Emergence Rate,Yield, and Nitrogen-Use Efficiency of Sunflowers (Helianthus annuus) Vary with Soil Salinity and Amount of Nitrogen Applied

For understanding the effects of soil salinity and nitrogen (N) fertilizer on the emergence rate, yield, and nitrogen-use efficiency (NUE) of sunflowers, complete block design studies were conducted in Hetao Irrigation District, China. Four levels of soil salinity (electrical conductivity [EC_e] = 2.44–29.23 dS m^?1) and three levels of N fertilization (90–180 kg ha^?1) were applied to thirty-six microplots. Soil salinity significantly affected sunflower growth (P < 0.05). High salinity (EC_e = 9.03–18.06 dS m^?1) reduced emergence rate by 24.5 percent, seed yield by 31.0 percent, hundred-kernel weight by 15.2 percent, and biological yield by 27.4 percent, but it increased the harvest index by 0.9 percent relative to low salinity (EC_e = 2.44–4.44 dS m^?1). Application of N fertilizer alleviated some of the adverse effects of salinity, especially in highly saline soils. We suggest that moderate (135 kg ha^?1) and high (180 kg ha^?1) levels of N fertilization could provide the maximum benefit in low- to moderate-salinity and high- or severe-salinity fields, respectively, in Hetao Irrigation District and similar sunflower-growing areas.     

Effect of Chloride and Sulfate Salinity on Micronutrients Release and Uptake from Different Composts Applied on Total Phosphorus Basis

Generation of different biowastes is increasing day by day, and ultimate load on agricultural lands has increased. Concerns over increased phosphorus (P) application with nitrogen (N)–based compost application shifted the trend to P‐based applications. But focus on only one or two nutritional elements will not serve the goals of sustainable agriculture. Full insight into nutrient availability from different composts is necessary. The need to understand the nutrient release and uptake from different composts has increased because of the use of saline irrigation water in the recent scenario of fresh water shortage. Therefore, current greenhouse studies were designed to evaluate the bioavailability and leachability of some micronutrients [calcium (Ca), magnesium (Mg), and zinc (Zn)] from different biocomposts under chloride (Cl^?) and sulfate (SO₄ ^?2) saline environment. In the first pot experiment, soil was amended with livestock compost (AC), poultry compost (PC), and composted sludge (SC) at the rate of 200 kg P ha^?1 equivalent bases. Pots were irrigated with artificial saline water of sodium chloride (NaCl) or sodium sulfate (Na₂SO₄; 60 mmol_c L^?1), and leachates were collected for Ca and Mg analysis. As composts were applied on total P bases, which left varying amounts of nutrients in each treatment, it was observed that nutrient uptake and release differed greatly regardless of the total amount applied with each compost type. Amount of Ca applied with PC (3.9 g pot^?1) was greater, but Ca concentration in leachate was greater under AC‐amended treatments. Magnesium concentration also varied greatly under compost types. Among the saline irrigation, Ca and Mg concentration in leachate increased under both saline irrigations compared to nonsaline treatment, and SO₄ ^?2 had relatively greater ionic strength to replace cations than Cl^?. Calcium, Mg, and Zn uptake by maize stem and leaves were greater from SC‐amended pots followed by PC, SC, and control. Irrespective of the salt types, Ca and Mg uptake reduced under both saline irrigations, whereas Zn uptake increased as compared to nonsaline treatment. Among the salt types, it was observed that plant growth and nutrient uptake was more influenced by Cl^? than SO₄ ^?2 saline irrigation. In the second experiment, soil was saturated with NaCl and NaSO₄ (75 mmol_c L^?1) and amended with AC. The trend of nutrient uptake under both salt types was similar to first experiment, and the results of AC amendments have been discussed. It can be inferred from the results that regardless of the total amount applied, nutrient uptake greatly varies under different composts and their availability depends upon the source rather than total amount applied. Analogously, sulfate‐dominated irrigation water can increase the leaching of Ca and Mg from root zone more than chloride.     

Evapotranspiration and Mineral Content of Sedum kamtschaticum Fischer Under Saline Irrigation

An alternative water resource such as graywater could be used for irrigation on green roofs during hot, dry summers, although it contains salt. In this study, the response to high-salt stress of a C3–CAM (Crassulacean acid metabolism) intermediate species, Sedum kamtschaticum Fischer, was evaluated over a 2-month experiment in terms of evapotranspiration (ET) and chemical compounds in plant tissue in triplicate for both experiments. High ET (10–15 mm day^?1) was observed under non-stressed conditions. On the day following the first saline irrigation, the peak ET at noon decreased as much as one-third of the maximum. After 9 days, ET remained below 3 mm day^?1, corresponding mostly to evaporation from the wet soil surface. The balance of chemical component contents in leaves changed depending on the electrical conductivity of irrigation water electrical conductivity (EC_i). The potassium to sodium (K⁺/Na⁺) ratio, which indicates levels of sodium toxic for plant growth, decreased with higher EC_i, while it excluded sodium from roots. However, based on enhanced water use efficiency under higher EC_i regardless of reduced carbon dioxide (CO₂) assimilation under salinity stress, the plant’s method of photosynthesis shifted from C3 to CAM metabolism. These findings show that S. kamtschaticum could survive for more than 2 months under low or moderate salinity of irrigation water in hot conditions.     

Effects of Irrigation Water Salinity and Leaching Fraction on Yield and Evapotranspiration in Spring Wheat

To determine the effects of irrigation water salinity and leaching fraction on crop evapotranspiration (ETc), grain yield, straw yield, shoot sodium (Na), and chloride (Cl) concentrations of spring wheat (Triticum aestivum L.) cultivar ‘Onfarom 9,’ a pot experiment was conducted using saline soil with electrical conductivity of soil paste extract (ECe) of 13.2 dS m^?1. A factorial experiment with a completely randomized design replicated seven times was used with three levels of saline irrigation water (4, 9, and 12 dS m^?1) and four leaching levels (0, 17, 29, and 37%) included as the factors. The results showed that ETc significantly decreased as a result of an increase in irrigation water salinity (ECi) and decrease in leaching level. Crop evapotranspiration deficit and decreasing irrigation and drainage water effectively resulted in grain and straw yield reduction. Increase in ECi increased accumulation of Cl and Na in crop shoot, but application of leaching decreased this accumulation.     

Influence of Laboratory Methods on Calcareous Saline Soils for EC Measurement and Leaching

Abstract

Electrical conductivity (EC) methods were tested using combinations of surrogate irrigation (SI) waters, soil salinity levels, and soils ground or retaining aggregates. The EC varied in low-salinity soils saturated with SI; the sum of the baseline EC_e and SI EC were not equal to the measured EC. The baseline EC_e and the SI EC sum in the high‐salinity ground soils were not equal to the any measured ECs. Salt‐removal potential from gypsiferous soils was examined using multiple extractions from the same soil sample. Calcium concentrations remained consistent over 14 extractions, whereas Na concentrations decreased. The EC_e decreased from more than 8 dS m^?1 in the initial extraction, to approximately 4 dS m^?1 by the 9th to 14th extraction. Multiple extraction data suggest that improved leaching will not lower soil ECs to less than approximately 4 dS m^?1 because of gypsum and calcite reservoirs in the tested soils.     

Effect of zeolite and saline water application on saturated hydraulic conductivity and infiltration in different soil textures

The effects of zeolite application (0, 4, 8 and16 g kg^?1) and saline water (0.5, 1.5, 3.0 and 5.0 dS m^?1) on saturated hydraulic conductivity (K _s) and sorptivity (S) in different soils were evaluated under laboratory conditions. Results showed that K _s was increased at salinity levels of 0.5‐1.5 dS m^?1 in clay loam and loam with 8 and 4 g zeolite kg^?1 soil, respectively, and at salinity levels of 3.0–5.0 dS m^?1 with 16 g zeolite kg^?1 soil. K _s was decreased by using low and high salinity levels in sandy loam with application of 8 and 16 g zeolite kg^?1, respectively. In clay loam, salinity levels of 0.5–3.0 dS m^?1 with application of 16 g kg^?1 zeolite and 5.0 dS m^?1 with application of 8 g zeolite kg^?1 soil resulted in the lowest values of S. In loam, all salinity levels with application of 16 g zeolite kg^?1 soil increased S compared with other zeolite application rates. In sandy loam, only a salinity level of 0.5 dS m^?1 with application of 4 g zeolite kg^?1 soil increased S. Other zeolite applications decreased S, whereas increasing the zeolite application to 16 g kg^?1 soil resulted in the lowest value of S.     

Physiological characteristics,gas exchange,and plant ion relations of quinoa to different saline groundwater depths and water salinity

The objective of this study was to investigate the influence of saline groundwater depths (SGDs) (0.3, 0.55, and 0.80 m) with salinity equivalent to irrigation water salinity (WS) and irrigation WS (10, 20, 30, and 40 dS m^?1) on physiological characteristics, gas exchange, and plant ion relations of quinoa in cylindrical lysimeters in greenhouse conditions. Root length density (RLD) in the soil layer close to the saline shallow groundwater decreased. Soil aeration was the key point for reduction in RLD by decreasing SGD that was intensified by the increase in WS. It is concluded that root of quinoa was sensitive to anaerobic soil conditions. Results showed that the mean value of leaf water potential (Ψ) dropped from ?1.53 to ?3.09 MPa by increasing WS from 10 to 40 dS m^?1. Increasing WS from the lowest to the highest level resulted in 48% decrease in leaf photosynthesis rate (A_n). Results revealed that leaf stomatal conductance (g_s) was more sensitive to salinity than A_n. Stomatal closure in quinoa started to occur when the Ψ value fell below approximately ?1.0 MPa. In general, increasing WS from 10 to 40 dS m^?1 resulted in about 4.6-fold, 2.1-fold, and 2.6-fold increase in plant Na⁺, Ca²⁺, and Cl^? concentration, respectively.     

INTERACTIVE EFFECTS OF SALINITY AND N ON PEPPER (CAPSICUM ANNUUM L.) YIELD,WATER USE EFFICIENCY AND ROOT ZONE AND DRAINAGE SALINITY

The aim of this study was to determine the salt tolerance of pepper (Capsicum annuum L.) under greenhouse conditions and to examine the interactive effects of salinity and nitrogen (N) fertilizer levels on yield. The present study shows the effects of optimal and suboptimal N fertilizer levels (270 kg ha^?1 and 135 kg ha^?1) in combination with five different irrigation waters of varying electrical conductivity (EC) (EC_iw = 0.25, 1.0, 1.5, 2.0, 4.0, and 6.0 dS m^?1) and three replicates per treatment. At optimal N level, yield decreased when the irrigation water salinity was above EC_iw 2 dS m^?1. At the suboptimal N level, a significant decrease in yield occurred only above EC_iw 4 dS m^?1. At high salinity levels the salinity stress was dominant with respect to yield and response was similar for both N levels. Based on the results it can also be concluded that under saline conditions (higher than threshold salinity for a given crop) there is a lesser need for N fertilization relative to the optimal levels established in the absence of other significant stresses.     

Determination of Application Effects of Sewage Sludge on Growth,Soil Properties,and N Uptake in Komatsuna by using the Indirect 15N Isotope Method

Abstract: By using the indirect ¹⁵nitrogen (N) method, the application effects of sewage sludge (SS) on growth indices, yield, and nutrient uptake in Komatsuna (Brassica campestris var. perviridis) grown in a low fertility soil were investigated and compared with those of chemical fertilizer (CF) and no‐fertilizer (NF) treatments. The N‐use efficiencies of CF and SS were 19.7% and 12.1%, respectively, of the applied N. Therefore, the relative efficiency of the sewage sludge to chemical fertilizer was 61.5%. In comparison to NF and CF, the application of SS apparently increased the soil microbial activity, which was evaluated by measuring hydrolysis of fluorescein diacetate. After cultivation, the electrical conductivity (EC) of CF soil (0.175 dS m^?1) was significantly higher than those of NF (0.067 dS m^?1) and SS soils (0.057 dS m^?1). The concentrations of phosphorus (P), calcium (Ca), and magnesium (Mg) in SS leaves were significantly higher than those in CF leaves; however, the concentration of potassium (K) was significantly lower in SS than in CF.     

Influence of the Modification of Nutritional Parameters in Aglaonema commutatum: K+, Ca2+, Mg2+ and Na+

Abstract

This trial was carried out to establish an appropriate nutrient solution for Aglaonema commutatum and to investigate the nutritional effects generated by modifications in the solution. Six treatments were tested: control (T₀; pH 6.5, E.C. 1.5 dS m^?1, 6 mmol L^?1 NO₃ ^?‐N, and 6 mmol L^?1 K⁺); high nitrogen (N) level (T₁; 9 mmol L^?1 6:3 NO₃ ^?–NH₄ ⁺); N form (T₂; 6 mmol L^?1 N‐NH₄ ⁺); high K⁺ level (T₃; 12 mmol L^?1 K⁺); high electrical conductivity (T₄; E.C. 4 dS m^?1, 25 mmol L^?1 NaCl), and basic pH (T₅; pH 8). At the end of the cultivation, leaf, shoot, and root dry weights and elemental concentrations were determined. Nutrient contents and total plant uptake were calculated from the dry weights and nutrient concentrations. Plant K⁺ uptake increased with application of K⁺ or basic nutrient solution. The uptake and transport of calcium (Ca) were enhanced by the use of NO₃ ^?‐N and inhibited by the presence of other cations in the medium (NH₄ ⁺, K⁺, Na⁺) and by basic pH. Magnesium (Mg) uptake increased with NO₃ ^?‐N application and with pH. Sodium (Na) uptake was the highest in the saline treatment (T₄), followed by the basic pH treatment. Sodium accumulation was detected in the roots (natrophobic plant), where the plant generated a physiological barrier to avoid damage. Dry weight did not differ significantly (p<0.05) among treatments except in the NaCl treatment. These results may help in the formulation of nutrient solutions that take into account the ionic composition of irrigation water and the physiological requirements of plants.     

Growth Response and Selenium and Boron Distribution in Broccoli Varieties Irrigated with Poor Quality Water

Abstract

Selenium (Se), and boron (B), and salinity contamination of agricultural drainage water is potentially hazardous for water reuse strategies in central California. This greenhouse study assessed tolerance and Se, B, and chloride (Cl^?) accumulation in different varieties (Emerald City, Samurai, Greenbelt, Marathon) of broccoli (Brassica oleracea L.) irrigated with water of the following different qualities: (1) non‐saline [electrical conductivity (EC) of <1 dS m^?1]; (2) Cl^?/sulfate salinity of ～5 dS m^?1, 250 µg Se L^?1, and 5 mg B L^?1; and (3) non‐saline and 250 µg Se L^?1. One hundred and ten days after transplanting, plants were harvested and dry weight (DW) yields and plant accumulation of Se, B, and Cl^? was evaluated in floret, leaf, and stem. Irrespective of treatments floret yields from var. Samurai were the lowest among all varieties, while floret yields from var. Marathon was the only variety to exhibit some sensitivity to treatments. For all varieties, plant Se concentrations were greatest in the floret (up to 51 mg kg^?1 DW) irrespective of treatment, and B and Cl^? concentrations were greatest in the leaves; 110 mg B kg^?1 DW and 5.4% Cl^?, respectively. At post harvest, treatment 2 (with salinity, B, and Se) increased soil salinity to almost 6 dS m^?1, total Se concentrations to a high of 0.64 mg kg^?1 DW soil, and water soluble B concentrations to a high of 2.3 mg B L^?1; soluble Se concentrations were insignificant. The results indicate that var. Emerald City, Greenbelt, and Marathon should be considered as recipients of moderately saline effluent enriched with Se and B under field conditions.     

Assessment of salinity tolerance threshold for two wheat genotypes in response to zinc

Plants’ tolerance to salt stress is different among species, nevertheless, mineral nutrition might also affect it. A greenhouse experiment was conducted to evaluate the effect of Zinc (Zn) on salinity tolerance using a sigmoid response model in two wheat (Triticum aestivum L.) genotypes ‘Falat’ and ‘Bam’ with different salinity tolerances. The treatments consisted of three Zn rates (0, 5 and 10 mg Zn kg^?1) and five levels of soil salinity (1.1, 6.5, 12.3, 18.7 and 25.1 dS m^?1). The results showed that dry weight of straw and grain decreased, as salinity increased in both genotypes although this decrease in ‘Falat’ genotype was higher than that of ‘Bam’ genotype. Application of 10 mg kg^?1 Zn increased the dry weight by 25% (straw) and 32% (grain) in ‘Falat’ but 67% (straw) and 60% (grain) in ‘Bam’ as compared with the absence of added Zn. According to the fitted function, in the absence of Zn, grain production began to decline at EC_e-values of 4.7 dS m^?1 in ‘Falat’ genotype, and 7.5 dS m^?1 in ‘Bam’ genotype. Application of Zn led to a decrease of salinity tolerance in ‘Falat’ genotype, but an increase in ‘Bam’ genotype. The study found that Zn application under saline conditions, depending on genetic differences of wheat genotypes, would have different effects on their tolerance to salinity.     

Calibration of Gypsum Blocks for Measuring Saline Soils Moisture

The proper management of irrigation requires an accurate measuring of soil moisture. One of the commonly applied methods for measuring soil moisture is the use of gypsum blocks – a method that is simple and quick to apply. However, measuring moisture in saline soils using this method is prone to errors due to the effect of soil salinity on the block. In this study, the effect of different salinities (1, 2, 6, 10, and 18 deci Siemens per meter (dS m^?1) on the measurements of a gypsum block type 5910 A was investigated with two repetitions in random blocks in sandy loam, loam, and clay loam soils, and corrective functions were obtained using multivariate regression for all soils with different salinity levels. The results showed different trends for measuring the soil moistures for salinities 1–6 dS m^?1 compared with salinities 10–18 dS m^?1, and the corrective functions in salinities 1–6 dS m^?1, which had higher accuracies than those with salinities 10–18 dS m^?1.     

RESPONSE OF ORNAMENTAL SUNFLOWER CULTIVARS ‘SUNBEAM’ AND ‘MOONBRIGHT’ TO IRRIGATION WITH SALINE WASTEWATERS

To explore the possibility that saline wastewaters may be used to grow commercially acceptable floriculture crops, a study was initiated to determine the effects of salinity on two pollen-free cultivars of ornamental sunflower (Helianthus annuus L.). ‘Moonbright’ and ‘Sunbeam’ were grown in greenhouse sand cultures irrigated with waters prepared to simulate wastewaters commonly present in two inland valley regions of California: 1) San Joaquin Valley (SJV) where saline-sodic drainage waters are dominated by sodium (Na⁺) and sulfate (SO ^2? ₄ ) and 2) Coachella Valley (CV) where major ions in tailwaters are Na⁺, chloride (Cl^?), SO ^2? ₄ , magnesium (Mg²⁺), calcium (Ca²⁺), predominating in that order. Ten-day-old seedlings were subjected to five salinity treatments of each water composition, each replicated three times. Electrical conductivities (EC) of the irrigation waters were 2.5, 5, 10, 15, and 20 dS·m^?1. Flowering stems were harvested when about 75% of the ray flowers were nearly horizontal. Stem length and fresh weight, flower and stem diameter were measured. Mineral ion concentrations in upper and lower stems, upper and lower leaves were determined. Sodium was excluded from the young tissues in the upper portions of the shoot and retained in the basal stem tissue. Inasmuch as sunflower is also a strong potassium (K)-accumulator, K⁺/Na⁺ selectivity coefficients were unusually high in the younger shoot organs. Despite a five-fold increase in substrate Ca²⁺ in both solutions, shoot-Ca decreased as salinity increased and this cation was retained in the older leaves. A few of the lower leaves of plants irrigated with ICV waters at EC = 10 dS·m^?1 and higher, exhibited necrotic margins which were undoubtedly caused by high concentrations of Cl^? in the tissues. Flowering stems produced in all treatments met florist quality standards in terms of diameters for stems (0.5 to 1.5 cm) and blooms (8 to 15 cm). Across treatments, stem lengths ranged from 60 to 175 cm. Both ornamental sunflower cultivars proved to be good candidates for production of marketable flowering stems using moderately saline wastewaters.     

Effect of drip irrigation and mulches on physiological parameters,soil temperature,picking patterns and yield in capsicum (Capsicum annuum L.)

Water and temperature are critical for producing vegetable crops, especially during winter, when the availability of water is meager and temperature falls. Studies of drip irrigation and mulch were undertaken to find the effect on different growth and yield parameters in pepper (Capsicum annuum L.). The experiment was laid out in a split-plot design with four main and four subplots. Irrigation levels were placed on main plots and mulches on subplots with three replicates for each. All recorded vegetative parameters were higher with drip irrigation at 1.0 pan evaporation (Epan) and black polythene mulch. Physiological parameters such as photosynthesis rate (18.01 and 17.45 μmol m^?2 s^?1), transpiration rate (6.19 and 5.86 mmol H₂O m^?2 s^?1) and chlorophyll content (27.34 and 28.39; 39.22 and 41.27 SPAD, respectively at 50 and 100 days after planting) were maximal in crops with drip irrigation at 1.0 Epan and mulched with black polythene. Soil and canopy temperature were significantly higher on flood irrigation at 1.0 Epan. Soil temperature was higher with the black polythene mulch, but canopy temperature was higher with no mulch. A higher level of drip irrigation and black polythene mulch result in early picking with higher yields compared with flood irrigation and no mulch.     

Variable inhibition of iron uptake by oat phytosiderophore in five soybean cultivars

Abstract

Greenhouse experiment was conducted to evaluate the effect of arbuscular mycorrhizal fungi (AMF) on plant growth, and nutrient uptake in saline soils with different salt and phosphorus (P) levels. The following treatments were included in this experiment: (i) Soil A, with salt level of 16.6 dS m^?1 and P level of 8.4 mg kg^?1; (ii) Soil B, with salt level of 6.2 dS m^?1 and P level of 17.5 mg kg^?1; and (iii) Soil C, with salt level of 2.4 dS m^?1 and P level of 6.5 mg kg^?1. Soils received no (control) or 25 mg P kg^?1 soil as triple super phosphate and were either not inoculated (control) or inoculated with a mixture of AM (AM1) and/or with Glomus intraradices (AM2). All pots were amended with 125 mg N kg^?1 soil as ammonium sulfate. Barley (Hordeum vulgar L., cv. “ACSAD 6”) was grown for five weeks. Plants grown on highly saline soils were severely affected where the dry weight was significantly lower than plants growing on moderately and low saline soils. The tiller number and the plant height were also lower under highly saline condition. The reduced plant growth under highly saline soils is mainly attributed to the negative effect of the high osmotic potential of the soil solution of the highly saline soils which tend to reduce the nutrient and water uptake as well as reduce the plant root growth. Both the application of P fertilizers and the soil inoculation with either inoculum mixture or G. intraradices increased the dry weight and the height of the plants but not the tiller number. The positive effect of P application on plant growth was similar to the effect of AM inoculation. Phosphorus concentration in the plants was higher in the mycorrhizal plant compared to the non mycorrhizal ones when P was not added. On the other hand, the addition of P increased the P concentration in the plants of the non mycorrhizal plants to as high as that of the mycorrhizal plants. Iron (Fe) and zinc (Zn) uptake increased with AM inoculation. The addition of P had a positive effect on micronutrient uptake in soil with low level of soil P, but had a negative effect in soil with high level of soil P. Micronutrient uptake decreases with increasing soil salinity level. Inoculation with AMF decreases sodium (Na) concentration in plants grown in soil of the highest salinity level but had no effect when plants were grown in soil with moderate or low salinity level. The potassium (K) concentration was not affected by any treatment while the K/Na ratio was increased by AM inoculation only when plant were grown in soil of the highest salinity level.     

Drip fertigation and irrigation interval effects on growth,productivity, nutrient,and water economy in summer peanut

ABSTRACT

The present investigation was carried out to study the effect of irrigation intervals and fertigation on growth, yield, and quality of peanut as well as an account of fertilizer and water savings under drip irrigation combined with fertigation. Pod and haulm yields and economics of peanut with application of irrigation water at I_1, i.e. 4 day interval through drip (10 day in surface irrigation) did not differ significantly compared with I_2, i.e. 6 day interval through drip (15 day in surface irrigation). However, significantly higher kernel and oil yields were obtained at I₁ and also recorded higher partial factor productivity (PFP). Our study showed that drip irrigation saved 37.2% irrigation water over surface method. Fertigation at 75% Nitrogen & potassium (NK) through drip with 75% P in soil (F₃) significantly improved pod, haulm, kernel, and oil yields by 14.3%, 11.5%, 13.9%, and 12.3%, respectively, while net returns increased by INR 13,499 ha^?1 over 50% NK through drip with 50% P in soil (F₂) and at par with others. Fertigation at 50–100% NK with 50?100% P in soil (F₂ to F₄) could save 36.4–37.3% irrigation water over F₁. Maximum PFP was recorded under F₂.

Abbreviations: N: Nitrogen; P: phosphorus; K: potassium; M: million     

Salt Tolerance of Four Potato Cultivars

Abstract

Tests are needed to evaluate the salt tolerance of new and untested potato cultivars under various cultural conditions. Two lysimeter experiments were conducted in two seasons to investigate the influence of irrigation water salinity on tuber yields of four potato (Solanum tuberosum L.) cultivars (Spunta, Alpha, Cara, and King Edward). Four salinity levels [EC_w 0.53 (control), 3.13, 6.25, and 9.38 dS m^?1] established by adding NaCI to fresh water, were used. Increasing irrigation water salinity reduced significantly total and average tuber yield for all cultivars in both seasons. Cara cultivar produced the highest tuber yield of all cultivars in both seasons. The salt tolerance curves of the potato cultivars in both seasons revealed that tolerant rating of the four cultivars can be assigned as follows: Cara > Alpha > Spunta > King Edward. The polynomial cubic equations developed for the four potato cultivars in fall and summer seasons were successful in predicting potato tuber yields response to irrigation water salinity.     

Nitrogen fertilization,irrigation, and harvest times affect biomass and energy value of Helianthus tuberosus L.

This study aimed to determine the effects of delayed harvest, irrigation and nitrogen fertilization on yield and fuel quality of the Jerusalem artichoke (JA) (Helianthus tuberosus L.). The biomass, calorific value, ash content and total calories per hectare of the Jerusalem artichoke were assessed in Inner Mongolia, China, at various harvest times, after irrigation and nitrogen application. The results showed that fresh and dry weights of tubers and underground biomass were higher when harvested after freezing; the dry yields of leaves and stems decreased with harvest time. In addition, irrigation significantly enhanced the yields of underground biomass, aboveground biomass and tubers, compared with non-irrigation conditions (p < 0.05). Interestingly, the highest yield was obtained with irrigation and treatment with nitrogenous fertilizers (20 to 50 kg ha^?1). The calorific values of tubers and roots were significantly higher for samples harvested after freezing (p < 0.05); the calorific values of leaves and stems significantly decreased with harvest time and without irrigation (p < 0.05). The calorific values of stems and leaves were higher than those of tubers and roots, when JA was harvested before freezing, and the opposite trend was obtained for harvest done after freezing. The highest calories per hectare was obtained in WN2 (585247.42 MJ ha^?1) on 30 September 2010 harvest. No correlation was found between the effects of water or nitrogenous fertilizers and ash content. However, the ash contents of stems, leafs, tubers and roots were significantly decreased (p < 0.05) with harvest time. Finally, in all treatment conditions, leaves produced the highest ash amounts among all plant parts, including stems, tubers, leaves and roots.     

Effects of Salinity and Nitrogen on Growth,Contents of Pigments,and Ion Accumulation of a Euhalophyte Suaeda Salsa in an Intertidal Zone and on Saline Inland

The different responses of two populations of Suaeda salsa (Linn.) Pall. (saline seepweed) from an intertidal zone and a saline inland zone to salinity [1 or 500 mM sodium chloride (NaCl)] and nitrogen [N; 0.05, 1, or 10 mM nitrate (NO₃ ^?)‐N] were investigated. Greater NO₃ ^?‐N supply (10 mM) increased shoot dry weight for the two populations of S. salsa, especially for S. salsa from the saline inland zone. Greater NO₃ ^?‐N supply (10 mM) increased the concentrations of chlorophyll and carotenoid in leaves and the NO₃ ^? and potassium (K⁺) concentrations in shoots for both populations. Greater NO₃ ^?‐N supply (10 mM) increased shoot Na⁺ in S. salsa from the intertidal zone. In conclusion, S. salsa from the saline inland zone is more responsive to NO₃ ^?‐N supply than the intertidal population. Greater NO₃ ^?‐N supply can help the species, especially the intertidal population, to grow and to mediate ion homeostasis under high salinity.