Role of Fine Roots in the Nitrogen Economy of Sugar Beet

In 31 field experiments with sugar beet, carried out in 1982–84 in Scania, southern Sweden, fertilizer nitrogen recovery in tops and beets, calculated with the difference method, amounted to 73%. To elucidate the role of the fine lateral roots in the fate of the nitrogen not accounted for, the lateral roots within depths of 0–25 and 25–60 cm were sampled at harvest in late September, 1984 in five sugar beet experiments. Irrespective of differences in nitrogen fertilization and plant-available soil nitrogen, a mean of ca. 3 kg/ha⁻¹ of nitrogen was found in the fine lateral roots. This corresponded to only ca. 2% of the nitrogen in the whole crop at harvest, whereas the beets and tops contained 43 and 55%, respectively. Using the difference method, calculations with, as well as without, fine roots therefore yielded the same recover (75%) of fertilizer nitrogen in the beet crop. The increase of residual mineral nitrogen in the soil at harvest caused by the fertilization corresponded to 2% of the fertilizer nitrogen applied. This means a total recovery of 77%.     

The Effects of Prolonged Drought and Nitrogen Fertilizer on Root and Shoot Growth and Water Uptake by Winter Wheat

Winter wheat growing on a silty clay loam soil was protected from rainfall by a mobile shelter for 100 days from tillering to maturity. During this time the crop was either irrigated according to demand or grew on stored soil water. The effects of this high and low water supply, in combination with a high and low N supply, on root and shoot growth and water uptake were studied.
The crop given both N and water yielded 9.7 t/ha of grain (85 % DM), drought reduced this to 7.9 t/ha, low N to 4.3 t/ha and drought and low N to 3.8 t/ha. Yield reductions were mainly due to fewer grains being produced.
Little root growth occurred in the topsoil during the drought but there was compensatory growth in the subsoil provided that N fertilizer was given. The droughted crops rooted to 160 cm, about 20 cm deeper than the irrigated crops, but the amount of root in the deep subsoil was very small, less than 0.1 cm/cm³ ai 140–160 cm, compared with 5–9 cm/cm³ in the topsoil.
The crop demand for water at any given time was partitioned throughout the root system but atmospheric demand was only met whilst the topsoil was wet. The fertilized, droughted crop extracted all of the potentially available water to a depth of 80 cm and a mean rooting density of 1 cm/cm³ was necessary to achieve this. Uptake from below this depth was limited by root growth.
The limiting value of the potential soil water deficit was 170 mm, and weather records showed that this would be exceeded one year in ten, on average. The likelihood of yield reduction due to drought could be reduced on this soil by improving root growth below 80 cm depth, although the chances of achieving this are low as root growth was probably limited by poor soil structure.     

水肥一体化条件下不同灌水量对甜菜产质量的影响

通过对甜菜在苗期、叶丛繁茂期、块根糖分增长期和糖分积累期的生理所需进行控水灌溉,研究不同灌水量对甜菜产质量的影响,确定少水、多糖、高产的最佳灌水方案,为甜菜节水灌溉提供理论依据,指导甜菜生产科学灌溉。试验设置3312.75、4005.30、4697.85、5390.40、6082.95、6775.50 m³/hm²等6个灌水梯度,在苗期、叶丛繁茂期、块根糖分增长期和糖分积累期分别按各生长期需水比例灌入不同水量,收获时测定甜菜含糖率、产量和产糖量,分析水分利用效率(WUE)和灌溉水分利用效率(IWUE)。结果表明,灌水量对甜菜含糖率、产量和产糖量影响明显,全生育期灌水量为3312.80 m³/hm²时甜菜的产质量处于较低水平,随着灌水量的逐渐增加,甜菜的含糖率、产量和产糖量呈现上升趋势,全生育期灌水量为4697.90 m³/hm²时甜菜的含糖率、块根产量和产糖量均为最高,但当灌水量高于4697.90 m³/hm²时甜菜的含糖率、块根产量和产糖量开始下降,在灌水量为6775.55 m³/hm²时,甜菜的含糖率、块根产量和产糖量均为最低。因此在新疆石河子地区甜菜全生育期灌水7次时,总灌水量在4697.90 m³/hm²,可以使甜菜含糖率、产量和产糖量达到最佳。     

Spatial and temporal distribution of the root system and root nutrient content of an established Miscanthus crop

Although a high biomass yield is obtained from established Miscanthus crops, previous studies have shown that fertilizer requirements are relatively low. As little information on the role of the Miscanthus roots in nutrient acquisition is available, a study was conducted to gather data on the Miscanthus root system and root nutrient content. Therefore in 1992, the root distribution pattern of an established Miscanthus crop was measured in field trials using the trench profile and the auger methods. Also, in 1994/1995, seasonal changes in root length density (RLD) and root nutrient content were monitored three times during the vegetation period.

The trench profile method showed that roots were present to the maximum depth measured of 250 cm. The top soil (0–30 cm) contained 28% of root biomass, while nearly half of the total roots were present in soil layers deeper than 90 cm. Using the auger method, we found that RLD values in the topsoil decreased with increasing distance from the centre of the plants. Below 30 cm, RLD decreased markedly, and differences in root length in the soil between plants were less pronounced. The total root dry weight down to 180 cm tended to increase from May 1994 (10.6 t ha⁻¹) to November 1994 (13.9 t ha⁻¹) and then decreased again until March 1995 (11.5 t ha⁻¹). Nutrient concentrations in the roots decreased with increasing depth. The concentrations of N (0.7–1.4%) and K (0.6–1.2%) were clearly higher than those of P (0.06–0.17%). The mean values for N, P and K contents of the roots of all three sampling dates in 1994/1995 were 109.2 kg N ha⁻¹, 10.6 kg P ha⁻¹ and 92.5 kg K ha⁻¹.

Although our results showed that RLD values for Miscanthus in the topsoil are lower than for annual crops, the greater rooting depth and the higher RLD of Miscanthus in the subsoil mean that nutrient uptake from the subsoil is potentially greater. This enables Miscanthus crops to overcome periods of low nutrient (and water) availability especially during periods of rapid above-ground biomass growth.     

Performance of Rapeseed-mustard Cultivars under Various Moisture Regimes on the Gangetic Alluvial Plain of West Bengal

A Field trial was conducted during 1988–89 and 1989–90 at Water Management Research Station, Memari. Bidhan Chandra Krishi Viswavidyalaya, Burdwan, to study the effect of three different irrigation regimes, namely rainfed (I₁) (No irrigation), one irrigation (I₂) at flowering and two irrigations (I₃ at flowering and at sihqua formation stages) on the grain yield and water expenses on four different rapeseed-mustard cultivars, namely Pusa Bold, Pusa Baroni, Varuna and DIR 247. The variety DIR 247 recorded maximum grain yield (12.1 qha') followed by Pusa Baroni (11.8 q ha⁻¹). The variety Varuna showed the lowest water use efficiency (48.1 kg ha⁻¹ cm⁻¹) while DIR 247 showed the maximum value of 57.0 kg ha⁻¹ cm⁻¹. The number of irrigations significantly increased the grain yield. Two irrigations, one at flowering and at siliqua formation stage increased grain yield by 28 % over the rainfed plots. During the crop growth period the actual water expenses among the cultivars in any moisture regime were more or less similar. The interaction between varieties and irrigation levels were, however, not significant.     

Physiological Responses of Wheat (Triticum Aestivum L.) –Aegilops Sharonensis Introgression Lines to Excess Copper

Two wheat lines (TL3 and TL5) derived from selection for Cu tolerance among wheat – Aegilops sharonensis hybrids were compared when grown as hydroponics at zero (control), 10⁻⁶ and 10⁻⁵  m CuSO₄. The morphometric measurements showed that the line TL5 with a more inhibited root system under 10⁻⁶  m CuSO₄ had a less inhibited shoot growth under 10⁻⁵  m CuSO₄ as compared to TL3. The decreased maximum efficiency of photosystem II and the more pronounced trend towards increased catalase activity suggested that despite the better shoot growth, the leaves of TL5 were more functionally injured. The increased content of carotenoids at excess Cu and the higher peroxidase and catalase activities of TL3 in control plants might contribute to its better stress tolerance. While no significant changes in enzyme activities were found at 10⁻⁶  m Cu, at 10⁻⁵  m the activities tended to increase. Although the close values of free phenolics concentrations in control plants, at Cu excess their content was higher in TL5 compared to TL3. The free phenolics content in roots at 10⁻⁶  m Cu decreased, and although higher at 10⁻⁵  m Cu, it remained below the control in TL3, and above the control in TL5. From the obtained results TL3 emerged to be more tolerant to excess Cu than TL5.     

Untersuchungen zum Wurzelwachstum von Jungpflanzen alter und neuer Winterweizensorten sowie eines Spelzweizens bei variierter N-Versorgung

Root growth of seedlings of old and new winter wheat cultivars and a spelt wheat at varying levels of nitrogen
Root growth of five old (time period 1882–1920) and five new (time period 1975–1982) winter wheal cultivars and a spelt winter wheat cultivar was investigated in two greenhouse trials. Nitrogen (NH₄NO₃) was supplied at six (Exp. I) and two (Exp. II) levels (sub- to supraoptimal for shoot growth). The seedlings were grown in sand-filled polyethylene tubes of 4.5 cm diameter and 50 cm length at 20 ^oC. The plants were harvested 11 (Exp. I) and 12 (Exp. II) days after emergence. At this early stage of development root growth o: old and new cultivars differed only slightly. The old T. aestivum cultivars had more seminal roots. The longest roots of the modern cultivars penetrated into deeper layers of the substrate. For some traits, cultivar: seemed to respond specifically to the varying N-supply. However, there were no significant difference: between old and new cultivars. Neither were old cultivars better adapted to low N-fertilization nor were modern cultivars superior in tolerating toxic concentrations of NH₄NO₃. Increasing N supply changes root growth as follows: decline in root dry matter, increase in shoot/root ratio of dry weight, decrease in number of seminal roots, shortening of axes and more laterals, increase in diameter of the laterals and less significantly of the main roots, increase in density of laterals, decline in root surface area. The number of apices was affected only to a very small degree.     

Root Yield and Quality of Sugar Beet (Beta vulgaris L.) in Relation to Plant Population

Introduction of genetic monogerm seed and the advancement of agricultural techniques raised the possibility of eliminating costly thinning operations in sugar beet farming. However, this requires high and uniform seedling emergence to provide prerequisite plant populations in the field. This work investigated the minimum levels of seedling emergence for non-thinned sugar beet farming. The experiment was carried out in a loamy soil to investigate the effects of three levels of emergence (60, 50 and 35%) and two intra-row spacings (8 and 15cm) with or without thinning using seed source of graded viability of cv Eva in 1992 and 1993 under field conditions in Eastern Anatolia. Plant population throughout the growing period was monitored and data were taken of yield and quality parameters. On average, 60, 50 and 35% emergence levels were achieved using seed source of 90, 72 and 54% viability range, which resulted in different levels of plant stands depending on intra-row spacing and thinning. Plant density at harvest ranged between 49 500 and 124 500 ha⁻¹ on average depending on initial establishment, intra-row spacing and thinning. Root yield and sugar yield were the highest at plant stands between 90 000 and 100 000 ha⁻¹, below or above of which declined. Impurity contents (e.g. Na, K and a-amino N contents) and extractable sugar content decreased but sugar content and clear juice purity enhanced as plant stands at harvest increased.     

欧洲椴树的分段压条繁殖技术的研究

旨在寻找适宜欧洲椴树压条生根的最佳激素浓度和生根部位,为快繁提供技术支撑。以8年生欧洲椴树枝条为试材,以NAA、IBA激素的不同浓度梯度进行分段处理枝条,通过EM50数据采集器连续监测其土壤温度和湿度,后期观察并记录根数、根长、根径,计算生根率等指标,观察其显著性差异。结果表明：以500 mg/L的IBA溶液处理欧洲椴树压条生根效果最好,生根率达到80%,平均主根数为29.6根,平均主根长为19.74 cm,平均主根径为2.75 mm,平均侧根数为15.8根,平均侧根长为8.64 cm;适宜欧洲椴树压条生根的部位是压条中段,生根率达到77.8%,平均主根数为10.7根,平均主根长为16.67 cm,平均主根径为1.9 mm,平均侧根数为10.8根,平均侧根长为5.15 cm。说明适宜的激素处理可以促进欧洲椴树压条苗的生根和成活;IBA激素的使用对欧洲椴树压条苗的生根效果较NAA及对照处理效果好;适宜欧洲椴树压条生根的部位位于枝条中段。     

施钾量对膜下滴灌甜菜光合性能以及对产量和品质的影响

膜下滴灌技术被广泛应用于内蒙古冷凉干旱地区的甜菜生产中。为探明施钾量对膜下滴灌甜菜光合生理特性和产质量的影响及其适宜钾肥用量, 于2014?2015年在内蒙古凉城县设K₂O 0、90、180、270和360 kg hm ^-25个施肥处理进行了研究。结果表明, 钾素能够提高甜菜的光合性能, 如促进株高、叶面积指数、净光合速率的增加; 施钾肥180、270和360 kg hm ^-2显著提高了叶丛快速生长期甜菜的净光合速率, 影响净光合速率的最主要因素是RuBPCase活性, 其次是气孔导度, 净光合速率与甜菜产量呈极显著正相关。适宜的钾肥用量有利于块根、叶柄和叶片干重的增加及产量增加, 但施钾过量, 块根干物质分配比例下降, 含糖率下降, 块根干物质分配比例与甜菜含糖率呈显著正相关。施钾量270 kg hm ^-2时产量最高, 90 kg hm ^-2时含糖率最高, 当施钾量大于180 kg hm ^-2时, 块根中K ⁺、Na ⁺含量增加, 大于270 kg hm ^-2时, 块根中α-氨基酸含量增加, 施钾量180 kg hm ^-2时产糖量最高。综合考虑施钾量对膜下滴灌甜菜产量和品质的影响, 内蒙古甜菜种植优势区域的钾肥推荐施用量为180 kg hm ^-2。     

Effect of the Organic Residues of Miscanthus × giganteus on the Soil Organic Matter Level of Arable Soils

During a complex investigation programme on the evaluation of the long-term ecological impact of cropping Miscanthus , the substrate composition of residues in 4–8-year-old stands of Miscanthus × giganteus and the contribution of Miscanthus residues to soil organic matter (SOM) were investigated. Only about 50 % of the above-ground biomass produced yearly was suitable for harvest because of pre-harvest losses and harvesting residues. The potential supply to SOM was therefore 3.1 t ha⁻¹ carbon annually accumulated by the litter, and 9.1 t ha⁻¹ carbon accumulated by rhizomes and roots in the long term. These organic residues mineralized differently in laboratory experiments at generally high rates of decomposition. Analysis of soluble portions of the organic substance of these biomass components by hydrolysis with hot water, 2 % HCl and 80 % H₂SO₄ confirmed the results. Setting the SOM effect of an equivalent farmyard-manure (FYM) supply to 100 %, Miscanthus residues reached 60 % (stubble, rhizomes), 80–90 % (pre-harvest losses) and 100 % (roots). Established Miscanthus stands are able to produce about 8.2 t ha⁻¹ organic substance, which is comparable with FYM in terms of SOM impact. This kind of calculation showed higher values for Miscanthus than for the agricultural crops investigated to date. An SOM increase of about 0.5 % on sandy soils and 0.2 % on silt soil was determined after 6–8 years of cropping Miscanthus × giganteus .     

Elongation Rate of Wheat Root Axes

The elongation rate of seminal root axes for two wheat ( Triticum aestivum L.) genotypes (one gene dwarf Sonalika RR-21 and three gene dwarf UP 301 ) grown in pots under three fluctuating soil water tension regimes of 0.3 to 0.8, 2.0 to 2.5 and 4.0 to 4.5 bars was measured throughout the growing period.
Two distinct peaks were observed for both genotypes. The first peak of highest elongation rate (25.0 to 35.5 mm day⁻¹) for both genotypes occurred during 22–28 days after planting which corresponds to the crown root initiation stage of the crop. The second lower peak (11.2 to 14.5 mm day⁻¹) occurred during 49–60 days after planting for Sonalika RR-21 but 60–72 days for UP 301. The time of occurrence of second peak corresponds to the stem elongation stage.
The elongation rate of root axes differed significantly for different stages and genotypes but when considered over the whole growing season, soil water tension regimes showed no effect. Over a period of 72 days from planting, average elongation rate ranged from 11.3 to 12.7 mm day⁻¹. The elongation rate of root axes bore no consistent relationship with either mean air or soil temperature at 5 and 15 cm depths that prevailed during crop growth period.     

Zum Einfluß von Untersaaten zur Begrünung von Ackerbrachen auf die Vegetationsentwicklung und die Nitratdynamik

The influence of undersown green manure crops for fallows – set-aside land – in view of vegetation-development and the dynamic of nitrate
In view of the establishment of rotational fallows - set-aside land - as well as the bridging of the vegetation-free winter period the suitability of different undersown grasses and legumes m winter cereals was investigated in field trials. Festuca rubra developed well in winter barley and winter wheat. The success of the cultivation of Lolium perenne, Trifolium pratense and Trifolium repens in winter cereals is uncertain because of the risk of light and water deficiences. Dactylis glomerata caused an negative influence on the yield of the cover crop. During the fallow period only low levels of nitrate could be found in the soil. Under fallow tilled repeatedly complete fallow- a nitrate accumulation could be observed during the fallow period. After ploughing up the fallow vegetation, nitrate concentrations - depth 0–150 cm – increased to 60 kg NO₃-N · ha^-1 after the natural fallow without seeding, between 60 and 130 kg NO₃-N · ha^-1 after Trifolium and between 160 and 210 kg NO₃-N · ha^-1 after complete fallow. Lowest nitrate levels were observed from the grass-sites. Undersown Festuca rubra seems to be the best choice in order to compete with weeds, to form a dense sod and to prevent nitrate leaching. In general a seed rate of 8 kg · ha^-1 can be recommended.     

切根对乌桕容器苗质量的影响

乌桕[Sapium sebiferum (L.) Roxb.]是中国特有的彩叶树种,春秋季叶片颜色红艳夺目,具有极高的园林观赏价值.随着中国"森林四化"工作的推进,乌桕逐渐被林业工作者们重视.本研究对乌桕容器苗开展3种不同比例的切根试验,并对其形态及生理指标进行对比分析.结果 表明:切根可显著促进苗高、地径、地上部分生...     

Optimum Seed Rate and Nitrogen Fertilizer Requirement of Rice Under Semi-deepwater Ecosystem

The effect of varying seed rates (100–1000 seeds m⁻²) and nitrogen fertilizer (0–60 kg N ha_-1) applied either in a single basal dose or in splits was investigated on a tall elongating, photosensitive rice variety, Nalini, under semi-deepwater conditions (0–100cm) during 1993 and 1994 at Cuttack, India. Seedling emergence was higher in 1993 (53.9 %) than in 1994 (44.1 %) and it increased proportionately with increasing seed rate, Increase in the number of tillers and panicles m⁻² at higher seed rates was associated with a corresponding decrease in panicle weight. Regression analysis indicated a decrease of 0.91–1.28g in panicle weight for an increase of 100 panicles m⁻². The grain yield of rice was significantly higher at 400 seeds m⁻² in 1993 and at 600 seeds m⁻² in 1994 than at low seed rates but further increase in seed rate did not increase the yield. Application of N fertilizer increased the panicle number and thereby grain yield significantly. The effect of basal and split applied N at active or maximum tillering stages as well as between 30 and 60 kg N ha⁻¹ was not significant on the grain yield. The results suggest that a basal dose of 30kg N ha⁻¹ and seeding density of 400–600 seeds m⁻², resulting in 40–50 % seedling emergence and 150–200 panicles m⁻², each with 2.0–2.5 g weight, may be adequate for optimum productivity of rice under semideepwater conditions.     

闽楠大田播种育苗及富根壮苗培育技术研究

为探讨闽楠大田播种育苗及富根壮苗培育的技术问题,以闽楠大田播种苗为试验材料,采用切根和使用生根壮苗剂2种处理方法对苗木的苗高生长、地径生长和侧根数等指标进行比较研究。结果表明：切根苗苗木高、地径、长度大于3 cm侧根数、侧根长度等指标明显优于未切根苗。生根壮苗剂不同浓度对苗木进行喷施处理后,其苗木根长大于3 cm根数及平均根长、苗高生长、地径生长有显著差异。采用生根壮苗剂1000倍液处理,可使苗木侧根数量比对照增加50%以上、侧根长度比对照增长20%以上,苗木高生长比对照增加30%以上、苗木地径生长比对照增加20%以上。     

Effects of Exogenous Injection of Different Sugars on Leaf Photosynthesis, Dry Matter Production and Adenosine 5'-Diphosphate Glucose Pyrophosphorylase (AGPase) Activity in Sweet Potato, Ipomoea batatas (Lam.)

Solutions of sucrose, glucose and fructose were artificially injected into the stems of sweet potato plants. The effects of solution injection on both dry matter production and the activity of adenosine 5'-diphosphate glucose pyrophosphorylase (AGPase) in tuberous roots were investigated and compared. The total weight of carbon (T_C) artificially and photosynthetically supplied to a plant during the treatment period of 40 days was 0.987–1.869 times the weight of photosynthetically assimilated carbon alone. At the final sampling time, the dry matter weight of tuberous roots in the plants injected with sugar solutions showed a 2.73–9.13-fold increase over that of the control plant. The root weight linearly increased with T_C. The activity of AGPase was also enhanced by solution injections, with 27–63 % increases compared to the control, but was not significantly related to T_C. The injection of sugar solutions is concluded to have a dual effect on root production in sweet potato. One effect is that the increased sugar concentration in the plant increases AGPase and sink activities, and the other effect is that the increased carbon supply quantitatively promotes starch synthesis and accumulation in roots.     

高铁胁迫对甜菜幼苗生长及保护系统的影响

为了探究高铁胁迫下甜菜幼苗生长和生理变化规律,本研究设置7个处理,即0.06、0.12、0.24、0.48、0.96、1.92、3.84 mmol/L,6次重复,并对甜菜进行水培试验。初步分析不同浓度Fe²⁺胁迫下甜菜幼苗中各项生理指标的变化。结果发现,随着Fe²⁺胁迫浓度的升高甜菜生长受抑制,地上部分叶面积变小,叶片相对电导率增大,相对含水量降低。地下部分表现出根系变短,面积变小,颜色变暗。与此同时高铁胁迫下甜菜植株抗氧化酶活性升高,参与渗透调节的可溶性糖和脯氨酸积累量均有不同程度的上升。变化趋势随着Fe²⁺的增加,先升高后降低,且在Fe²⁺胁迫浓度为0.96 mmol/L时达到最大值。说明甜菜植株抗氧化酶和渗透调节物质在高铁胁迫中起到了重要的调节作用,但当Fe²⁺超过一定浓度时,这种调节机制会明显受到抑制。     

甜菜种质资源苗期耐盐性评价及筛选

为筛选出耐盐性较高的甜菜品种,营养液培养33份甜菜幼苗,并进行盐胁迫处理。通过比较这些材料处理组与对照组幼苗的根长、株高等指标,对甜菜种质资源苗期的耐盐性进行综合评价。结果表明：（1）盐胁迫对甜菜幼苗根的影响最大,对SPAD值影响最小,对株高、植株鲜重和地上部鲜重3个指标影响一般。（2）最终将33个供试材料分为3类：第1类为耐盐材料,包括‘54338’、‘FLORES’、‘44581’等19个材料;第2类为敏盐材料,包括‘52212-1’、‘2928’、‘54303’等6个材料;第3类为耐盐性一般的材料,包括‘44176’、‘28010’、‘KUHN1387’等8个材料。研究结果可为甜菜的耐盐处理研究和耐盐育种提供材料基础。     

Studies on Sowing Depth for Chickpea (Cicer arietinum L.), Faba Bean(Vicia faba L.) and Lentil (Lens culinaris Medik) in a Mediterranean-type Environment of South-western Australia

Pulses such as chickpea, faba bean and lentil have hypogeal emergence and their cotyledons remain where the seed is sown, while only the shoot emerges from the soil surface. The effect of three sowing depths (2.5, 5 and 10 cm) on the growth and yield of these pulses was studied at three locations across three seasons in the cropping regions of south-western Australia, with a Mediterranean-type environment. There was no effect of sowing depth on crop phenology, nodulation or dry matter production for any species. Mean seed yields across sites ranged from 810 to 2073 kg ha⁻¹ for chickpea, 817–3381 kg ha⁻¹ for faba bean, and 1173–2024 kg ha⁻¹ for lentil. In general, deep sowing did not reduce seed yields, and in some instances, seed yield was greater at the deeper sowings for chickpea and faba bean. We conclude that the optimum sowing depth for chickpea and faba bean is 5–8 cm, and for lentil 4–6 cm. Sowing at depth may also improve crop establishment where moisture from summer and autumn rainfall is stored in the subsoil below 5 cm, by reducing damage from herbicides applied immediately before or after sowing, and by improving the survival of Rhizobium inoculated on the seed due to more favourable soil conditions at depth.