水钾耦合对褐土养分及花生养分累积的影响

为明确水钾耦合对土壤养分含量及花生养分吸收累积量的影响,以"花育25"为试验材料,采用水分(35%,50%,65%,80%的田间持水量)和钾肥(0,0.15,0.30,0.45g K_2O/kg)2因素4水平随机区组设计,通过遮雨棚盆栽试验探讨水钾耦合下褐土有机质、全量(全氮、全磷和全钾)和速效养分(碱解氮、有效磷和速效钾)含量的变化,以及花生植株养分累积量的差异。结果表明:钾肥用量增加会促进有效氮的吸收;在土壤水分缺乏时,水分胁迫低钾(W_1K_1)和轻度胁迫低钾(W_2K_1)两个处理在土壤全磷含量下降时有效磷含量不降反增,这表明施入少量钾肥有助于旱地磷的释放。施低钾K_1(135kg/hm~2)促进土壤速效钾的增加及土壤养分的平衡,较初始土壤提高0.43~0.59倍,且随钾肥用量的增加而不断升高。相同钾肥用量下,花生植株氮、磷和钾累积量随灌水量的增加均呈上升趋势;氮吸收量仅在水分胁迫时随着钾肥用量的增多而先增后减;除水分充足(W_4)外,在其他灌水处理下植株磷累积量随钾肥用量的增加均表现为先增后降;而钾累积量在各土壤水分下均随钾肥用量的增加呈现"低-高-低"的变化趋势,最高值均在中钾K_2(270kg/hm~2)处理。花生植株对营养元素的吸收累积与总生物产量和荚果产量相关性均达显著(p0.05)或极显著(p0.01)水平,总生物量与荚果产量呈极显著(p0.01)相关。综合考虑土壤养分的可持续供应、花生养分的累积和产量形成,建议土壤水分保持在65%FC,钾肥(K_2O)用量控制在135~270kg/hm~2为宜。

Coupling Effects of Irrigation and Potassium on Soil Nutrient of Cinnamon Soil and Accumulation of Nutrient by Peanut

A pot experiment under the conditions of awning was conducted to clarify the coupling effects of different irrigation and potassium supply on the changes of soil organic matter,total nutrients (total nitrogen,total phosphorus,and total potassium) and available nutrients (available nitrogen,available phosphorus,and available potassium),and accumulation of nutrients by peanut (Arachis hypogaea Linn.),by using the random block design with two factors and four levels for each factor,i.e.Wl-35％ field capacity,W2-50％ field capacity,W3-65％ field capacity,W4-80％ field capacity,and K0-K2O 0 g/kg soil,K1-K2O 0.15 g/kg soil;K2-K2O 0.30 g/kg soil,Ka-K2O 0.45 g/kg soil.Peanut variety ‘Huayu 25’ was the tested material.The results showed that the absorption of available nitrogen was promoted as the potassium fertilizer amount was increased.Soil available phosphorus in W1K1 and W2K1 treatments increased with decreasing soil total phosphorus under water stress.It showed that a small amount of potassium fertilizer helped to the release of phosphorus for the dryland.The fertilizer K1 (135 kg/hm2) treatment could promote the increase of soil available potassium and soil nutrient balance,the concentration of available potassium in K1 was 0.43 to 0.59 times more than that in the initial soil,and increased with increasing potassium fertilizer amount.The accumulation of nutrients (N,P and K) by peanut showed a rising trend with increasing irrigation amount when the potassium fertilizer amount was the same.N uptake increased firstly and then decreased with increasing irrigation amount,but only under the condition of water stress.Except the adequate moisture treatment (W4),the accumulation of P by peanut increased firstly and then decreased with increasing K application in other water treatments.No matter how the water supply was changed,K accumulation showed a parabolic pattern with the increase of potassium supply,and all the maximal values appeared in the mild potassium (K2) treatment.The correlations between peanut nutrient accumulation and total biomass yield,and pod yield were significant or extremely significant,there was also a significant positive correlation between total biomass and pod yield.Based on the comprehensive consideration of sustainable soil nutrient supply,the accumulation of nutrients by peanut and the formation of yield,it was recommended to maintain the soil moisture at 65％ FC,and to control the amount of potassium fertilizer (K2O) at 135 kg/hm2 to 270 kg/hm2.