EURASIAN JOURNAL OF SOIL SCIENCE

1-12

Authors: Khuram Shahzad Ahmad, Naghmana Rashid, Sundus Azhar

Sorption and desorption efficiency of Chlorosulfuron that is sulfonylurea herbicide was checked by selecting different minerals and two types of Pakistani soils that were different on spatial scale. In Pakistan, sulfonylurea herbicide is being used against wide varieties of broad leaf weeds and for some grasses as well. Results obtained after the experimental work showed that adsorption co-efficient isotherm for Chlorosulfuron in tested soils data well fitted the Freundlich equation. In all the cases, slope n<1 was resembling the C type curve and isotherm was nonlinear. Due to low adsorption, distribution co-efficient (Kd) parameters were also low. Results indicated that soil samples (silt loam) collected from northern hilly areas Ayubia, Khyber Pukhtunkhwa showed more adsorption for Chlorosulfuron herbicide i.e. 25.5% than the sandy soil of Multan Punjab. The major difference between the sorption capacities of both of the soil was due to the difference in soil organic matter and soil pH. Among both these factors, organic matter plays more significant role in sorption. Adsorption efficiency of synthesized compounds on different soil types of known composition can be predicted by the adsorption and desorption results of the present study.

17 - 23

Authors: Mingli Zhang, Hao Yang, Biao Xie, Panpan Sun, Jing Li, Jun Zou, Yanhua Wang

The change from forest to agricultural land in the last three decades represents a significant shift in land use in China. This study was conducted to evaluate how change from forest to greenhouse cabbage production affected soil organic carbon (SOC) and total nitrogen (TN) stocks in surface soil. Our results showed that converting forest to greenhouse vegetable production led to increases in SOC and TN concentrations and stocks, and decreases in C:N ratio in the top soil. The accumulation rates of SOC and TN in the surface soil (0-40cm) were estimated to be 4.638 Mg ha-1 yr-1 and 1.113 Mg ha-1 yr-1 respectively, over an average period of 8 years after change of forest to greenhouse vegetable production. We conclude that greenhouse vegetable production system could be an effective strategy to improve SOC and TN stocks in the subtropical Dianchi lake watershed.

30 - 38

Authors: Gülay Karahan, Sabit Erşahin

Many studies have been conducted to predict soil saturated hydraulic conductivity (Ks) by parametric soil properties such as bulk density and particle-size distribution. Although soil morphological properties have a strong effect on Ks, studies predicting Ks by soil morphological properties such as type, size, and strength of soil structure; type, orientation and quantity of soil pores and roots and consistency are rare. This study aimed at evaluating soil morphological properties to predict Ks. Undisturbed soil samples (15 cm length and 8.0 cm id.) were collected from topsoil (0-15 cm) and subsoil (15-30 cm) (120 samples) with a tractor operated soil sampler at sixty randomly selected sampling sites on a paddy field and an adjecent grassland in Central Anatolia (Cankırı), Turkey. Synchronized disturbed soil samples were taken from the same sampling sites and sampling depths for basic soil analyses. Saturated hydraulic conductivity was measured on the soil columns using a constant-head permeameter. Following the Ks measurements, the upper part of soil columns were covered to prevent evaporation and colums were left to drain in the laboratory. When the water flow through the column was stopped, a subsample were taken for bulk density and then soil columns were disturbed for describing the soil morphological properties. In addition, soil texture, bulk density, pH, field capacity, wilting point, cation exchange capacity, specific surface area, aggregate stability, organic matter, and calcium carbonate were measured on the synchronized disturbed soil samples. The data were divided into training (80 data values) and validation (40 data values) sets. Measured values of Ks ranged from 0.0036 to 2.14 cmh-1 with a mean of 0.86 cmh-1. The Ks was predicted from the soil morphological and parametric properties by stepwise multiple linear regression analysis. Soil structure class, stickiness, pore-size, root-size, and pore-quantity contributed to the Ks prediction significantly (P<0.001, R2 = 0.95). Soil morphological properties can be used along with basic soil properties in predicting Ks.

47 - 52

Authors: Mahmoud Radaei, Masomeh Izadi

The study was conducted to evaluate the effects of spruce (Picea abies), alder (Alnus subcordata), and spruce with alder and maple (Picea abies with Alnus Subcordata and Acer cappadocicum) plantations on the soil properties and earthworm’s abundance and biomass in the Lajim, north of Iran. Soil sampling with 50 × 50 cm samples to 50 cm depth in the studied stands was conducted in order to measure soil and earthworm abundance and biomass. Soil texture, C, N, pH, K, and P were measured in all samples in the laboratory. Earthworm’s abundance was measured by handpicked and dried for 48 h at 60 °C and then the biomass was measured per unit area. The results showed that the percentage of organic carbon, N, and C/N ratio reached the climax and acidity had the lowest value in spruce stand, and K was significantly higher in alder stand. The maximum and minimum abundance of earthworms was observed in alder and spruce stands, respectively. The results of this study support the effects of plantations on soil properties, earthworm abundance, and biomass.

62 - 73

Authors: Jiang Houlong, Wang Daibin, Xu Chen, Liu Shuduan, Wang Hongfeng, Yang Chao, Li Najia, Chen Yiyin, Geng Lina

Sampling methods are important factors that can potentially limit the accuracy of predictions of spatial distribution patterns. A 10 ha tobacco-planted field was selected to compared the accuracy in predicting the spatial distribution of soil properties by using ordinary kriging and cross validation methods between grid sampling and simple random sampling scheme (SRS). To achieve this objective, we collected soil samples from the topsoil (0-20 cm) in March 2012. Sample numbers of grid sampling and SRS were both 115 points each. Accuracies of spatial interpolation using the two sampling schemes were then evaluated based on validation samples (36 points) and deviations of the estimates. The results suggested that soil pH and nitrate-N (NO3-N) had low variation, whereas all other soil properties exhibited medium variation. Soil pH, organic matter (OM), total nitrogen (TN), cation exchange capacity (CEC), total phosphorus (TP) and available phosphorus (AP) matched the spherical model, whereas the remaining variables fit an exponential model with both sampling methods. The interpolation error of soil pH, TP, and AP was the lowest in SRS. The errors of interpolation for OM, CEC, TN, available potassium (AK) and total potassium (TK) were the lowest for grid sampling. The interpolation precisions of the soil NO3-N showed no significant differences between the two sampling schemes. Considering our data on interpolation precision and the importance of minerals for cultivation of flue-cured tobacco, the grid-sampling scheme should be used in tobacco-planted fields to determine the spatial distribution of soil properties. The grid-sampling method can be applied in a practical and cost-effective manner to facilitate soil sampling in tobacco-planted field.