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Comparison of variable liming strategies in organic farming systems using online pH-measurements
(2011)
In organic farming, soil pH is one of the most important soil characteristics affecting nutrient availability, soil microbial activity and plant growth. Using the soil pH mapping sensor system Veris MSP, detailed information on in-field variability of soil pH can be obtained enabling spatial variable lime application. Scenario calculations for an organically managed field in Germany reveal that compared with the standard farm practice (i.e. uniform liming rate) variable lime application does not lead to higher costs while soil pH is optimized in different field zones resulting in increased crop productivity. Using two different lime qualities increases liming costs moderately but gives farmers the chance to increase pH quickly in extreme low pH areas.
Duckweed is gaining attention in animal nutrition and is considered as a potential alternative protein source for broiler chickens. In order to evaluate the nutritional value of duckweed, three individual batches were investigated. They consisted of a mixture of Lemna minuta and Lemna minor (A, 17.5% crude protein), Spirodela polyrhiza (B, 24.6% crude protein) and Lemna obscura (C, 37.0% crude protein). Treatment diets contained 50% batch A, 50% batch B, and 25, 50 and 75% of batch C. All diets were fed to broiler chickens (Ross 308) from an age of 21 to 27 days. Diets with a share of 50 and 75% of batch C led to decreased feed intake (109.3 and 74.9 g/day, respectively) compared to the control. Standardized ileal digestibility of crude protein and amino acids differed significantly between duckweed batches, at values for methionine between 49.9 and 90.4%. For all amino acids, batch A consistently had the lowest and batch C the highest digestibility. Batches had different tannin contents of 2943, 2890 and 303 mg/kg for batches A, B and C, respectively. The apparent ileal digestibility of phosphorus differed significantly between all batches (50.8–78.9%). Duckweed can be used as a protein feed for broiler chickens. However, a defined and stable biomass composition optimized for the requirements of broiler chickens is needed.
pH-Wert online messen
(2011)