nan Amanullah

Plant Density and Nitrogen Effects on Maize Phenology and Grain Yield

ABSTRACT Nitrogen (N) and plant density are considered some of the most important factors affecting crop phenology (days to tasseling, silking, and maturity), morphology (leaves plant−1, seeds ear−1, ears 100 plants−1) and grain yield. The effects of plant density and N on phenology, morphology, and yield of maize (Zea mays L.) at Peshawar in northwestern Pakistan were evaluated during 2002 to 2004. The 2 × 3 × 6 factorial experiment was designed having two plant densities (60,000 and 100,000 plants ha−1) and three N levels (60, 120, and 180 kg N ha−1) applied to main plots, while six split application of N in different proportions were applied to subplots in two equal, three equal, three unequal, four equal, five equal and five unequal splits at sowing and with 1st, 2nd, 3rd, and 4th irrigation at two week intervals. All the phenological characteristics were significantly affected by year, plant density, rate and timing of nitrogen application. Year and plant density had no significant effect while rates and split application of N had significant effects on the leaf number plant−1 and seed number ear−1. Year, plant density and N rate had significant effects while N splits had no significant effects on the number of ears 100 plants−1 of maize. Significantly higher grain yield was observed under high plant densities, high N rate and split application of N, while its response to year effects was statistically non-significant. Tasseling, silking and physiological maturity were delayed and maximum grain yield was obtained from those plots maintained at higher plant density. Delaying in the phenological characteristics while increasing the number of leaves and seeds plant−1, and number of ears 100 plant−1 through high rate and split application of N results in maximum yield of maize at Peshawar. This study suggested that maize production can be maximized through high plant density and high N split application.

Responses of rapid viscoanalyzer profile and other rice grain qualities to exogenously applied plant growth regulators under high day and high night temperatures

High-temperature stress degrades the grain quality of rice; nevertheless, the exogenous application of plant growth regulators (PGRs) might alleviate the negative effects of high temperatures. In the present study, we investigated the responses of rice grain quality to exogenously applied PGRs under high day temperatures (HDT) and high night temperatures (HNT) under controlled conditions. Four different combinations of ascorbic acid (Vc), alpha-tocopherol (Ve), brassinosteroids (Br), methyl jasmonates (MeJA) and triazoles (Tr) were exogenously applied to two rice cultivars (IR-64 and Huanghuazhan) prior to the high-temperature treatment. A Nothing applied Control (NAC) was included for comparison. The results demonstrated that high-temperature stress was detrimental for grain appearance and milling qualities and that both HDT and HNT reduced the grain length, grain width, grain area, head rice percentage and milled rice percentage but increased the chalkiness percentage and percent area of endosperm chalkiness in both cultivars compared with ambient temperature (AT). Significantly higher grain breakdown, set back, consistence viscosity and gelatinization temperature, and significantly lower peak, trough and final viscosities were observed under high-temperature stress compared with AT. Thus, HNT was more devastating for grain quality than HDT. The exogenous application of PGRs ameliorated the adverse effects of high temperature in both rice cultivars, and Vc+Ve+MejA+Br was the best combination for both cultivars under high temperature stress.

Effects of Phosphorus Fertilizer Source and Plant Density on Growth and Yield of Maize in Northwestern Pakistan

ABSTRACT Phosphorus (P) fertilizer source and plant density are considered some of the most important factors affecting crop growth and yield. A field experiment was conducted to determine the impact of P source [zero-P control, DAP (diammonium phosphate), SSP (single super phosphate), and NP (nitrphos)] and plant density (D1 = 40,000, D2 = 60,000, D3 = 80,000, and D4 = 100,000 plants ha−1) on growth and yield of maize (Zea mays L cv. Azam) on a P-deficient soil (6.6 mg P kg−1) at New Developmental Agricultural Research Farm, North-West Frontier Province (NWFP) Agricultural University, Peshawar, Pakistan, during summer 2006 in wheat-maize cropping system. Physiological maturity was delayed, plant height was increased and leaf area was decreased significantly when maize was planted at highest (D4) than at lowest plant density (D1). Application of SSP resulted in earlier physiological maturity of maize than other P fertilizers. Grain and stover yield, harvest index, shelling percentage, thousand grain weight and grains ear−1 were maximized at D3 (80,000 plants ha−1) and with application of P fertilizer. Highest benefit in growth and grain yield was obtained with application of DAP to maize planted at D3. Application of DAP at D3 gave 15, 29, and 19% higher grain yield than its application at D1, D2, and D4, respectively. In conclusion, the findings suggest that growing maize at 80,000 plants ha−1 applied with DAP can maximize productivity of maize in the wheat-maize cropping system on P-deficient soils.

AGRONOMIC EFFICIENCY AND PROFITABILITY OF P-FERTILIZERS APPLIED AT DIFFERENT PLANTING DENSITIES OF MAIZE IN NORTHWEST PAKISTAN

The use of appropriate source of phosphorus (P) fertilizer at different planting densities has considerable impact on growth, grain yield as well as profitability of maize (Zea mays L). Field experiment was conducted in order to investigate the impact of P sources [(S0 = P not applied, S1 = SSP (single super phosphate) S2 = NP (nitrophos), and S3 = DAP (diammonium phosphate)] on maize growth analysis, yield and economic returns planted at different planting densities (D1 = 40,000, D2 = 60,000, D3 = 80,000, and D4 = 100,000 plants ha−1) at the New Developmental Agricultural Research Farm of Khyber Pakhtunkhwa Agricultural University, Peshawar, Pakistan, during summer 2006. This paper reports the profitability data with two objectives: 1) to compare agronomic efficiency and profitability of P-fertilizers, and 2) to know whether plant densities affect agronomic efficiency and profitability of P-fertilizers. Application of DAP and SSP resulted in higher partial factor productivity (PFP) (63.58 and 61.92 kg grains kg−1 P), agronomic efficiency (AE) (13.01 and 13.71 kg grains kg−1 P) and net returns (NR) (Rs. 16,289 and 16,204 ha−1), respectively, while NP stood at the bottom in the ranking with lower PFP (57.16 kg grains kg−1 P), AE (8.94 kg grains kg−1 P) and NR (Rs. 4,472 ha−1). Among the plant densities, D3 stood first with maximum PFP (69.60 kg grains kg−1 P), AE (18.21 kg grains kg−1 P) and NR (Rs. 21,461 ha−1) as compared to other plant densities. In conclusion, the findings suggest that growing maize at D3 applied with either SSP or DAP is more profitable in the wheat-maize cropping system in the study area.

PHENOLOGY, GROWTH, AND GRAIN YIELD OF MAIZE AS INFLUENCED BY FOLIAR APPLIED UREA AT DIFFERENT GROWTH STAGES

Foliar urea application is considered an important factor affecting phenology, growth, yield, and yield components of maize. A field experiment was conducted to study effects of urea spray on Azam variety of maize (Zea mays L.) in Mardan district of the North West Frontier Province (NWFP) of Pakistan during 2005–06. The 5 × 4 factorial experiment was designed with five urea levels (U0 = control, U1 = 2, U2 = 4, U3 = 6 and U4 = 8% urea) applied to main plots and four application timings (T1 = at V9, T2 = V12, T3 = VT and T4 = R1 stages) assigned to subplots. Days to tasseling, silking, and maturity were delayed significantly when urea was applied at the rate of 6% and when applied at the V12 stage. Earlier tasseling, silking, and maturity were observed in urea control plots and in plots that received urea at the V9 stage. Plant height, leaf area, number of grains per cob and per line as well as (1000) grain weight, and grain and stover yields increased significantly up to the 6% urea level. Maize yield and yield components were higher when urea was applied at the V12 and VT stages than at the V9 and R1 stages. It is concluded that urea spray at the rate of 6% during the V12 stage would improve the grain yield and yield components of maize in the study area and contribute significantly to increased production.

Phosphorus and Compost Management Influence Maize (Zea mays) Productivity Under Semiarid Condition with and without Phosphate Solubilizing Bacteria

Phosphorus (P) unavailability and lack of organic matter in the soils under semiarid climates are the two major constraints for low crop productivity. Field trial was conducted to study the effects of P levels, compost application times and seed inoculation with phosphate solubilizing bacteria (PSB) on the yield and yield components of maize (Zea mays L., cv. Azam). The experiment was conducted at the Agronomy Research Farm of The University of Agriculture Peshawar-Pakistan during summer 2014. The experiment was laid out in randomized complete block design with split plot arrangement using three replications. The two PSB levels [(1) inoculated seed with PSB (+) and (2) seed not inoculated with PSB (- or control)] and three compost application times (30, 15, and 0 days before sowing) combination (six treatments) were used as main plot factor, while four P levels (25, 50, 75, and 100 kg P ha-1) used as subplot factor. The results confirmed that compost applied at sowing time and P applied at the two higher rates (75 and 100 kg P ha-1) had significantly increased yield and yield components of maize under semiarid condition. Maize seed inoculated with PSB (+) had tremendously increased yield and yield components of maize over PSB-control plots (-) under semiarid condition.

SEED YIELD AND YIELD COMPONENTS RESPONSE OF RAPE (B. NAPUS) VERSUS MUSTARD (B. JUNCEA) TO SULFUR AND POTASSIUM FERTILIZER APPLICATION IN NORTHWEST PAKISTAN

Improper sulfur (S) and potassium (K) fertilizer management, particularly with continued soil nutrient mining, is one of the major factors contributing to low seed yield of canola in northwestern Pakistan. A field experiment was conducted in 2007−2008 on a S and K deficient clay loam soil at the Research Farm of NWFP (Northwest Frontier Province) Agricultural University, Peshawar, Pakistan, with an objective to determine seed yield and yield components response of Brassica oilseed rape versus mustard to S and K application. Twenty treatments in a randomized complete block design were consisted of two oilseed rape (B. napus canola) and mustard (B. juncea canola) genotypes at three rates each of S (15, 30, and 45 kg S ha−1) and K (30, 60, and 90 kg K ha−1) fertilizers plus one control (no S and K applied). Seed yield and yield components increased significantly with K and S fertilization as compared to the zero-S/zero-K control. Both genotypes responded positively for seed yield and yield components to K and S fertilization, but the magnitude of response varied with levels of S and K, as well as combined K + S applications. It is concluded that a combination of 60 kg K + 30 kg S ha−1 would improve seed yield and yield components of rape and mustard in the study area and contribute significantly to increased production. Growing B. napus was better than B. juncea in the study area, because B. napus produced significantly higher seed yield and yield components than B. juncea, indicating that yield components are the most important criteria for selection of Brassica genotypes for higher seed yield.

Phosphate-Solubilizing Bacteria Nullify the Antagonistic Effect of Soil Calcification on Bioavailability of Phosphorus in Alkaline Soils

Phosphate-solubilizing bacteria (PSB) reduce the negative effects of soil calcification on soil phosphorus (P) nutrition. In this incubation study, we explored the ability of PSB (control and inoculated) to release P from different P sources [single super phosphate (SSP), rock phosphate (RP), poultry manure (PM) and farm yard manure (FYM)] with various soil lime contents (4.78, 10, 15 and 20%) in alkaline soil. PSB inoculation progressively enriched Olsen extractable P from all sources compared to the control over the course of 56 days; however, this increase was greater from organic sources (PM and FYM) than from mineral P sources (SSP and RP). Lime addition to the soil decreased bioavailable P, but this effect was largely neutralized by PSB inoculation. PSB were the most viable in soil inoculated with PSB and amended with organic sources, while lime addition decreased PSB survival. Our findings imply that PSB inoculation can counteract the antagonistic effect of soil calcification on bioavailable P when it is applied using both mineral and organic sources, although organic sources support this process more efficiently than do mineral P sources. Therefore, PSB inoculation combined with organic manure application is one of the best options for improving soil P nutrition.

Effects of Nitrogen Supply on Water Stress and Recovery Mechanisms in Kentucky Bluegrass Plants

Non-irrigated crops in temperate and irrigated crops in arid regions are exposed to an incessant series of drought stress and re-watering. Hence, quick and efficient recuperation from drought stress may be amongst the key determinants of plant drought adjustment. Efficient nitrogen (N) nutrition has the capability to assuage water stress in crops by sustaining metabolic activities even at reduced tissue water potential. This study was designed to understand the potential of proper nutrition management by studying the morphological and physiological attributes, and assimilation of nitrogen in Kentucky bluegrass under drought stress. In present study, one heterogeneous habitat and four treatments homogenous habitats each with four replications were examined during field trial. Drought stress resulted in a significant reduction in the nitrogen content of both mother and first ramets, maximum radius, above and below ground mass, number of ramets per plot, leaf water contents and water potential and increased the carbon content and the C:N ratio in both homogenous and heterogeneous plots compared to well-watered and nutritional conditions. Observation using electron microscopy showed that drought stress shrunk the vessel diameter, circumference and xylem area, but increased the sieve diameter, and phloem area in the leaf crosscutting structure of Kentucky bluegrass, first, second, and third ramet leaf. Thus, it can be concluded that water stress markedly reduced all the important traits of Kentucky bluegrass, however, proper nutritional management treatment resulted in the best compensatory performance under drought assuaging its adversity up to some extent and may be considered in formulating good feasible and cost-effective practices for the environmental circumstances related to those of this study.

Compost and Nitrogen Management Influence Productivity of Spring Maize (Zea mays L.) under Deep and Conventional Tillage Systems in Semi-arid Regions

On-farm research was conducted to investigate the effects of nitrogen (N) and compost (C) on yield and yield components of spring maize (Zea mays L.) under conventional and deep tillage system (T) at the research farm of the University of Agriculture, Peshawar, Pakistan, during spring 2013. The experiment was laid out in a randomized complete block design with split-plot arrangement, using three replications. Three compost levels (0, 1, and 2 t ha−1) and two tillage systems (conventional and deep tillage) were allotted to the main plot, whereas N levels (60, 90, 120, and 150 kg N ha−1) were allotted to subplots in the form of urea. Nitrogen and compost levels had significantly affected all the parameters. Plots treated with 150 kg N ha−1 increased ear length (31 cm), grains ear−1 (413), thousand-grain weight (240.2 g), grain yield (3097 kg ha−1), straw yield (9294 kg ha−1), harvest index (24.7 percent), and shelling percentage (81.7 percent). Compost applied at 2 t ha−1 increased ear length (32 cm), grains ear−1 (430), thousand-grain weight (242.3 g), grain yield (2974 kg ha−1), straw yield (8984 kg ha−1), harvest index (24.6 percent), and shelling percentage (83.2 percent). Tillage system had significant effect on all parameters except ear length and harvest index. Deep tillage system produced more grains ear−1 (365), thousand-grain weight (233.3 g), grain yield (2630 kg ha−1), straw yield (8549 kg ha−1), and shelling percentage (79.6 percent). It was concluded from the results that application of 120 kg N ha−1 + 2 C t ha−1 under a deep tillage system could improve spring maize yield and yield-contributing traits under semi-arid conditions.