate (SSP), nitrophos (NP) and triple super phosphate (TSP) on crop production and P utilization efficiency (PUE) of maize was studied. Both inorganic P fertilizers and PM applied alone or combined in 50:50 proportions at equivalent rate of 90 kg P2O5 ha−1. Results indicated that inorganic P sources with PM significantly increased plant height, leaf area and chlorophyll content. Average values showed that combined application of inorganic P with PM increased grain yield by 19 and 41% over inorganic P and PM alone, respectively. Similarly, increase in P-uptake due to the combined application of inorganic P + PM was 17% compared to sole inorganic P. Phosphorus utilization efficiency of inorganic P was increased with PM and the highest PUE was recorded in DAP + PM. Generally, combination of DAP + PM proved superior over the remaining P fertilizers.

Nitrogen Mineralization of a Loam Soil Supplemented with Organic–Inorganic Amendments under Laboratory Incubation

The quantification of nitrogen (N) supplying capacity of organic amendments applied to a soil is of immense importance to examine synchronization, N release capacity, and fertilizer values of these added materials. The aims of the present study was to determine the potential N mineralization and subsequent nitrification of separate and combined use of poultry manure (PM), wheat straw residues (WSR), and urea N (UN) applied to a loam soil incubated periodically over 140 days period. In addition, changes in total soil N and carbon contents were also monitored during the study. Treatments included: PM100, WSR100, PM50 + WSR50, UN100, UN50 + PM50, UN50 + WSR50, UN50 + PM25 + WSR25, and a control (unfertilized). All the amendments were applied on an N-equivalent basis at the rate of 200 mg N kg-1. Results indicated that a substantial quantity of N had been released from the added amendments into the soil mineral pool and the net cumulative N mineralized varied between 39 and 147 mg N kg-1, lowest in the WSR and highest in the UN50 + PM50. Significant differences were observed among the amendments and the net mineral N derived from a separate and combined use of PM was greater than the other treatments. The net cumulative N nitrified (NCNN) varied between 16 and 126 mg kg-1, highest in UN50 + PM50 treatment. On average, percentage conversion of added N into available N by different amendments varied between 21 and 80%, while conversion of applied N into NO3-–N ranged between 9 and 65%, and the treatment UN50 + PM50 displayed the highest N recovery. Urea N when applied alone showed disappearance of 37% N (N unaccounted for) at the end while application of PM and WSR with UN reduced N disappearance and increased N retention in the mineral pool for a longer period. Organic amendments alone or in combination with UN improved organic matter buildup and increased soil N concentration. These results demonstrate the existence of substantial amounts of N reserves present in PM and WSR that can be utilized efficiently and effectively as potential N source for the management of nutrient poor soils and plant growth.

Wheat Residue Incorporation Modulate Emergence and Seedling Growth of Canary Grass by Affecting Biochemical Attributes and Soil Properties

Residue incorporation greatly modifies the soil chemical properties, and regulates seed germination and subsequent growth of neighboring species by inducing metabolic changes. Such growth regulatory effects often vary among cultivars and the stage of growth of donor plants. Little information is available on the induced biochemical changes in receiver plants and the soil chemical properties when wheat residue collected at different growth stages is incorporated into the soil. Bioassays were conducted to appraise the allelopathic potential of residue (8 g kg soil) of hexaploid wheat (Triticum aestivum L.) cultivars (Millat-2011, AARI-2011, Lasani-2008 and Faisalabad-2008) collected at tillering (Z-30), anthesis (Z-60) and maturity (Z90)] against canary grass (Phalaris minor Retz.). Mean emergence time of canary grass was prolonged over control by soil incorporation of residue at anthesis and maturity stages of cultivars AARI-2011 and Lasani-2008. Final emergence percentage declined by 13‒31% for residue collected at different growth stages. Maximum suppression in shoot (33‒51% and 28‒53%) and root (34‒52% and 28‒54%) length and seedling dry biomass (66‒88% and 58‒86%) of canary grass over control was also recorded under aforementioned treatment combinations. Total chlorophyll contents in canary grass declined in response to soil incorporation of residue at anthesis and maturity stages of all wheat cultivars but an increase was recorded for residue incorporated at tillering stage. Phenolic contents in residue and residue-amended soil increased with advancement in stage of wheat growth. Biochemical bases of phytotoxicity and changes in activities of enzymatic antioxidants in canary grass seedling are discussed. Such information suggests the growth regulatory potential of residue of specific wheat cultivars against weeds of economic significance in wheat based cropping systems and scope for increasing nutrient status of soils.

Interactive effect of cobalt and nitrogen on growth, nodulation, yield and protein content of field grown pea

Pea (Pisum sativum L.) has increasing nutritional, commercial, and economical value, and initial low supply of N and Co is needed to increase nodulation, yield, and profit. A field experiment in 2010 was conducted at the University of Poonch Rawalakot located in the hilly region of the state of Azad Jammu and Kashmir, Pakistan. The aim of the study was to evaluate the effects of fertilization of N and Co on growth, nodulation, seed yield, seed composition of, and uptake of N and Co by pea plant. Treatments included three levels of N (0, 30, and 60 kg N·ha−1 and represented as N0, N30, and N60, respectively) combined with three levels of Co (0, 10, and 20 g Co·ha−1 and represented as Co0, Co10, and Co20, respectively), and the control represented as N0Co0. Results indicated that most of the morphological characteristics were increased with N60. The greatest shoot length, root length, and chlorophyll content were recorded in the N60Co20. The number of root nodules increased from 6 in the control to 19 with fertilization of N and Co. Yield responses to N-Co fertilization occurred to all rates, and the highest yield, 2536 kg·ha−1, was observed in the treatment N60Co10. Total N and Co uptake in the plant (shoot + root + seed) ranged between 16–147% and 3–331% over the control, while seed protein increased by 13–198% over the control by application of N and Co. This study demonstrates that N- and Co-deficient soils are likely to produce crops with low yields and seeds with low protein levels, and therefore, appropriate management of soil N and Co could be an effective approach to increase and sustain pea production in the small holding mountain ecosystems.

Soil-plant micronutrients dynamics in response to integrated fertilization under wheat–soybean cropping system at Rawalakot, Pakistan

ABSTRACT This study provided an insight on improving soil-plant micronutrients availability in response to poultry manure (PM), wheat milling residues (WMR) and urea N (UN) and their integration in wheat–soybean cropping system. The treatments were: control; poultry manure full, PM100; wheat milling residues full, WMR100; urea N full, UN100; PM half and WMR half, PM50+WMR50; UN50+PM50; UN50+WMR50; UN50+PM25+WMR25. All amendments were added at the rate or equivalent to 100 kg total N ha–1. Results indicated that the integrated treatments increased Cu, Fe, Mn and Zn uptake of wheat by 35.7–103%, 48.4–111.1%, 85.2–267.0% and 33.8–128.2%, respectively over control. In soybean the corresponding increase in micronutrient uptake (Cu, Fe, Mn and Zn) was 18.3–60.3%, 27.5–87.4%, 14.1–54.6% and 13.2–58.0% in integrated treatments. The post-harvest soil analysis indicated 2 to 3-fold increase in micronutrient content with highest values in PM100 i.e., 2.66 mg kg−1 for Cu, 14.41 mg kg−1 for Fe, 18.58 mg kg−1 for Mn and 2.44 mg kg−1 for Zn, respectively. The results showed that the PM either alone or in integrated with WMR and UN can be an effective management strategy for improving micronutrient content of soil–plant.