套作春玉米氮磷钾化肥和有机肥合理配比的生产函数分析

采用田间试验的方法，对苏南地区麦玉米稻三热制中套作春玉米的合理施肥量肥料配比进行了研究。     

水稻栽培因素对北方粳稻产量及米质的影响[Ⅵ]--穗肥追肥时间对产量及米质的影响

通过田间对比试验研究穗肥追施时间对水稻产量及米质的影响,结果表明,水稻的穗肥追施时间越晚,加工品质越好,而产量和食味品质明显降低.这种趋势以出穗前25 d为准,有跳跃式的质的变化.所以为了提高产量和增加食味品质,水稻的穗肥追肥时间不应晚于出穗前25 d.     

内蒙古锡林浩特地区土壤-牧草-家畜系统中Cu、Fe、Zn、Mn、Mg、Se六种元素含量的分析

对内蒙古锡林浩特地区土壤，牧草，家畜（羊）被毛中6种元素含量进行了测定。结果表明：土壤硒含量于缺乏的临界水平；尖草，羊草及针草中锌含量低于羊正常生长对锌的需求数量，兔毛草及羊草中的硒的含量很低，不能满足其正常生长需要，被毛中硒含量低于临界值，提示羊群缺硒。     

肥料三要素与日本落叶松苗木生理的关系

对肥料三要素与日本落叶松苗木生理的关系进行了研究，结果表明，叶绿素含量与氮、磷肥关系密切（rN=0.91^**,rp=0.61^**)；混施三要素比单施氮肥能提高苗木根系吸收能力；并且三要素混施比单施氮肥提高苗茎纤维素含量，平均提高10．7％。生产上适宜三要素施肥比例为N：P2O5：K2O＝1：0．6：0．4。     

Effects of Time and Rate of Nitrogen and Phosphorus Application on the Growth and the Seed and Oil Yields of Canola (Brassica napus L.)

A field study was conducted to investigate the influence of variable rates of application of N and P fertilizers in splits at various times on the growth and the seed and oil yields of canola (Brassica napus L.) during 1995–97. Rates of fertilizer application were 0 and 0 (F0), 60 and 0 (F1), 0 and 30 (F2), 60 and 30 (F3), 90 and 60 (F4) and 120 and 90 (F5) kg N ha^?1 and kg P₂O₅ ha^?1. All the P was applied at sowing while N was applied in splits, i.e. all at sowing, half at sowing and half with first irrigation, or half at sowing and half at flowering. The responses of growth, seed yield and components of yield were consistent in both years. Increasing the rate of fertilizer application from F4 (90/60 kg N/P₂O₅ ha^?1) to F5 (120/90 kg N/P₂O₅ ha^?1) increased the leaf area index (LAI) relative to the control and to lower rates of fertilizer application. For both crops, application of 90/60 kg N/P₂O₅ ha^?1 significantly enhanced total dry matter (TDM) and seed yield. Seed yield increased mainly due to a greater number of pods per plant and seeds per seed‐pod. The time of fertilizer application did not significantly affect seed yield or components of yield in either season. Oil yield generally followed seed yield, increasing with increasing rate of fertilizer application up to 90/60 kg N/P₂O₅ ha^?1. The maximum oil contents were obtained from the control. The results show that seed and oil yields of canola were maximized at the F4 (90/60 kg N/P₂O₅ ha^?1) rate of application under the agro‐ecological conditions of Faisalabad, Pakistan.     

Temperature,Mg and Al Interaction Effects on Grass Tetany Potential of Ryegrass Forage1

Two annual ryegrass (Lolium multiflorum Lam.) cultivars differing in Al sensitivity were grown in nutrient solution at pH 4.2 to assess the effects of temperature (10/6 and 22/18 °C day/night), Mg (0.1 and 1 mM) and Al solution concentrations (0, 3.7 and 74 μ M) on several factors influencing grass tetany potential of forage. Added Al depressed Mg and Ca shoot concentrations and increased shoot K/(Ca + Mg) equivalent ratio especially after prolonged treatment at higher temperature and lower Mg solution concentrations. These effects were more pronounced in the relatively Al-sensitive cultivar Wilo which appeared to be less Mg-efficient as well. Grass tetany potential will therefore be higher following a temperature rise if Al-sensitive ryegrass is grown in a medium containing low Mg and high Al levels.     

不同施肥量对甜荞主要产量指标的影响

通过对定西地区甜荞不同施肥量下株高、分枝数、产量、降水利用效率等指标的综合比较认为,最佳的施肥量为:施纯N22.5kg/hm2、P2O530.46kg/hm2、K2O65.48kg/hm2,其对应株高73.4cm,分枝数4.4个,产量896.18kg/hm2,降水利用效率5.38kg/(hm2·mm)。     

Function of controlled release fertilizer in maintaining high agronomic use efficiency and minimizing environmental pollution in rice field of southern China

Development and use of controlled release fertilizer （CRF） in southern China, potential advantages of CRF in increasing rice yield and nutrient use efficiency were introduced, as well as its role of minimizing rice field＇s environmental contamination was discussed. Meanwhile, some suggestions were proposed.     

磷酸二铵作水稻基肥的效果

在水稻上进行不同基肥施用对比试验 ,结果表明 :分别用磷酸二铵 15 0、2 2 5kg/hm2 ,与习惯用碳铵 3 75kg/hm2 +普钙 3 75kg/hm2 作基肥的水稻相比 ,产量分别增加 169.5和 3 15kg/hm2 ,增产 2 .3 %和 4.4% ,达显著水平。用磷酸二铵代替碳铵和普钙作水稻基肥 ,具有省力、增产等优点。