Effect of Application of Soil Amendments in Deficit Irrigation Conditions on the Yield and Physical Productivity of Maize in Khoram Abad Region

Iran is located in the dry belt of the earth and its rainfall is one third of the global average. Therefore, proper management of water resources is necessary, especially in the agricultural sector. For this purpose, in 2022, a research was conducted with the aim of investigating the effect of several soil amendments in Khorram Abad region, in the research farm of Lorestan University. The experiment was factorial with a randomized complete block design in three replications. Treatments were irrigation water at 4 levels of I1=100%, I2=80%, I3=60%, and I4=40% of the water requirement and different soil moisture amendments including vermicompost (C) 6 t/ha, biochar (B) 1.5 t/ha, superabsorbent (S) 63 kg/ha, and organic mulch (M) 7.5 t/ha and the control treatment (I). Results showed that the highest productivity, biological yield, and plant height were related to I1-C treatment, which were 126.71 t/ha, 46.27 t/ha and 2.35 meters, respectively. The highest water productivity and biological productivity at the probability level of 5% was I2-C, which was calculated as 16.79 kg of fresh fodder/m3 of irrigation water and 5.9 kg of dry matter/m3 water. In general, vermicompost and biochar also increased the fresh and biological yield, height, and water productivity of corn. The use of mulch in 100% and 80% treatments had better effect, but with the increase in water stress (i.e. I3 and I4), effect of mulch decreased (5.3% and 1% relative to the control). Superabsorbent in I100, I80, I60 treatments showed lower effect (9.3%,7.2%, 3% less fresh weight than the control, respectively). However, with increasing stress, I4 had better results (7.6% higher fresh yield than the control). Therefore, in Khorram Abad region, the amount of 6 t/ha of vermicompost and 80% of the water requirement applied by drip tape irrigation for fodder corn is recommended to increase the production rate while saving 20% of water consumption.