Requirement of rice crop for phosphorus and potassium at varying sodicity levels

Qadar, Ali

doi:10.1080/01904169509365065

Cited by 9 publications

(6 citation statements)

References 7 publications

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“…Tillering was not only faster in plants grown in normal soil (pH 8.0), but maximum number of tillers was achieved 10 and 16 days earlier than in plants at pH 9.7 and 9.9, respectively (data not included). This agreed with earlier findings of sodicity effects on delayed initiation of tillering and production of total tillers in rice (Qadar, 1995b). However, a significant difference in the final total number of tillers was found only at pH 9.9 (Table 3).…”

Section: Resultssupporting

confidence: 94%

“…This showed that yield and yield attributes (fertile tillers, total number of spikelets, and filled grain per panicle) are more sensitive to sodicity stress compared to total number of tillers and shoot dry weight. This is in agreement with earlier observations where yield showed higher sensitivity to sodicity (Qadar, 1995b). Phosphorus fertilization, up to 0.4 kg hm −2 , significantly improved total shoot dry weight (Table 3).…”

Section: Resultssupporting

confidence: 93%

“…To these soils, P was mixed at the rate of 0.2, 0.4, 0.6, and 0.8 kg hm −2 using single super phosphate and these treatments were referred to as P0.2, P0.4, P0.6, and P0.8, respectively. Only a single dose (0.6 kg hm −2 ) of K was applied as muriate of potash, as it was not very effective in alleviating the adverse effects of sodicity on rice in earlier studies (Qadar, 1995b(Qadar, , 1998. Also, the present study was targeted to determine the adequate level of Olsen's P for CSR 10 at each sodicity level and K fertilization would ensure that plants did not become K deficient.…”

Section: Methodsmentioning

confidence: 99%

“…It is best reflected by a reported decrease in K concentrations in shoots of rice and wheat resulting in high Na/K ratios in various studies (Afridi, Qadar, and Dwivedi, 1988;Joshi, Qadar, and Rana, 1979;Qadar, 1988Qadar, , 1995a. Applications of nutrients to plants grown under salinity and sodicity stresses have resulted in mixed responses on plant growth and yield depending upon the stress level, nature of salts, crops or varieties, the nutrient in question, and its available status (Chhabra, 1985;Grattan and Grieve, 1999;Qadar, 1995b;Rogers, Grieve, and Shannon, 2003;Singh, Bhumbla, and Kanwer, 1969).…”

Section: Introductionmentioning

confidence: 95%

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Phosphorus Requirements of Rice Grown in Soils With Different Sodicity

Qadar

Ansari

2006

Journal of Plant Nutrition

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Phosphorus (P) fertilization is reported to alleviate the adverse effects of sodicity on survival of the seedlings, growth, and yield of rice. However, it is not known if required levels of Olsen's P to alleviate the adverse sodicity effects varies with increased sodicity stress. The present study, conducted at various pH values (8.0, 9.3, 9.7, and 9.9) with varying levels of P fertilization (P0.0, P0.2, P0.4, P0.6, and P0.8 kg hm −2 ), showed that P requirements of rice increased with increases in sodicity stress. At a pH of 8.0, 4.3 mg kg −1 Olsen's P was sufficient for survival of the seedlings, but not for grain weight (6.3 mg kg −1 ). Seedlings required 7.0 and 9.5 mg kg −1 Olsen's P to survive at pH 9.7 and 9.9, respectively. Similarly, high P levels were needed for more total and fertile tillers and spikelets numbers. One thousand (1000) grain weight and grain yield responded to 6.3, 7.7, 8.8, and 10.4 mg kg −1 Olsen's P at pH values of 8.0, 9.3, 9.7, and 9.9, respectively. Total chlorophyll in the leaves was significant in P fertilized plants. At a pH of 9.7, plants with 7.9 mg kg −1 Olsen's P had 52% more chlorophyll per 100 ppm sodium (Na) in the leaves compared to those at 6.3 mg kg −1 Olsen's P. This could possibly be due to improved tissue tolerance to Na in P-fertilized plants. Plants fertilized with P had higher P and potassium (K) concentrations in their shoots. Olsen's P levels of 7.7 mg kg −1 , 7.9 mg kg −1 , and 9.5 mg kg −1 were effective in restricting increases of Na (a potentially toxic ion) in shoots at pH 9.3, 9.8, and 9.9, respectively, thus helping plants have better yields.

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Section: Resultssupporting

confidence: 94%

Section: Resultssupporting

confidence: 93%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 95%

See 2 more Smart Citations

Phosphorus Requirements of Rice Grown in Soils With Different Sodicity

Qadar

Ansari

2006

Journal of Plant Nutrition

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“…Generally, osmotic stress is the primary effect in short-term salinity treatment while specific ion toxicity and nutritional imbalance are the main effects in long-term salinity treatment (Munns, 2002). For long-term experiments, high salinity in the root zone increased sodium content in rice shoots (Flowers and Yeo, 1981), affected potassium and phosphate nutrition, and further reduced growth in rice (Aslam et al, 1996;Khan et al, 1992;Qadar, 1995). The concentration of Na + and K + /Na + in rice plants was correlated with seedling growth and grain yield under salt stress (Flowers and Yeo, 1981;Khatun et al, 1995;Lutts et al, 1995).…”

Section: Introductionmentioning

confidence: 99%

Exploration of relationships between physiological parameters and growth performance of rice (Oryza sativa L.) seedlings under salinity stress using multivariate analysis

Zeng

2005

Plant Soil

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Knowledge of relationships between physiological parameters and growth performance of seedlings and respective genotypic differences would permit selection of salt tolerance at early growth stages. The goals of this study were to investigate the relationships between physiological parameters and growth performance and quantify the respective genotypic differences using multivariate analysis.. Plants of thirty-one genotypes were grown in sand tanks in a greenhouse and irrigated with Yoshida nutrient solution. Two salinity treatments were imposed at 0.9 dS m −1 (control) and 6.4 dS m −1 with sodium chloride and calcium chloride (∼ 6:1 molar ratio). Seedlings were sampled 34 days after planting (7 th to 8 th leaf stage). The characters of Na + , K + , Ca 2+ , K-Na selectivity (SK,Na) and Na-Ca selectivity (S Na,Ca ) were measured as physiological parameters. The characters of tiller number, leaf area, plant height and shoot dry weight were measured as growth performance. Under salinity stress, S K,Na increased whereas S Na,Ca decreased compared to the controls. Canonical correlation analysis indicates a strong relationship between physiological parameters and growth performance. Tiller number is a desirable parameter among the growth parameters analyzed to predict seedling growth under salinity stress. Genotypes grouped into four clusters based on ion contents and ion selectivity using Ward's minimum-variance cluster analysis. S K,Na and shoot Na + content contributed the most to the cluster formation. Similarly, genotypes grouped into four clusters based on growth performance. Genotypes were classified into three categories based on ion cluster rankings: Category 1 with high S K,Na and low shoot Na + content; Category 2 with intermediate S K,Na and shoot Na + content; Category 3 with low S K,Na and high shoot Na + content. The classification of the genotypes into Categories 1 and 3 based on their high or low S K,Na was generally consistent with their growth performance under salt stress. In contrast, ion selectivity was a less dominant mechanism controlling salt tolerance in Category 2 with intermediate S K,Na . It was concluded that ion selectivity was a relatively dominant mechanism controlling salt tolerance among rice genotypes although multiple mechanisms may be involved under moderate salt stress. The results also provide the first example of the effectiveness of cluster analysis for physiological responses to salinity stress.

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