Applied Boron Increases Alfalfa Petiole Boron Concentration across Water Regimes, Not Yield

Abstract

Boron (B) fertilization based on soil B status may prevent negative effects on alfalfa (Medicago sativa L.) yield and quality. Our objective was to determine the effects of foliar-applied B and water regimes on alfalfa yield and quality. A 2-yr (2016)(2017) study was done at Creston, MT in a fine sandy loam soil that tested 0.2 mg kg -1 B. Alfalfa was planted in 2016. Levels of B ranging from 0 to 2.24 kg B ha -1 were applied in association with three water regimes including rainfed, 50%, and 100% evapotranspiration (ET). There was no effect of B on yield or crude protein (P > 0.05) in either year. Both B fertilization and irrigation application increased petiole B concentration. In 2017, the water regime × B level interaction was significant specifically for the yield of the second cutting (P = 0.02), as well as for the relative feed value, neutral detergent fiber, and petiole B concentration in the third cutting (P < 0.05). Irrigation decreased (P < 0.01) forage quality only in the second cutting of 2016. Irrigation increased alfalfa yield by 45% in the establishment year (2016), but only by 12% in the following year. However, there was no yield difference observed (P > 0.05) between the 100ET and 50ET treatments each year, and irrigation water productivity decreased in the second year of alfalfa growth. The foliar application of B on a B-deficient soil did not increase yield or crude protein content of alfalfa, regardless of soil moisture availability. core Ideas• Application of B or irrigation increase petiole B concentration of alfalfa. • Increases of petiole B due to B fertilization did not increase alfalfa yield and crude protein.• Deficit irrigation did not reduce yield in alfalfa.• Regardless of water regime, application of B on B-deficient soil did not improve yield and crude protein of alfalfa.

Estimating fall‐harvested alfalfa (Medicago sativa L.) yield using unmanned aerial vehicle–based multispectral and thermal images in southern California

“…Additionally, rapid and timely yield estimations can help inform planning of harvest relative to farm labor, equipment, crop market demands, and environmental conditions. Alfalfa (Medicago sativa L.) is a major perennial forage crop well-known for its high dry matter yield, nutritional quality, and palatability (Higginbotham et al, 2008;Sapkota et al, 2019). In the United States, it was the fourth most widely grown crop with an approximate production of 50 million Mg of alfalfa and alfalfa mixtures from over 6.8 million ha of harvested area in 2019 (USDA-NASS, 2020).…”