红壤旱地上4种冬绿肥适宜播种量研究

A study of the appropriate seeding rates for four winter green manure crops in an upland red soil of Southern China

以红壤旱地4种冬绿肥(鼠茅草、毛叶苕子、冬油菜和肥田萝卜)为研究对象,通过田间试验研究不同播种量对供试绿肥品种生物量、养分含量和养分积累量的影响,以期确定4种冬绿肥在红壤旱地的适宜播种量,为绿肥种植提高土壤肥力、保障红壤区农业可持续发展提供理论依据。试验设5个播种量处理,分别为15、30、45、60和75 kg·hm^(-2)。结果表明,随播种量增加,4种冬绿肥地上部生物量(鲜重和干重)呈先上升后下降或趋于平稳的变化趋势。所有播种量处理中,鼠茅草在30 kg·hm^(-2)播种量下生物量最大,而其余3种绿肥生物量达最大时的播种量为60 kg·hm^(-2)。播种量显著影响绿肥植株体内碳、氮、磷、钾、钙和镁元素的含量,不同绿肥品种的同一养分元素含量对播种量的响应也有明显差异。4种绿肥养分元素的积累量均随播种量增加呈先上升后下降的变化趋势。综合考虑绿肥的生物量和养分积累量,通过回归方程拟合发现,本试验条件下鼠茅草、毛叶苕子、冬油菜和肥田萝卜在红壤旱地上的适宜播种量范围分别为30.7~32.7 kg·hm^(-2)、50.4~63.4 kg·hm^(-2)、53.5~61.4 kg·hm^(-2)和63.0~80.1 kg·hm^(-2)。

This research studied effects of seeding rate in four winter green manure crops:Vulpia myuros,Vicia villosa,Brassica napus and Raphanus sativus,sown in a field trial in an upland red soil.The trial included five seeding rate treatments:15,30,45,60 and 75 kg·ha^(-1).The effects of the different seeding rates on aboveground biomass,nutrient contents and nutrient accumulations of the tested varieties were investigated to determine the appropriate seeding rates of the four winter green manures,and to provide the relevant technical information for increasing soil fertility by green manure planting,so as to ensure sustainable agricultural development in the red soil region.It was found that the aboveground biomass(fresh and dry weight)of the four winter green manures followed a pattern of increase with increasing seeding rate at lower seeding rates and then decreased or tended to be stable at higher seeding rates.The biomass of V.myuros was highest when sown at the seeding rate of 30 kg·ha^(-1),while biomass of the other three crops was highest when sown at 60 kg·ha^(-1).Seeding rates significantly affected elemental concentrations of carbon,nitrogen,phosphorus,potassium,calcium and magnesium of the various green manure crops.Also,particular nutrient elements of different green manure crops responded differently to crop seeding rate.The nutrient accumulation of the four green manure crops increased with increasing seeding rate at lower seeding rates,and decreased at higher seeding rates.From multivariate evaluation of biomass and nutrient accumulation and based on regression equations,the appropriate seeding rates of V.myuros,V.villosa,B.napus and R.sativus in upland red soil under this experimental condition were 30.7-32.7 kg·ha^(-1),50.4-63.4 kg·ha^(-1),53.5-61.4 kg·ha^(-1) and 63.0-80.1 kg·ha^(-1),respectively.