Calcisol

Abstract: The utilization of chicken manure as an organic fertilizer is essential in improving soil productivity and crop production. We carried out the study to assess the effects of chicken manure on soil chemical properties and the response of application rate on the yield of spinach (Spinacia oleracea) as well as the uptake of nitrogen and phosphorus nutrients. To quantify these effects, we added chicken manure to samples of Calcisols, Arenosols and Luvisols at application rates: 5, 10, 20 and 40% chicken manure. The addition of chicken manure irrespective of application rate did not change the acidity or pH of Calcisol, suggesting its hypo-buffering capacity. While the results reveal increases of EC with increasing rate, at rate above 40%, the ECs were above the critical salinity level of 4 mS/cm indicating potential threat to soil productivity. The exchangeable bases increased with application rate, suggesting the positive effects of chicken manure in enhancing soil fertility. Similarly significant increase of nitrogen and phosphorus were observed following the addition of chicken manure. Initially the spinach yield increases up to optimum rate of 0.06, 0.07 and 0.16 g/plant for Luvisol, Arenosol and Calcisol, respectively and subsequently drops after critical threshold values; 15, 5 and 1% for Calcisol, Arenosol and Luvisol, respectively. Interestingly above the rate of 40%, the yield was almost zero for all soils, suggesting the ineffectiveness of chicken manure in enhancing soil productivity. Key words: Chicken manure, soil chemical properties, soil types, spinach (Spinaciaoleracea).

Abstract: In semi-arid areas under rainfed agriculture water is the most limiting factor of crop production. To investigate the best way to perform fallow and its effect on soil water content (SWC) and root growth in a barley (Hordeum vulgare L.) crop after fallow, an experiment was conducted on two soils in La Segarra, a semi-arid area in the Ebro Valley (Spain). Fallow was a traditional system used in these areas to capture out-of-season rainfall to supplement that of the growing period, usually lasting 16 months, from July to October of the next year. Soil A was a loamy fine Fluventic Xerochrept (Haplic Calcisol, FAO) of 120 cm depth and Soil B was a loamy Lithic Xeric Torriorthent (Calcaric Regosol, FAO) of only 30 cm depth. The experiment was continued for four fallow-crop cycles in Soil A and for two in Soil B. In Soil A, three tillage systems were compared: subsoil tillage (ST), minimum tillage (MT) and no-tillage (NT). In Soil B, only MT and NT were compared. In the fields cropped to barley, SWC and root length density (LV) were measured at important developmental stages during the season, lasting from October to June. In the fallow fields SWC was also monitored. Here, evaporation (EV), water storage (WS) and water storage efficiency (WSE) were calculated using a simplified balance approach. The fallow period was split in two 8-month sub-periods: July–February (infiltration) and March–October evaporation (EV). In Soil A, values of WSE were in the range 10–18% in 1992–1993, 1993–1994 and 1994–1995 fallow, but fell to 3% in 1995–1996. Among tillage systems, NT showed significantly greater WSE in the July–February sub-period of 1992–1993 and 1993–1994 fallow, but significantly lower WSE in the March–October sub-period, due to greater EV under NT. Consequently, no differences in total WSE were found between tillage systems. In Soil B, WSE was low, about 3–7%, and there were no difference between tillage systems. During the crop period, the differences in SWC and LV between tillage systems were small. Regarding yields, the best tillage system depended on the year. NT is potentially the best system for executing fallow, but residues of the preceding crop must be left spread over the soil.

Abstract: Strategic tillage (or occasional tillage) has been touted as a potential solution for the severe weed infestations of long-term no-till (NT). Nevertheless, there is little information on the influence of strategic tillage on microbial properties of Australian NT soils. In the present study, we assessed the influence of strategic tillage on the microbial properties of a seven years’ NT Calcisol in Moonie, Queensland, Australia. We tested the hypothesis that the application of one-time strategic tillage with chisel or offset disc does not cause major impacts on soil biological health in a NT system. Strategic tillage was applied once and soil samples were collected 13 months after tillage from the depths 0–10 and 10–20 cm. The measured biological indicators included soil microbial biomass carbon, catabolic activity (MicroResp™ assay) and total microbial activity (fluorescein diacetate method). The structure of bacterial communities was profiled by quantitative polymerase chain reaction (qPCR) and terminal reaction fragment length polymorphism (T-RFLP). Principal components analyses based on qPCR and T-RFLP data did not show tillage effects on soil bacterial communities. However, relative to the NT, chisel tillage led to significant increases in microbial biomass carbon (+34.4%), abundances of Alphaproteobacteria (+74.6%), Bacteroidetes (+113.7%) and Firmicutes (+36.5%), and the utilisation of D+ cellubiose (+178.4%) as well as mannitol (+167.2%) at 0–10 cm depth. In contrast, the influence of offset disc tillage was restricted to an increased abundance of Alphaproteobacteria (+64.6%) at 0–10 cm depth. Our study suggests that, overall, one-time strategic tillage using either chisel or offset disc had a minor positive influence on soil biological attributes of the NT Calcisol 13 months after tillage.