Fertility Status of Some Lateritic Soils of Birbhum District with Special Reference to Nitrogen, Phosphorus, Potassium and Sulphur

A laboratory experiment was conducted to study soil fertility status of some selected soils of Birbhum district of West Bengal with one hundred soil samples collected from five blocks viz., Mayureswar, Nalhati-1, Bolpur, Md Bazar and Rajnagar. The soils of this zone are characterized by sandy loam to sandy clay loam in texture and strong to moderately acidic in reaction. Total soluble salt content (EC as dSm-1) was found to be under very low level (<1.0) indicating the safe limit for soils, where low to medium organic carbon contents, low to medium in available N, P and K content, while available Sulphur content of all the soil samples was low.

Irrigation Salinity Risk Assessment and Mapping in Arid Oasis, Northwest China

Irrigation salinity is a common environmental threat for sustainable development in the Keriya Oasis, arid Northwest China. It is mainly caused by unreasonable land management and excessive irrigation. The aim of this study was to assess and map the salinity risk distribution by developing a composite risk index (CRI) for seventeen risk parameters from traditional and scientific fields, based on maximizing deviation method and analytic hierarchy process, the grey relational analysis and the Pressure-State-Response (PSR) sustainability framework. The results demonstrated that the northern part of the Shewol and Yeghebagh village has a very high salinity risk, which might be caused by flat and low terrain, high subsoil total soluble salt, high groundwater salinity and shallow groundwater depth. In contrast, the southern part of the Oasis has a low risk of salinity because of high elevation, proper drainage conditions and a suitable groundwater table. This achievement has shown that southern parts of the Oasis are suitable for irrigation agriculture; for the northern area, there is no economically feasible solution but other areas at higher risk can be restored by artificial measures. Therefore, this study provides policy makers with baseline data for restoring the soil salinity within the Oasis.

Effects of Different Flooding Frequencies on Soil Nitrogen Mineralization in Typical Floodplain Wetlands under Aerobic Conditions

Soil profiles from 0 to 80 cm depth were collected at five typical zones (including permanently flooded floodplain (B), 1-year floodplain (O), 5-year floodplain (F), 10-year floodplain (T), and 100-year floodplain (H)) which are divided by different flooding frequencies along the direction penperdicular to the river channel in different floodplain wetlands of Xianghai National Nature Reserve of China. A 14-day incubation experiment was carried out at 25°C in the dark to reveal the effects of different flooding frequencies on nitrogen mineralization rates. Our results showed that nitrogen mineralization rates showed an alternative tend of “increasing and decreasing”in the soil profiles at five sampling zones except the 1-year floodplain and permanent floodplain. The nitrogen mineralization rates were lower in permanently flooded floodplain soils compared to another four floodplain wetlands with different flooding frequencies. Additionally, nitrogen mineralization rates were significantly correlated with electrical conductivity, total soluble salt, pH values and salinity.

Effects of Soil Moisture on Nitrogen Mineralization in a Typical 10-Year Floodplain Wetland

Soil profiles from 0 to 80 cm depth were collected and a 14-day incubation experiment at three soil moisture levels (initial moisture, water holding capacity, and flooding) was carried out at 25°C in the dark to reveal the effects of soil moisture on nitrogen mineralization rates in a 10-yr floodplain wetland. Our results showed that nitrogen mineralization rates decreased with depth along soil profiles and the maximal nitrogen mineralization rates appeared at the 10-20cm soil layer. The nitrogen mineralization rates were higher under flooding treatment compared to another two soil moisture treatments. Nitrogen mineralization rates in the top 20cm soils exhibited an increasing tendency with increasing soil moisture. Additionally, nitrogen mineralization rates were significantly correlated with electrical conductivity, total soluble salt, and salinity under three soil moisture treatments.

The effect of growing media and concentration of nutrient solution on growth, flowering and macroelement content of media and leaves of Tymophylla tenuiloba Small

Effects of growing media and concentration of nutrient solution on growth, flowering, evapotranspiration and macroelement content of media and leaves of Tymophylla tenuiloba were evaluated under ebb-and-flow conditions. Two media: peat and peat + perlite (3:l, v/v), and four concentrations of nutrient solution: 1.0, 1.5, 2.0, 2.5 mS cm^-1 were applied. High quality plants were produced in both media and all concentration of nutrient solution. The lowest evapotranspiration was measured at the highest concentration of nutrient solution. N concentration of leaves was high in all treatments. Concentrations of K, Ca, and Mg decreased with increasing concentration of nutrient solution. Opposite was found for P. At the end of cultivation the lowest pH was measured in the upper layer of growing media. The highest total soluble salt level was measured in the upper layers. Upper layers accumulated more N-NO₃, P, Ca, and Mg. Mineral element content of both media was high in all concentrations of nutrient solution. Low concentration of nutrient solution at 1.0 mS cm^-1 is recommended, although <sup>-1<i>Tymophylla tenuiloba<sup>-1</i> can be also cultivated at higher concentrations of nutrient solution up to 2.5mS cm^-1, if placed on the same bench with other bedding plants requiring more nutrients.

Effect of second-pond dairy effluent on turnip dry matter yield, nutritive characteristics, and mineral content

Dairy farms in southern Australia generally use a 2-pond system to manage dairy shed effluent. This system consists of a deep anaerobic first pond and a shallow aerobic second pond. The liquid in the second pond contains a range of nutrients that may have agronomic benefits for forages. The effect of applying second-pond dairy effluent to a summer turnip (Brassica rapa L.) crop over 3 consecutive summer periods was measured. Effluent was applied at 6 rates, 0, 15, 30, 45, 60, and 75 mm, approximately 6–8 weeks after turnips were sown each year. Turnips were assessed for dry matter (DM) accumulation, nutritive characteristics, and mineral content. In addition, total annual production for years 1 and 2 was calculated by including the DM accumulation from annual ryegrass grown from autumn to spring each year. Concentrations of nutrients within the effluent as an average over the 3 years were 31, 454, 20, and 149 kg/ML for phosphorus (P), potassium (K), sulfur (S), and nitrogen (N), respectively. In addition, effluent also contained 152 kg/ML of calcium (Ca), 225 kg/ML of magnesium (Mg), and 529 kg/ML of sodium (Na). Soil pH was generally unaffected with effluent application, while soil EC and total soluble salt (TSS) content increased with effluent addition. In the first year, application of effluent at 15 mm and higher resulted in increases in available K; however, in subsequent years, rates of 45 mm and higher led to an increase in available K, while for the control and lower effluent rates there was a marked decline in K status. In all years there was a linear increase (P < 0.05) in leaf, root, and total DM yields with applied effluent. For leaf, responses were 19, 50, and 26 kg DM per mm applied effluent and for roots, 10, 39, and 25 kg DM per mm applied effluent for years 1, 2, and 3, respectively. In years 2 and 3, turnip leaf crude protein (CP) content increased (P < 0.05) in a linear manner at rates of 0.046 and 0.044% per mm applied effluent, respectively. There was also a linear increase (P < 0.05) in turnip root CP in years 2 and 3 of 0.033 and 0.021% per mm applied effluent, respectively. In all years there was a linear increase (P < 0.05) in leaf K content, while for root K there was a quadratic trend (P < 0.05) for year 1 and a linear increase (P < 0.05) for years 2 and 3. The results from this study indicate that the use of dairy effluent can increase DM yield and improve the nutritive value of turnips through an increase in CP content. The data also indicate that this effect can be maintained over consecutive years, which in turn may provide greater flexibility for returning effluent to farm land. While results appear to indicate that the primary responses are due to N, further work is required to determine the effects of water and other nutrients within dairy effluent.

Chemical Characteristics of Water Used for Cranberry Production

Since up to 2.4 m (8 ft) of water may be applied annually to cranberry beds for various production purposes, water quality can alter soil chemical properties and potentially affect plant health. Many cranberry plantings have recently been developed in nontraditional production regions and on atypical sites, wherechemical properties of the available water may differ from those in cranberry sites in the traditional production regions. Water currently being used for cranberry production was sampled from farms in most major production regions to characterize its chemical characteristics. High alkalinity in many samples was a concern, since alkalinity can increase soil pH above the desired level for cranberries. Total soluble salt concentrations and sodium adsorption ratios were seldom high enough to be of concern. Water samples from long-established plantings were lower in alkalinity, pH, and soluble salt concentrations than samples from newer plantings without production histories.

Reducing phosphorus leaching from sandy soils with red mud bauxite processing residues

This study used field lysimeters to investigate the reduction in the leaching of phosphorus (P) applied as superphosphate fertilizer from a very sandy Swan Coastal Plain soil treated with bauxite processing residue (red mud) neutralized with either waste gypsum from the phosphate industry or ferrous sulfate (copperas) from the titanium dioxide industry. Addition of 500 t ha-' red mud/gypsum or 200 t hap1 red mud/copperas were found to reduce the leaching of P to below 3 kg ha-l for application rates of 270 and 80 kgP ha-1, respectively. Water retention from these excessively well drained soils was increased by 14 and 50% by the addition of 200 and 2000 t ha-l red mud, respectively. The pH of the leachate for all rates of red mud/copperas application increased from approximately 4 to range between 7 and 7-5. The concentrations of Na and SO4 were about 8 and 17 g1-l, respectively, in the initial leachates collected from the 2000 t ha-' red mud treatment but declined to approximately 0.4 and 2.0g l-1 after 3 years of leaching. The Ca leaching appeared to be initially controlled by the solubility of the excess CaSO4 remaining after red mud neutralization, with concentrations ranging between 0.3 and 0.5 g l-1 before declining to approximately the levels for untreated soils of 0.01-0.06g l-1. The Na, So4 and Ca concentrations in the leachates from the 500 t ha-l red mud/copperas treated soil decreased to acceptable levels after 2 years. High total soluble salt (TSS) levels associated with high levels of residue application may affect pasture production in the years immediately following soil amendment

Numerical classification of saline groundwater chemistry in the Murrumbidgee irrigation area

Numerical classification techniques were used to examine the chemical composition of 169 shallow groundwater samples in relation to their geographical distribution within the Murrumbidgee Irrigation Area. The ionic proportions are very similar throughout the whole area, but the total soluble salt concentrations are very variable. The classification was more coherent when primary variables were used rather than derived variables such as Saturation Indices.