Broiler litter and inorganic nitrogen fertilizers influence on earliness and yield on strawberry and cabbage

Author.Comparison of broiler litter (BL) rates to inorganic nitrogen fertilizers was studied during 1994-1995 as to its effect on earliness and yield of strawberry and cabbage grown on a calcareous soil. Strawberry (Frag aria x ananassa Duch.cv.Oso Grande) was grown using BL at rates which supplied 100 (BL1) or 200 (BL2) Kg N/ha, ammonium nitrate or nitrogen+trace elements applied at 150 Kg N/ha in six equally split applications throughout the growing season. Crop yield was higher (P<0.05) under the BL treated plots with the higher rate of the BL yielding the highest. Yields ranged between 172.4 to 324.4 g/plant. Fruit number per plant ranged from 14 to 24 frt/plant among the treatments and was highest (P<0.05) under the BL2 treatment. Earliness was comparable among all treatments (P<0.05); nevertheless, it was more pronounced under the BL treated plots. Leaf nitrate-nitrogen and total P, though not significant, were higher (P>0.05) under the litter treated plots especially the BL2 rate. Leaf Fe was comparable among treatments (P>0.05) and no Fe chlorosis symptoms were observed, even though the soil is calcareous. Residual soil nitrate-nitrogen was comparable (P>0.05) among all the treatments with the ammonium nitrate and the BL2 having the highest values, indicating that BL at 200 Kg N/ha apparently released an amount of N equivalent to that from the 150 Kg N/ha of ammonium nitrate. Available soil P (water soluble), although comparable among treatments (P>0.05), was higher under the BL treated plots especially at the 200 Kg N/ha rate reflecting the P content of the manure. It is recommended to apply BL at a rate of 200 Kg N/ha to fertilize strawberry over the use of inorganic N fertilizers at similar rates. O-S-Cross cabbage (Brassica oleracea var. Capitata) was tested using the same rates of BL described previously, ammonium nitrate or nitrogen+trace elements at 125 Kg N/ha split as 25 Kg N/ha early in the season, 50 Kg N/ha just before heading, and 50 Kg N/ha at heading. Total yield and marketable yield were higher under the inorganic treated plots than under BL (P<0.05), and yield ranged from 5.7 to 11.1 Kg/m2. The higher yields under the inorganic N fertilizer treated plots were also reflected in leaf nitrate-nitrogen. Leaf blade P was comparable (P>0.05) among all treatments indicating a high soil P level at the beginning of all treatments before heading (P>0.05) and at heading, where as at first harvest it was higher (P<0.05) under the nitrogen-trace elements treatment. Residual soil nitrate-nitrogen was comparable among all treatments (P<0.05) and was above the sufficiency level. Soil water soluble P was higher (P<0.05) under the BL treated plots indicating a more release of P in the litter treated plots. It is concluded that cabbage yield may not get increased by the use of poultry litter instead of inorganic N fertilizers, as only with the inorganic N fertilizers their application could be coincided with the peak demand for N by the developing heads