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1.
Abstract

Due to the discrepancy in metabolic sodium (Na) requirements between plants and animals, cycling of Na between humans and plants is limited and critical to the proper functioning of bio‐regenerative life support systems, being considered for long‐term human habitats in space (e.g., Martian bases). This study was conducted to determine the effects of limited potassium (K) on growth, Na uptake, photosynthesis, ionic partitioning, and water relations of red‐beet (Beta vulgaris L. ssp. vulgaris) under moderate Na‐saline conditions. Two cultivars, Klein Bol, and Ruby Queen were grown for 42 days in a growth chamber using a re‐circulating nutrient film technique where the supplied K levels were 5.0, 1.25, 0.25, and 0.10 mM in a modified half‐strength Hoagland solution salinized with 50 mM NaCl. Reducing K levels from 5.0 to 0.10 mM quadrupled the Na uptake, and lamina Na levels reached ‐20 g kg?1 dwt. Lamina K levels decreased from ‐60 g kg?1 dwt at 5.0 mM K to ‐4.0 g kg?1 dwt at 0.10 mM K. Ruby Queen and Klein Bol responded differently to these changes in Na and K status. Klein Bol showed a linear decline in dry matter production with a decrease in available K, whereas for cv. Ruby Queen, growth was stimulated at 1.25 mM K and relatively insensitive to a further decreases of K down to 0.10 mM. Leaf glycinebetaine levels showed no significant response to the changing K treatments. Leaf relative water content and osmotic potential were significantly higher for both cultivars at low‐K treatments. Leaf chlorophyll levels were significantly decreased at low‐K treatments, but leaf photosynthetic rates showed no significant difference. No substantial changes were observed in the total cation concentration of plant tissues despite major shifts in the relative Na and K uptake at various K levels. Sodium accounted for 90% of the total cation uptake at the low K levels, and thus Na was likely replacing K in osmotic functions without negatively affecting the plant water status, or growth. Our results also suggest that cv. Ruby Queen can tolerate a much higher Na tissue concentration than cv. Klein Bol before there is any growth reduction.  相似文献   

2.
Due to the discrepancy in metabolic sodium (Na) requirements between plants and animals, cycling of Na between humans and plants is limited and critical to the proper functioning of bio-regenerative life support systems, being considered for long-term human habitats in space (e.g., Martian bases). This study was conducted to determine the effects of limited potassium (K) on growth, Na uptake, photosynthesis, ionic partitioning, and water relations of red-beet (Beta vulgaris L. ssp. vulgaris) under moderate Na-saline conditions. Two cultivars, Klein Bol, and Ruby Queen were grown for 42 days in a growth chamber using a re-circulating nutrient film technique where the supplied K levels were 5.0, 1.25, 0.25, and 0.10 mM in a modified half-strength Hoagland solution salinized with 50 mM NaCl. Reducing K levels from 5.0 to 0.10 mM quadrupled the Na uptake, and lamina Na levels reached -20 g kg-1 dwt. Lamina K levels decreased from -60 g kg-1 dwt at 5.0 mM K to -4.0 g kg-1 dwt at 0.10 mM K. Ruby Queen and Klein Bol responded differently to these changes in Na and K status. Klein Bol showed a linear decline in dry matter production with a decrease in available K, whereas for cv. Ruby Queen, growth was stimulated at 1.25 mM K and relatively insensitive to a further decreases of K down to 0.10 mM. Leaf glycinebetaine levels showed no significant response to the changing K treatments. Leaf relative water content and osmotic potential were significantly higher for both cultivars at low-K treatments. Leaf chlorophyll levels were significantly decreased at low-K treatments, but leaf photosynthetic rates showed no significant difference. No substantial changes were observed in the total cation concentration of plant tissues despite major shifts in the relative Na and K uptake at various K levels. Sodium accounted for 90% of the total cation uptake at the low K levels, and thus Na was likely replacing K in osmotic functions without negatively affecting the plant water status, or growth. Our results also suggest that cv. Ruby Queen can tolerate a much higher Na tissue concentration than cv. Klein Bol before there is any growth reduction. Grant numbers: 12180.  相似文献   

3.
Cell saps from leaves, petioles and storage root of sugar beet plants were analysed to indicate the possible specific and/or non-specific (osmotic) function of K and Na ions for the regulation of assimilate partitioning in sugar beet. Plants were cultivated up to 94 days in nutrient solutions containing either 4.5 mol m?3 K + 0.5 mol m?3 Na (K plants) or 0.5 mol m?3 K + 4.5 mol m?3 Na (Na plants) or 0.5 mol m?3 K + 0.5 mol m?3 Na (control). Osmotic potentials of the cell sap of leaf blades (?1.4 to ?1.6 MPa) and petioles (?1.6 to ?2.0 MPa), respectively, were rather low and similar. It was concluded that in these organs Na may replace K in its osmoregulatory functions. While shoot growth was favoured by Na, a principally improved translocation of K into the taproot was noted. This was - especially in the K-treatment - associated with increased growth of the storage root and a simultaneously stimulated sucrose accumulation. The results are discussed in terms of a different compartmentation of K, Na and Cl within the cell and within the whole plant and of a specific role of potassium in the process of assimilate translocation and storage.  相似文献   

4.
Alluvial soils with illite and vermiculite clay minerals are highly potassium (K)‐fixing. Such soils have been reported to require a huge amount of K fertilization for optimum plant growth. For halophytic plants such as sugar beet, sodium (Na) can be an alternative to K under such conditions. This study was conducted to investigate the possible substitution of K by Na fertilization with reference to K‐fixing soils. Three soils, i.e., Kleinlinden (subsoil), Giessen (alluvial), and Trebur (alluvial), differing in K‐fixing capacities, were selected, and sugar beet plants were grown in Ahr pots with 15 kg soil pot–1. Three treatments (no K and Na, K equal to K‐fixing capacity of soil, and Na equivalent to regular K fertilization) were applied. In a second experiment, containers (90 cm × 40 cm × 40 cm) were used with 170 kg Kleinlinden soil each, and one sugar beet plant per container was grown. In both experiments, plants were grown till beet maturity, and beets were analyzed for sucrose concentration and other quality parameters such as α‐amino nitrogen to calculate white‐sugar yield with the New Brunswick formula. The results showed that growth and quality of sugar beet were not affected by Na application, and ultimately there was no decrease in white‐sugar yield. Moreover, the soils with more K‐fixing capacity were more suitable for K substitution by Na. It is concluded that Na can substitute K in sugar beet nutrition to a high degree and soils with high K‐fixing capacity have more potential for this substitution.  相似文献   

5.
Experiments were conducted in two consecutive years in a multilayered plastic-covered greenhouse, of the “raspa and amagado” (covered skeleton structure) types in the fields of Almeria (south-eastern Spain), to evaluate the production and quality of a triploid watermelon crop (Citrullus lanatus Thunb) cv. ‘Queen of Hearts’ grafted onto the (Cucurbita maxima x Cucurbita moschata) squash hybrid cv. ‘Strongtosa’. A 2.5% solution of the monosilicic acid [Si(OH)4] product was applied to this crop in the drip irrigation system at a dose of 260 mL·ha?1 in both experiments. Results showed that the product did not influence productive parameters in terms of kg of product·m?2, kg plant?1, or number of fruits plant?1. Nevertheless the monosilicic acid [Si(OH)4] product appeared to have a positive effect on some quality aspects of the fruit with an approximate 10% increase in pulp consistency and rind width.  相似文献   

6.
Physiological responses to salt stress were investigated in two cotton (Gossypium hirsutum L.) cultivars (Pora and Guazuncho) grown hydroponically under various concentrations of NaCl. Dry matter partitioning, plant water relations, mineral composition and proline content were studied. Proline and inorganic solutes were measured to determine their relative contribution to osmotic adjustment. Both leaf water potential (Ψw) and osmotic potential (Ψs)decreased in response to NaCl levels. Although Ψwand Ψs decreased during salt stress, pressure potential Ψp remained between 0.5 to 0.7 MPa in control and all NaCl treatments, even under 200 mol m?3 NaCl. Increased NaCl levels resulted in a significant decrease in root, shoot and leaf growth biomass. Root / shoot ratio increased in response to salt stress. The responses of both cultivars to NaCl stress were similar. Increasing salinity levels increased plant Na+ and Cl?. Potassium level remained stable in the leaves and decreased in the roots with increasing salinity. Salinity decreased Ca2+ and Mg2+ concentrations in leaves but did not affect the root levels of these nutrients. The K/Na selectivity ratio was much greater in the saline treated plants than in the control plants. Osmotic adjustment of roots and leaves was predominantly due to Na+ and Cl? accumulation; the contribution of proline to the osmotic adjustment seemed to be less important in these cotton cultivars.  相似文献   

7.
We observed that the growth of three Amaranthaceae species was promoted by sodium (Na), in the order dwarf glasswort (Salicornia bigelovii Torr.) >> Swiss chard (Beta Burgaris L. spp. cicla cv. Seiyou Shirokuki) > table beet (Beta vulgaris L. spp. vulgaris cv. Detroit Dark Red). In the present study, these Na-loving plants were grown in solutions containing 4 mol m?3 nitrate nitrogen (NO3-N) and 100 mol m?3 sodium chloride (NaCl) and potassium chloride (KCl) under six Na to potassium (K) ratios, 0:100, 20:80, 40:60, 60:40, 80:20 and 100:0, to elucidate the function of Na and K on specific characteristics of Na-loving plants. The growth of dwarf glasswort increased with increasing Na concentration of the shoot, and the shoot dry weight of plants grown in 100:0 Na:K was 214% that of plants grown at 0:100. In Swiss chard and table beet, growth was unchanged by the external ratio of Na to K. The water content was not changed in Swiss chard or table beet by the external Na to K ratio. These observations indicate that both Na and K have a function in osmotic regulation. However, dwarf glasswort could not maintain succulence at 0:100; therefore, Na has a specific function in dwarf glasswort for osmotic regulation to maintain a favorable water status, and the contribution of K to osmotic regulation is low. NO3-N uptake was promoted by Na uptake in dwarf glasswort and Swiss chard. NO3-N uptake and transport to shoots was optimal at 100:0 in dwarf glasswort and at 80:20 in Swiss chard. These functions are very important for the Na-loving mechanism, and the contribution of K was lower in dwarf glasswort than in Swiss chard.  相似文献   

8.
Field experiments were conducted in 2002–03 and 2003–04 growing seasons to determine wheat response to four irrigation regimes applied at different growth stages and four nitrogen levels of 0, 50, 100, and 150 kg nitrogen (N) ha?1. The experiment was conducted at the research area of the Department of Crop Physiology, University of Agriculture, Faisalabad, Pakistan. Recommended wheat variety “Inqlab-91” was used as the experimental crop. Both irrigation and nitrogen application have positive effects on grain yield increase. The grain crude protein decreased with increasing number of irrigations whereas in contrast, nitrogen application significantly improved grain crude protein at all irrigation levels. Grain phosphorus (P) and potassium (K) percentage increased with the application of irrigation and nitrogen. Grain yield, number of spikes m?2, grains spike?1 and grain weight responses were greater at the higher N rates. Mean grain yield in four, three and two irrigation treatments compared with that in one irrigation treatment increased 47, 23, and 9% during 2002–03 and 91, 84, and 23% in 2003–04, respectively. Water deficit reduced spikes m?2. In both years, the average reduction in spikes m?2 at maximum irrigation deficit (one irrigation) at all N levels was 24%. Similar reduction occurred in grains spike?1 where water deficit decreased this component on an average of 36%.  相似文献   

9.
The amaranthaceous dwarf glasswort, Swiss chard, table beet, spinach and Mexican tea were grown in solutions containing 0, 20, 40, 80, 120, 160, 180 and 200 mol m?3 sodium chloride (NaCl). Maximum growth and increase of biomass production compared to that at 0 mol m?3 of dwarf glasswort was observed at 200 mol m?3 (245%), and Swiss chard (146%), table beet (128%) and spinach (138%) at 80 mol m?3. The growth of these species increased with increasing sodium (Na) concentration of shoot until it reached 4.18, 2.42, 1.60 and 1.58 mol kg?1, respectively. These indicate that the order of Na-loving character is dwarf glasswort >> Swiss chard > table beet = spinach. The water contents increased with increasing Na concentration until growth reached maximum in dwarf glasswort and Swiss chard. In these highly Na-loving species, Na is activity transported to shoots and utilized for producing osmotic pressure to absorb water.  相似文献   

10.
The effects of four salinity levels [0, 1000, 2000, and 3000 mg sodium chloride (NaCl) kg?1 soil] and three zinc (Zn) levels [0, 5, and 10 mg kg?1 soil as zinc sulfate (ZnSO4.7 H2O)] on growth and chemical composition of pistachio seedlings (Pistacia vera L.) cv. ‘Badami’ were studied in a calcareous soil under greenhouse conditions in a completely randomized design with three replications. After 26 weeks, the dry weights of leaves, stems and roots were measured and the total leaf area determined. Salinity decreased leaf, stem, and root dry weights and leaf area, while this effect diminished with increasing Zn levels. Zn fertilization increased leaf, stem and root Zn concentrations, leaf potassium (K) concentration, and stem and root sodium (Na) concentrations, while decreased leaf Na concentration, and stem and root K concentrations. Salinity stress decreased leaf, stem, and root Zn concentrations, and leaf K concentration, while salinity increased leaf, stem and root Na concentrations, and stem and root K concentrations. Proline accumulation increased with increasing salinity levels, whereas the reverse trend was observed for reducing sugar contents. Zn application decreased proline concentration but increased reducing sugar contents. These changes might have alleviated the adverse effects of salinity stress.  相似文献   

11.
The effect of increasing manganese (Mn) concentrations on calcium (Ca), potassium (K), magnesium (Mg), sodium (Na), and phosphorus (P) absorption and translocation was studied in rice (Oryza sativa L. cv. Safari), before and after the end of mobilization of seed reserves. Rice plants were grown over a 15-, 21-, and 28-day period in nutrient solutions containing Mn concentrations varying between 0.125 and 32 mg L?1. It was found that increasing Mn concentrations in the nutrient solution was coupled to an increasing net uptake, total shoot accumulation, and root and shoot contents of this metal during all the experimental periods. Concerning the translocation rates, in 15-day-old plants a decrease was found after the 2 mg L?1 Mn treatment, but from the 21st day onward an increase was found until the highest treatment. The modulating action of Mn in macronutrient accumulation displayed different patterns among the experimental periods. In the root tissues of 15-day-old plants, Ca decreased significantly until the 2 mg L?1 treatment and Na increased. In the shoots, the contents of P and Na decreased, but K and Mg showed significant increases. Until the 32 mg L?1 Mn treatment, the ratio between root and shoot concentrations of K and Mg decreased in these plants. A similar pattern was also found for Ca until the 2 mg L?1 Mn treatment. That ratio increased for Na. Plant total amount of Ca sharply decreased. Shoot total amount of Na and P also decreased, but the pattern of Ca increased until the 2 mg L?1 Mn treatment. The concentrations of K increased in the root tissues 21 days after germination, but the levels of Ca, Mg, Na, and P decreased. In the shoots, the concentrations of Ca and Mg decreased significantly. Until the 32 mg L?1 Mn treatment, the ratio between root and shoot concentration of Na and P increased, whereas those of Ca and Mg decreased. An increase was found for the plant and shoot total amount of Ca, K, and Mg until the last Mn treatment, but an opposite trend was found for Na and P. Additionally, until the 32 mg L?1 Mn treatment, an increase was found for the proportions of Ca and Mg translocated to the shoot, but an opposite trend was detected for P. It was concluded that before and after the end of the mobilization of seed reserves, the net uptake rate of Ca is reversed, and, moreover, a similar trend is shown for the net translocation of Mg. A major implication of this process is the alteration of the related pattern for shoot accumulation. Eventually a different selectivity of the K+:Na+ ratio is also developed in the roots.  相似文献   

12.
In order to investigate the effect of nitrogen (N) and sulfur (S) fertilizers on yield and seed quality of three canola cultivars, a factorial based on randomized complete block experiment was conducted during 2005–2006 in Iran. Treatments included four nitrogen rates (0, 75, 150, and 225 kg N ha?1 source of urea), four sulfur rates (0, 100, 200, and 300 kg S ha?1), and three cultivars (‘Pf’, ‘Option-500’, and ‘Hyola-401’). Results indicated cultivar had a significant effect on all studied traits. ‘Option-500’ and ‘Hyola-401’ cultivars had the highest seed yield, protein content, and N:S ratio in seed. The levels of 150 and 220 kg N ha?1 resulted in the maximum protein content. Increasing N levels resulted in N content and decreased the oil content. The interaction effect between S and N levels showed the highest N content in seed was obtained with 300 kg S ha?1 and 225 kg N ha?1.  相似文献   

13.
The self-diffusion coefficients of Cl, Na, Sr and phosphate have been measured in Upper Greensand, sandy clay loam (CEC 7.45 me/100 g.) between pF 1.8 and 5.4 and, for Na and phosphate, over a range of soil-solution concentrations. An attempt has been made to estimate the relative contributions of solution- and exchangeable-ions to diffusion. There is some indication that exchangeable Na may contribute to diffusion at the lowest moisture contents used, but little indication of this at pF 2.1 (15 per cent moisture content) when the proportion of ions on the solid was as high as possible. Exchangeable Sr appears to make no significant contribution to diffusion at any moisture content when the soil-solution concentration is 0.1M. Exchangeable phosphate appears to make no contribution to diffusion at pF 2.1 between 5 × 10?6M and 9 × 10?4M.  相似文献   

14.
Field screening of 83 groundnut cultivars was undertaken for two seasons to assess their tolerance of salinity based on plant mortality and yield attributes. During the dry season, soil salinity of 4 dS m?1 at sowing and 6–7 dS m?1 21–98 days after sowing (DAS) caused high mortality without seed formation in any cultivars, however, at salinity 4.5 dS m?1 during sowing and 3.5–3.0 dS m?1 15–80 DAS during wet season, 61 cultivars produced seed. The cultivars ‘VRI 3’, ‘UF 70–103’, ‘TKG 19A’, ‘S 206’, ‘Tirupati 4’, ‘M 522’, ‘Punjab 1’, ‘BG 3’, ‘Somnath’ and ‘ICGV 86590’, with high plant stand during both the seasons and over 75 g m?2 seed yield during wet season, were identified salinity tolerant. However, 15 cultivars with more than 50 g m?2 seed yield were moderately tolerant and 28 cultivars with less than 25 g m?2 seed yield were sensitive to salinity.  相似文献   

15.
Field studies were conducted to assess boron (B) requirement, critical concentrations in diagnostic parts based on yield response curves and genotypic variation by growing three peanut (Arachis hypogaea L.) cultivars (‘Golden’, ‘BARD-479’, ‘BARI-2000’) on two B-deficient calcareous soils. Boron application significantly increased pod yield of all the cultivars over control. Maximum pod yield increases were: ‘Golden’, 16?23%; ‘BARD-479’, 21?27%; and ‘BARI-2000’, 25?31%. The cultivars varied in B efficiency and cv. ‘Golden’ was the most B efficient (81?86%) while cv. ‘BARI-2000’ was the least efficient (76?80%). Boron requirements for near-maximum (95%) dry pod yield were 0.65 kg ha?1 for ‘Golden’, 0.75 kg ha?1 for BARD-479 and 0.80 kg ha?1 for BARI-2000. Critical B concentrations in shoots and seeds were: ‘Golden’, 33 mg kg?1 and 26 mg kg?1; ‘BARD-479’, 38 mg kg?1 and 31 mg kg?1; and ‘BARI-2000’, 42 mg kg?1 and 33 mg kg?1.  相似文献   

16.
《Journal of plant nutrition》2013,36(10):1535-1550
Variations of nitrogen and phosphorus levels in reproductive shoots and their leaves of self-rooting olive (Olea europaea) cultivars ‘Amfissis’ (A), ‘Kalamon’ (K), ‘Manzanillo’ (M), and ‘Chalkidikis’ (C) were monitored from the end of harvest until the emergence of the inflorescences. This 90-days period was divided into three sub-periods: before (pre-BD), during (BD), and after (post-BD) bud differentiation. The nitrogen (N)-content in leaves of the reproductive shoots varied between 10–20 mg g?1 and among cultivars the order of decreasing concentration levels was C > K > A > M. The N-content in reproductive shoots varied between 6–14 mg g?1 (K > A > C > M). Patterns of time-course variations are presented. Partitioning of N between leaves and shoots (NL:NS) varied with time, with a ratio between 1.5–2. The fluctuations in the NL:NS ratio over the 90 days showed two distinct phases: during pre-BD either increased (‘Amfissis’ and ‘Chalkidikis’) or remained relatively constant (‘Kalamon’ and ‘Manzanillo’), while during BD and post-BD decreased in all cultivars. The order of decreasing NL:NS ratio among cultivars was K > C > M > A.

Phosphorus (P) content in leaves of the reproductive shoots varied between 0.1–2.5 mg g?1, (A > C > K > M). Phosphorus content in reproductive shoots varied between 0.2–1.6 mg g?1, with the highest levels in ‘Amfissis’ compared to the other cultivars. Patterns of P partitioning between leaves and shoots were similar in all cultivars. The PL:PS ratio varied between 0.9–2 (A > C > K > M).

The N:P ratio varied between 5:1–20:1 in reproductive shoots and 10:1–35:1 in their leaves, increasing over the examined period. The increase rate of the N:P ratio varied between the three sub-periods, the lowest rate being during BD. The pattern of changes in the N:P ratio was similar in both leaves and shoots and an increase of N:P ratio in leaves was highly correlated with the corresponding increase of N:P in shoots.  相似文献   

17.
田间矿化水灌溉下小麦和甜菜的离子区隔化   总被引：2，自引：0，他引：2  
通过田间灌溉试验,研究了矿化水灌溉下小麦和甜菜对离子的选择吸收及其区隔化.随着灌溉水中NaCl含量的增加,小麦茎、鞘、叶、颖的离子吸收的选择系数SK,Na逐渐降低,而根和籽粒的SK, Na逐渐增加.小麦和甜菜各器官的离子吸收的选择系数SCl、Na都随灌溉水中NaCl含量的增加而逐渐降低.小麦地上部各器官的SK, Na;SCl, Na都大于根;而甜菜叶的SK, Na大于根, SCl , Na在二者之中的差异不大,由于K+的再转移和分配,甜菜枯叶的Na/K大于叶.小麦和甜菜对离子的选择吸收和运输使Na 和Cl主要分布于对生长和产量影响最小的部分,即小麦的茎和鞘,甜菜的枯叶.  相似文献   

18.
Salinity and sodicity are prime threats to land resources resulting in huge economic and associated social consequences in several countries. Nutrient deficiencies reduce crop productivity in salt‐affected regions. Soil fertility has not been sustainably managed in salt‐affected arid regions. Few researchers investigated the crop responses to phosphorus and potassium interactions especially in saline–sodic soils. A research study was carried out to explore the effect of diammonium phosphorus (DAP) and potassium sulphate (K2SO4) on sugar beet (Beta vulgaris L.) grown in a saline–sodic field located in Kohat district of Pakistan. The crop was irrigated with ground water with ECiw value of 2.17–3.0 dS/m. Three levels each of K2O (0, 75 and 150 kg/ha) as K2SO4 and P2O5 (0, 60 and 120 kg/ha) as DAP were applied. The application of P significantly affected fresh beet and shoot yield while K fertilizers had significant effect on fresh beet yield and ratio of beet:shoot, while non‐significant effects on the fresh shoot were observed. The application of K1 and K2 promoted sugar beet shoot yield by 49.2 and 49.2% at P1 and 64.4 and 59.7% at P2, respectively over controls. In comparison with controls, fresh beet yield was increased (%) by 15 and 51, 45 and 84, and 50 and 58 for corresponding K1 and K2 at P0, P1 and P2, respectively. Addition of P1 and P2 increased beet yield by 37 and 47% over control. The shoot [P] (mmol/kg) were achieved as 55.2, 73.6 and 84.3 at P0, P1 and P2, respectively. The shoot [Mg] and [SO4] tended to decrease with increasing P levels, while [SO4] was markedly reduced at P2. The effect of P on leaf [Na] was non‐significant, but increasing levels of K decreased [Na] substantially at P0 and P1, but there was no difference in the effect of K level on [Na] at P2. Consequently, K application reduced leaf Na:K ratios. Fresh shoot yield was weakly associated with leaf [P] (R2 = 0.53). The leaf Na:K ratio showed a negative relationship (R2 = 0.90) with leaf [K]. A strongly positive relationship (R2 = 0.75) was observed between leaf [K] and fresh beet yield. The addition of K2SO4 also enhanced [SO4] and SO4:P ratios in leaf tissues. The ratio of Na:K in the shoot decreased with increasing K application. These results demonstrated that interactions of K and P could mitigate the adverse effects of salinity and sodicity in soils. This would contribute to the efficient management of soil fertility system in arid‐climate agriculture.  相似文献   

19.
A two-year field study was conducted to determine the effect of two zinc (Zn) levels [0 and 10 kg zinc sulfate (ZnSO4) ha?1] in respect with four potassium (K) levels (0, 20, 40 and 60 kg K2O ha?1) on growth, yield and quality of forage sorghum. The soil of the experimental field was loamy sand (Inceptisol), carrying 70, 08, 77, and 0.51 mg nitrogen (N), phosphorus (P), K, and Zn kg?1 soil, respectively. Increasing K levels significantly improved most of the growth, yield, and quality attributes gradually irrespective of the Zn levels. Zinc applied at 10 kg ZnSO4 ha?1 proved significantly better than no zinc application at various K application rates. The benefit of zinc application increased progressively with increasing K rates for most of the parameters studied, indicating significant response of the crop to positive K × Zn interaction in plants in respect with K and Zn application to the soil. Accordingly, 60 kg K2O ha?1 applied with10 kg ZnSO4 ha?1 boosted most of the attributes maximally. It resulted in about 20–40% increase in growth attributes, 25% increase in fresh matter yield, 36–38% increase in dry matter yield, and 38% increase in protein yield compared to the comparable K level applied without zinc. It also enhanced N uptake by 38%, P uptake by 5–19%, K uptake by 40–42%, and Zn uptake by 114–144%. Across the K rates, application of 10 kg ZnSO4 surpassed no zinc application by 30–35% in N uptake, by 8–15% in P uptake, by 33–36% in K uptake, by 120–140% in Zn uptake, by 19–21% in fresh matter yield, by 29–31% in dry matter yield, and by 30–34% in protein yield.  相似文献   

20.
To determine the effects of irrigation water quality, plants were irrigated with normal potable water [0.25 dS m?1 electrical conductivity (EC), 25 mg L?1 sodium (Na), 55 mg L?1 chloride (Cl)], treated effluent (0.94 dS m?1 EC, 122 mg L?1 Na, 143 mg L?1 Cl) and saline water with low salinity (1.24 dS m?1 EC, 144 mg L?1 Na and 358 mg L?1 Cl) and high salinity (2.19 dS m?1 EC, 264 mg L ?1Na and 662 mg L?1 Cl) for snow peas, and high salinity (3.07 dS m?1 EC, 383 mg L?1 Na and 965 mg L?1 Cl) and very high salinity (5.83 dS m?1 EC, 741 mg L?1 Na and 1876 mg L?1 Cl) for celery. The greater salts build up in the soil and ion toxicity (Cl and Na) with saline water irrigation contributed to significantly greater reduction in root and shoot biomass, water use, yield and water productivity (yield kg kL?1 of water used) of snow peas and celery compared with treated effluent and potable water irrigation. There was 8%, 56% and 74% reduction in celery yield respectively with treated effluent, high salinity and very high salinity saline water irrigation compared with potable water irrigation. The Na concentration in snow peas shoots increased by 54%, 234% and 501% with treated effluent, low and high salinity saline water irrigation. Similarly, the increases in Na concentration in celery shoots were 19%, 35% and 82%. The treated effluent irrigation also resulted in a significant increase in soil EC, nitrogen (N) and phosphorus (P) content compared with potable water irrigation. The heavy metals besides salts build up appears to have contributed to yield reductions with treated effluent irrigation. The study reveals strong implications for the use of saline water and treated effluent for irrigation of snow peas and celery. The salt build up within the root zone and soil environment would be critical in the long-run with the use of saline water and treated effluent for irrigation of crops. To minimize the salinity level in rhizosphere, an alternate irrigation of potable water with treated effluent or low salinity level water may be better option.  相似文献   

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