Showing papers in "Journal of Plant Nutrition in 2007"
TL;DR: The reproductive growth stage is the most sensitive to biotic and abiotic stresses, followed by spikelet filling and vegetative growth stage, and new opportunities for improving rice yield components in favor of higher yield are offered.
Abstract: Rice (Oryza sativa L.) is a staple food for more than 50% of the world's population, including regions of high population density and rapid growth. Rice is produced under both upland and lowland ecosystems with about 76% of the global rice produced from irrigated lowland rice systems. The objective of this article is to discuss growth and formation of yield components in rice during crop growth cycles. The yield components of rice are the number of panicles per unit area, number of spikelets per panicle, weight of spikelet and spikelet sterility or filled spikelet. In addition, shoot dry weight, grain harvest index, and nitrogen (N) harvest index are also positively associated with grain yield. These yield components and yield associated parameters are formed during crop growth cycle. Growth cycle of the rice plant is divided into three stages. These stages are designated as vegetative, reproductive and spikelet filling or ripening. Yield potential of rice is formed or defined during these growth stages. Plant height, tillering (associated with panicle number), root growth, leaf area, and morphology are the main features of vegetative growth stage. In the reproductive growth stage panicle development takes place. Booting and flowering are part of the reproductive growth stage. Panicle size or spikelets per panicle are determined in the reproductive growth stage. Spikelet size or weight is determined during the spikelet filling growth stage. The reproductive growth stage is the most sensitive to biotic and abiotic stresses, followed by spikelet filling and vegetative growth stage. Recent advances in molecular linkage maps of rice and other developments of molecular biology offer new opportunities for improving rice yield components in favor of higher yield.
490 citations
TL;DR: Seed inoculation with Rhizobium, Bacillus subtilis and Bacillus megaterium, especially dual and triple combinations, may substitute costly NP fertilizers in chickpea production even in cold highland areas such as in Erzurum.
Abstract: Drawbacks of intensive farming practices and environmental costs of nitrogen (N) and phosphorus (P) fertilizers have renewed interest in biofertilizers. A study was conducted in order to investigate seed inoculation of chickpea with Rhizobium, N2-fixing Bacillus subtilis (OSU-142) and P-solubilizing Bacillus megaterium (M-3) in comparison to control and mineral fertilizer application in controlled environment and in field conditions in 2003 and 2004 in Erzurum (29° 55′ N and 41° 16′ E with an altitude of 1950 m), Turkey. In the controlled environment and in the field trials, single, dual, and triple inoculations with Rhizobium, OSU-142, and M-3 significantly increased all the parameters investigated (plant height, shoot, root and nodule dry weight, N%, chlorophyll content, pod number, seed yield, total biomass yield, and seed protein content) compared with the control treatment, equal to or higher than N, P, and NP treatments. In the field all the combined treatments containing Rhizobium were bet...
245 citations
TL;DR: In this article, the authors review recent advances in green manuring practice, in the context of potential benefits and drawbacks in use of this practice for agricultural applications, in order to evaluate the potential benefits of green manures in crop production.
Abstract: The positive role of green manuring in crop production has been known since ancient time. Importance of this soil ameliorating practice is increasing in recent years because of high cost of chemical fertilizers, increased risk of environmental pollution, and need of sustainable cropping systems. Green manuring can improve soil physical, chemical, and biological properties and consequently crop yields. Furthermore, potential benefits of green manuring are reduced nitrate (NO3 −) leaching risk and lower fertilizer N requirements for succeeding crops. However, its influence may vary from soil to soil, crop to crop, environmental variables, type of green manure crop used, and its management. Beneficial effects of green manuring in crop production should not be evaluated in isolation; however, in integration with chemical fertilizers. The objective of this article is to review recent advances in green manuring practice, in the context of potential benefits and drawbacks in use of this practice for ann...
171 citations
TL;DR: Genistein addition could partially overcome the salt and acidity stresses by increasing soybean yields up to 21% and 23%, respectively, and may be very useful for planting soybean under salinity and Acidity stresses.
Abstract: Soil stresses such as salinity and acidity may adversely affect nitrogen (N)2-fixation. The hypothesis of this study is that soil salinity and acidity inhibit soybean [Glycine max (L.) Merr.] nodulation and N2-fixation due to, at least in part, disruption of the signal exchange process. The objectives were: 1) to determine the effects of stressful soil salinity and acidity on the signal exchange processes between soybean and Bradyrhizobium japonicum, and 2) to determine whether or not the addition of signal molecule genistein to B. japonicum can overcome at least part of the inhibition of nodulation, caused by stressful soil salinity and acidity. Salt (sodium chloride) and sulfur (S) were applied. Genistein (0, 5, and 20μ M) was tested. Genistein addition could partially overcome the salt and acidity stresses by increasing soybean yields up to 21% and 23%, respectively. These novel findings may be very useful for planting soybean under salinity and acidity stresses.
125 citations
TL;DR: In this article, ammonium toxicity in cucumber (Cucumis sativus L.) was investigated following growth with different N sources [nitrate (NO3 −), NH4 +, or NH4NO3] supplied in concentrations of 1, 5, 10, or 15 mM.
Abstract: Aspects of ammonium (NH4 +) toxicity in cucumber (Cucumis sativus L.) were investigated following growth with different N sources [nitrate (NO3 −), NH4 +, or NH4NO3] supplied in concentrations of 1, 5, 10, or 15 mM. Plant dry weights and root: shoot ratios were lower with NH4 +-fed plants than with NO3 −-fed plants. Ammonium accumulated strongly in leaves, stem, and roots when the concentration in the growth medium exceeded 1 mM. The increase in tissue NH4 + coincided with saturation of glutamine synthetase activity and accumulation of glutamine and arginine. Low tissue levels of calcium and magnesium in the NH4 +-fed plants constituted part of the NH4 +-toxicity syndrome. Additions of small amounts of NH4 + to NO3 − -grown cucumber plants markedly increased the growth.
117 citations
TL;DR: The drylands in the semi-arid regions of India were not only thirsty, but also hungry (nutrient deficiencies), and results show widespread deficiencies of S, B, and Zn under dryland agricultural conditions.
Abstract: On-farm studies were conducted during 2002–2004 to determine fertility status, including sulfur (S) and micronutrients, and crop response to fertilization on farmers' fields in the semi-arid zone of India. Nine hundred-twenty four soil samples taken from farmers' fields, spread in the three districts of Andhra Pradesh (India), were analyzed for soil chemical fertility parameters. Results showed that samples were low in organic carbon (C), total nitrogen (N), and low to moderate in extractable phosphorus (P), but adequate in available potassium (K). Analyses of soil samples for extractable S and micronutrients was most revealing and showed that 73–95% of the farmers' fields were deficient in S, 70–100% in boron (B), and 62–94% in zinc (Zn). On-farm trials conducted during three seasons (2002–2004) showed significant yield responses of maize, castor, groundnut, and mung bean to the applications of S, B, and Zn. The yield responses were larger when S, Zn, and B were applied along with N and P. Appli...
95 citations
TL;DR: In this paper, the authors discuss the use of tropical cover crops in a sustainable crop production system and their agronomic and physiological aspects in the selection of appropriate cover crops and their management.
Abstract: Cover crops are important components of a sustainable crop production system. They can be planted with plantation crops such as cacao, coffee, banana, rubber, and oil palm or in rotation with cash crops. Their use in a cropping system is mainly beneficial for soil and water conservation, recycling of nutrients, control of pests and improved microbiological activities. However, beneficial effects depend on the selection of appropriate cover crops and their management. Hence, understanding their agronomy and physiology is fundamental for their use in sustainable cropping systems. Growth and development of a crop (physiological aspects) is determined genetically as well as influenced by environmental variables. This information can be useful in improving production of these crops and, consequently, their incorporation in farming systems, wherever it is possible. There are hundreds of tropical cover crops and, therefore, it is not possible to include all of them in one article. Hence, selected cereals and legumes are included.
75 citations
TL;DR: Wang et al. as mentioned in this paper showed that Bt-transgenic cotton was more susceptible to K+ deficiency than conventional cultivars CCRI 36 and CCRI 35, when grown at high K+ than low K+ conditions.
Abstract: Bacillus thuringensis (Bt) transgenic (insect-resistant) cotton cultivars senesce prematurely under potassium (K+) deficiency, more often than conventional cultivars, in the North China Plain. To verify if Bt-transgenic cotton was more susceptible to K+ deficit, two transgenic cultivars, ‘CCRI 41’ and ‘DP 99B’, and two conventional cultivars, ‘CCRI 35’ and ‘CCRI 36’, selected from widely used cultivars in China, were used in a seedling hydroponic study. The culture solution K+ concentration was 0.5 mM for high K+ and 0.02 mM for low K+ conditions. Seedlings of all four cultivars accumulated more dry matter and K+ when grown at high K+ than low K+ conditions. However, under low K+ condition, the dry weight and K+ content of Bt-transgenic cultivars CCRI 41 and DP 99B were lower than those of the conventional cultivars CCRI 36 and CCRI 35. The results indicated that Bt-transgenic cultivars CCRI 41 and DP 99B were more sensitive to K+ deficiency than conventional cultivars CCRI 36 and CCRI 35, which ...
73 citations
TL;DR: In this paper, a pot experiment was conducted in a greenhouse on a calcareous soil (fine, mixed, mesic, fluventic Haploxerepts) to study the interaction of zinc (Zn) and boron (B) on the growth and nutrient concentration of corn.
Abstract: A pot experiment was conducted in a greenhouse on a calcareous soil (fine, mixed, mesic, Fluventic Haploxerepts) to study the interaction of zinc (Zn) and boron (B) on the growth and nutrient concentration of corn (Zea mays L.). Treatments consisted of a factorial arrangement of seven levels of B (0, 2.5, 5, 10, 20, 40, and 80 mg kg− 1as boric acid), two sources of Zn [zinc sulfate (ZnSO4 · 7H2O) and zinc oxide (ZnO)], and three levels of Zn (0, 5, and 10 mg kg− 1) in a completely randomized design with three replications. Plants were grown for 70 d in 1.6 L plastic containers. Applied Zn significantly increased plant height and dry matter yield (DMY) of corn. Source of Zn did not significantly affect growth or nutrient concentration. High levels of B decreased plant height and DMY. There was a significant B × Zn interaction on plant growth and tissue nutrient concentration which were rate dependent. In general, the effect of B × Zn interaction was antagonistic on nutrient concentration and syner...
73 citations
TL;DR: In this article, a study was carried out by soaking the seeds of two spring wheat (Triticum aestivum L) for 12 hours in distilled water or 100 mol m−3 of calcium chloride (CaCl2), potassium chloride (KCl), or sodium chloride (NaCl).
Abstract: In order to assess whether seed priming could improve salt tolerance in spring wheat (Triticum aestivum L.) a study was carried out by soaking the seeds of two cultivars, MH-97 (salt sensitive) and Inqlab-91 (salt tolerant), for 12 h in distilled water or 100 mol m–3 of calcium chloride (CaCl2), potassium chloride (KCl), or sodium chloride (NaCl). The primed seeds (P-seeds) of each treatment and non-primed seeds (NP-seeds) were sown in a field in which NaCl salinity of 15 dS m− 1 was developed. Calcium chloride followed by KCl and NaCl was found to be effective in alleviating the adverse effect of salt stress on both cultivars of wheat in terms of biomass production, grain yield, and net CO2 assimilation rate. Although all priming agents were found to be effective in reducing the shoot Na+ levels in both cultivars, the effect of KCl was very pronounced, because it significantly reduced shoot Na+ in both cultivars under saline conditions. In conclusion, although all three priming agents CaCl2, KCl...
73 citations
TL;DR: In this paper, the effects of increasing levels of Boron toxicity on plant growth, proline accumulation, membrane permeability, nitrate reductase activity (NRA), and mineral nutrient interactions of tomato and pepper plants were investigated in greenhouse conditions.
Abstract: Boron (B) toxicity is an important disorder that can limit plant growth on soils of arid and semi arid environments throughout the world. Although of considerable agronomic importance, our understanding of B toxicity is rather fragmented and limited. The effects of increasing levels of B (0, 0.5, 5, 50 mg kg− 1) on plant growth, proline accumulation, membrane permeability, nitrate reductase activity (NRA), and mineral nutrient interactions of tomato and pepper plants were investigated in greenhouse conditions. Increasing levels of B increased the B contents of plants. Boron toxicity symptoms occurred at 5 and 50 mg kg− 1 levels. Fresh and dry weights of the plants clearly decreased with the application of the 50 mg kg− 1 level of B. Membrane permeability and proline accumulation were significantly increased by the 50 mg kg− 1 level of B. Nitrate reductase activity of tomato plants was increased with increasing levels of B. With the exception of potassium (K) and calcium (Ca) in pepper and magnesi...
TL;DR: For both plant species, an increase in Mn supply levels stimulated the exudation of carboxylates and the activity of peroxidase, which was related to stress conditions.
Abstract: The effects of differential manganese (Mn) supply (0 to 355 μ M) and pH (4.8 and 6.0) on dry weight (DW), tissue concentrations of Mn, exudation of carboxylates, and the peroxidase activity were studied in ryegrass (Lolium perenne L.) and white clover (Trifolium repens L.) grown in nutrient solution. In both plant species, the increase in Mn supply caused a significant reduction in DW due to severe Mn toxicity, especially at pH 4.8. The critical toxicity concentration of Mn in shoots was 421 mg kg− 1 for ryegrass and 283 mg kg− 1 for white clover. For both plant species, an increase in Mn supply levels stimulated the exudation of carboxylates and the activity of peroxidase, which was related to stress conditions. The highest amount of carboxylates was exuded at pH 4.8. There was no clear effect of carboxylates on the complexation of Mn2 +.
TL;DR: In this article, the short-term responses to phosphorus deficiency of two contrasting maize hybrids, L3x228-3 (P-efficient) and HS 2841x5046 (Pinefficient), were compared to nutrient solution culture and quartz sand amended with or without rock phosphate.
Abstract: Nutrient solution culture and quartz sand amended with or without rock phosphate, were used to compare the short-term responses to phosphorus (P) deficiency of two contrasting maize hybrids, L3x228-3 (P-efficient) and HS 2841x5046 (P-inefficient). In solution-grown seedlings, the rapid P deficiency-induced enhancement of root growth and of the root/shoot ratio was a sign of P deficiency stress rather than of P efficiency. In sand culture, uptake of P from sparingly soluble rock phosphate was higher in P-efficient plants than in P-inefficient maize. In the variety L3-228-3, P efficiency seemed due to enhanced P acquisition rather than to an enhanced P use efficiency. In sand, but not in solution culture, higher citrate concentrations were detected in the rhizosphere of P-efficient than of P-inefficient maize. Quartz sand amended with rock phosphate was a better substrate than nutrient solution for revealing the varietal differences in P acquisition efficiency in short-term experiments.
TL;DR: In this article, the effect of hydrophilic polymer (HG) on survival and growth of buttonwood (Conocarpus erectus L) seedlings grown in sandy soil under drought stress was investigated.
Abstract: The effect of 00 (control), 01, 02, 04, and 06% of the hydrophilic polymer “Stockosorb K-400” hydrogel (HG) on survival and growth of buttonwood (Conocarpus erectus L) seedlings grown in sandy soil under drought stress was investigated The ability of the soil to retain water increased with increasing hydrogel concentrations The highest level of the HG was capable of changing the typical sandy soil to a loam or even silty clay in terms of water potential and water content The highest HG concentration prolonged the time of water loss from the soil by about 66% more than the control soil During drought stress, the seedlings grown in 06% HG-mixed soil survived three times as long as those grown in the control soil Shoot and root growth increased significantly in HG-amended soil as compared with non-amended soil Plant water potential increased significantly with HG application, thus it aided in the establishment and growth of C erectus seedlings under water stress conditions There were
TL;DR: In vitro freeze tests indicated trees fertilized with lower rates of N were more cold hardy during the fall, winter and spring than those receiving the higher rates, whereas various legume species were prevalent at the low rates.
Abstract: Four rates of ammonium nitrate (NH4NO3) (0, 151, 454, and 908 g actual N/tree) were applied each spring for 6 years to ‘Golden Delicious’ (Malus domestica) apple trees. High rates of nitrogen (N) increased N concentration of Orchardgrass (Dactylis glomerata) blades and increased cover-grass growth whereas various legume species were prevalent at the low rates. Leaf N in spur or mid-terminal leaves increased yearly, and was related to leaf color by visual comparison and reflectance. Fruit from the higher N rates had greener peel and lower firmness, soluble solids content and titratable acidity. In vitro freeze tests indicated trees fertilized with lower rates of N were more cold hardy during the fall, winter and spring than those receiving the higher rates. In a similar long-term study on ‘Delicious,’ cold hardiness was related not only to seasonal temperature cycles and shoot dry matter, but to total sugars and sorbitol content in wood or sap.
TL;DR: The combined ratios with SPAD (Chl) and Dualex readings were strongly related to applied N dose at all samplings dates, and found the most sensitive and robust through the season.
Abstract: The Dualex is a new leaf-clip instrument that can be used to monitor corn nitrogen (N) status. It is based on the measurement of polyphenolics (Phen), which are secondary metabolites affected by stress factors. The purpose of this study was to compare Dualex to SPAD (chlorophyll meter), the latter having been used for several years in monitoring crop N status. As well, the interest of combining Dualex and SPAD information in Chl/DUAD (ratio of SPAD to Dualex reading on adaxial side), Chl/DUAB (ratio of SPAD to Dualex reading on abaxial side), and Chl/Phen (ratio of SPAD to the sum of DUAD and DUAB) ratios were considered. Significantly positive and negative correlations with corn leaf N concentration were found for SPAD and Dualex, respectively. Successful N status diagnosis could be achieved with either Dualex or SPAD for corn within 21 days after topdressing while the Dualex lost sensitivity at later stages. Dualex measurements could be limited to leaves abaxial side or adaxial side, instead of...
TL;DR: In this paper, changes in concentrations of B, calcium (Ca), potassium (K), magnesium (Mg), manganese (Mn), and zinc (Zn) were comparatively investigated in the structural parts of the fruit (rind and pulp) and leaves (old leaves from last season and spring-flush leaves from current year) of Citrus sinensis Osbeck navel orange during the growing season.
Abstract: In southern Jiangxi province of China, 'Newhall'(Citrus sinensis Osbeck) navel orange presented a conspicuous symptom of boron (B) deficiency in mature leaves, whereas B deficiency symptoms were not manifested on 'Skagg's Bonanza'(C. sinensis Osbeck) navel orange. In this study, changes in concentrations of B, calcium (Ca), potassium (K), magnesium (Mg), manganese (Mn), and zinc (Zn) were comparatively investigated in the structural parts of the fruit (rind and pulp) and leaves (old leaves from last season and spring-flush leaves from current year) of 'Newhall' and 'Skagg's Bonanza' navel orange during the growing season. Two peaks of B concentrations were observed in the rind of the two cultivars during fruitlet growth and fruit enlargement, respectively. Boron concentrations were relatively high in the rind during fruitlet growth, and then decreased in both rind and pulp, whereas, during middle and late fruit enlargement significant increases were found for B in both rind and pulp of the two cultivars. Boron concentrations in old leaves of 'Newhall' decreased progressively and remained relatively low, whereas that of 'Skagg's Bonanza' was relatively high and changed slightly as the season progresses. Both Ca and K concentrations were above the critical threshold values, while their dynamics were reverse to that of B in fruit and leaves during certain times. Old leaf Mg concentrations of samples at 140 days after full bloom from the two cultivars and spring-flush leaves from 'Newhall' were below the threshold limit for sufficiency. In addition, Mg in old leaves was much lower from 'Newhall' than from 'Skagg's Bonanza'. Spring-flush leaf concentrations of Mn and Zn and Mn concentrations in old leaves from 'Newhall' were relatively lacking during middle and late season, which accelerated the occurrence of B deficiency symptoms on mature leaves of 'Newhall.'
TL;DR: In this paper, α-amino-N, which was tightly correlated with the contents of free amino acids, can be regarded a suitable rapid test for free asparagine for a given variety.
Abstract: Fried potato products may accumulate substantial amounts of acrylamide due to high precursor contents, namely reducing sugars and asparagine. In a two-factorial experiment increasing N supply, increased the contents of reducing sugars in most cases, and resulted in higher contents of free amino acids. α-amino-N, which was tightly correlated with the contents of free amino acids, can be regarded a suitable rapid test for free asparagine for a given variety. Increasing K addition always raised the citrate contents, but lessened the contents of reducing sugars. Selected treatments were processed into French fries. Highest acrylamide contents were observed in tubers grown with high N and inadequate K supply, which also contained the highest contents of precursors. The experiment clearly demonstrates that nutrient supply has significant impact on the contents of acrylamide precursors and thus for the acrylamide formation during frying.
TL;DR: In this article, the Honey Bunch tomato to nitrogen (N) rates were evaluated on a Lakeland fine sand in North Florida using plasticulture and N rates of 0, 78, 157, 235, 314, and 392 kg/ha.
Abstract: Grape tomatoes (Lycopersicon esculentum Mill.) are gaining popularity among consumers because of their flavor, sweetness, potential health benefits, and ease of consumption. Most grape tomatoes are indeterminate varieties. Hence, current production practices (including fertilization rates) may need to be adjusted to larger plants, longer growing seasons, and harvests over several months of the indeterminate varieties. The responses of physical (color and moisture content) and chemical [vitamin C, pH, total titratable acidity (TTA), carotenoids, and soluble solid content (SSC)] parameters for ‘Honey Bunch’ yellow grape tomato to nitrogen (N) rates were evaluated. In Spring 2005, tomatoes were grown on a Lakeland fine sand in North Florida using plasticulture and N rates of 0, 78, 157, 235, 314, and 392 kg/ha. Tomatoes were harvested fully ripen on 81 and 105 d after transplanting (DAT = 0 on March 24th), and uniform 20-fruit samples were carefully selected. Increasing N rate significantly reduced ...
TL;DR: Fe-reduction capacity was a better physiological indicator for screening Fe-efficient peanut genotypes of the mechanisms measured and Fe-deficiency chlorosis symptoms among peanut cultivars in the same soil showed considerable variability.
Abstract: Iron (Fe) deficiency has been a widespread problem in peanut (Arachis hypogaea L.) grown on calcareous soils of northern China and has resulted in significant yield losses. Field observations showed considerable variability in visual chlorosis symptoms among peanut cultivars in the same soil. The objective of this study was to confirm the genetic differences in resistance to Fe-deficiency chlorosis in peanut and to identify feasible indicators for screening Fe-efficient genotypes. Resistance to Fe chlorosis of sixteen peanut cultivars grown on calcareous soil was evaluated in the field and physiological responses to Fe-deficiency stress were studied in nutrient solution. There were significant differences in resistance to Fe-deficiency chlorosis among the sixteen peanut cultivars tested, which was identified with SPAD readings, active Fe concentrations in young leaves in the early growth stages, and the pod yield. For Fe-resistant peanut cultivars, Fe-reduction capacity and quality of releasing h...
TL;DR: In this article, a perlite trickling biofilter (root growth medium) exposed to hydroponic nutrient solution, varying NO3 −-N concentrations, and to pH levels optimum for plants (6.5) and nitrification (8.5).
Abstract: Reconciling water quality parameters in sustainable aquaponic (integrated hydroponic and recirculating aquaculture) systems requires balancing nutrients and pH for the optimal growth of three organisms: the plant, the fish, and the nitrifying bacteria. Nitrifying bacteria convert fish waste into nitrate (NO3 −)-nitrogen (N) that may be used by the plants. Fish waste rarely supplies nutrients in adequate amounts for plants without supplementation. Increasing nitrification rate and efficiency would allow greater stocking density for fish and increased nutrient loads for plants. The objective of this research was to determine the nitrification rate response in a perlite trickling biofilter (root growth medium) exposed to hydroponic nutrient solution, varying NO3 −-N concentrations, and to pH levels optimum for plants (6.5) and nitrification (8.5). The experiment used recirculating tank batch culture and was based on typical startup characteristics for bringing biological filters up to full capacity ...
TL;DR: It is suggested that P deficiency impaired symbiotic N2 fixation through delaying onset of nodule function and decreasing nodule development.
Abstract: Effects of phosphorus (P) deficiency on nodulation were examined in soybean grown in nutrient solution for 7 weeks. Increasing P supply increased shoot growth of nitrogen (N2)-fixing plants from week 5 and that of nitrate-fed plant from week 4 after treatment. Nitrogen (N2)-fixing plants had a greater P requirement for maximum growth at week 5. Increasing P supply from 1 to 16 μ M increased N concentration in N2-fixing plants at week 4 but did not affect it from week 5. By contrast, P deficiency increased N concentration in nitrate-fed plants. Increasing P supply improved nodule formation from week 3. Nodule mass was affected more by P supply than nodule number, which, in turn, was affected more than plant growth. However, P supply did not decrease nodule specific N2 fixation from week 5. The results suggest that P deficiency impaired symbiotic N2 fixation through delaying onset of nodule function and decreasing nodule development.
TL;DR: The results suggest that a collective effect of superior morphological and physiological root traits confers better nutrition of chickpea genotypes in low-nutrient soils.
Abstract: Plant nutrients such as potassium (K), phosphorus (P), iron (Fe), manganese (Mn), zinc (Zn), and copper (Cu) mostly remain fixed in soils and their bio-availability to plant roots is diffusion-limited. Hence, superior root traits, that can enhance their dissolution and capture from the soils, can play a central role in its productivity. Root morphological (root length and root hairs) and physiological traits (root exudation of protons and phosphatase enzymes) of ten selected varieties/breeding lines of chickpea (Bari-chhola-3, Bari-chhola-4, Bari-chhola-5, Bari-chhola-6, Bari-chhola-7, Bari-chhola-8, BGM-E7, ICCV-98926, ICCV-94924, and ICCV-98916) were studied and related them to the uptake of the nutrients in a pot experiment. There were significant (P < 0.05) genotypic differences in root length (RL) and root hair length (RHL). The RL ranged between 70 m plant− 1 and 140 m plant− 1. The variation in RHL was significant (P < 0.05) and it ranged between 0.58 ± 0.09 mm (Bari-chhola-5) and 0.26 ± 0...
TL;DR: It is suggested that for high seed yields, there should be adequate supply of nutrients for plants, particularly to sustain high nutrient uptake rate at branching to bud forming stage and high biomass accumulation rate at early to late bud formingStage, suggesting interrelated absorption.
Abstract: Seed yield and nutrient use efficiency are related to biomass accumulation and nutrient uptake in the growing season. Biomass accumulation and nutrient uptake of canola (Brassica napus L. and Brassica rapa L.), mustard (Brassica juncea L.) and flax (Linum usitatissimum L.) and the relationship to days after emergence (DAE) or growing degree days (GDD) were determined during the 1998 and 1999 growing seasons in field experiments at Melfort, Saskatchewan, Canada. In general, biomass accumulation and nutrient uptake increased with time at early growth stages and reached a maximum at late growth stages. Significant R2 values for both biomass accumulation and nutrient uptake indicated that a cubic polynomial type equation was suitable to represent these parameters as a function of DAE. All oilseed crops maximized biomass at mid way to the end of pod forming stages (74–84 DAE or 750–973 GDD). Maximum biomass accumulation rate occurred at the early to late bud forming stage (42–49 DAE or 390–498 GDD), a...
TL;DR: The beneficial effect of AMF for alleviation of HCO3 − plant stress is indicated, as indicated by greater growth, leaf elemental concentration, higher mycorrhizal inoculation effect, lower root Fe reductase activity, and generally lower soluble ALP activity.
Abstract: High bicarbonate (HCO3 −) of irrigation water can be detrimental to plant growth in sustainable horticultural production systems. The ability of arbuscular mycorrhizal fungi (AMF), ZAC-19, (composed of Glomus albidum, Glomus claroideum, and Glomus diaphanum) to enhance tolerance to HCO3 − was tested on Rosa multiflora cv. Burr. Arbuscular mycorrhizal colonized and non-inoculated (non-AMF) plants were treated with 0, 2.5, 5, and 10 mM HCO3 −. Increasing HCO3 − concentration and associated high pH and electrical conductivity (EC)—reduced plant growth, nutrient uptake, and acid phosphatase activity, while increasing alkaline phosphatase activity (ALP). Inoculation with AMF enhanced plant tolerance to HCO3 −, as indicated by greater growth (leaf, stem, and total plant dry weight, leaf area and leaf area ratio), leaf elemental concentration [nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), iron (Fe), zinc (Zn), aluminum (Al), boron (B)], leaf chlorophyll concentration, higher mycorrhizal ino...
TL;DR: In this article, a study was conducted for three years to better understand wheat plant response to optimize N fertilizer and how to reduce the risk of ground water pollution, which is one of the most growth restricting nutrients in cereal grain.
Abstract: Nitrogen (N) is one of the most growth restricting nutrients in cereal grain and represents one of the highest input costs in agricultural systems; therefore, environmental and economic considerations require the effective use of N fertilizer in plant production. This study was conducted for three years to better understand wheat plant response to optimize N fertilizer and how to reduce the risk of ground water pollution. Two of the most important durum wheat cultivars in Southern Italy and four N fertilization levels (0, 60, 120, and 180 kg N ha− 1, indicated as N0, N60, N120, and N180, respectively) were compared in this experiment. During plant growth, fresh and dry matter, plant nutritional state (SPAD readings and stem nitrate content), and N uptake were determined. At harvest, plant N content, N uptake, grain yield, yield components and quality were determined, allowing the calculation of the pre- and postanthesis N uptake and the N utilization efficiency indices. Furthermore, at the beginn...
TL;DR: Soil microbial biomass was strongly related to the N concentration and/or the inverse of the C:N ratio of the cover crops and in the soil, suggesting that cover crops increase soil microbiological biomass through the decomposition of organic C.
Abstract: In order to understand how soil microbial biomass was influenced by incorporated residues of summer cover crops and by water regimes, soil microbial biomass carbon (C) and nitrogen (N) were investigated in tomato field plots in which three leguminous and a non-leguminous cover crop had been grown and incorporated into the soil. The cover crops were sunn hemp (Crotalaria juncea L., cv ‘Tropic Sun’), cowpea (Vigna unguiculata L. Walp, cv ‘Iron clay’), velvetbean (Mucuna deeringiana (Bort) Merr.), and sorghum sudangrass (Sorghum bicolor × S. bicolor var. sudanense (Piper) Stapf) vs. a fallow (bare soil). The tomato crop was irrigated at four different rates, i.e., irrigation initiated only when the water tension had reached −5, −10, −20, or −30 kPa, respectively. The results showed that sorghum sudangrass, cowpea, sunn hemp, and velvetbean increased microbial biomass C by 68.9%, 89.8%, 116.8%, and 137.7%, and microbial N by 58.3%, 100.0%, 297.3%, and 261.3%, respectively. A legume cover crop, cowpea...
TL;DR: In this article, the effects of growing Eichhornia crassipes on removal of nitrogen (N) from the eutrophicated water were investigated in a large-scale enclosure system installed in hyper-eutrophic water in Hua-jia-chi pond, Hangzhou city, China.
Abstract: Aquatic plants can be used for treating eutrophicated water in a simple and cost-effective manner, but many such plant systems remain to be characterized. The effects of growing Eichhornia crassipes on removal of nitrogen (N) from the eutrophicated water were investigated in a large-scale enclosure system installed in hyper-eutrophicated water in Hua-jia-chi pond, Hangzhou city, China. Total N concentration in the enclosures decreased from 2.1 to 0.50 mg L− 1 after growing Eichhornia crassipes for 44 d. Ammonium concentration decreased at least 2-fold after plant growth. Nitrite concentration decreased to below detection limit after growing Eichhornia crassipes for only 14 d and was maintained at that level afterwards. Chlorophyll a concentration (an indicator of water eutrophication) decreased to 10 μ g L− 1 after 44 d. The water transparency increased significantly, reaching the depth of 1.8 m (i.e., to the bottom of the pond) after 44 d. Eichhornia crassipes removed 21.7 kg nitrogen from 6,000...
TL;DR: In this article, the effect of various combination of macro (N, Mg, and K) and micronutrients (Fe and Zn) on yield, fruit quality, and tissue mineral concentrations of an important commercial table grape cultivar (Vitis vinifera cv) was studied over three growing seasons of 1999-2001.
Abstract: The effect of various combination of macro (N, Mg, and K) and micronutrients (Fe and Zn) on yield, fruit quality, and tissue mineral concentrations of an important commercial table grape cultivar (Vitis vinifera cv. Bidaneh Qermez) was studied over three growing seasons of 1999-2001. Yield, fruit set, cluster weight, cluster number, berry size and quality attributes (soluble solid concentrations, pH, K-skin) were influenced by N, K, Mg, Fe, and Zn applications. Potassium application increased cluster number and weight, which resulted in a significant increase in the yield. Potassium influenced berry quality attributes more than other applied mineral elements. Yield was positively correlated to the soil total N at 30-60 cm depth. Nitrogen application increased growth of the main and lateral canes. Soil N did not correlate strongly with tissue N status.
TL;DR: In this article, the effects of solarization on soil microbial biomass, soil respiration, and soil enzymatic activity in the presence of organic amendments and the soil fumigant dazomet were investigated.
Abstract: Soil solarization, obtained by covering soil with plastic films, is a useful practice able to reduce soil pathogen populations. Light plastic films (LPFs) are nowadays widely used especially in open and greenhouse vegetable crop cultivations in Southern Italy, as they are able to raise soil temperature more than 20°C above air temperature. The solarization treatment with LPFs is characterized by a low cost and low environmental impact. The wide use of these technique causes a concern about the side effect of solarization on soil microbial populations, which are affected the same as plant pathogens by soil heating. As scientific literature pays scant attention to the effect of soil heating on soil microbial parameters, this paper studied the effects of solarization on soil microbial biomass, soil respiration, and soil enzymatic activity in the presence of organic amendments and the soil fumigant dazomet. Solarization appears to be an effective practice able to control nematodes, even though it may cause serious stress on the soil microbial biomass. In addition, it was demonstrated that the organic amendments exert a protective role keeping soil microbial biomass and enzymatic activities protected from the detrimental effect of heating.