Saline Sandy Loam Research Articles

Effects of a Furrow-Bed Seeding System on Stand Establishment, Soil Bacterial Diversity, and the Yield and Quality of Alfalfa Under Saline Condition.

Salt stress account for large decreases in crop yield all over the world. Furrow-bed system is an efficient practice to promote plant growth in saline soil. However, the effects of Furrow-bed system on the soil environment and the growth of alfalfa (Medicago sativa L.) in salinity are not clear. For a wider and more detail evaluation, alfalfa were planted in saline sandy loam soil in fall, the effects of two plant systems (FU, furrow-bed seeding system; FL, flat-bed seeding system) on soil moisture, root zone salinity, soil microbial community structure, seedling emergence number in the early stage of the growth period and soil nutrient contents, alfalfa production characteristics in the second growth year were determined in a 2-year field experiment. The result showed that, compared with FL, FU resulted in increased soil moisture content and seedling emergence, and significantly reduced relative abundance of Actinobacteria and Choroflexi in soil, but it did not affect root zone salinity at the seedling stage. In April of second growth year, the soil salinity was lower, and the soil available phosphorus, potassium, nitrogen, and soil organic matter contents of the root zone were higher in FU than in FL. Compared with FL, FU resulted in increased yield (by 37.5%), protein content (by 3.6%), and potassium concentration (by 33.2%), and decreased ash content (by 7.7%), and sodium concentration (by 19.0%) in alfalfa plants. Pearson’s correlation analysis indicated that the increased yield was positively correlated with seedling emergence, soil available potassium, total nitrogen, and organic matter contents, and shoot potassium content and negatively correlated with shoot sodium content. The relative abundance of Actinobacteria was negatively correlated with alfalfa ash, calcium, and sodium concentrations, and positively correlated with shoot potassium content. Taken together, the results indicate that Furrow-bed seeding in early fall alleviated salt stress of alfalfa and have the potential to enhance the yield and quality of alfalfa cultivated in saline soils by improving the soil environment and regulating the growth and physiology of alfalfa. Graphical

Blessed thistle a promising species on North Dakota, USA marginal lands: Agronomic productivity, oil properties and biodiesel potential

Screening new alternative vegetable oil sources as biodiesel feedstocks has attracted worldwide attention as world oil reserves decline and environmental concerns increase. Blessed thistle (Cnicus benedictus L.) has recently been identified as a multipurpose crop with optimal economic yield in poor soils. Blessed thistle was seeded into three different site soil conditions (site 1: silt clay loam, site 2: sandy loam, site 3: saline sandy loam) in eastern North Dakota, USA to evaluate agronomic performance and seed properties as well as biodiesel potential. The highest biomass and plant heights were obtained from the sandy loam soil, while plants grown in saline sandy loam soil had similar seed and oil yield, and similar oil content as plants grown in other site soil conditions. Biodiesel obtained from blessed thistle oil in the saline site was an excellent substitute for fossil fuels. The saline soil did not influence the blessed thistle oil yield; however, the saline soil did affect the fatty acid composition and biodiesel properties with some improvement in biodiesel quality. Results showed that blessed thistle was a promising species for biodiesel feedstock, especially for marginal soils such as the saline soil conditions in North Dakota.

Influence of salinization on seeds germination of the fodder semi-shrub of the eastern saltwort (Salsola orientalis S.G. Gmel.)

Eastern saltwort (Salsola orientalis S. G. Gmel.) belongs to the goosefoot family (Chenopodiaceae Vent.), the genus Salsola L., a semi-shrub with 25-70 cm high with fleshy leaves. It is distributed on saline sandy loam and stony soils from plains to low mountains. It is widely used to restore productivity of degraded natural pastures in arid regions of Russia and Central Asia countries. It is characterized by good palatability, nutritional value, exceptional resistance to salt stress, drought and other adverse environmental conditions. The objective of the study is to find out the effect of different salt concentrations on the germination of eastern saltwort seeds. The influence of various types of salinization on the germination of eastern saltwort seeds in concentrations was tested (0.2; 0.4; 0.6; 0.8; 1.0; 1.2; 1.4; 1.6; 1.8 and 2.0% to the absolutely dry mass of sand): chloride, sulphate, sulphate-chloride, chloride-sulphate, control – sand moistened with distilled water. With chloride salinization at concentrations of 0.2-0.4%, the germination energy and germination of eastern saltwort seeds decreased slightly, and at concentrations of 1.2-1.4%, germination stopped. Sulfate salinization was the least toxic. With all types of salinization, with an increase in the salt concentration, the sowing – germination period is delayed and the process of germination of eastern saltwort seeds is expanded. Although eastern saltwort is a true halophyte, its seeds germinate better on a nonsaline substrate.

Reclamation of Coastal Saline Wasteland Using Drip Irrigation and Embedded Subsurface Pipes

A 3‐yr field experiment investigated the impact of drip irrigation and embedded subsurface drain pipes on salt leaching and Chinese rose (Rosa chinensis Jacq.) growth in a severely degraded saline soil located in north China. The experiment consisted of five soil matric potential (SMP) treatments where the soil matric potential at 0.2 m below the emitter was −5, −10, −15, −20 and −25 kPa in 2014 and 2015 and then decreased to −15, −20, −25, −30 and −35 kPa in 2016. With time, the size of the low salinity zone increased and the soil extract electrical conductivity (ECe) in surface 40 cm decreased from 27.32 to <1.5 dS m−1. Soil water content increased with increasing SMP threshold values in the surface soil profile, but there were no significant differences among treatments in the deep layer. Soil pH values increased and then decreased for all treatments and obvious alkalization occurred, especially in the root zone. High survival rates of Chinese rose with values >96% were obtained in 2014 for all treatments and these decreased with time, especially in the lower SMP treatments in 2016. An SMP higher than −5 kPa in the first year, −10 kPa in the second year and −20 kPa in the third year, combined with an irrigation water event of 10 mm, can be used for rose drip‐irrigation scheduling, which can maintain survival rates of >85% on reclamation of coastal saline sandy loam soil with embedded subsurface pipes.Core Ideas Chinese roses were grown on coastal saline soils under drip irrigation and embedded subsurface pipe. Five soil matric potential thresholds were set for drip irrigation. The drip irrigation scheduling for rose grown in coastal saline soils was determined.

A modified physical-based water-retention model for continuous soil moisture estimation during infiltration: experiments on saline and non-saline soils

ABSTRACT Water infiltration is an issue of vital concern to farmland irrigation. Besides, a soil-water evaluation during infiltration benefits irrigation determination and salt leaching, which has still not been well revealed through a physical-based model regarding continuous soil-water estimation. We conducted one-dimensional infiltration on non-saline loam soil and saline sandy loam soil to propose a modified water-retention model which was expected to estimate continuous soil-water changes during infiltration. Results indicated that for the non-saline soil and the saline soil with different salinities, the modified water-retention model can be established based on the vertical one-dimensional algebraic model and the Kostiakov model. But different from the traditional vertical one-dimensional algebraic model, the new established model can be adopted for calculating and predicting continuous water content during infiltration at any duration, with higher accuracy than using HYDRUS, due to direct parameter acquisition from the observed infiltration data rather than indirect acquisition from soil water characteristic curve. The established potential relationship between soil moisture and cumulative infiltration promotes the development of precise agriculture.

Chemical Properties of the Salt-affected Soils and Performance of Wheat (Triticum aestivum) with Saline and Alkali Water Irrigation

Effect of different quality of irrigation water viz., normal tap water (NTW, EC 0.7 dS m−1), dilute saline water (DSW, EC 5.0 dS m−1; SAR 5.0 mmol½ L−½), concentrated saline water (CSW, EC 10.0 dS m−1; SAR 5.0 mmol½ L−½), dilute alkali water (DAW, RSC 2.5 me L−1) and concentrated alkali water (CAW, RSC 10.0 me L−1) on the soil chemical properties and its impact on growth and yield of wheat (cv. KRL 213) was evaluated in normal (pHs 7.5, ECe 1.0 dS m−1), saline (pHs 7.7, ECe 10.6 dS m−1) and alkali (pHs 9.15, ECe 2.9 dS m−1) sandy loam soils in the micro-lysimeter. The ECe increased by 9.5, 12.5 and 5.5, 7.0 times due to DSW and CSW irrigation in normal and alkali soils, respectively as compared to initial values, whereas decrease in ECe was observed in all water treatments except CSW in saline soil. Increase in pHs of normal and saline soils was more pronounced in case of NTW, DAW and CAW as compared to alkali soil. On application of DSW and CSW, decrease in pHs was observed in alkali soil, whereas it remained constant in normal and saline soils as compared to initial. Exchangeable sodium percentage (ESP) increased with all water treatments in normal, saline and alkali soils. This increase was more pronounced under NTW, DAW and CAW in alkali soil as compared to normal and saline soils. Sodium concentration in saturation paste increased by 15 to 17 times in normal soil, 3.5 to 4.5 times in alkali soil under DSW and CSW, respectively. Sodium leaching was observed in saline soil under all water treatments except under CSW where it increased to 1.2 times. Sodium build-up was increased 1.5 to 2.0 times under all water treatments in normal, saline and alkali soils as compared to post rice sodium concentration. Increase in organic carbon content was observed in surface samples in normal soil, whereas it was not as pronounced in saline and alkali soils. Calcium carbonate increased significantly in all depths in three soils under DAW and CAW. Wheat yield reduced approximately by 4, 11 and 34 per cent under normal, saline and alkali soils, respectively in DAW as compared to NTW, whereas CAW reduced grain yield by 31 per cent in normal, 87 per cent in saline and near total loss of crop was observed in case of alkali soil as compared to NTW. The DSW reduced yield by about 22 per cent each in normal and saline soils and about 70 per cent in alkali soil. Application of CSW reduced yield by 70 per cent in normal soil, whereas near complete loss of crop was observed in saline and alkali soils as compared to NTW.

Evaluating performance of macroscopic water uptake models at productive growth stages of durum wheat under saline conditions

Water management in agricultural lands largely depends on quantity and quality of available soil and water resources. In arid and semi arid regions, scarcity of fresh water and soil salinity are two main important limiting factors for crop production. Under such limiting conditions, one practical alternative for crop production is the use of unconventional or brackish water. If used, the quantitative response of plants to salinity must be carefully analyzed by means of modeling. On the other hand, plant response to salinity varies under different growth stages. Durum wheat (Triticum turgidum L.) is an important crop cultivated in some arid and semi-arid areas across the world such as Middle East and North Africa. This study was aimed to quantitatively characterize the Durum wheat response to salinity under different productive growth stages. Consequently, a large experiment in natural saline sandy loam soil (Typic Toriorthent) with five natural saline water treatments including 2, 4, 6, 8 and 10 dS/m each with three replicates was conducted. Furthermore, four predictive linear and nonlinear models of Maas and Hoffman, van Genuchten and Hoffman, Dirksen et al. and Homaee et al. were evaluated to predict relative transpiration and relative yield of durum wheat under heading and ripening growth stages. Three statistics including modified coefficient efficiency (E'), modified index of agreement (d') and coefficient of residual mass (CRM) were used to compare the used models and to assess their performances. Results indicated that among the examined models, the macroscopic model of Homaee et al. can provide more reasonable predictions at heading stage, while the piece-wise linear model of Maas and Hoffman provided slightly better prediction at ripening growth stage. The obtained threshold value and slope of reduction yield were quite different from those previously reported in the literature. These findings reveal that the widely cited tables describing the relationship between relative yield and electrical conductivity of saturated extract, averaged over the root zone as well as the entire growing season, are quite approximate and carry significant uncertainty. More experimental studies are still needed to obtain reliable data under different growth stages.

Effect of different water application intensity and irrigation amount treatments of microirrigation on soil-leaching coastal saline soils of North China

In coastal regions, Bohai Gulf is one of the most affected areas by salinization. To study the effects of mocrosprinkler irrigation on the characteristics of highly saline sandy loam soil (ECe (saturated paste extract)=22.3 dS m−1; SAR (sodium adsorption ratio)=49.0) of North China, a laboratory experiment was conducted. Five water application intensity (WAI) treatments (1.7, 3.1, 5.3, 8.8, and 10.1 mm h−1), five irrigation amount (IA) treatments (148, 168, 184, 201, and 223 mm) and three time periods of water redistribution (0, 24 and 48 h) were employed in the study. A compounding microsprinkler system was used for the WAI treatments, and a single microsprinkler was used for the IA treatments. The results indicated that, as soil depth increased, soil water content (θ) increased and then slightly decreased; with WAI and IA consistently increasing, the relatively moist region expanded and the average θ increased. Meanwhile, soil ECe increased as soil depth increased, and the zone with low soil salinity expanded as WAI and IA increased. Although the reduction of the average SAR was smaller than that of the average electrical conductivity of the ECe, these variables decreased in similar fashion as WAI and IA increased under microsprinkler irrigation. The average pH decreased as soil depth increased. Longer time periods of water redistribution led to lower salinity and slight expansion of the SAR zone. Considering the effects of leached salts in coastal saline soils, greater WAI and IA values are more advantageous under unsaturated flow conditions, as they cause better water movement in the soil. After leaching due to microsprinkler irrigation, highly saline soil gradually changes to moderately saline soil. The results provide theoretical and technological guidance for the salt leaching and landscaping of highly saline coastal environments.

MUTUAL EFFECT AMONG COMPOST AND FOLIAR SPRAYING WITH ZINC AND BORON ON SUGAR BEET (Beta vulgaris l.) GROWN ON SALINE SANDY LOAM SOIL

Two field experiments were conducted at the village (7) in Gelbana, North Sinai Governorate, Egypt during two successive winter seasons of 2013/2014 and 2014/2015 to study the response of sugar beet (Mirodor) grown on saline sandy loam soil to study the interaction effect of compost, (CO) amendment and foliar spraying with micronutrients (Zn and B) solely or in combinations on some growth parameters, productivity and nutrients content in sugar beet roots. The obtained results reveal that CO and foliar application with Zn and B enhanced the growth and yield productivity of sugar beet roots as well as nutrient contents. Available N, P, K, Fe, Mn, Zn and B contents were increased due to the above mentioned treatments. On the other hand, the electrical conductivity (EC dSm-1) and soil pH values decreased due to these treatments. Foliar spray with micronutrients in combination with CO substantially elevated these parameters N, P, K, Fe, Mn, Zn and B contents in roots were significantly increased by application of the treatments. The highest response of productivity and nutrients content in root were achieved by application of CO in combination with foliar spray of Zn + B followed by foliar spray of Zn + B in both seasons . Highest values of yield, yield components, nutrient contents and sucrose percent as well as sugar yield were obtained due to the application of compost at rate of 5 Mg fed.-1 + foliar spray with Zn + B in both seasons.

Impact of Bi ̊Char on Water Characteristics of a Chinese Severe Saline Agricultural Soil

Bi ̊Char soil amendment has been accepted as a low-risk soil carbon sequestration method. Some other agricultural benefits also reported in previous researches. Two kinds of bi ̊Chars, produced from walnut shell and soft wood, with significantly different surface characteristics and a severe saline sandy loam soil was used in our research. Physical and chemical parameters of bi ̊Char and soil were analyzed. The results pressure plate analysis indicated that high surface area bi ̊Char can increase water retention and plant available water in severe saline agriculture soil, however, such effect wasn’t observed in all the low surface area bi ̊Char treatments. Based on these results, a simulated soil water loss experiment was conducted under 3 different temperatures (from 25 ̊C to 40 ̊C), with 4 bi ̊Char doses for 120 h. Our results shown that high dose of high surface area bi ̊Char can reduce the rate of soil water loss under high temperature. Such effect indicated that high surface area bi ̊Cahr can help soil hold more water under lab condition and simulated field condition. In bi ̊Char soil application, the interaction between bi ̊Char, soil and climate condition needs to be considered carefully to acheive optimum solution for both environmental and agricultural purposes.

Modeling sorghum response to irrigation water salinity at early growth stage

Agricultural water management in arid and semi-arid regions largely depends on availability and quality of irrigation water at different plant growth stages. In saline environments, plant response to salinity varies at different growth stages. Information on plant response to salinity at various growth stages can be used in managing saline waters for irrigation. This study was conducted to quantitatively assess response of sorghum (Sorghum bicolor L. Moench) to salinity at seedling stage. Consequently, an extensive experiment in natural saline sandy loam soil with five natural saline water treatments including 4, 6, 8, 10, and 12dS/m was conducted. The reason for selecting natural sources of saline water and a saline soil was to minimize deviations from natural conditions under which sorghum grows. Sorghum seeds were planted and seedles counted at 24h time intervals. The macroscopic models of Maas and Hoffman, van Genuchten and Hoffman, Dirksen et al., and Homaee et al. were used to predict relative seedlings at different salinity levels. The obtained results indicated that salinity threshold value EC* for sorghum at seedling stage is 1dS/m and the seedling rate reduces to 50 percent at 11dS/m of soil salinity. All evaluated models overestimated the EC* value. Calculated statistics indicated that the nonlinear salinity models are more accurate than the linear model. Among those, Homaee et al. model provided better predictions at seedling growth stage.

Biofortified, selenium enriched, fruit and cladode from three Opuntia Cactus pear cultivars grown on agricultural drainage sediment for use in nutraceutical foods

Three different cultivars of drought, salt and boron (B) tolerant Opuntia ficus indica (Cactus pear) were grown in poor-quality agricultural drainage sediment high in salt, B and selenium (Se) that originated from the Westside San Joaquin Valley. Nutritional contents were then measured in these Cactus pear fruit (purple, red, or orange-coloured), and vegetative cladodes (modified stem-like leaves) compared to the same cultivars grown adjacent on a low saline sandy loam soil. After harvesting fruit and cladodes, the mineral nutrients, chemical speciation of Se, total phenolics, vitamin C and antioxidant status were analyzed. The results demonstrated positive nutritional changes in both cladodes and fruit within the Cactus pear cultivars when grown on agricultural drainage sediment compared to those grown on normal soil. Under these conditions Cactus pear plants contained nutraceutical qualities and represent a useful anticarcinogenic Se-enriched chemotherapeutic food crop for providing advanced dietary seleno-pharmacology in order to help fight human diseases.

Microbial activity and biomass and N and P availability in a saline sandy loam amended with inorganic N and lupin residues

Plant residue can be a cost effective source of N and P fertilisers, which may enhance plant growth in saline soils. Salinity and limited availability of N may limit microbial activity and thus residue decomposition N and P availability. A laboratory experiment was conducted to investigate the effects of NH 4–N or NO 3–N on microbial activity and biomass and N and P availability in a saline sandy loam. Three levels of salinity (EC 1:5 0.21, 0.51 and 0.85 dS m −1) were imposed in the sandy loam using solutions of Na + and Ca 2+. Soil was amended with or without 2% (w/w) lupin residues (C/N ratio 15.4) or 50 μg N g −1 soil as KNO 3 or (NH 4) 2.SO 4. With no residue or inorganic N added, the concentration of available N and P remained unchanged over 45 days. Soil respiration and microbial biomass C, N and P decreased with increasing salinity, but significantly increased with residue addition. Addition of inorganic N had no significant effect, but addition of NO 3–N with residue significantly increased soil respiration and microbial biomass C, N and P. Salinity had no effect on N availability and decreased P availability. Nitrogen availability was lower with addition of NH 4–N, N than with NO 3–N. Available N and P increased with residue addition and increased further with addition of NO 3–N than with NH 4–N. The greater C availability in the lupin residue amended saline sandy loam stimulated microbial activity and biomass with greater N demand, thus promoted immobilization of NO 3. Hence, N and P availability increased in the saline sandy loam.

Wheat response to combined application of nitrogen and phosphorus in a saline sandy loam soil

Fertilization with nitrogen (N) or phosphorus (P) can improve plant growth in saline soils. This study was undertaken to determine wheat (Triticum aestivum L; cv Krichauff) response to the combined application of N and P fertilizers in the sandy loam under saline conditions. Salinity was induced using sodium (Na+) and calcium (Ca2+) salts to achieve four levels of electrical conductivity in the extract of the saturated soil paste (ECe), 2.2, 6.7, 9.2 and 11.8 dS m−1, while maintaining a low sodium adsorption ratio (SAR; ≤1). Nitrogen was applied as Ca(NO3)2 · 4H2O at 50 (N50), 100 (N100) and 200 (N200) mg N kg−1 soil. Phosphorus was applied at 0 (P0), 30 (P30) and 60 (P60) mg kg−1 soil in the form of KH2PO4. Results showed that increasing soil salinity had no effect on shoot N or P concentrations, but increased shoot Na+ and chlorine ion (Cl−) concentrations and reduced dry weights of shoot and root in all treatments of N and P. At each salinity and P level, increasing application of N reduced dry weight of shoot. At each salinity and N level P fertilization increased dry weights of shoot and root and shoot P concentration. Addition of greater than N50 contributed to the soil salinity limiting plant growth, but increasing P addition up to 60 mg P kg−1 soil reduced Cl− absorption and enhanced the plant salt tolerance and thus plant growth. The positive effect of the combined addition of N and P on wheat growth in the saline sandy loam is noticeable, but only to a certain level of soil salinity beyond which salinity effect is dominant.

Equivalent cohesion of frozen saline sandy loams at temperatures close to their freezing point

Determinations of the equivalent cohesion of a frozen saline sandy loam at a negative temperature close to the freezing point of the pore solution are examined. Strength and deformation characteristics obtained under these conditions are analyzed.

Wheat growth in a saline sandy loam soil as affected by N form and application rate

Plant growth in saline soils may be increased by fertilisation, but little is known about the effect of different forms of N on wheat growth in soils with different salinity levels. The aim of this study was to investigate the response of wheat (Triticum aestivum L., cv Krichauff) to (NH4)2SO4 or KNO3 or NH4NO3 at 0 (N0), 50 (N50), 100 (N100) and 200 (N200) mg N kg−1 soil in a saline sandy loam. Salinity was induced using Na+ and Ca2+ salts to achieve three ECe levels, 2.8, 6.6 and 11.8 dS m−1 denoted S1, S2 and S3, respectively, while maintaining a low SAR (>1). Dry weights of shoot and root were reduced by salinity in all N treatments. Addition of N significantly increased shoot and root dry weights with significant differences between N forms. Under non-saline conditions (S1), addition of NO3 − N at rates higher than N50 had a negative effect, while N100 as NH4 − N or NH4NO3 − N increased shoot and root dry weights. At N100, shoot concentrations of N and K were higher and P, Ca, Fe, Mn, Cu and Zn were lower with NO3 − N than with NH4 − N nutrition. The concentration of all nutrients however fell in ranges did not appear to be directly associated with poor plant growth with NO3 − N. At all N additions, calculations indicated that soil salinity was highest with N addition as NO3 − N and decreased in the following order: NO3−N > NH4−N > NH4NO3−N. Addition of greater than N50 as NO3 − N, compared to NH4 − N or NH4 − NO3, increased soil salinity and reduced micronutrient uptake both of which likely limited plant growth. It can be concluded that in saline soils addition of 100 mg N kg−1 as NH4 − N or NH4NO3 − N is beneficial for wheat growth, whereas NO3 − N can cause growth depression.

Influence of leaching with different amounts of water on desalinization and permeability behaviour of chloride and sulphate-dominated saline soils

Desalinization studies were carried out in Cl-dominated (Cl:S0 4 = 7:3) and SO 4-dominated (Cl:S0 4 = 3:7), saline (ECe = 9 dS m −1, ESP = 10) sandy loam soils, filled in plexiglass columns up to a height of 60 cm at uniform bulk density. Both soils were subjected to leaching with three amounts, i.e. 20, 40 and 60 cm of distilled water, 5 cm at a time until the three leaching cycles were completed. The S0 4 profiles had 20–75% faster percolation than their Cl counterparts, when 40 cm of water was leached. With higher amounts of leaching water, the differences in permeability between the two soils narrowed and became indistinguishable when 60 cm of water was leached. Desalinization of the Cl-profiles was more efficient than the S0 4-profiles, but the reverse was the case with desodification. When the depth of water (dW) leached was less than or equal to the depth of soil WS), desalinization was less efficient (10–25%) under S0 4 than under Cl-salinity. However, when dW was greater than dS, the differences in the magnitude of leaching of salts under the two salinities narrowed and became equal at a dW/dS ratio of 2. An increase in the soil ESP from 10 to 35 resulted in a 75% decrease in soil permeability under Cl compared with a 64% decrease in S0 4-salinity. At ESP of 10, application of farmyard manure (FYM) as an amendment increased soil permeability for both Cl- and S0 4-dominated soils. However, at higher ESP levels (30–35), FYM application decreased soil permeability under Cl-dominated soil, but increased it under S0 4-dominated soil.

PLANT DOMESTICATION AND THE DEVELOPMENT OF SEA STARWORT (ASTER TRIPOLIUM L.) AS A NEW VEGETABLE CROP

The germination, growth and quality of Aster tripolium L. was analysed to study cultivation of the wild leafy plant into a commercial vegetable crop. Soil type and soil condition (non-saline, brackish and saline)were basically proved in relation to germination capacity, yield and plant behaviour with respect to external and internal quality aspects. Germination at constant and variable temperature regime resulted in the best figures for temperatures between 21° and 17°C only within non saline conditions, For both, riversand and sandy loam plant growth was established with the best results for non-saline conditions in sandy loam. Ageing diminished plant quality demonstrated for external as well as for internal analysed parameters. The rather easy domestication and the available variation offers all possibilities for the development of Sea starwort as a new vegetable crop.

Leaching of salts as affected by the method of water application and atmospheric evaporativity under shallow and saline water-table conditions

SummaryField studies on leaching a highly saline sandy loam soil having a shallow groundwater table showed that application of 150 mm water in two equal parts at 10 days interval had no distinct advantage over a single application of the whole amount. On the contrary, the surface-accumulated salts were displaced to a lesser extent and the salt peak remained at a shallower depth under split application, particularly during periods of high atmospheric evaporativity when the leached salts tended to move upward between successive water applications. A soil mulch created by shallow tillage reduced evaporation losses and curtailed upward movement of salts, resulting in nearly 10% increase in leaching efficiency. Significantly a small quantity of water (0·41 cm leaching water per unit soil depth) sufficed for 70% chloride removal, indicating that under the prevailing conditions a larger fraction of the pores contributed to the leaching process. A compact layer, having a bulk density of 1·69 g/cm3, at the soil surface, also appeared to be related to the higher leaching efficiency by maintaining a preponderance of unsaturated flow.