Effect of compost amendments on soil physicochemical properties, plant growth and efficient use of water, nitrogen and phosphorus in maize (zea mays l).

Abstract

Compost is used across the world to sustain soil fertility and crop yield. This investigation consists of two experiments, which were conducted at BUAN greenhouses and farmers field in the Central District of Botswana in the period November 2018 to April 2019 involving maize (Zea mays.L). The experiments were carried out to test the hypotheses that soil amendments with compost as organic fertilizer improved soil physico-chemical properties, plant growth, WUE, NUE and PUE of maize under irrigated and drought stressed conditions. A completely randomized block design was used with the following treatments; (1) Soil + Urea (SU), (2) Soil + Urea + Compost (SUC), (3) Soil + Compost (SC), (4) and Soil (Control) replicated four times. The treatments for greenhouse trial comprised of two levels of irrigation, (W1= stressed at flowering stage, W2= irrigated). Data was collected on soil physico-chemical properties, plant growth, water use efficiency (WUE), nitrogen use efficiency (NUE) and phosphorus use efficiency (PUE). The results showed that compost amendments significantly increased soil pH, EC, CEC, total carbon, total N, available P and cation exchange capacity (CEC). This study also revealed that WUE improved in stressed plants compared to irrigated plants; drought stressed treatments were more water use efficient than the irrigated treatments. PUE and NUE in SC and SUC were maintained higher than in control and SU under both conditions. The highest NUE 24.66kg/kg was exhibited for SUC treatments under irrigated condition as compared to the rest of the treatments. Moreover, SUC and SC recorded the highest PUE 210.35kg/kg and 141.89kg/kg under irrigated condition and 24.71kg/kg and 20.37/kg/kg under drought stressed condition respectively. In conclusion combination of compost and urea fertilizer significantly enhanced NUE, PUE and WUE in maize. These could decrease the amount of fertilizer and water-use required for the sustainable production in maize under unstressed and stressed environment