Adem Gunes

Effects of Boron Fertilizer on Tomato, Pepper, and Cucumber Yields and Chemical Composition

In many parts of the world, boron (B) levels are insufficient for potential production. Boron deficiency is also widespread in the Anatolia region of Turkey. Boron deficiency could impact production and quality of tomatoes (Lycopersicon esculentum L.), pepper (Capsicum annum L.), and cucumber (Cucumis sativus L.). A two-year greenhouse experiment was conducted to study yield and quality response of three vegetables to B addition (0, 1, 2, 3, and 4 kg B ha−1). The optimum economic B rates (OEBR) were 2.3, 2.6, 2.4 kg B ha−1, resulting in soil B concentrations of 0.33, 0.34 and 0.42 mg kg−1. Independent of plant species, B application decreased tissue nitrogen (N), calcium (Ca), and magnesium (Mg) but increased tissue phosphorus (P), potassium (K), iron (Fe), manganese (Mn), zinc (Zn), and copper (Cu) concentrations. We conclude that a B addition of 2.5 kg ha−1 is sufficient to elevate soil B levels to nondeficient levels. Similar studies with different soils and initial soil-test B levels are needed to conclude if these critical soil test values and OEBR can be applied across the region.

Boron application improves on yield and chemical composition of strawberry

Abstract Boron (B) is an essential micronutrient required for normal plant growth and development. Boron management is challenging because the optimum B application range is narrow and the application rates vary from one soil to another. Boron deficiency is widespread in the Anatolia region of Turkey. This may impact on yield and mineral contents of leaves and fruits of strawberry (Fragaria×ananassa cv. Fern) especially in B-deficient calcareous Aridisols in Eastern Anatolia, Turkey. A 2-year field experiment was conducted to study yield and quality response of strawberry to B application. Boron fertilizer application affected plant yield and chemical composition. B application decreased tissue nitrogen (N) and calcium (Ca) but increased tissue phosphorus (P), potassium (K), manganese (Mn), zinc (Zn) and copper (Cu) content. We conclude that a B addition of 5.5 kg ha−1 is sufficient to elevate soil B levels to non-deficient levels.

Boron fertilization of Mediterranean aridisols improves lucerne (Medicago sativa L.) yields and quality

Abstract Lucerne (Medicago sativa L.) is grown as a forage crop on many livestock farms. In calcareous soils in eastern Turkey, lucerne production requires boron (B) addition as the soils are naturally B deficient. Field experiments with four B-application rates (0, 1, 3, and 9 kg ha−1 B) were conducted in 2005 and 2006 to determine the optimum economic B rate (OEBR), critical soil test and tissue B values for dry matter (DM) production for lucerne grown on B-deficient calcareous aridisols in eastern Turkey. Boron application increased yield at each site in both years of production. The OEBR and critical soil and tissue B content were not impacted by location. Averaged over the two years and three locations, the OEBR was 6.8 kg B ha−1 with an average DM yield of 12.0 Mg ha−1. The average soil B content at the OEBR was 0.89 mg kg−1 while leaf and shoot tissue B content amounted to 51.8 and 35.5 mg kg−1, respectively. Boron application decreased tissue calcium (Ca), zinc (Zn), and copper (Cu), and increased tissue nitrogen (N), phosphorus (P), potassium (K), magnesium (Mg), iron (Fe), and manganese (Mn). Tissue and soil B increased without impacting yield at B levels up to 9 kg ha−1. We conclude that 7 kg ha−1 B is sufficient to elevate soil test B levels from 0.11 to 0.89 mg kg−1 and overcome B deficiency at each of the sites in the study. Similar studies with different soils and initial soil test B levels are needed to conclude if these critical soil and tissue values can be applied across the region.

Roles of Bacillus megaterium in Remediation of Boron, Lead, and Cadmium from Contaminated Soil

Phytoremediation is an attractive, economical alternative to soil removal and burial methods to remediate contaminated soil. The objective of this study was to investigate the effects of adding different rates of Bacillus megaterium on the capacity of Brassica napus plants to take up boron (B), lead (Pb), and cadmium (Cd) from polluted soils under field conditions. Field experiments were conducted using a randomized complete block design with control (without pollution and B. megaterium application) and B, Pb, and Cd in two doses (0 and 100 mg kg−1), B. megaterium with four doses (no application and 108 cfu B. megaterium ml−1 sprayed at 50 ml plot−1, 100 ml plot−1, 150 ml plot−1). Results indicated that soil pollution treatments significantly decreased seed (SDMY), shoot (SHDMY), root (RDMY), and total dry-matter yield (TDMY) of plants at 42.9, 3.8, 62.6, and 23.4% for B-polluted treatment; 25.8, 8.7, 17.6, and 14.2% for Pb-polluted treatment; and 33.2, 7.0, 14.0, and 16.4% for Cd-treatment without B. megaterium application, respectively. However, the application of B. megaterium ameliorated the negative effects of B, Pb, and Cd at 41.4, 52.7, and 10.9% for B; 24.4, 21.6, and 4.9% for Pb; and 22.8, 22.0, and 3.3% for Cd, respectively. The potentially bioavailable and relatively available fraction of soil B, Pb, and Cd increased with increases in the B. megaterium application but total fraction and stable fraction decreased. It is concluded that the seed and shoot parts of B. napus can be used as hyperaccumulators for plant B, Pb, and Cd remediation according to remediation factors but the shoot is the biggest part of the plant, and thus an important portion of the plant to remove B, Pb, and Cd from the B-, Pb-, and Cd-contaminated soils. To decrease desired concentration for 8 mg B kg−1, 4 mg Pb kg−1, and 3 mg Cd kg−1 in the active rooting zone of soil, approximately 2, 6, and 21 years would be necessary with only 150 ml plot−1 B. megaterium–sprayed soil cultivated with B. napus, respectively.

Effect of Harvest Timing on Yield and Mineral Nutritional Value of Kabuli Type Chickpea Seeds

ABSTRACT Chickpea (Cicer arietinum L.) seeds are a good source of protein and mineral nutrients. However, there is no information regarding harvest timing on yield and mineral composition of chickpea seeds. The effect of harvest timing on seed yield, some yield components and mineral nutritional value of seeds of field grown chickpea plants in two different sites were studied. The mineral composition of chickpea straw depending on harvest timing was also evaluated in order to explain the variations of seed mineral concentrations in sink-source relationship manner. Yield and mineral nutritional value of chickpea were significantly affected by harvest timing. When compared to the seed yield at optimal harvest time, seed yield was 18% and 9% lower in the early harvest and 27% and 31% in the late harvest in Site 1 and Site 2, respectively. Late harvest of chickpea crops resulted in significant pod dropping and shattering. Generally, protein, phosphorus (P), calcium (Ca), magnesium (Mg), copper (Cu), zinc (Zn), and manganese (Mn) concentrations of the seeds in optimal harvest were found to be greater than in early and late harvested plants. Harvest timing also results in significant variations in straw mineral nutrient concentrations of the plants. As the results of this study, it was concluded that the harvest timing is critical for yield losses and mineral nutritional value of chickpea seeds.

Nitrate versus chloride nutrition effects in a soil‐plant system on the growth, nitrate accumulation, and nitrogen, potassium, sodium, calcium, and chloride content of carrot

Abstract The experiment was conducted to evaluate the effects of various nitrate/ chloride (NO3/Cl) ratios on growth, nitrate accumulation, and mineral absorption in carrot, Daucus carota L., plants in a controlled environment. The experiment included two Cl sources [potassium chloride (KC1) and calcium chloride (CaCl2)] and five NO/Clratios at 100/0, 90/10, 80/20, 70/30, and 60/40 with total‐nitrogen (N) concentration of 400 mg NO3 kg‐1 soil in 100/0 treatment. Fresh and dry weights of shoots and storage roots, and length and diameter of storage roots increased significantly with mixed NO3/C1 treatments with both Cl sources as compared to single NO3 (100/0) treatment. Growth was enhanced up to the 80/20 NO3/C1 treatments. With Cl present in the treatments, the concentration of total‐N unchanged and NO3 decreased in plants, and Cl and potassium (K) increased with the Cl sources. In KC1 treatments, Na absorption decreased. Calcium (Ca) content of the plants significantly differed by the treatments. It was ...

Making Soil More Accessible to Plants: The Case of Plant Growth Promoting Rhizobacteria

Plant Growth Promoting Rhizobacteria (PGPR) are beneficial soil bacteria that can live either symbiotically with plants at rhizosphere or as endophytes living on or inside of the host plants. There are two main mechanisms via PGPR contribute to the plant growth. Direct mechanism consists of phytohormone production (i.e. auxins (IAA), cytokinins and gibberellins), biological nitrogen fixation, solubilizing inorganic phosphates, mineralizing organic phosphate and producing organic matter such as amino acids. As indirect mechanisms, PGPR aid plants in combat against the pathogen microorganisms by means of stimulating the disease-resistance mechanism of plants, promote favorable symbiosis, decontaminate the soil of xenobiotics. PGPR can also help plants to cope against abiotic stress by lowering ethylene levels, or against pathogenic microorganism by means of secreting antibacterial/antifungal substances. Exact mechanisms of PGPR characteristics which stimulate the plant growth or product formation are still under investigation, yet in agriculture, PGPR are used as environmental friendly biofertilizers, biocontrol agents or biostimulants. These beneficial bacteria are usually introduced to the plants either in powder or liquid form or the seeds are covered with the inoculants before sowing. Plants are subject to many different environmental elements. Abiotic factors such as drought or water stress have been one of the main plant growth limiting factors. Agricultural PGPR application is an alternative solution against loss due to the environmental stresses, since breeding a plant with stress resistance trait is a very long and tricky process due to the fact that such traits are controlled by multiple genes. PGPR phytohormone and enzyme (i.e. ACC deaminase) production can decrease the stress levels of plants while enhancing the root structures.

Plant Growth Promoting Rhizobacteria's (PGPRS) Enzyme Dynamics in Soil Remediation

Soil is the basis of agriculture and consists of organic matters, minerals, water, and several gasses. All plants require soil both as an anchor to attach and as water and nutrient source. Unfortunately, lifestyles of humans, industrial progress, chemicals used in agriculture contaminate soil and cause soil pollution. A pollutant may be natural or human‐made in origin such as petroleum hydrocarbons, pesticides, heavy metals, and solvents. Since the quality of the soil affects the growth and product yield of plants, soil pollution is a crucial problem needs to be addressed urgently. Plant growth promoting rhizobacteria (PGPR) are microorganisms living in soil, on the plants roots, or inside the plant. PGPRs synthesize chemicals to stimulate plant growth and promote nutrient uptake, help degrading soil pollutants and fending off pathogens. While some pollutants can be degraded by enzymes produced by bacteria and fungi, degradation of heavy metals requires alternative methods. In this chapter, three enzymes produced by PGPRs are reviewed briefly. Aminocyclopropane‐1‐carboxylate (ACC) deaminase is responsible of lowering the ethylene levels of plants during stress conditions, whereas nitrogenase is responsible for N2 reduction to NH3. Moreover, phytase enables the degradation of phytate which is a main storage form of phosphate in plants.

OPTIMUM ECONOMIC BORON FERTILIZER DOSES OF WHEAT GROWN ON CALCAREOUS SOIL

Field experiments with boron (B) (0, 1, 3, 6, and 9 kg ha−1 B) were conducted in 2005 and 2006 to determine the optimum economic B rate (OEBR). Critical soil test and tissue B values for grain yield (GY) and total yield (TY) production for ‘Krik’ cv. and ‘Bezostiya’ cv. grown on B-deficient calcareous Aridisols in Eastern Turkey were determined. Averaged over the two years, ‘Krik’ and ‘Bezostiya’ cvs., the OEBR was 6.4–5.6 kg B ha−1 with an average GY yield of 2.0–3.8 Mg ha−1, and 5.9–5.6 kg B ha−1 with an average TY yield of 5.5.0–10.8 Mg ha−1, respectively. The average soil B content at the OEBR was 1.15–0.92 mg kg−1 while leaf tissue B content amounted to 24.0 and 30.3 mg kg−1 for ‘Krik’ and ‘Bezostiya’ cvs., respectively. Boron application decreased tissue calcium (Ca), and magnesium (Mg), and increased tissue nitrogen (N), phosphorus (P), potassium (K), zinc (Zn), iron (Fe), copper (Cu) and manganese (Mn).