Effect of applying filter cake and biogas manures on improving some desertic soil properties and their implications on plants grown thereon. II. Implications on plant growth

The present investigation aims at studying the implications of applying biogas manure and filter cake (Filter mud) as a natural soil amendments on   barely plant grown on desertic soils.  Two surface soil samples (0 - 30 cm) differed in their texture and calcium carbonate content were collected from El-Hammam region, north-western coast of Egypt. A pot experiment was carried out at the greenhouse of Soils and Water Department, Faculty of Agriculture, Benha University, Egypt, using perforated PVC pots of 5 kg capacity. Biogas manure and filter cake (filter mud) were added at a rate of 0, 1, and 2 % (w/w) and thoroughly mixed with the soil and incubated for two months at moisture equivalent to field capacity. Barely plant (Hordum vulgare cv. Giza 123) was used as an indicator plant. Ten grains were planted in each pot. Irrigation was done using tap water so as to reach the water holding capacity of the soil. After complete germination plants were thinned to 5 per pot.  Macronutrients; N, P and K were added to all pots according to the rates recommended by the Ministry of Agriculture. The experimental design was factorial randomized complete block design with two factors in three replicates. At maturity, the number of tillers and spikes and plant height were recorded. Plants were harvested and separated into grains and straw and analyzed for N, P and K.  The obtained results show that:
The number of tillers and of spikes per pot significantly increased with increasing the rate of application of both amendments from R0 up to R2, whereas plant height (cm) significantly and progressively decreased with the rate. Filter cake was more efficient than biogas manure in this respect.
Application of biogas manure and filter cake significantly and progressively increased straw and grain yields in the sandy loam soil (S1), whereas significantly and progressively increased straw yield and decreased grain yield in the loamy sand soil (S2) and there was significant difference between biogas manure and filter cake in this respect. Application of biogas manure and filter cake significantly and progressively increased N, P and K uptake in barley straw with increasing the rate of application and there was significant difference between the two amendments in this respect. Nutrients uptake in barley grains significantly and progressively increased with increasing the rate of the applied amendment except for N uptake in grains of barley plants grown on the loamy sand soil (S2), where it decreased with increasing the application rate.  In the case of the sandy loam soil (S1), biogas manure was more efficient than filter cake in increasing nutrients uptake in barley grains except for P uptake where filter cake was more efficient than biogas manure in this respect. In the case of the loamy sand soil (S2) biogas manure, also, was more efficient than filter cake in increasing P and K uptake in barley grains, whereas, both amendments decreased N uptake compared with R0 (non application of amendment) and the decrease was higher with the application of filter cake than with the application of the biogas manure. In conclusion the effect of the applied amendments on barley growth parameters, yield and nutrients uptake depends on the chemical properties and the rate of the applied amendment, and the soil characteristics developed upon the application of the organic amendment.