ABSTRACT
The sequence of the preceding crops in a no-tillage farming system, could interact with the integrated use of mineral and organic nitrogen (N) sources in a way that improves the growth and productivity of the terminal maize crop, meanwhile, enhancing its N use efficiency (NUE). In the current study, six legume-cereal crop sequences, including faba bean, soybean, Egyptian clover, wheat, and maize were evaluated along two experimental rotations that ended up by planting the terminal maize crop. In addition, the effects of applying variable mineral nitrogen (MN) rates with and without the incorporation of farmyard manure (FYM) on the productive performance of maize and its NUE were tested. The field experiments were conducted in a no-tillage irrigated farming system in Northern Egypt, a location that is characterized by its arid, Mediterranean climate. Results revealed that increasing the legume component in the evaluated crop sequences, up to 75%, resulted in improved maize ear leaf area, 1000-grain weight, and harvest index, thus, a higher final grain yield, with the inclusion of Egyptian clover was slightly better than faba bean. Comparing the crop sequences with 50% legume contribution uncovered the positive effects of soybean preceding crop on the terminal maize crop. Substituting 25% of the applied MN with FYM resulted in similar maize yields to the application of the equivalent 100% MN rates. The fertilizer treatments significantly interacted with the crop sequences in determining the maize grain yield, where the highest legume crop contribution in the crop sequence (75%) equalized the effects of the different fertilizer treatments on maize grain yield. The integrated use of FYM with MN in maize fertilization improved the NUE compared to the application of MN alone. Comparing fertilization treatments with similar MN content, with and without FYM, revealed that the difference in NUE was attributed to the additional amount of FYM. In similar conditions to the current study, it is recommended to grow faba bean two years before maize, while Egyptian clover could be grown directly preceding maize growth, with frequent inclusion of soybean in the sequence, this could be combined with the application of an average of 200 kg MN ha-1 in addition to FYM.
ABSTRACT
BACKGROUND: Berseem clover is the main forage crop grown in Mediterranean regions. There are plenty of cultivars that possess variability in their productivity and quality among the different cuts. Therefore, accurate agronomic and qualitative characterization is crucial for selecting the most promising cultivars for breeding and feeding purposes. In the present study, the agronomic characteristics, ruminal degradability and fermentation measures of five cuts of the five most prominent Egyptian beseem clover cultivars (Helaly, Serw, Giza6, Gemmeza1 and Sakha4) were evaluated. RESULTS: The Giza6 cultivar produced a significantly higher fresh yield and high whole plant dry matter content on the 3rd cut. Giza6 was among the superior cultivars in crude protein content and had the highest values of gas production at the 3rd cut, and ruminal degraded acid detergent fiber and propionate concentrations at the 2nd cut, at the same time as presenting the lowest ammonia concentrations at the 3rd and 5th cuts. Overall, the 3rd cut produced significantly higher fresh yield across all cultivars, except for Sakha4. The 3rd cut also produced a higher leaf to stem ratio compared to the 4th and 5th cuts. The 1st three cuts had higher degraded neutral detergent fiber than the 4th and 5th cuts. The 1st cut was characterized by low propionate concentration in the Helaly and Gemmeza1 cultivars compared to the other cuts. CONCLUSION: Expanded production of the high-yielding, high-quality cultivar Giza6 is recommended. When harvesting, three cuts is optimal for berseem clover cultivation for breeding and feeding programs. © 2020 Society of Chemical Industry.
