Nutritional status, Na+ and Cl- concentrations, and yield of sugarcane irrigated with brackish waters

ABSTRACT Salinization reduces the osmotic potential of soil solutions and promotes the accumulation of toxic ions (Na+ and Cl-) in plants, causing nutritional imbalance and yield reductions. Thus, the objective of the present study was to evaluate foliar concentrations of nutrients and Na+ and stalk yields in sugarcane RB92579 under different electrical conductivities of irrigation water and leaching fractions (LF). The experiment was conducted in drainage lysimeters in a 5 × 2 factorial scheme with five electrical conductivities of irrigation water - ECw (0.5, 2.0, 4.0, 6.0, and 8.0 dS m-1) without (LF1 = 0) or with a leaching fraction (LF2 = 0.17), and four replicates. Increased ECw decreased the concentrations of N, P, K, Mg, S, Fe, Mn, Cu, and Zn and increased those of Ca, Cl, and Na, reducing the biomass production in two cycles (plant-cane and first ratoon). The use of a leaching fraction of 0.17 mitigated the deleterious effects of salinity on nutrient concentration and yield.

摘要：土壤盐渍化会降低土壤溶液的渗透势，促进植物体内有毒离子（Na⁺和Cl⁻）积累，引发营养失衡并导致产量下降。本研究旨在评估不同灌溉水电导率（electrical conductivity of irrigation water, ECw）与淋洗份额（leaching fraction, LF）条件下，甘蔗RB92579的叶片养分浓度、Na⁺含量及茎秆产量。实验采用5×2因子试验设计，在排水渗漏计中开展，设置5个灌溉水电导率水平（ECw：0.5、2.0、4.0、6.0、8.0 dS·m⁻¹），以及2个淋洗份额处理（无淋洗LF1=0、淋洗份额0.17 LF2=0.17），共4次重复。结果显示，随着ECw升高，N、P、K、Mg、S、Fe、Mn、Cu、Zn的养分浓度显著降低，而Ca、Cl、Na的浓度则升高，抑制了两个生长周期（新植蔗与头季宿根蔗）的生物量生产。施加0.17的淋洗份额可有效缓解盐渍化对养分浓度与产量的有害影响。