Effects of P, Ca with four k levels on nodule histology, nitrogenase activity and improved “Spanco”; peanut yields

Abstract

Soil fertility with effective nodulation and favorable mycorrhizal colonization favor production of high quality, sound mature peanuts within the warm humid and tropical regions of the world. Total top growth of well nodulated and mycorrhizal infected Spanco peanuts, grown on Dougherty sand loam, was depressed with only soil K additions but increased linearly with increased K amendment when combined with P + Ca. Mature peanut yields plant^‐1 increased with K additions only when combined with P, Ca or P + Ca treatments. Highly significant linear increases of improved marketable, mycotoxin free, sound mature kernels (SMK) resulted with K additions when combined with P and Ca. Nodules plant^‐1 increased significantly with Ca, P and P + Ca. Nitro‐genase = 1.7 top growth + 3.69 nut yield + 1.12% SMK + 3.89 nodules, R² = 0.78 and C.V. = 13.2%. Plant nutrient content of nodule cytosol increased significantly with soil addition of the corresponding element. Na decreased significantly with increased K. Nitrogenase = 11.2 P + 10.5 Ca + 5.4 K + 1.1 Mg ‐ 0.9 Na, R² = 0.727 and C.V. = 10.7%. Nodule cytosol lipid components were almost equally composed of acylglycerides and phosphoglycerides with significant correlation for nitrogenase activity (r = 0.69). Fatty acid composition was directly related to nodule histology and histochemical cytoenzyme transformations. Brilliant, iridescent anisotropic “Maltese Cross”; birefringence within nonrhizoidal cytosol was related to highly unsaturated phosphoglycerides. This dicroism, within endothelial parenchyma, was highest at anthesis and decreased significantly with increased plant and seed maturity being virtually absent at mature seed harvest, 120 day age from germination. Mycorrizal rootlets, colonized with Glomus fasciculatum were antibiosic to Rhyzoctonia solani, Fusarium oxysporum and Pythuim myriotylum.

Notes

Professor, Soil Microbiology, Oklahoma State Univ. Stillwater, 74078 and Associate, Pathology, Univ. of Florida, Gainesville, 32610.