Niaz Ahmed

Zinc Fertilization Impact on Irrigated Cotton Grown in an Aridisol: Growth, Productivity, Fiber Quality, and Oil Quality

Zinc (Zn) deficiency is widespread in calcareous soils. Therefore, we conducted a 2-year field experiment to investigate the impact of graded Zn levels on growth, yield, and fiber and oil quality of cotton (Gossypium hirsutum L., cv. CIM-473) grown in a calcareous Aridisol having 0.54 mg diethylenetriaminepentaacetic acid (DTPA)-extractable Zn kg−1 soil. Zinc use increased boll bearing, boll weight, seed index, and seed cotton yield (P ≤ 0.05). Maximum yield increase was 15%, with 7.5 kg Zn ha−1; however, greater Zn levels depressed yield. Leaf chlorophyll, membrane permeability, seed protein, and oil content and quality improved (P ≤ 0.05), and fiber quality remained unaffected with Zn use. Critical Zn concentration in cotton leaves was 36 mg kg−1. Positive relationships of leaf Zn concentration were observed with boll weight, protein content, total unsaturated fatty acids, and fiber characteristics. Thus, Zn fertilization of low-Zn Aridisols is suggested for improving cotton productivity and seed quality.

Boron Requirement of Irrigated Cotton in a Typic Haplocambid for Optimum Productivity and Seed Composition

Boron (B) deficiency hampers cotton (Gossypium hirsutum L.) growth and productivity globally, especially in calcareous soils. The crop is known as a heavy feeder of B; however, its reported plant analysis diagnostic norms for B-deficiency diagnosis vary drastically. In a 2-year field experiment on a B-deficient [hydrochloric acid (HCl)–extractable 0.47 mg B kg−1], calcareous, Typic Haplocambid, we studied the impact of soil-applied B on cotton (cv. CIM-473) growth, productivity, plant tissue B concentration, and seed oil composition. Boron was applied at 0.0, 1.0, 1.5, 2.0, 2.5, and 3.0 kg B ha−1, as borax (Na2B4O7·10H2O), in a randomized complete block design with four replications, along with recommended rates of nitrogen (N), phosphorus (P), potassium (K), and zinc (Zn). Boron use improved crop growth, decreased fruit shedding, and increased boll weight, leading to seed cotton yield increases up to 14.7% (P < 0.05). Improved B nutrition of plants also enhanced seed oil content (P < 0.05) and increased seed protein content (P < 0.05). Fiber quality was not affected. Fertilizer B use was highly cost-effective, with a value–cost ratio of 12.3:1 at 1 kg B ha−1. Fertilizer B requirement for near-maximum (95% of maximum) seed cotton yield was 1.1 kg B ha−1 and HCl-extractable soil B requirement for was 0.52 kg ha−1. Leaf tissue B requirement varied with leaf age as well as with plant age. In 30-day plants (i.e., at squaring), B-deficiency diagnosis critical level was 45.0 mg kg−1 in recently matured leaves and 38.0 mg kg−1 in youngest open leaves; at 60 days old (i.e., at flowering), critical concentration was 55.0 mg kg−1 in mature leaves and 43.0 mg kg−1 in youngest leaves. With advancement in plant age critical B concentration decreased in both leaf tissues; that is, in 90-day-old plants (i.e., at boll formation) it was 43.0 mg kg−1 in mature leaves and 35.0 mg kg−1 in the youngest leaves. As critical concentration range was narrower in youngest leaves (i.e., 35–43 mg kg−1) compared with mature leaves (i.e., 43–55 mg kg−1), B concentration in youngest leaves is considered a better indicator for deficiency diagnosis.

Guar, jantar, wheat straw, and rice hull composts as replacements for peat in muskmelon transplant production

PurposeThe demand for soilless media for vegetable transplant production is increasing. Economic constraints paired with concerns over the sustainability of peat mining have necessitated the replacement of peat with renewable and regionally abundant alternatives. The aim of this study was to develop from composts complete or partial substitutes for peat.MethodsComposted guar (Cyamopsis tetragonoloba), jantar (Sesbania aculeata), wheat (Triticum aestivum) straw, and rice (Oryza sativa) hulls adjusted to 10% air-filled porosity (AFP) were blended on a volumetric basis with peat moss at discrete levels (0–50%). Total water-holding capacity, shrinkage, dry and wet bulk density, pH, electrical conductivity, N, P, K, FE, B, and Zn concentrations of each compost, their blends, and a peat control were measured. The experimental media were used to grow muskmelon (Cucumis melo) plants in a greenhouse. Seed germination, shoot fresh weight, shoot height, leaf area, stem diameter, root length, and mineral nutrient concentrations of transplants were quantified. After transplanting in the field, the growth rates and yields were measured. Nonparametric regression was used to analyze the data.ResultsThe physiochemical parameters measured for most of the experimental media fell within the recommended range for growing media; however, pH for all media exceeded the recommended range. Media-containing guar and jantar composts generally contained more nutrients than media-containing rice hull or wheat straw composts. Fresh weight, height, and root length were generally greater for seedlings grown in media-containing rice hull compost than for those grown in media-containing other composts. Seedlings grown in media-containing guar or jantar composts generally had greater tissue nutrient concentrations.ConclusionsAll blends produced acceptable seedlings; however, the largest seedlings, and greatest post-transplant growth rate and yield were produced in media containing 30–50% rice hull compost.

Influence of Boron Nutrition on Membrane Leakage, Chlorophyll Content and Gas Exchange Characteristics in Cotton (Gossypium Hirsutum L.)

Understanding the effect of boron (B) on plant physiology will help to refine the diagnosis of B deficiency and improvement in B fertilizer recommendations for cotton (Gossypium hirsutum L.) growing areas. This study shows the testing of hypotheses “that application of B-fertilizer improves net photosynthetic rate (PN) and water use efficiency (WUE) for cotton plant on a B-deficient soil [< 0.50 mg B kg−1 hydrochloric acid (HCl)-extractable] in an arid environment”. Thus, a permanent layout [two-year field experiment (2004 and 2005)] was conducted to study the impact of B fertilizer at 0, 1.0, 1.5, 2.0, 2.5, and 3.0 kg ha−1 on gas exchange and electrolyte leakage (EL) characteristics of cotton crop (cv. ‘CIM-473’). The soil at experimental site was alkaline (pH 8.1), calcareous [calcium carbonate (CaCO3 5.6%)], and silt loam (Typic Haplocambid). Boron use decreased EL of plant membrane (P ≤ 0.05), and increased PN, transpiration rate (E) and stomatal conductance (gs), while intercellular concentration of carbon dioxide (CO2; Ci) significantly decreased (P ≤ 0.05) during both experimental years. There was a positive, but non-significant effect of B concentration on chlorophyll content in plant leaves. Application of 3.0 kg B ha−1 improved WUE up to 9.7% [4.62 μmol (CO2) mmol−1 water (H2O)] compared to control plants (4.21 [μmol (CO2) mmol−1 (H2O)]. Principal component analysis (PCA) of data indicates positive correlations between leaf B concentration and PN, E, gs, and WUE, while a negative relationship existed between leaf B concentration and intercellular CO2 (Ci). This study showed that addition of B fertilizer in the B-deficient calcareous soil proved beneficial for growth and development for cotton crop by enhancing its WUE and gas exchange characteristics.

Determination of Residual and Cumulative Boron Requirements for Cotton and Wheat Crops Grown Under Calcareous Soil Conditions

ABSTRACT A two-year field experiment was conducted to elucidate the residual and cumulative boron (B) requirements for cotton and wheat crops. For the first time, cotton was sown in randomized complete blocks those received 0.0, 1.0, 1.5, 2.0, 2.5 and 3.0 kg B ha−1 as borax (Na2B4O7.10H20). Later, each plot was divided into two subplots for successive wheat and cotton crops and half of the pots received B at similar rates. Our results revealed that direct application of B at the rate of 2 and 2.5 kg ha−1 produced optimum cotton yield during 2005. The same rates of B were consistent in residual plots but not in cumulative plots for both of the crops in successive years. It was thus concluded that soil applied B at the rate of 2.0 and 2.5 kg ha−1 had significant residual effects on cotton and wheat yields.