Effect of PGPR and mixed cropping on mycorrhizal status, soil fertility, and date palm productivity under organic farming system

A field study was carried out for two years at an organic farm under arid climate in Morocco to investigate the effect of an integrated biofertilization approach on Arbuscular Mycorrhizal Fungal (AMF) abundance and infectivity, soil fertility, yield, and fruit quality of date palm. The biofertilization approach included three management practices namely application of compost, inoculation with a consortium of native PGPR strains originally isolated from date palms of Drâa-Tafilalet region (Pseudomonas koreensis, Serratia nematodiphila, S. marcescens, and Klebsiella sp.) and using mixed-cropping with sorghum. Accordingly, four treatments were established in this study: 1) mixed-cropping with sorghum, 2) PGPR inoculation, 3) sorghum + PGPR, and 4) control (without sorghum or PGPR). All treatments received compost as organic amendment. Results revealed that mixed-cropping with sorghum significantly increased AMF colonization intensity and spore density by more than 50% and 29%, respectively. Sorghum association also resulted in a significant increase in organic matter concentrations of up to 2.95% against 2.45% in monocropping soils. The integrated biofertilization approach resulted in the highest yield with an increase rate of 10.6% and 12.1% in the first and the second year, respectively compared to date palms receiving compost alone. Similarly, the mineral composition and quality characteristics of date fruits were significantly improved. The enhancement of soil fertility and date palm productivity under harsh environmental conditions represents a first step towards the adoption of sustainable practices in the region and in similar areas

Effect of Organic Amendment on Soil Fertility, Mineral Nutrition, and Yield of Majhoul Date Palm Cultivar in Drâa-Tafilalet Region, Morocco

The low fertility in soils where date palms are grown in Morocco is the first cause leading to low yields when compared to other producing countries. The aim of this study is to investigate the effect of organic amendment on mineral nutrition and yield of Majhoul date palm cultivar under Moroccan oasis conditions in relation with soil fertility. A field study was carried out for 2 years at two farms located at different sites in Drâa-Tafilalet region (Jorf and Tinjdad). The effect of different fertilization treatments on soil organic matter mineralization, soil mineral nutrients, plant nutrition, and date palm yield was investigated. The four treatments that were studied in this experiment are described as follows: mineral nitrogen (urea), organic amendment (compost), organic amendment combined with mineral nitrogen, and control with no fertilization. The compost, alone or combined with urea, enhanced the soil fertility through the improvement of the soil organic matter content and its mineralization and the increase in soil macro- and microelement concentrations at two depths compared to the urea alone and the control. The mineral nutrition of date palms was significantly enhanced by applying compost and/or urea. The application of compost combined with urea, for 2 years, increased the yield at Jorf farm by more than 78% and at Tinjdad farm by 41%. The adoption of the fertilization management, based on the application of both compost and urea, could restore the degraded soils, increase the date palm yield, and ensure more returns to farmers