Possibility of Allelopathic and Residues Effects of the Rotated Crops on Productivity, Chemical Composition, Nitrogen Utilization of Wheat (Triticum aestivum) and Soil Fertility

Aims: To evaluate the possibility of allelopathic effects of the rotated crops on productivity, chemical composition, N utilization of wheat and soil fertility.

Study Design: A split plot design with three replications was used. The main plots were assigned with three previous crops, The sub plots were assigned by three nitrogen fertilizer rates (0, 35 and 70 kg N fed-1).

Place and Duration of Study: A field study was carried out at Sakha Agricultural Research Station farm, ARC, Kafr El-Sheikh governorate, Egypt, during two successive seasons of 2016/2017and 2017/2018

Methodology: The local wheat cultivar (Sids 12) was sown after three crops (fahl berseem) after rice, (Drawa) after rice and Fallow after rice as preceded crops.

Results: The results showed that fahl berseem roots and residues in the clover (berseem)-wheat rotation secreted biologically active chemical compounds which have a positive effect on growth and development of wheat. The preceding clover (fahl berseem) wheat rotation appeared to be promising for wheat productivity, N, P, K concentrations, N-uptake, N utilization, protein content of wheat grain and straw, availability of N, P and K after wheat harvest compared with fallow after rice, green maize (drawa-wheat rotation). The interaction between the preceded crops and N fertilizer rates was significantly for all the studied traits. The highest performance of wheat traits were observed when wheat was grown after fahl berseem and fertilized with 70 kg N.fed-1. While the lowest performance was obtained following cereal crops rice (fallow) and the lowest N level in both seasons. Treatment of fahl berseem with nitrogen fertilizer (70 kg N.fed-1) had given a best values from grain yield with relative increments of (37.54%) compared with preceding rice-wheat rotation and (23.26%) compared with rice-drawa rotation.

Conclusions: Cereal winter crops can be sow after preceding legume crops rather than summer cereal crops. We can sow fahl berseem crop as a forage to animals after cereal crop (rice) and before sowing wheat crop to improve soil properties and its availability of the essential elements and consider additional revenue to farmer. Fahl barseem had be sown in the end of august month after rice crop to produce approximetly 20 ton fresh forage.fed-1 (~ 9 ton dry grass.fed-1) which provides farmers with (~ 9 thousands EL) in 88 days only.