Search

The animal feed nutritional value is dependent on the feed chemical composition and which could be affected by sulfur fertilization and irrigation regimes. Therefore, the present study was formulated to evaluate the effect of sulfur fertilization and irrigation regimes on fodder sorghum in semi-arid region. A two-year field experiment (2016/2017) was conducted on multi-cut hybrid sorghum with three moisture regimes (60 and 120 Cumulative Pan Evaporation (CPE), and no irrigation) and three sulfur (S) levels (0, 15 and 30 kg/ha S) as sub-plot treatment in split-plot design replicated thrice. Statistical analysis of the data revealed that individually irrigation scheduling at 60 CPE and sulfur application at 30 kg/ha resulted maximum plant height, leaf area index and number of tillers. The application of 30 kg/ha S observed with higher total green fodder yield which was 20.1% in 2016 and 16.8% more than control in 2017 and nearly, similar results were also obtained in relation to dry matter yield. Sulfur fertilization and irrigation at 60 CPE showed 39.5% mean reduction in hydrocyanic acid and the average crude protein of 10.5% and in vitro dry matter digestibility of 55.5% at 1st cut was recorded. Application of S and irrigation regimes improved the nitrogen and sulfur concentration in fodder. In conclusion, the application of sulfur @ 30 kg/ha through any sulfur source could be considered as the potential sulfur fertilizer in improving the injurious effects of water deficit condition of hybrid multi-cut fodder sorghum through alterations in nutrient uptake, yield and quality. [ABSTRACT FROM AUTHOR]

Maize is a valuable crop with high genetic variability, and understanding this variability is essential for improving crop productivity and resilience to environmental stressors. This study evaluated the genetic variability and heritability of yield and yield‑related traits among 27 drought‑tolerant maize genotypes in a humid climate region of Southwestern Nigeria. The experiments followed rigorous agronomic, soil, and climatic requirements for maize cultivation. Our findings revealed significant genetic variability among the traits of the maize genotypes, particularly in the number of ears per plant, which had the highest genetic advancement as a percentage of the mean (68.25% and 67.83%) under both well‑watered and drought conditions, respectively. This suggests that breeding programs targeting this trait could significantly improve maize productivity and resilience to drought stress. Additionally, most of the agronomic traits targeted were highly heritable with heritability values ranging from 0.76 to 0.99 under both environments where the genotypes were evaluated, thus indicating that selective breeding for these traits could lead to consistent improvements in maize yields over time. Overall, this study highlights the importance of evaluating yield‑related traits' genetic variability and heritability in maize breeding programs. Findings suggest that targeting the number of ears per plant in drought‑tolerant maize genotypes as revealed in the study could be an effective approach for improving crop productivity and resilience in regions with variable moisture regimes. [ABSTRACT FROM AUTHOR]

Groundnut is cultivated largely as a rain-fed crop and hence the crop is exposed to intermittent moisture stress resulting in reduced productivity and crop loss. Therefore, there is a need to tolerate dehydration stress by maintaining superior water relations to sustain the growth under water deficit stress conditions. The plant has evolved several mechanisms to maintain water relations such as better water mining by water use efficiency (WUE) and water conservation traits. The present study was focused to evaluate the alterations in physiological parameters: relative water content (RWC), canopy temperature, cell membrane leakage, photosynthesis, transpiration, stomatal conductance and water use efficiency and biochemical attributes: total chlorophyll and proline content at different water regimes/field capacities (FC) (100% FC (control), 50% FC and 25% FC). Tolerant genotypes revealed significantly higher values of RWC and lower cell membrane leakage at the end of stress induction period than the sensitive genotypes. The gas exchange traits viz., photosynthetic rate, stomatal conductance and transpiration rate also recorded high in tolerant genotypes under stress conditions. Further the major aim of the study was to analyze the expression pattern of seven candidate drought responsive genes in drought stress tolerant (Kadiri-9 and TCGS-1694) and sensitive (Kadiri-6 and JL-24) groundnut genotypes. Among the seven genes, HSP17.9 exhibited the highly elevated transcript accumulation in all the genotypes under stress conditions and the relative expression of the gene was profoundly higher (10.7-folds) in the tolerant genotypes compared to the susceptible types followed by HSP60, PRP2 and LEA5 genes. The differential expression of these important drought responsive genes in tolerant genotypes of groundnut indicates its further usefulness in developing varieties with improved water deficit stress tolerance. [ABSTRACT FROM AUTHOR]

Mosses are a common type of organism found colonising stone in both the natural and built environment. People responsible for managing and conserving historic buildings often worry that mosses can cause biodeterioration, but there is very little research to date on what controls moss growth and the nature and magnitude of their impact. To help fill this knowledge gap, research has been carried out on limestone walls at Kelmscott Manor, the churchyard at Chipping Norton, and in the laboratory on limestone test blocks, to examine the impact of microclimate variations on both the initial colonisation and spread of mosses, and the impact of moss colonisation on temperature, relative humidity, and moisture conditions. The research used a combination of non-destructive and invasive tests to determine the impact of mosses on moisture relations through direct impacts on surface moisture, water absorption capacity, and open porosity. From the results presented, we can infer that mosses have an impact on water uptake and retention on mortar and limestone at both the surface and subsurface level, and that they may play a role in 'shielding' the underlying substrate from light rainfall events. The experimental data also suggests that in certain cases, removing mosses may have more of an impact on moisture regimes than leaving them in situ. [ABSTRACT FROM AUTHOR]

Background: Potato (Solanum tuberosum L.) ranks fourth in terms of worldwide production. The states of Uttar Pradesh, West Bengal, Bihar and Gujarat accounted for more than 80 per cent share in total production; India ranks second, next to China in global production of potato. Potato crop is extremely sensitive to the deficit or surplus moisture and requires an optimum amount of irrigation at frequent intervals for its proper growth. Phosphorus (P) is an element that is potatoes require in large amounts following Nitrogen and Potassium, P application rates influence on the P efficiency for tuber yield and P uptake. Methods: In field study, total 36 treatment combinations consisting of three moisture regimes as main plot treatment and 12 combinations of two levels of FYM, three levels of P, carriers as sub-plot treatments evaluated in split plot design with three replications using potato variety Kufri pukhraj as test crop. Result: Among different moisture regimes tested, the treatment receiving maintenance of moisture between 100 and 75 per cent availability at 0-30 cm soil depth (W1) gave significantly higher plant height (52.24 cm), number of tubers per plant (6.74), total tuber yield (335.74 q/ha) and haulm yield (16.64 q/ha) during pooled results. Combinations of FYM and levels of P carriers tested, the treatment combinations FYM and application of P @ 180 kg P2O5/ha in the form of MAP(P3S1M1) showed significantly higher plant height (50.04 cm), tuber per plant (6.87), total tuber yield (323.98 q/ha) and haulm yield (17.16 q/ha) gave during pooled results. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Leaves and pod shells contain glycosides which posses laxative properties. • Attack of white fly can be avoided by optimizing sowing and harvesting dates. • Optimum moisture regime can enhance sennoside content and yield. • Highest sennoside content was obtained in rainfed condition. • Sennoside yield was maximum in 20% ASM at 90 days of crop maturity. Abstract Cassia angustifoli a Vahl is known for the production of leaves and pod shells containing high-value glycosides (sennosides) with enormous medicinal properties to cure constipation in all over the world. However, data on its agricultural practices is limited. The present study aim to optimize the sowing time, moisture regime, and harvesting date at sub-tropical conditions for getting maximum marketable produce. Experiments were performed over two years (2016 and 2017) into two sets. First one comprised of seven dates of sowing, and second experiments having four moisture regimes and four dates of harvest. In sub-tropical north Indian conditions, 15 March was the best sowing date with highest biological yield (17.446 q ha−1), sennoside content (2.18% in leaves and 3.26% in pods), and sennoside yield (45.943 kg ha−1). The 20% available soil moisture with 90 days of harvesting time was suitable for the maximum biological yield of senna (17.296 q ha−1). The maximum net return (67,989.0 Rs ha−1) was observed at 20% available soil Moisture (ASM) condition at 90 days harvesting. Hence, the study recommended that the 15 March sowing date, 20% available soil moisture and 90 days harvest for the Cassia angustifoli a Vahl. provide more income to the farmers and industry. Development of cost-effective package of practices leading to the quality assurance will encourage its cultivation and availability of raw material to the industry. [ABSTRACT FROM AUTHOR]

Supplying organic compost and mulching could be a practical solution to alleviate the negative effects of water stress on sorghum (bicolor L. Moench ) in newly reclaimed soils. For this purpose, two field experiments were conducted during 2016 and 2017 seasons. This investigation was conducted as split-split experiments based on randomized complete blocks design with organic compost (OC) as a soil amendment at three levels (0, 15 and 30 t ha −1 ), rice straw as a soil mulching (M) at two levels (0, and 10 t ha −1 ) and soil moisture at three levels (100, 85 and 70% of ETc) using three replications. Sorghum yields (forage and seed), and forage and seed water use efficiencies (F-WUE and S-WUE) were significantly (P < 0.05) affected by irrigation quantity and by both compost and mulching application. Plant growth (e.i. plant height, shoot dry, and leaf area), leaf photosynthetic pigments, plant water status (canopy temperature, relative water content (RWC%), and harvest index (HI) were also significantly (P < 0.05) affected in two seasons. The highest yields (41.41 and 7.8 t ha −1 for forage and seed yields) as the average for both seasons were recorded under full irrigation, 10 t ha −1 of M and 30 10 t ha −1 of OC. It can be concluded that organic compost and soil mulching improved significantly seed and forage yield production under deficit irrigation conditions. The results indicate that under scarcity water, application of (I 85 ×OC 30 ×M 10 ) treatment was found to be favorable to save 15% of the applied irrigation water, to produce not only the same yields, approximately, but also to save more of water as compared to I 100%. [ABSTRACT FROM AUTHOR]

High evaporative conditions, scarcity of groundwater and deficient rainfall condition are detrimental to cotton yields in Saurashtra region of Gujarat. Climatic change adds another dimension to this complex nexus of soil-water-plant-atmosphere. Adverse environmental conditions coupled with water scarcity intrigued farmers of this region to adopt drip irrigation with mulch in Bt. cotton for mitigating the impact of climatic aberrations. So far, no study has reported the conjunctive impact of different mulches (silver black plastic mulch and biodegradable plastic mulch), irrigation regimes (0.6, 0.8, and 1.0 ETc) and frequency (2, 3 and 5 days) on economic productivity of Bt. cotton. An experiment was undertaken consecutively for two years (2013-14 and 2014-15) to address this issue. Irrigation scheduling was done based on actual evapotranspiration measured with help of soil moisture sensors. The control treatment was taken as drip with no mulch. Silver black plastic mulch recorded the highest plant height (1.92m), number of sympodial (30.9) and monopodial branches (6.1), number of bolls (61.5), mean boll weight (4.77g), seed cotton yield (4661 kg ha-1), water use efficiency (20.48 kg ha-1mm-1) at 0.8 ETc and 3 days of irrigation frequency. These attributes increased with increase in irrigation regimes and decreased with increase in irrigation frequency in control treatment. The highest benefit cost ratio of 3.28 and internal rate of return of 141.52% was observed in silver black plastic mulch at 0.8 ETc and 3 days of irrigation frequency and the lowest was observed in no mulched treatment at 0.6 ETc and 5 days of irrigation frequency. [ABSTRACT FROM AUTHOR]

A field experiment was conducted during rabi season 2011-2012 at Research Farm, CCS Haryana Agricultural University, Hisar, Haryana (India) to study the periodic soil moisture depletion and ground water use by bed planted barley as influenced by cultivars, crop geometry and moisture regimes under shallow water table conditions. The experiment was laid out in split plot design with three replications keeping combinations of three cultivars viz., BH 393, BH 902 and BH 885 and two crop geometries viz 2 rows per bed and 3 rows per bed (70 cm wide with 40 cm top and 30 cm furrow) in main plots and three moisture regimes (irrigation at IW/CPE 0.3, 0.4 & 0.5) in sub plots. The results revealed that maximum soil moisture depletion (105 mm) and ground water contribution (62 mm) were recorded in BH 902, followed by BH 393 and BH 885. Among crop geometries, soil moisture depletion (96.6 mm) and ground water contribution (61 mm) were recorded higher in 3 rows per bed than 2 rows per bed. Among three moisture regimes, the soil moisture depletion (108 mm) and ground water contribution (65 mm) decreased with increase in moisture regime from irrigation at IW/CPE 0.3 to irrigation at IW/CPE 0.4 or 0.5. [ABSTRACT FROM AUTHOR]

The present paper focused on content, quality and composition of soil organic matter in different pedoclimatic zones of Bulgaria. The country has temperate continental climate with Mediterranean influence. There are six combinations of soil temperature and moisture regimes over the territory of Bulgaria, such as Thermic-Xeric, Mesic- Xeric, Mesic-Ustic, Mesic-Udic, Cryic-Udic and Pergelic - Udic. Typical soil types for Bulgaria are Chernozems, Luvisols. Vertisols, Cambisols, Phaeozems, Leptosols, Regosols, Planosols, Umbrisols and etc. Fifteen soil profiles were studied which are representative for the area. The content and composition of organic matter were determined according to the method of Kononova-Belchikova. The purpose of this study is to determine the influence of pedoclimatic conditions over soil organic matter content and composition of various areas with different soil cover, vegetation, management and etc. Grouping soil types in different soil temperature and moisture regimes shows that there are similarities in soil carbon content and composition. Soils developed under cooler and moister conditions accumulate more organic carbon. In such areas the content of organic carbon can reach about 255 t.ha-1 in a surface horizon and the type of humus is predominantly Fulvic. Respectively, soils developed under dry and warmer conditions have lower organic carbon content and the type of humus is usually Humic. [ABSTRACT FROM AUTHOR]

An experiment was conducted to evaluate the effects of water deficit on physiobiochemical and yield parameters on sorghum during rabi season (September 2009 to February 2010) in Maharashtra. The treatment combinations consisted of four moisture regimes viz., M1, M2, M3 and M4 upto harvest and six genotypes viz., Phule Yashoda, RSV-1006, Phule Chitra, Phule Vasuda, Phule Anuradha, Phule Maulee. The study revealed that, Phule Yashoda and Phule Revati genotypes had maximum mean growth parameters and hence had maximum yield and yield contributing characters at lower moisture regime M1 than non-stress condition M4. RSV-1006 and Phule Chitra genotypes had maximum total soluble sugar content. The proline content increased with a decrease in the soil moisture content in all the genotypes with predominance in Phule Maulee, Phule Chitra and Phule Anuradha which also reported positive correlation of proline accumulation with grain yield. The degree of reduction in protein content as a function of water stress was less in Phlule Maulee, Phule Chitra and Phule Anuradha respectively. The genotypes Phlule Maulee, Phule Chitra and Phule Anuradha had lowest nitrate reductase activity under moisture regime M1. Among the six genotypes, Phule Yashoda and Phule Revati showed higher grain yield and yield contributing parameters. The present study revealed that genotypes Phule Chitra and Phule Maulee are more suited under limited soil moisture condition. Irrespective of moisture regime Phule Yashoda and RSV-1006 found better than rest of genotypes. Therefore, these genotypes are well suited for medium soil under stress as well as non-stress conditions. [ABSTRACT FROM AUTHOR]

The abiotic stress such as water, temperature, and drought influences the production of pharmacologically important secondary metabolites of plant as a defense mechanism. Cassia angustifolia Vahl. is a potent medicinal plant which yields sennosides from its leaves and pods and grow well under water stress condition. Its leaves and pods are used for the treatment of habitual constipation as a safe herbal laxative. The present study aimed to determine the response of Cassia angustifolia Vahl. to water stress in terms of expression of targeted genes involved in the synthesis of its major secondary metabolites i.e., sennosides. The four moisture regimes i.e., 60% available soil moisture (ASM), 40% ASM, 20% ASM, and rainfed along with control were imposed from 20 days after seed sowing to the harvesting of the crop. The four ages of the plant (60 days, 75 days, 90 days, and 105 days) were taken for evaluation of differential gene expression due to water stress. Results demonstrated that water stress significantly affected the morphophysiological characters, sennoside content and gene expression. Sennosides determination was done by performing HPLC, which showed an increasing trend with increasing moisture stress. Proline, MDA, carotenoid, and electrolyte leakage were also increased in support of sennoside increment at higher moisture stress conditions. The gene expression, stress enzymes, and morphophysiological parameters such as chlorophyll, carotenoid, and Fv/Fm demonstrated a significant correlation of sennoside content. The RT-PCR analysis showed the upregulation of genes associated with the Mevalonate (HMGR, PMK), Shikimate (SDH, SMK, CS) , Menaquinone (menF) , and Glycosylation (UDPG) pathways at rainfed and 20% ASM conditions, suggesting their involvement in increased secondary metabolite production under moisture stress conditions. However, plant age does not have any significant effect on gene expression. [Display omitted] • Maximum yield of sennosides was reported in 20% ASM and rainfed condition. • Upregulation of SDH, SMK, CS and menF in 20% ASM and rainfed 60 days onwards. • Downregulation of all genes in 60% and 40% ASM at 105 days of plant age. • Mevalonate, Shikimate, and Menaquinone pathway genes are involved. • Enhancement in sennosides is interrelated with gene and metabolites under water stress. [ABSTRACT FROM AUTHOR]

Crop response to changing climate can be examined considering variability in thermal and moisture regimes using real time crop data. An analytical approach has been attempted to find the variations in productivity of groundnut grown under arid climate of Anantapur region in Peninsular India. Results revealed that increase in temperature has profound influence on productivity during deficit rainfall years. During the seasons with the seasonal rainfall less than 319 mm, increase in seasonal maximum temperature by 1°C resulted in decline of average productivity by 150 kg/ha. However, during the seasons with good rainfall of 477 mm, increase in maximum temperature by 1°C has resulted in decline of average productivity by 500 kg/ha. During dry seasons, an increase in minimum temperature by 1 and 2°C resulted in decreased average productivity by 400 and 800 kg/ha, respectively. It can be concluded that the groundnut productivity appeared to be more influenced by thermal regime compared to moisture regime. The analytical approach proposed in the present investigation can be extended to various crops and agro-climatic zones to understand the climate change effects on crop productivity in dryland ecosystems in particular. [ABSTRACT FROM AUTHOR]

This study was conducted with an objective of selecting the appropriate moisture regimes and to identify the key indicators of soil quality for different moisture regimes in NSLBC (LBC) of Nalgonda district of Andhra Pradesh. Soils are degrading due to several physical, chemical and biological constraints. Appropriate soil moisture regimes may help to check further soil degradation. This study was conducted in 2011 with six different soil moisture regimes of command and adjacent upland areas: command area- head reach, middle reach, tailend and upland area -- having assured irrigation, protective irrigation, rainfed. Sixty soil samples were collected from six different moisture regimes ten each from each moisture regime and were analyzed for physical, chemical and biological parameters. A standard methodology using principal component analysis (PCA) and linear scoring technique (LST) was adopted to identify the key indicators and for computation of soil quality indices. Among six moisture regimes, the soil quality index (SQI) ranged from 0.848 -- 0.945. The highest SQI was obtained in assured irrigation (0.945) followed by tail end (0.927) = protective irrigation (0.927), rainfed (0.897), head reach (0.889) while the lowest was under middle reach (0.848). The key indicators, which contributed considerably towards SQI, were bulk density, water holding capacity, organic carbon, dehydrogenase activity, available N, available Mn, ESP, available P, available K, pH and exchangeable Mg. [ABSTRACT FROM AUTHOR]

Background and Aims: Ecosystem recovery following disturbance requires the reestablishment of key soil biogeochemical processes. This long-term 7 year study describes effects of organic material, moisture, and vegetation on soil microbial community development in the Athabasca Oil Sands Region of Western Canada. Methods: Phospholipid fatty acid analysis was used to characterize and compare soil microbial community composition and development on reclaimed and natural forest sites. Additionally, we conducted a laboratory moisture manipulation experiment. Results: The use of forest floor material as an organic amendment resulted in a greater percent cover of upland vegetation and placed the soil microbial community on a faster trajectory towards ecosystem recovery than did the use of a peat amendment. The soil microbial composition within the reclaimed sites exhibited a greater response to changes in moisture than did the soil microbial communities from natural sites. Conclusion: Our research shows that the use of native organic amendment (forest floor) on reclaimed sites, and the associated establishment of native vegetation promote the development of soil microbial communities more similar to those found on natural forest sites. Additionally, soil microbial communities from natural sites may be more resistant to changes in soil moisture than those found on reclaimed sites. [ABSTRACT FROM AUTHOR]

Iron (Fe) deficiency is one of the serious nutritional disorders in aerobically grown rice on upland alkaline and calcareous soils, which leads to a decline in productivity. With a view to resolve the Fe-deficiency syndrome in aerobic rice, the influence of soil moisture regimes, farmyard manure (FYM) and applied Fe on the release of Fe was assessed under an incubation study. A field experiment was also conducted to evaluate the relative effectiveness of soil and foliar applications of Fe in alleviating Fe deficiency using four rice cultivars ('IR 36', 'IR 64', 'IR 71525-19-1-1' and 'CT 6510-24-1-2'). Results of incubation study indicated that the application of FYM marginally improved the diethylene triamine pentaacetic acid (DTPA)-Fe status of soil over control. However, application of iron sulfate (FeSO4 · 7H2O) at 14 mg Fe/kg with FYM released as much Fe as did the application of 27 mg Fe/kg as FeSO4 7H2O alone. Comparatively higher amounts of Fe were released under water saturation than that under drier soil moisture regimes and the effect of incubation period in releasing Fe was pronounced only under water saturation. Under field study, supplementation of Fe through integrated or inorganic source caused improvement in the DTPA and ammonium acetate (NH4OAc) extractable Fe similar to that recorded under incubation. The foliar application of Fe (3% FeSO4 7H2O solution, thrice at 40, 60, and 75 days after sowing of rice, i.e., 45 kg FeSO4.7H2O/ha) was most effective and economical in correcting Fe deficiency in aerobic rice, followed by soil application of 150 kg FeSO4.7H2O + 10 t FYM/ ha and 305 kg FeSO4.7H2O/ha. Among the rice cultivars, 'CT 6510-24-1-2' and 'IR 71525-19-1-1' performed better under aerobic condition compared to 'IR 36' and 'IR 64'. Differential response of rice cultivars to applied Fe was not related to Fe-nutrition; rather it was apparently related with inherent ability of cultivars to grow under water-stress condition. Ferrous iron (FeII) content in rice plants proved to be a better index of Fe-nutrition status compared to total plant Fe and chemically extractable soil Fe. The FeII concentration of ≥ 37 mg kg-1 in plants (on dry weight basis) appeared to be an adequate level at 60 days after sowing for direct seeded rice grown under upland aerobic condition. [ABSTRACT FROM AUTHOR]

The emphasis on integrated use of organic amendments and fertilizers has made it imperative to study the effect of crop residues and organic manures on urea hydrolysis, which governs the release of N from urea fertilizer. Urea hydrolysis in soils is an enzymatic decomposition process facilitated by the extracellular enzyme urease. Our aim was to assess the influence of crop residues (rice straw, wheat straw) and organic manures (poultry manure, farm yard manure, cowpea, and sesbania) on urea hydrolysis by conducting a laboratory incubation experiment employing a Hasanpur silt loam soil (coarse loamy, mixed, hypothermic Typic Haplustept). The study was conducted at a constant temperature of 33 ± 1°C at two moisture levels (1:1 soil:water ratio and field capacity). The results showed that the rate of urea hydrolysis decreased with an increase in time of incubation (12 to 96 h), while the disappearance of urea N was associated with the corresponding increase in ([image omitted] + [image omitted])-N content in soils treated with crop residues and organic manures. In the nonamended soil, the time required for the complete hydrolysis of the applied urea (200 μg urea N g-1 soil) was more than 96 h at both the moisture levels, whereas in amended soils, 60 to 72 h of incubation periods were required for urea hydrolysis. The rate of urea hydrolysis in the amended soil was of the following order: sesbania > cowpea > poultry manure > farmyard manure > rice straw and wheat straw, irrespective of the moisture regime. Urea hydrolysis followed first-order kinetics in all the treatments at both moisture levels. The rate constant value for urease activity was higher at field capacity, indicating that urea hydrolysis proceeded rapidly under the condition of field capacity rather than saturated conditions (1:1 soil:water ratio). [ABSTRACT FROM AUTHOR]

Desorption of Zn from sorbed Zn in soils is controlled by different moisture regimes in rice fields and thus control the Zn availability to rice. A laboratory experiment was conducted at different moisture regimes viz. flooded-dried, alternate wetting and drying and preflooding condition in two Inceptisols and two Alfisols of West Bengal, India, with (50 g kg-1) and without starch as control to investigate the desorption of adsorbed Zn from Zn-EDTA (0.0, 0.1, and 0.2 Mg Zn g-1 soil). Percent desorption of Zn was found significantly higher on alternate wetting and drying condition in Alfisols. Starch applications enhanced desorption under flooded-dried and alternate wetting and drying, but decreased it under preflooding conditions. The variations in Zn desorption among soils and moisture treatments are the result of changes in soil pH, Fe-oxides, bonding energy constants, and free energies for Zn adsorption. After desorption experiment a pot trial was conducted with rice (cv. IET-4094) under alternate wetting and drying moisture conditions. The results show that the dry matter yield and 1000 grain weight of rice are appreciably higher when alternate flooding and drying moisture condition was maintained. This finding was in close agreement with the Zn desorption studies under the alternate flooding and drying moisture regimes. [ABSTRACT FROM AUTHOR]

Summary 1. The effects of experimental long-term summer drought and irrigation on soil fauna were studied in a Norway spruce stand in south-western Sweden. The treatments, carried out over 8 and 10 years respectively, were chosen to simulate two scenarios of climate change, involving drier and wetter summers. 2. Different microarthropod communities developed in the different treatments. The abundances of enchytraeids, mesostigmatid mites and macroarthropod predators were all lowest in the drought plots. Drought decreased and irrigation increased the abundance and diversity of Oribatida. Drought decreased the abundance of Collembola. 3. The dominance structure of Oribatida and Collembola also changed, but less markedly. Drought affected community composition of both groups more than irrigation. 4. The study confirms that soil microarthropods can be useful environmental indicators, but their responses did not support the widely held view that deviations from a log-normal dominance structure indicates a stressed community. 5. The results also indicate that a drier climate with summer drought will lead to the local extinction of some soil animal species in this region. [ABSTRACT FROM AUTHOR]