Calcium nutrition of the sugarbeet

Abstract

When sugarbeet seedlings are transferred from a complete nutrient solution to one from which Ca has been withheld, the rootlets and tops fail to develop. The same transfer at the eight‐leaf stage causes the rootlets to become stubby and swollen at the tips and blade expansion becomes modified; particularly the upper portions of the blades attaining nearly full development, which pucker and often develop a cupping or hooding effect; a unique symptom characteristic of Ca deficiency. As each new leaf develops, the blade area becomes smaller until only a black tip remains at the apex of the petiole, which is the symptom referred to as tip‐burn for this petiole and the successively . shorter petioles formed as Ca deficiency increases in severity. Strangely, these symptoms also appear during periods of rapid growth when the nutrient solution contains as much as 10 to 28 milliequivalents per liter of Ca or when soils are high in Ca. This implies that Ca absorption and possibly translocation limits the Ca supply at the growing point. Increasing Mg in the nutrient solution decreases Ca uptake and increases Ca deficiency. Potassium deficiency, unexpectedly, induces Ca deficiency apparently by decreasing the translocation of Ca to the growing point.

These phenomena suggest the hypothesis that when ion absorption takes place from the root exchange site that has the affinity for H > Ca > Mg > K > Na, then the H generated internally replaces, and the roots absorb, Na, K and Mg preferentially. Externally, Ca would be adsorbed preferentially from the nutrient solution by the exchange complex, and with the addition of Mg, it would compete for the common adsorption site of Ca and limit Ca absorption internally. Under these conditions potassium‐deficient nutrient solutions would not induce Ca deficiency by decreasing Ca absorption but rather by decreasing Ca translocation. Theoretically, Ba would replace H more readily than Ca on the exchange complex, and therefore, Ba would be adsorbed preferentially and Ca uptake would increase. This effect of Ba was verified experimentally.

Since the translocation of ⁴⁵Ca to the growing point was found to be unrestricted under Ca‐sufficient and Ca‐deficient conditions and since the formation of insoluble Ca compounds such as phosphate or oxalate did not account for the Ca deficiency at the growing point, the cause of the Ca deficiency at the growing point is most likely the higher priority of the storage root for Ca over tops when leaf blades and storage root are both expanding rapidly. However, Ca retransport from older to younger parts of the sugarbeet plant may be restricted by the formation of Ca phosphate under Ca‐deficient conditions and Ca oxalate under Ca‐sufficient conditions.

Calcium deficiency increases net photosynthesis per unit blade area initially, probably because of blade puckering, but not on a per unit chlorophyll basis.     

Nutritional composition,growth and enzymatic response of vetiver grass grown under crude oil contamination as influenced by gibberellic acid and surfactant

Abstract

Although crude oil contamination is a constraint for crop production, some plants can develop under crude oil contaminated conditions by utilizing crude oil as nutrients after decomposition. A greenhouse trial was conducted to investigate growth, nutritional composition and enzymatic response of vetiver grass in confronting with crude-oil contamination as affected by gibberellic acid (GA) and Tween 80. Application of GA or co-application of GA with Tween 80 significantly increased mean shoot dry weight. Application of Twee 80 alone or in combination with GA significantly increased mean root dry weight as compared to control which was attributed to the effectiveness of Tween 80 alone or in combination with GA on the removal of total petroleum hydrocarbons from polluted soil. Application of crude oil diminished shoot phosphorus, iron, zinc and manganese uptakes. Application of GA and Tween 80, however, compensated the decrease in nutrient uptakes in vetiver grass resulted from crude-oil contamination. Application of crude oil at both 2 and 4% (W/W) levels increased catalase (CAT) activity and proline (PRO) content. Superoxide dismutase (SOD) activity increased only following the application of 2% crude oil level, while addition of all amendments decreased CAT activity. Addition of GA decreased activity of SOD. None of the studied amendments had a significant effect on PRO content. Application of a combination of GA and Tween 80 under crude oil contamination are recommendable since such treatments not only inhibited adverse effect of crude oil on nutrients uptake but also caused that vetiver grass tolerated high level of crude oil contamination.     

Physical activation of biochar and its meaning for soil fertility and nutrient leaching – a greenhouse experiment

The slow alteration of the surface of charred biomass (biochar) over time may contribute to an improved nutrient retention and thus fertility of tropical soils. Here, we investigated soils from temperate climates and investigated whether a technical steam activation of biochar could accelerate its positive effects on nutrient retention and uptake by plants relative to nonactivated biochar. To this aim, we performed microcosm experiments with sandy or silty soil, mixed with 2.0, 7.5 and 15.0 g/kg soil of fine (<2 mm) or coarse‐sized (2–10 mm) biochar from beech wood (Fagus sp.). After initial fertilizer (NPK), ashes and excess nutrients were leached with water, and the microcosms were planted for 142 days with Italian Ryegrass (Lolium multiflorum ssp. italicum). Thereafter, leachate, soil and plant samples were analysed for their nutrient contents. The results showed that biochar additions of ≤15 g/kg soil left elevated contents of available P and N in the surface soil but reduced their uptake into the plants. As a result, total biomass production was unchanged. Different particle size and application amounts influenced these findings only marginally. Nitrate leaching was enhanced in the sandy soil (+41% for nitrate, but reduced in the silty soil ?17%) and P was immobilized. Hence, the fertility of the temperate soils under study was only marginally affected by pure biochar amendments. Steam activation, however, almost doubled the positive effects of biochars in all instances, thus being an interesting option for future biochar applications.     

紫色土地区秸秆覆盖耕层土壤养分动态分析

通过田间试验,研究了不同秸秆(水稻秸秆和玉米秸秆)不同量覆盖条件下早地油菜株高、花序数和分枝数的差异,以及0～10cm和10～20cm土层土壤有机质、全氮、碱解氮、全磷、有效磷、全钾、速效钾和pH的动态变化过程,并进行了产量分析.结果表明:秸秆覆盖处理下油菜株高高于对照,有速腐剂处理的株高最高;秸秆覆盖处理花序数多于对照;速腐剂处理下一级分枝数高于不加速腐剂处理;覆盖处理的有机质和碱解氮含量均略高于对照;加速腐剂覆盖处理的产量最高.     

园地主要经济作物氮磷钾与PH相关性研究

为了解古田县果园作物土壤氮、磷、钾养分状况,探讨了果园土壤氮、磷、钾含量与土壤pH值之间的关系。结果表明,古田县园地土壤pH的平均值为5.07,处于酸性水平;全氮的含量均值为1.20g/kg,总体处于中等水平;供试园地土壤碱解氮均值为143.4mg/kg,处于中等水平;供试土壤有效磷均值为29.90mg/kg,处于丰富水平;速效钾含量均值为59.2mg/kg,处于严重缺乏水平。土壤中的氮、磷、钾养分状况与土壤中的pH值呈显著或极显著正相关。因此,改良土壤酸度是供试果园土壤改善氮、磷、钾养分供应的主要措施。     

水、氮供应和土壤空间所引起的根系生理特性变化

在限制根系生长的胁迫条件下.,研究了补充和不补充供应水、氮对玉米根系生理特性及养分吸收的影响。结果表明.,正常生长条件下.,水、氮供应促进了根系生长.,增加了根系吸收总面积、活跃吸收面积和TTC还原量.,促进了根系对养分的吸收.,从而提高了产量.;限制根系生长.,水分的作用与正常条件下相同.,氮素的作用则受控于土壤水分。补充灌水增强了氮肥作用.,供氮促进了根系生长.,改善了根系生理特性.,减少了限制根系生长所引起的不良影响.;不补充灌水限制了氮肥作用的发挥.,供氮导致了根系生物量和生理特性下降.,加重了限制根系生长的不良影响。     

Effects of Moringa oleifera silage on milk yield,nutrient digestibility and serum biochemical indexes of lactating dairy cows

This study investigated the effects of Moringa oleifera (MO) as a partial substitute of alfalfa hay on milk yield, nutrient apparent digestibility and serum biochemical indexes of dairy cows. MO was harvested at 120 days post‐seeding. Fresh MO was cut, mixed with chopped oat hay (425:575 on a DM basis), ensiled and stored for 60 days. Sixty healthy Holstein dairy cows were allocated to one of three groups: NM (no MO or control), LM (low MO; 25% alfalfa hay and 50% maize silage were replaced by MO silage) or HM (high MO; 50% alfalfa hay and 100% maize silage were replaced by MO silage). The feeding trial lasted 35 days. The LM and HM diets did not affect dry matter (DM) intake, milk yield or milk composition (lactose, milk fat, milk protein and somatic cell count). The apparent digestibility of DM and NDF was lower for HM group than NM group. Additionally, there were no significant differences in serum biochemical indexes between the LM and NM groups. The HM group had lower serum concentrations of total cholesterol, high‐density lipoprotein cholesterol, and low‐density lipoprotein cholesterol and higher serum concentrations of urea than the NM group. The partial replacement of alfalfa hay (≤50%) and maize silage with MO silage had no negative effects on milk yield, in vivo nutrient apparent digestibility or serum biochemical indexes of lactating cows.     

Effects of the nitrification inhibitor dicyandiamide on soil mineral N, pasture yield, nutrient uptake and pasture quality in a grazed pasture system

Recent lysimeter studies have demonstrated that the nitrification inhibitor, dicyandiamide (DCD), can reduce nitrate (NO) leaching losses from cow urine patches in grazed pasture systems. The objective of this study was to quantify the effects of fine particle suspension (FPS) DCD on soil mineral N components, pasture yield, nutrient uptake and pasture quality under grazed pasture conditions. A field study was conducted on the Lincoln University dairy farm, Canterbury, New Zealand, from 2002 to 2006. FPS DCD was applied to grazed pasture plots at 10 kg ha^?1 in early May in addition to applied cow urine patches at a nitrogen (N) loading rate of 1000 kg N ha^?1, with DCD reapplied in early August. Soil mineral N levels in the urine patches were monitored. Pasture yield, N and cation concentrations and uptake were measured in treatment urine patches and inter‐urine areas of the pasture. Comparisons were made with control plots which did not receive DCD. NO levels under the DCD‐treated urine patches (0–7.5 cm) were in the order of 10 kg N ha^?1 compared with 40–80 kg N ha^?1 under untreated patches, and soil ammonium (NH) levels were consistently higher under the DCD‐treated patches. The DCD significantly and consistently increased pasture yield in both the urine patches, and inter‐urine areas of the pasture in all 4 years of the trial. Mean annual dry matter (DM) yields over 4 years were inter‐urine areas, 10.3; inter‐urine + DCD, 12.4; urine, 12.4 and urine +DCD 16.0 t DM ha^?1, representing an average DM yield increase of 20 and 29% in inter‐urine and urine patch areas, respectively. On a whole paddock basis, the increase in annual DM yield resulting from DCD application was estimated to be 21%. N, calcium (Ca), magnesium (Mg) and potassium (K) concentrations in pasture were unaffected by treatment with DCD; however, total annual uptake of these nutrients by pasture was significantly higher in all years where DCD had been applied. Pasture DM, protein, carbohydrate, metabolizable energy and fibre levels and sward clover content were not affected by treatment with DCD. The results demonstrate the agronomic value of the DCD treatment in addition to the environmental benefits in a grazed pasture system.     

Effects of fermented garlic powder supplementation on growth performance,nutrient digestibility,blood characteristics and meat quality in growing‐finishing pigs

One hundred pigs (BW = 50.7 ± 1.89 kg) were used to investigate the effects of fermented garlic powder (FGP) in growing‐finishing pigs. Pigs were allotted to one of five treatments, included: (i) NC (basal diet); (ii) PC (NC + 44 mg/kg of Tylosin); (iii) FGP1 (NC + 1 g/kg FGP); (iv) FGP2 (NC + 2 g/kg FGP); and (v) FGP4 (NC + 4 g/kg FGP). Supplemental FGP increased average daily gain (ADG) and gain/feed ratio compared with those fed NC diet throughout the experiment (P < 0.05, linearly). Dietary PC treatment increased the ADG and average daily feed intake during the first 6 weeks (P < 0.05). The inclusion of FGP2 and FGP4 treatments had higher apparent total tract digestibility of dry matter and nitrogen (P < 0.05) than those in the NC treatment. Dietary NC treatment exhibited lower (P < 0.05) lymphocyte count (6 and 12 weeks) and immunoglobulin G (12 weeks) than those in the other treatments. Marbling scores were higher (P < 0.05) in FGP treatment groups than the NC treatments. Pigs fed on FGP2 and FGP4 diets evidenced lower 2‐thiobarbituric acid reactive substances value (P < 0.05) than those in the NC and PC treatments. Collectively, our findings demonstrated that the administration of FGP at a level of 2 or 4 g/kg improved growth performance, nutrient digestibility and meat quality in growing‐finishing pigs.