EFFECT OF MATURITY STAGES FOR WINTER- AND SPRING-SOWN CHICKPEA (CICER ARIETINUM L.) ON SEED MINERAL CONTENT

Two-year field experiments were conducted to study the effect of two planting dates and seed maturity on mineral content of chickpea seeds. In 2003 and 2004, chickpea ‘Jubiha-2’ seeds were planted in late December (winter-sown) and early March (spring-sown). For both planting dates, pods were harvested at five maturity stages: 1) beginning of seed fill (BS), 2) full-size seed (FS), 3) greenish-yellow pod (GY), 4) yellow pod (Y), and 5) brown pod (B). The concentrations of nitrogen (N), potassium (K), phosphorus (P), magnesium (Mg), calcium (Ca), and zinc (Zn) on a dry weight basis significantly decreased as the seeds developed from the BS to the FS stage, then did not change significantly at the Y and B stages. Nutrient content (mg seed^?1) increased as the seed dry weight increased. Seeds from spring-sown plants had higher concentrations of N and manganese (Mn) than winter-sown plants. The maximum mineral content of chickpea was achieved at seed physiological maturity.     

Grain legumes differ in nitrogen accumulation and remobilisation during seed filling

In grain legumes, the N requirements of growing seeds are generally greater than biological nitrogen fixation (BNF) and soil N uptake during seed filling, so that the N previously accumulated in the vegetative tissues needs to be redistributed in order to provide N to the seeds. Chickpea, field bean, pea, and white lupin were harvested at flowering and maturity to compare the relative contribution of BNF, soil N uptake, and N remobilisation to seed N. From flowering to maturity, shoot dry weight increased in all crops by approximately 50%, root did not appreciably change, and nodule decreased by 18%. The amount of plant N increased in all crops, however in field bean (17?g?m^?2) it was about twice that in chickpea, pea, and lupin. The increase was entirely due to seeds, whose N content at maturity was 26?g?m^?2 in field bean and 16?g?m^?2 in chickpea, pea, and lupin. The seed N content at maturity was higher than total N accumulation during grain filling in all crops, and endogenous N previously accumulated in vegetative parts was remobilised to fulfil the N demand of filling seeds. Nitrogen remobilisation ranged from 7?g?m^?2 in chickpea to 9?g?m^?2 in field bean, and was crucial in providing N to the seeds of chickpea, pea, and lupin (half of seed N content) but it was less important in field bean (one-third). All the vegetative organs of the plants underwent N remobilisation: shoots contributed to the N supply of seeds from 58% to 85%, roots from 11% to 37%, and nodules less than 8%. Improving grain legume yield requires either reduced N remobilisation or enhanced N supply, thus, a useful strategy is to select cultivars with high post-anthesis N₂ fixation or add mineral N at flowering.     

Uptake and Distribution of Arsenic in Chickpea: Effects on Seed Yield and Seed Composition

Chickpea plants were grown in arsenic (As)–contaminated soils (5 mg kg^?1 of dry soil) and investigated for As uptake, distribution, and effects on growth, yield, and quality of seeds. The roots accumulated the greatest As (7 mg kg^?1 dry weight), followed by stem (4.8 mg), leaves (4.0 mg), and seeds (0.7 mg). Arsenic inhibited the growth of the roots and shoots (as dry weight) by 65% and 60%, respectively, over controls. The shoot/root ratio declined from 4.3 in the control to 3.5 in As-treated plants. The seed yield (g) and number of pods plant^?1 decreased by 66 and 53%, respectively, over controls. A marked increase in membrane damage coupled with reduction in chlorophyll and relative leaf water content occurred in As-treated plants. The contaminated plants showed 34% and 25% decrease over control in sucrose content in their leaves and seeds, respectively. The accumulation of seed reserves such as starch, proteins, sugars, and minerals was inhibited significantly due to As-treated plants. Storage proteins such as albumins, globulins, glutelins and prolamins decreased significantly with larger effect on glutelins. The contents of minerals such as calcium (Ca), phosphorus (P), and iron (Fe) declined greatly in the seeds of As-treated plants. The accumulation of amino acids such as lysine, methionine?+?cystine, phenylalanine?+?tyrosine, proline, threonine, tryptophan, and valine was inhibited significantly in the seeds of As-applied plants compared to the control. The findings indicated that As application markedly reduced the quality of the chickpea seeds, especially in terms of proteins and minerals.     

Potassium Uptake in Relation to Drought Tolerance of Chickpea Under Rain-Fed Conditions

Potassium is accumulated in substantial amount in water stressed plants, contributing to osmotic adjustment. Eight varieties of chickpea were field grown according to randomized block design with three replications during two consecutive crop seasons to explore the role of K uptake in drought tolerance of chickpea under rain-fed conditions. Plant water relation and other physiological parameters were measured at 70 days after planting, while potassium uptake and yield parameters were recorded at harvest. The varieties were divided into high (HKU), medium (MKU) and low (LKU) K uptake groups, using average K uptake across the seasons. All the data were statistically analyzed group-wise. The HKU, followed by MKU and LKU (i.e. HKU>MKU>LKU) gave the highest values for most of the parameters studied including seed yield and crop biomass. The HKU also exhibited the lowest osmotic potential together with maintenance of elevated water content and turgor in plants compared to MKU and LKU. There was significant season-group interaction regarding most parameters including seed yield and crop biomass. However, such an interaction was not significant regarding K uptake, though varietal group pattern of K uptake was similar to that of seed yield and crop biomass (i.e. HKU>MKU>LKU), indicating that promising chickpea varieties might be selected under rain-fed conditions using K uptake.     

EFFECTS OF DIFFERENT HARVEST TIME AND SULFUR FERTILIZATION ON AMINO ACID COMPOSITION OF LENTIL

The effects of sulfur (S) fertilization and harvest time on amino acid composition of seeds of field-grown lentil (Lens culinaris Medik.) at two different sites were studied. The aim of this study was to determine amino acid content of seed protein and to increase low levels of sulfur amino acids and trytophan in lentil seeds, which are major components for grain quality, with sulfur fertilization and farming practices in lentil. For this purpose, lentil was sown at two locations on 18 and 19 October 2007, 0 kg S ha^?1, 25 kg S ha^?1, and 50 kg S ha^?1 rates were used in the study. The plants were harvested at three different periods: early, optimal, and late period. According to the results, amino acid contents of protein were increased by sulfur fertilization and by the late harvest period.     

Evaluating internal phosphorus requirement of rapeseed,chickpea, lentil,and wheat by seed analysis

Abstract

Foliar tissue in contrast to seed is considered a superior plant part for determining the nutrient‐element status of crops and soils. This study tested that generalization for oilseed, legume, and cereal crops. Internal phosphorus (P) requirements were estimated in pot culture experiments using a P deficient alkaline calcareous soil of Pakistan. The order of response (of grain yield) to P fertilization was rapeseed > wheat > lentil > chickpea. Phosphorus concentrations in whole shoots (≤ 30 cm) associated with 95% grain yields were: wheat and lentil, 0.28%; rapeseed, 0.27%; and chickpea, 0.18%. Critical P concentration in recently matured leaves were: chickpea, 0.39%; lentil, 0.33%; wheat, 0.30%; and rapeseed, 0.28%. Mature grains of crops, particularly of rape‐seed and chickpea, proved a good indicator tissue for evaluating P status of soils and plants. Phosphorus concentrations in seeds were associated with the P status of soil on which they grew. Internal P requirement in seeds were: rapeseed, 0.72%; chickpea, 0.37%; lentil, 0.26%; and wheat, 0.22%.     

Effect of integrated management on Fusarium wilt progression and grain yield of chickpea in Syria

Fusarium wilt, caused by Fusarium oxysporum Schlechtend.: f. sp. ciceris (Padwick) Matuo & K. Sato, is a major production problem in many countries. A study was conducted to develop an integrated management of Fusarium wilt of chickpea using genotypes, sowing dates (January as early sowing and March/April as spring sowing) and fungicide seed treatments under natural infested plots in research plots and farmers’ fields 2007–2009 cropping seasons. In most cases, sowing date and fungicides did not affect disease parameters and seed yield. Chickpea genotypes showed significant differences in seed yield but different responses for disease parameters. Averaged over locations and seasons, the rate of disease development was higher in early (0.035 units day^?1) than spring (0.023 units day^?1) sowing. Chickpea genotypes showed different responses in affecting rate of disease development and cumulative wilt incidence in early and late sowing periods. Higher mean seed yield (1.3 t ha^?1) was recorded in early than late sowing (1.0 t ha^?1) of chickpea. The average seed yield reduction due to spring sowing ranged from 9% to 60% and highest yield losses were observed in FLIP-97–706 and Ghab-3. This study showed that integrating January sowing with genotypes having good levels of resistance for Fusarium wilt and Ascochyta blight helps farmers to narrow chickpea yield gaps in Syria.     

Synergistic effect of bio-inoculants on yield,nodulation and nutrient uptake of chickpea (Cicer arietinum L) under rainfed conditions

The use of efficient bio-inoculants in chickpea is the best way to increase crop productivity under rainfed conditions. To assess the combined effect of bio-inoculants on crop yield, field experiments were conducted during Rabi seasons at Research Station, Punjab Agricultural University, Ballowal Saunkhri, Punjab, India. The application of different bio-inoculants significantly improved number of pods, grain and straw yield of chickpea over the un-inoculated treatment. The combined application of Rhizobium + PSB?+?AM fungi?+?azotobactor inoculums as seed treatment with 75% of recommended phosphorus produced highest grain yield. The nodule count, nodule weight, per cent root colonization of AM fungi and different enzymes activities in soil were also highest in combined bio-inoculants treatment. The present study concluded that combined application of bio-inoculants (Rhizobium, PSB, AM fungi and azotobactor) can save 25% of recommended phosphorus by sustaining the crop yield and improving the soil health.     

Compatibility of Mesorhizobium sp. Cicer with seed treatment of fungicide and insecticide in chickpea

This investigation was undertaken to study the compatibility of Mesorhizobium sp. Cicer with captan (fungicide) and chlorpyrifos (insecticide) for growth, symbiotic parameters and yield in chickpea. In an in vitro experiment, a significant reduction in the number of viable mesorhizobia was observed in Mesorhizobium sp. Cicer treated chickpea seeds at the recommended doses of captan (3 g kg^?1 seed) and chlorpyrifos (10 ml kg^?1 seed) after 4 h storage at 4°C, and further reduction was seen after 8–16 h contact with Mesorhizobium. The results showed that captan was more toxic than chlorpyrifos. In field experiments, improved growth and symbiotic parameters (plant height, dry weight of shoot, nodulation, leghaemoglobin content, chlorophyll content and nitrogen content) and a reduction in per cent damaged by termites and diseases were observed in the Mesorhizobium alone treatment compared with the uninoculated control. Grain yield was increased significantly in treatments with Mesorhizobium alone or in a mixture with fungicide and insecticide (captan and chlorpyrifos) compared with the control treatment. It is evident that chemically treated seeds should always be sown as soon as possible after inoculation. Recommended rates of captan and chlorpyrifos application with Mesorhizobium inoculant as a seed treatment was innocuous to chickpea–Mesorhizobium symbiosis.     

Drainage,sowing date and variety effects on chickpea grown on a Vertisol in Ethiopia

A field experiment was conducted for three years at Ginchi in Ethiopia to study the effects of three drainage methods [broad-bed-and-furrow (BBF), ridge-and-furrow (RF) and flat beds (FB)] arranged as main plots. Sub-plots comprised a factorial combination of four sowing dates (18 and 31 August, and 14 and 28 September) and three Desi-type chickpea varieties (Worku, Akaki and a landrace) in a split-plot design with three replications. Improved drainage methods (BBF and RF) increased chickpea seed yield by an average of 45% over the flat seedbed. There was a quadratic relationship between seed yield and sowing date with a peak yield in mid-September. Improved varieties (Worku and Akaki) yielded 15–19% more than the local check. Improved varieties were significantly more yielding than the landrace variety under the improved drainage system but not under the flat bed system. Also, improved varieties yielded significantly more than the landrace variety in the first three sowing dates when waterlogging was a problem but not in the last sowing date after which drought stress normally sets in. Sowing of improved chickpea varieties in mid-September using BBF could markedly increase productivity of chickpea on Vertisols in Ethiopia.     

Optimum rate of nitrogen application and seed rate for deteriorated wheat (Triticum aestivum L.)

In order to study the effect of seed quality (SQ), seed rate (SR), and nitrogen rate (NR) on yield and yield components of wheat, an experiment was conducted as a factorial-split plot based on the randomized complete block design with four replications in Golestan Province, Iran. Treatments included the combination of SR and NR (recommended rate, 15 and 30% higher than the recommended rate) as the main plots, and SQ (control, 15, 30 and 45?h of accelerated aging) as the subplots. The interaction of NR?×?SR was significant on 1000-seed weight, seed yield, plant height, the number of seeds, biological yield, and harvest index. There was a significant reduction in all traits with an increase in seed aging. Seed yield had a significant and positive correlation with yield components. Using higher density and applying higher nitrogen fertilizer than those of recommended could reduce the negative effects of seed aging in wheat.     

Impact of Boron Deficiency on Changes in Biochemical Attributes,Yield, and Seed Reserves in Chickpea

To determine the effect of boron (B) deficiency on biomass, reproductive yield, metabolism, and alterations in seed reserves of chickpea (Cicer arietinum L.) cv. ‘13.G‐256,’ plants were grown in refined sand until maturity at deficient (0.033 mg L^?1) and adequate (0.33 mg L^?1) B, supplied as boric acid (H₃BO₃). Boron‐deficient plants exhibited visible deficiency symptoms in addition to reduced number of pods and seeds, resulting in lowered biomass and economic yield. Boron deficiency lowered the concentration of B in leaves and seeds, photosynthetic pigments (leaves), Hill reaction activity, starch (in leaves and seeds), and proteins and protein N (in seeds), whereas phenols, sugars (in leaves and seeds), and nonprotein N (in seeds) were elevated. Specific activity of peroxidase (POX) increased in leaves and pod wall and decreased in seeds, while activity of acid phosphate and ribonuclease were stimulated in leaves, seeds, and pod wall in B‐deficient chickpea.     

Variation of Seed Mineral Concentrations in Seven Quinoa Cultivars Grown in Two Agroecological Sites

Variations in concentration and tissue distribution of mineral elements in seeds of seven quinoa cultivars from both a “natural” habitat (Patacamaya, Bolivia, 3,960 m above sea level) and a “nonnatural” habitat (Encalilla, Argentina, 1,980 m above sea level) were analyzed. Data clearly showed inter‐ and intravarietal differences in seed mineral concentrations between the two sites. Correlation analysis revealed that concentrations of major and minor dietary minerals as well as essential ultratrace elements of Encalilla seeds showed, in general, higher correlations with both seed protein and seed yield than did element concentrations of Patacamaya seeds. Results of scanning electron microscopy combined with energy dispersive X‐ray spectroscopy showed clearly differences in the contents of major mineral elements (calcium, magnesium, potassium, phosphorus, and sulfur) in the pericarp and embryonic axis (cotyledon + radicle). Obtained data could indicate that genotype × environment interactions are responsible for mineral variations occurring in quinoa cultivars. Results can also be useful for developing mineral biofortification strategies for the world's poorest regions.     

Does Lupinus angustifolius L. need sulfur fertilization under central European conditions?

In order to answer the question of whether narrow‐leaf lupin (Lupinus angustifolius L.) needs sulfur (S) fertilization under central European conditions, field trials were carried out at several sites in Germany on long‐term (> 10 years) organically cultivated arable land from 2012 to 2014. The effect of S‐containing fertilizers kieserite, gypsum, epsom salt, and elemental sulfur on S accumulation, yield, yield structure, and nitrogen (N) accumulation in narrow leaf lupin as well as the recovery of fertilized S was investigated. Under the given conditions, the fertilization did not influence seed yields. The S accumulation in shoots ranged from 11.8 kg ha^?1 to 14.1 kg ha^?1. The bulk of the absorbed S was accumulated in the straw (average S harvest index: 0.40). The N : S ratio in the youngest open leaf at BBCH 60–65 was about 20 and the corresponding S concentration was 0.24% in the leaf dry mass. The apparent recovery efficiency of S (RE) of kieserite, gypsum, and epsom salt, whose S form is generally plant‐available, was low with 4.0%, –2.1%, and 6.6%, respectively. The S requirement of the lupin was obviously completely filled by plant‐available S from the soil as well as atmospheric S deposition in all tested environments. Application of kieserite, gypsum, and epsom salt resulted in a partially significant increase in S concentration of seeds and straw, and also partly significantly narrowed the N : S ratios in the plants but did not increase yield. Application of elemental S did not lead to an increase in plant S concentration in the year of application.     

Growth,nutrient uptake and yield parameters of chickpea (Cicer arietinum L.) enhance by Rhizobium and Azotobacter inoculations in saline soil

Abstract

A field experiment was conducted during two consecutive growing seasons (2013 and 2014) to evaluate the effects of inoculations with Rhizobium and Azotobacter on the growth and yield of two chickpea (Cicer arietinum L.) varieties under saline (5.8 dS m^?1) arid condition. The single treatment of either Rhizobium or Azotobacter exhibited to promote the growth of chickpea to some level, however, co-inoculation produced more effects and increased the shoot dry weight (30.3 and 26.4%), root dry weight (17.5 and 26.3%), nodule number (79.1 and 43.8 piece per plant), nitrogen content in roots (9.62 and 10.9%), in shoots (12.6 and 8.3%) and seed protein (7.1 and 4.3%) in both Flip06-102 and Uzbekistan-32 chickpea varieties compared to the control. Our studies showed that the highest yield response of 429 (27.9%) and 538 (23.9%) kg?ha^?1 over the control was revealed by the co-inoculation with Rhizobium and Azotobacter inoculants in Flip 06-102 and Uzbekistan-32, respectively. A new introduced Flip 06-102 chickpea variety was more salt tolerant and had higher root nodulation than the local Uzbekistan-32 chickpea variety. Nitrogen (N), phosphorus (P), and potassium (K) contents in the shoots and roots were significantly (p?Rhizobium plus Azotobacter could be applied to improve the vegetative growth and yield of chickpea and to alleviate the effects of salt stress.     

Straw management and optimal N fertilization in seed production of timothy (Phleum Pratense L.) and Meadow Fescue (Festuca Pratensis Huds.)

The market for herbage seed straw has diminished in many seed-production areas due to less livestock. Seed growers are therefore looking for alternatives to straw removal, which up to now has been the most common practice. During 2000–2006, different alternative straw chopping methods, both at the back of the combiner and with a tractor-mounted flail-chopper, and field burning strategies were evaluated in seed crops of timothy (Phleum pratense) and meadow fescue (Festuca pratensis) in southeast Norway. The requirement for an extra N input in autumn (30–40?kg ha^-1) when practising straw chopping was also examined. Compared to straw removal, straw chopping at the back of the combiner during seed harvest did not reduce seed yield in the following year as long as stubble height was low (<10?cm in timothy) and the straw spread uniformly in the field. On average, seed yield was 1–4% and 1–9% higher compared to straw removal in timothy and meadow fescue, respectively. If the chopped straw was spread unevenly, or long stubble was left at combining, it is recommended to use a tractor-mounted flail-chopper after harvest. The experiments did not provide any support for an extra input of nitrogen in autumn, either in timothy or meadow fescue, when the straw was chopped rather than removed. Burning of stubble and straw soon after seed harvest was another efficient clean-up method after harvest, which increased seed yield 9–15% and 17–20% compared to straw removal in the two species, respectively. However, as the burning method is risky and causes smoke emissions, it is normally not recommended. It is concluded that for most seed growers, the most effective, least laborious and most environment-friendly alternative to straw removal will be to chop the straw at the back of the combiner during seed harvest.     

不同收获方式含水率对油菜收获物流损失的影响

收获物流损失是影响油菜生产成本的重要因素,以DMH145油菜品种为对象,在丹麦FOULUM 农业研究中心试验研究了油菜籽粒含水率对油菜分段收获和联合收获中3种主要损失的影响,建立了含水率与3种主要损失及总损失之间的数学函数,另外秸秆含水率对秸秆收获物流损失的影响也进行了研究。结果表明：随着含水率的降低,脱粒损失和清选损失降低,但是过低的含水量会使割台损失增大。总损失与含水率之间存在CUBIC函数关系且关系显著;不同含水率情况下,分段收获和联合收获籽粒平均损失率分别为16.358%和18.771%,分段收获平均高出联合收获2.4%;在三大损失中割台损失最低值0.976%,平均低于脱粒损失和清选损失;秸秆含水率对秸秆收获物流损失影响不显著。     

Interspecific Facilitative Root Interactions and Rhizosphere Effects on Phosphorus and Iron Nutrition Between Mixed Grown Chickpea and Barley

A glasshouse study was conducted to investigate the effects of interspecific complementary and competitive root interactions and rhizosphere effects on phosphorus (P) and iron (Fe) nutrition of mixed grown chickpea (Cicer arietinum L.) and barley (Hordeum vulgare L.). In order to provide more physiological evidence on the mechanisms of interspecific facilitation, we determined phosphatase activities in plant and rhizosphere, and root ferric reducing capacity (FR), Fe-solubilizing activity (Fe-SA) and rhizosphere pH. The results of the experiment revealed that biomass yield of barley was significantly increased by associated chickpea as compared to monocultured barley, while mixed cropping caused a slight decreases in the biomass yield of chickpea. The rhizosphere was strongly acidified under chickpea and chickpea/barley mixed cropping and this acidification, in turn, increased the available P, Fe(II) and DTPA-Fe concentrations in the rhizosphere. Fe-solubilizing activity (Fe-SA) and ferric reducing (FR) capacity of the roots were higher in both species grown in mixed culture relative to their monoculture which may improve Fe nutrition of both species. Leaf acid phosphatase (APase, EC 3.1.3.2) activity was higher in both plants under mixed cropping that may improve P nutrition of barley by chickpea.     

秸秆还田与耕作方式对麦后复种花生田土壤性质和产量的影响

小麦-花生一年两熟是解决粮油争地矛盾,实现粮油自给的重要途径,小麦收获后直播花生是麦油两熟的主要种植方式。试验在前茬小麦收获后设计秸秆还田与耕作方式2种处理因素,共6个处理:旋耕秸秆不还田(RT)、旋耕秸秆还田(RTS)、免耕秸秆不还田(NT)、免耕秸秆覆盖(NTS)、深耕秸秆不还田(DT)和深耕秸秆还田(DTS)。研究秸秆还田与耕作方式对土壤理化性质以及花生产量的影响。结果表明:不同耕作方式对土壤理化性质的影响不同,在0—10 cm土层中,与深耕处理和旋耕处理相比,免耕处理增加了大粒径团聚体的质量比例,提高了团聚体的稳定性,增加了土壤细菌、真菌、放线菌的数量。而深耕处理主要改善了10—20,20—30 cm土层土壤理化性质,深耕处理还增加了干物质积累量,提高了花生荚果产量和籽仁产量。在相同的耕作方式下,与秸秆不还田处理相比,秸秆还田处理降低了土壤容重,增加了土壤孔隙度,增加了粗大团聚体的质量比例以及土壤有机碳和全氮含量,提高了团聚体的稳定性,增加了土壤细菌、真菌、放线菌的数量,增加了干物质积累量,提高了花生荚果产量和籽仁产量。DTS处理荚果产量和籽仁产量比DT处理分别增加了10.89%和14.65%,RTS处理荚果产量和籽仁产量比RT处理分别增加了10.00%和11.77%,NTS处理荚果产量和籽仁产量比NT处理分别增加了16.31%和19.82%。处理间比较,与其他5个处理相比,DTS处理不仅改良了土壤理化性质,而且提高了花生荚果产量和籽仁产量。     

Agronomic Evaluation of Dry Bean Genotypes for Potassium Use Efficiency

Dry bean is an important legume worldwide, and potassium (K) deficiency is one of the important constraints for bean production in most of the bean growing regions. A greenhouse experiment was conducted with the objective to evaluate fifteen dry bean genotypes grown on a Brazilian lowland (Inceptisol) United States Soil Taxonomy classification and Gley humic Brazilian Soil Classification system), locally known as “Varzea” soil. The K rate used was 0 mg kg^?1 (low, natural soil level) and 200 mg kg^?1 (high, applied as fertilizer). Straw yield, seed yield, pods per plant, seeds per pod, 100 seed weight, and seed harvest index were significantly increased with the addition of K fertilizer. These traits were also significantly influenced by genotypic treatment. Similarly, root length and root dry weight were also influenced significantly by K and genotype treatments. The K X genotype interactions for most of these traits were also significant, indicating variation in these traits with the variation in K level. Based on seed yield efficiency index (SYEI), genotypes were classified as efficient, moderately efficient, and inefficient in K use efficiency. Maximum grain yield was obtained with 74 mg K kg^?1 extracted by Mehlich 1 extracting solution. Similarly, K saturation required for maximum grain yield was 1.1%.