• Agricultural soil properties and crop production on Lithuanian sandy and loamy Cambisols after the application of calcareous sapropel fertilizer

      Bakšienė, Eugenija; Fullen, Michael A.; Booth, Colin A. (Taylor & Francis, 2006)
      Lake-derived organic-rich mud (sapropel) is used as a soil fertilizer on sandy loam Haplic Luvisols in Lithuania. Various application rates (50, 100, 150 and 200 t ha-1) were applied to crop rotations (maize, barley, clover, winter rye, potatoes and oats) and their subsequent long-term influences on soil physico-chemical properties and crop production determined. Soil agrochemical properties were evaluated before (1984 – 1985) and after the end of the first (1989 – 1990), second (1995 – 1996) and third (2001 – 2002) crop rotations from seven treatments with four replications. In most cases, after each crop rotation, there were notable increases in pH, total absorbed bases, total nitrogen content, available phosphorus and potassium and soil organic matter content (humus). After three rotations, changes in soil acidity, total nitrogen and humus on all sapropel treatments were significant (p < 0.05), but effects on phosphorus and potassium were not significant. In comparison, for most treatments, manure produced greater improvements in soil properties than sapropel. However, after 18 years of application, sapropel did improve crop productivity almost to the level achieved by applications of manure and fertilizers. Therefore, results demonstrate there are long-term benefits of sapropel applications, namely improvements in soil properties and crop productivity.
    • Carbon sequestration and relationship between carbon addition and storage under rainfed soybean–wheat rotation in a sandy loam soil of the Indian Himalayas

      Kundu, S.; Bhattacharyya, Ranjan; Prakash, Ved; Ghosh, B.N.; Gupta, H.S. (Elsevier, 2007)
      Soil organic matter (SOM) contributes to the productivity and physical properties of soils. Although crop productivity is sustained mainly through the application of organic manure in the Indian Himalayas, no information is available on the effects of long-term manure addition along with mineral fertilizers on C sequestration and the contribution of total C input towards soil organic C (SOC) storage. We analyzed results of a long-term experiment, initiated in 1973 on a sandy loam soil under rainfed conditions to determine the influence of different combinations of NPK fertilizer and fertilizer + farmyard manure (FYM) at 10 Mg ha−1 on SOC content and its changes in the 0–45 cm soil depth. Concentration of SOC increased 40 and 70% in the NPK + FYM-treated plots as compared to NPK (43.1 Mg C ha−1) and unfertilized control plots (35.5 Mg C ha−1), respectively. Average annual contribution of C input from soybean (Glycine max (L.) Merr.) was 29% and that from wheat (Triticum aestivum L. Emend. Flori and Paol) was 24% of the harvestable above-ground biomass yield. Annual gross C input and annual rate of total SOC enrichment were 4852 and 900 kg C ha−1, respectively, for the plots under NPK + FYM. It was estimated that 19% of the gross C input contributed towards the increase in SOC content. C loss from native SOM during 30 years averaged 61 kg C ha−1 yr−1. The estimated quantity of biomass C required to maintain equilibrium SOM content was 321 kg ha−1 yr−1. The total annual C input by the soybean–wheat rotation in the plots under unfertilized control was 890 kg ha−1 yr−1. Thus, increase in SOC concentration under long-term (30 years) rainfed soybean–wheat cropping was due to the fact that annual C input by the system was higher than the required amount to maintaining equilibrium SOM content.
    • Effect of tillage and crop rotations on pore size distribution and soil hydraulic conductivity in sandy clay loam soil of the Indian Himalayas

      Bhattacharyya, Ranjan; Prakash, Ved; Kundu, S.; Gupta, H.S. (Elsevier, 2006)
      Tillage management can affect crop growth by altering the pore size distribution, pore geometry and hydraulic properties of soil. In the present communication, the effect of different tillage management viz., conventional tillage (CT), minimum tillage (MT) and zero-tillage (ZT) and different crop rotations viz. [(soybean–wheat (S–W), soybean–lentil (S–L) and soybean–pea (S–P)] on pore size distribution and soil hydraulic conductivities [saturated hydraulic conductivity (Ksat) and unsaturated hydraulic conductivity {k(h)}] of a sandy clay loam soil was studied after 4 years prior to the experiment. Soil cores were collected after 4 year of the experiment at an interval of 75 mm up to 300 mm soil depth for measuring soil bulk density, soil water retention constant (b), pore size distribution, Ksat and k(h). Nine pressure levels (from 2 to 1500 kPa) were used to calculate pore size distribution and k(h). It was observed that b values at all the studied soil depths were higher under ZT than those observed under CT irrespective of the crop rotations. The values of soil bulk density observed under ZT were higher in 0–75 mm soil depth in all the crop rotations. But, among the crop rotations, soils under S–P and S–L rotations showed relatively lower bulk density values than S–W rotation. Average values of the volume fraction of total porosity with pores <7.5 μm in diameter (effective pores for retaining plant available water) were 0.557, 0.636 and 0.628 m3 m−3 under CT, MT and ZT; and 0.592, 0.610 and 0.626 m3 m−3 under S–W, S–L and S–P, respectively. In contrast, the average values of the volume fraction of total porosity with pores >150 μm in diameter (pores draining freely with gravity) were 0.124, 0.096 and 0.095 m3 m−3 under CT, MT and ZT; and 0.110, 0.104 and 0.101 m3 m−3 under S–W, S–L and S–P, respectively. Saturated hydraulic conductivity values in all the studied soil depths were significantly greater under ZT than those under CT (range from 300 to 344 mm day−1). The observed k(h) values at 0–75 mm soil depth under ZT were significantly higher than those computed under CT at all the suction levels, except at −10, −100 and −400 kPa suction. Among the crop rotations, S–P rotation recorded significantly higher k(h) values than those under S–W and S–L rotations up to −40 kPa suction. The interaction effects of tillage and crop rotations affecting the k(h) values were found significant at all the soil water suctions. Both S–L and S–P rotations resulted in better soil water retention and transmission properties under ZT.
    • Long-term effects of grass ley set-aside on erosion rates and soil organic matter on sandy soils in east Shropshire, UK

      Fullen, Michael A.; Booth, Colin A.; Brandsma, R.T. (Elsevier, 2006)
      The contribution of ryegrass (Lolium perenne) ley set-aside to soil conservation and soil organic matter (SOM) content was investigated. Ten runoff plots (7–15°, 12–27% slope) at the Hilton Experimental Site, Shropshire, UK, were put to a grass ley in April 1991. Runoff and erosion rates during 9 years were low, despite the occurrence of potentially erosive rains. Mean runoff was 0.24 ± 0.20% (±S.D.) of precipitation (n = 89 plot-years), compared with a 15-year mean value of 0.13 ± 0.04% on permanent (control) grassland. Mean erosion rate was 0.21 ± 0.14 t ha−1 year−1 (n = 69 plot-years). Erosion rate and slope were poorly correlated, suggesting leys are highly effective for soil conservation. Mean SOM content increased consistently and significantly on the set-aside plots from 20.4 g kg−1 in 1991 to 31.1 g kg−1 in 2001. Contrary to the usually strong relationship between SOM and clay content, the percentage silt exhibited a stronger correlation with SOM than percentage clay content. Furthermore, there were equally strong correlations between SOM and cumulative particle size fractions of both clay and silt contents. In the absence of significant quantities of clay in these sandy soils, silts assist binding of SOM, which has significance for assessing soil carbon sequestration potential.
    • Soil Organic Matter Changes in Lithuanian Soils: Experiences and Results

      Jankauskas, Benediktas; Jankauskienė, Genovaitė; Fullen, Michael A.; Booth, Colin A.; Slepetiene, Alvyra (Lithuanian Institute of Agriculture, 2009)
      Data has been obtained from sandy loam Eutric Albeluvisol-ABe at the Kaltinenai Research Station of the Lithuanian Institute of Agriculture on the undulating topography of Western Lithuania. Results from 18 years of investigations show significant increases in soil organic matter (SOM) content under grass-grain crop rotations compared with field and grain-grass crop rotations, which thus provides evidence for carbon sequestration in soil.