The effect of the previous crop on the growth,nitrogen uptake and yield of winter barley intended for malting

Winter barley which received a range of nitrogen rates, was grown at Rothamsted as a test crop after winter oats, winter barley, winter beans, oilseed rape or potatoes, to compare the effects of previous crop on growth and N uptake. In the autumn following the first year crops, the largest amount of residual inorganic N found in the soil was after potatoes, the smallest after oats. Throughout the second season the heaviest crops of barley, which also contained the most N, were after potatoes, and the lightest were after barley. To produce grain with a N concentration of less than 1.8% N (w/w, dry wt), acceptable for malting, it was found that not more than 75 kg N ha⁻¹ after barley and 125 kg N ha⁻¹ after oats, 100 kg N ha⁻¹ after beans and 50 kg N ha⁻¹ after rape or potatoes could be applied. The results demonstrated that barley of acceptable quality for malting can be grown after a break crop, providing that the rate of N fertiliser is suitably adjusted to take account of the residual fertility, but the results do not suggest that residual soil N affects the grain N concentration differently to N applied as fertiliser early in the season.     

Effects of single and multiple waterloggings on the growth and yield of winter wheat on a clay soil

The response of winter wheat to surface waterlogging in monoliths of clay soil in lysimeters was studied. The treatments, selected as corresponding to the most extreme likely in Britain, were: 5 days of waterlogging in October between germination and emergence; 42 days of waterlogging during tillering in January and February; and 21 days from mid-April during stem elongation. These treatments were used singly and in all combinations and were compared with a freely-drained control. During waterlogging, the oxygen concentration in the soil declined most rapidly when the soil was warmer (in October and April) and at the shallower depths (5, 20cm): also, a decrease in soil solution nitrate was accompanied by an increase in nitrous oxide evolution. Pre-emergence waterlogging restricted plant population to 35 m^?2 compared to 338 m^?2 under free drainage. Subsequently, compensatory growth resulted from diminished interplant competition for nitrogen, water and light: a greater proportion of tillers survived and the flag leaves were larger, although ears at harvest were fewer in all treatments waterlogged before emergence. After waterlogging during tillering, grain loss was accounted for entirely by a decrease in the number of ear-bearing tillers. After waterlogging during stem elongation, yield losses were associated primarily with fewer grains per spikelet. Grain yield was depressed by about 4–12% after single waterloggings, by 20% after any two waterloggings, and by 32% when plants were waterlogged on all three occasions.     

Effect of nitrogen and manure fertilizer on grain quality,baking and rheological properties of wheat grown in sandy soil

Winter wheat was grown under various nitrogen (N) fertilizer regimes (with/without manure application) under calcareous sandy soils, control wheat being grown without fertilization. Six levels of N fertilizer were applied. The technological and baking characteristics of the wheat were closely related to N and nitrogen + manure (NM) fertilization. Contents of protein increased with increase in fertilization level, which also improved the rheological properties of dough and baking quality. N fertilization increased farinograph stability time, which increased with increasing flour protein content. NM fertilization affected protein content as well as farinograph stability time and farinograph maximum viscosity, thereby affecting the relationship between these properties. The increase in bread volume due to fertilizers was more noticeable with NM than with N. Application of 60 t ha^?1 manure along with 200 kg ha^?1 N onwards improved technological properties of flour in comparison with wheat grown with the basic N fertilizer only. Copyright © 2005 Society of Chemical Industry     

氮营养水平对植烟土壤养分含量及土壤酶活性的影响

田间试验研究了植烟土壤不同土层养分含量及土壤酶活性的变化规律。结果表明:在同一氮水平条件下,随着土层深度的增加,土壤有机质、全氮、速效氮、速效磷、速效钾以及土壤脲酶,蛋白酶,转化酶活性均呈降低趋势,通过方差分析可知,各处理间差异达到5%显著水平;0~40 cm土层范围内,随着施氮量的增加,土壤有机质、全氮、速效氮含量也增加,土壤脲酶活性增加,而蛋白酶活性呈降低趋势,转化酶活性呈先增加后降低的趋势,且在该土层范围内,酶与土壤养分之间存在显著或极显著的相关关系;60~80 cm土层范围内,氮对土壤养分及土壤酶的影响能力相对降低。以上说明在植烟土壤-土壤养分-土壤酶相互作用的系统中,土壤养分含量和土壤酶活性明显受氮营养水平和土层深度的共同影响。     

Effects of long-term herbicide use,irrigation and nitrogen fertiliser on soil fertility in an apple orchard

In 1972 an experiment was set up to investigate the long-term effects of herbicide, irrigation and two rates of nitrochalk fertiliser application on soil fertility in a Cox's Orange Pippin apple orchard. Samples taken in 1986 showed that uncultivated soil which had been maintained bare by herbicide had much lower organic C, total N and extractable K and Mg concentrations than soil which had been maintained under grass. Extractable P concentrations were lower in soil under grass than in soil under herbicide. In the absence of grass, soil pH was slightly lower than in its presence. All these effects were much greater at depths above 7·5 cm than below. Irrigation of the grass slightly increased organic C and total N levels at 0–7·5 cm compared with unirrigated grass but had no effect on extractable P, K and Mg. Increasing the fertiliser rate from 63 to 189 kg N ha^?1 had no effect on organic C, total N, extractable P and K. Yet, throughout the soil profile, extractable Mg concentrations were greater at the low than at the high N fertiliser rate. In a seedling growth test on soil taken from the orchard in 1988 (and confirmed to be free from residual herbicide), apple seedlings grown in soil which had previously been under grass grew significantly better than those in soil which had been bare. These differences were ascribed to a greater rate of N mineralisation in the soil formerly under grass. The results of this trial indicate that to safeguard soil fertility it is necessary to maintain a grass cover in the orchard. In addition, fertiliser application on newly planted trees should be adjusted to take account of the presence or absence of grass in the previous soil management treatment.     

Effects of soil management systems and nitrogen fertiliser on the firmness and mean fruit weight of Cox's Orange Pippin apples at harvest

The firmness and mean fruit weight, at harvest, of Cox's Orange Pippin apples from a soil management and N fertiliser trial planted in 1972 were measured from 1979 to 1985 (excluding 1984). Trees growing in overall herbicide, or in 0.3-m herbicide-treated strips with irrigated grassed alleyways, produced significantly softer and/or larger apples than those from trees growing in unirrigated grass with narrow (0.3 m) or wide (1.7 m) herbicide-treated strips in 1982 and 1983. Both these years had drier than average summers. N fertiliser applied annually produced slightly larger and softer apples at 189 kg N ha^?1 than at 63 kg N ha^?1.     

滴灌方式及定额对北疆冬灌棉田土壤水盐分布及次年棉花生长的影响

为探寻解决干旱区棉田冬季灌水问题,明晰北疆棉田不同冬灌方式及灌水定额对土壤水分、盐分分布以及翌年棉花生长及产量的影响,采用大田试验方法,以未冬灌大田作为对照(CK),设置滴灌和漫灌2种灌水方式下4个梯度的灌水定额(1 800、2 400、3 000、3 600、 3600 m3/hm²)共9个处理进行冬灌试验,分析了冬灌灌水后到播种前0~300 cm土层的水分、盐分的动态变化以及翌年各处理棉花的出苗率、群体生理指标(群体光合势、群体净同化率、叶面积指数)和产量数据。结果表明,冬灌对次年播前土壤水盐分布及含量的大小均具有一定的影响,无论漫灌还是滴灌方式进行冬灌,随灌水定额增加土壤水分和盐分的影响深度也随之加深,灌水定额达到3 000和3 600 m3/hm²时,冬灌对土壤水盐影响深度可达300 cm。冬灌可显著改变次年播前土壤盐分的自然分布状态,有效淋洗并降低上层土壤盐分含量;相对漫灌方式而言,滴灌冬灌方式土壤水分入渗更加均匀且规律明显。冬灌对次年滴灌棉花的生长发育及产量均具有重要影响,冬灌后次年棉花群体指标与未冬灌处理的差异随冬灌灌水定额的增加愈加显著,灌水定额3 000 m3/hm²滴灌冬灌处理的次年棉花群体光合势与叶面积指数较未冬灌处理分别提升34.30%和42.60%;冬灌有利于次年棉花产量的提高,滴灌冬灌灌水定额3 000、3 600 m3/hm²处理时的棉花产量相对未冬灌处理分别增产10.66%和12.36%。综合考虑冬灌方式及灌水定额对次年土壤水盐分布及棉花生长和产量的影响,研究认为滴灌条件下灌水定额3 000 m3/hm²的冬灌在试验条件下比较适宜,既可淋洗盐分至耕层以下300 cm处,亦可获得6 107.75 kg/hm²的较高产量。