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1.
The trend towards specialization in conventional farming led to large agricultural areas in Germany and in Europe lacking livestock. Also stockless organic farming has increased during recent years. In organic farming clover/grass-ley (CG) provides nitrogen (N) to the whole cropping system via symbiotic N2 fixation and also controls certain weeds. A common practice in organic farming, when ruminants are not present, is to leave the biomass from CG in the field for their residual fertility effect. CG biomass, crop residues (CR) and cover crops (CC) represent a large unexploited energy potential. It could be used by anaerobic digestion to produce biogas. A field experiment was carried out by implementing a whole cropping system with a typical crop rotation for such farming systems on the research station Gladbacherhof from 2002 to 2005. The crop rotation consisted of six crops (two legumes and four non-legume crops). The aim was to evaluate whether the use of N could be improved by processing biomass from CG, CR and CC in a biogas digester and using the effluents as a fertilizer, compared to common practice. In the control treatment, represented by the usual stockless system, the CG, CR and CC biomass were left on the ground for green manure purposes. In the biogas systems these substrates were harvested for digestion in a biogas plant. The effluents of digestion were used to manure the non-legumes in the same crop rotation. Results indicate that digestion of CG, CR and CC can increase the crop dry matter and N yields and the N content of wheat grains in organic stockless systems. Harvesting and digestion of residues and their reallocation after digestion resulted in a better and more even allocation of N within the whole crop rotation, in a higher N input via N2 fixation and lower N losses due to emissions and probably in a higher N availability of digested manures in comparison to the same amounts of undigested biomass. 相似文献
2.
The Montepaldi Long Term Experiment (MOLTE) trial in central Italy has been comparing three agroecosystems with different management: two organic (Old Organic since 1992 and Young Organic since 2001) and one conventional. After sixteen years of comparison, the agronomic performance and environmental sustainability of the three agro-ecosystems were assessed. Crops grain yield, total C inputs and N budget at field level were evaluated. N use efficiency (NUE) at micro-agroecosystem level was determined. Soil samples were collected from the three agroecosystems in order to quantify soil C and N pools.Results showed comparable grain yields in the three agro-ecosystems. The conventional system showed a larger N surplus and a lower crop N use efficiency in comparison with the organic ones. Moreover, the organic systems presented a lower potential risk of N losses with respect to the conventional one. The Young Organic agro-ecosystem was the most effective in terms of long term soil C (13% higher than conventional) and the oldest organic agro-ecosystem was the most effective in terms of soil N storage (9% higher than conventional).The results obtained demonstrated that the application of the organic farming method could increase the environmental sustainability in stockless arable systems under Mediterranean type of climate. 相似文献
3.
This paper assesses and compares risk in conventional and organic arable farming in The Netherlands with respect to family farm income and underlying price and production variables. To investigate the risk factors the farm accountancy data network was used containing unbalanced panel data from 196 conventional and 29 organic representative Dutch arable farms (for the period 2002 up to and including 2011). Variables with regard to price and production risk were identified using a family farm income analysis scheme. Price risk variables are input and output prices, while yield volatility of different crops is the main production risk variable. To assess risk, an error components implicit detrending method was applied and the resulting detrended standard deviations were compared between conventional and organic farms. Results indicate that the risk at the level of family farm income is higher in organic farming. The underlying variables show higher risk for organic farms in crop yields, crop prices and variable input costs per crop. 相似文献
4.
有机栽培对杂交粳稻产量和品质的影响 总被引：2，自引：0，他引：2
以杂交粳稻(常优2号、常优5号、甬优8号)和常规粳稻(淮稻5号、南粳46、南粳5055)为试材,比较研究了有机和常规栽培方式对两种类型粳稻的产量和品质的影响,探索了有机栽培条件下杂交粳稻实现稳产优质的可能性。结果表明,有机栽培杂交、常规粳稻平均产量分别为8.11 t hm–2和6.29 t hm–2,前者比后者高28.93%。有机栽培杂交粳稻的群体总茎蘖数低于常规粳稻,但成穗率较常规粳稻增加了6.5个百分点。两种类型水稻叶面积指数和光合势在各生育期均表现为有机栽培常规栽培,但有机栽培杂交粳稻叶面积指数和光合势降幅较小。有机栽培条件下,杂交粳稻生育后期平均群体生长率是常规粳稻1.29倍,干物质积累比例高出8.81个百分点。有机栽培略微降低了杂交粳稻的加工品质,但显著改善了外观品质,提高胶稠度、降低直链淀粉含量,对蛋白质含量影响较小,总体上改善了蒸煮食味品质。有机栽培下杂交粳稻产量优势明显且有较好的品质性状,在有机稻米产业发展中具有独特的应用价值。 相似文献
5.
Increased per capita food production in the tropics is closely tied to soil organic matter and water management, timely nitrogen (N) supply and crop N use efficiency (NUE) which are influenced by farming systems. However, there is lack of data on the effect of organic farming systems on NUE and how this compares to conventional farming systems under tropical conditions. Therefore, the objectives of this study were to determine the effect of conventional and organic farming systems at low and high management intensities on N uptake and N use efficiency of potato (Solanum tuberosum L.), maize (Zea mays L.), cabbage (Brassica oleracea var. Capitata), kale (Brassica oleracea var. Acephala) and Swiss chard (Beta vulgaris sub sp. Cicla). The organic high input (Org-High) and conventional high input (Conv-High) farming systems are managed as recommended by research institutions while organic low input (Org-Low) and conventional low input (Conv-Low) farming systems are managed as practiced by small scale farmers in the Central highlands of Kenya. The study was conducted during three cropping seasons between October 2012 and March 2014 in an ongoing long-term trial established since 2007 at Chuka and at Thika, Kenya. Synthetic N-based fertilizer and cattle manure were applied at ∼225 kg N ha−1 yr−1 for Conv-High and at ∼50 kg N ha−1 yr−1 for the Conv-Low. Composts and other organic inputs were applied at similar N rates for Org-High and Org-Low. Nitrogen uptake efficiency (NUpE) of potato was highest in Conv-Low and Org-Low at Thika and lowest in Org-High and Org-Low at Chuka site where late blight disease affected potato performance. In contrast, the NUpE of maize was similar in all systems at Chuka site, but was significantly higher in Conv-High and Org-High compared to the low input systems at Thika site. The NUpE of cabbage was similar in Conv-High and Org-High while the NUpE of kale and Swiss chard were similar in the low input systems. Potato N utilization efficiencies (NUtE) and agronomic efficiencies of N use (AEN) in Conv-Low and Conv-High were 11–21 % and 1.4–3.4 times higher than those from Org-Low and Org-High, respectively. The AEN of maize was similar in all the systems at Chuka but was 3.2 times higher in the high input systems compared to the low input systems at the Thika site. The AEN of vegetables under conventional systems were similar to those from organic systems. Nitrogen harvest index (NHI) of potato was similar between Conv-High and Org-High and between Conv-Low and Org-Low. N partitioned into maize grain was similar in all the system at Chuka, but significantly lower (P < 0.001) in Conv-low and Org-Low at Thika site. The NHI of cabbage in Org-High was 24 % higher than that of Conv-High. The study concluded that for maize and vegetables, conventional and organic farming systems had similar effects on NUpE, AEN, NUtE and NHI, while for potato conventional systems improved NUE compared to organic systems. The study recommends that management practices for potato production in organic systems should be improved for a more efficient NUE. 相似文献
6.
为给茭白与鸭共作系统中适宜放养鸭密度提供参考依据,本研究通过大田试验,比较了茭白单作、茭白田放鸭300、375、450只/hm~2条件下茭白的生物学性状、产量和品质。结果表明:茭鸭共作能显著提高茭白后期叶片数、干物重及产量,并延缓茭白后期叶片衰败。放鸭密度从375只/hm~2增加至450只/hm~2时,茭白后期叶片衰败加快,且茭白产量不再增加。茭鸭共作显著提高茭白蛋白质、维生素C和氨基酸含量。茭鸭共作系统灌溉养殖池塘富营养化水4500 m~3/hm~2时,输入的N、P、K相当于99.75 kg尿素、38.25 kg过磷酸钙和83.55 kg氯化钾的养分含量。本试验条件下,茭白常规种植密度27795株/hm~2,田间适宜放鸭密度为375只/hm~2,可显著提高茭白产量及品质。 相似文献
7.
Organic farming has become increasingly important in recent decades as the consumer has grown its focus on the food and environmental benefits of the technique. However, when compared to conventional farming systems, organic farm system are known to yield less.Presented in this paper are the results from two organic cropping systems following six years of organic management. Fertilisation management differentiated the two systems; one was fertilised with green manure and commercial organic fertilisers, while the other was fertilised with dairy manure. A conventional cropping system, managed with mineral fertiliser as typical in the southern Piemonte region (Italy), served as the bussiness as usual crop management. The first hypothesis tested related to crop yield variation during the initial phase of organic management; we expected a sharp reduction in the early phase, then minor reductions later on. The second hypothesis tested related to soil fertility variation; we expected enhanced soil fertility under organic management.Overall, the organic system produced less, relative to the conventional system in interaction with year effect. Yield reduction seemed related to the lower soil nutrient availability of organic fertilisers that provided nutrients consequent to mineralisation. Therefore, summer crops are well-suited to manure-fertilised organic farms as mineralisation happens at higher temperatures, as opposed to winter wheat, which is largely reduced in such systems. Commercial organic fertilisers can, however, limit this effect through their high nutrient availability in the winter and early springAlso shown was that soil quality, defined as a general decrease in soil organic carbon (SOC) over time in the three analysed arable systems, can be mitigated by manure additions. Green manuring can maintain SOC and increase total N in soil, only if introduced for a sufficient number of years during crop rotation. Finally, soil fertility and Potential Mineralisable N in the different systems demonstrated that organic systems managed with commercial organic nitrogen fertilisers and green manure do not improve soil quality, compared to systems managed with mineral fertilisers. 相似文献
8.
我国南方地区旱作农业发展概况与对策分析 总被引：1，自引：1，他引：0
近年来中国南方地区频繁遭遇干旱,给农业生产和人民生活造成了巨大危害。为促进中国南方地区旱作农业的发展,保障南方地区粮食和经济作物安全,总结了中国南方地区旱作农业发展的现状、意义;重点分析了南方地区旱作农业发展中存在的主要问题;提出了南方旱作农业发展的主要对策：加强农田工程建设、选育抗旱品种、加强抗旱保水技术的开发和应用、利用节灌补水技术,提高水资源利用率。 相似文献
9.
Kurt Mller 《European Journal of Agronomy》2009,31(4):204-212
Organic farming systems are characterized by the strong regulation of the import of nutrients into the farming system. Recently, nutrient budgets in organic farming especially with regard to potassium (K) and phosphorus (P) have gained interest. In the present study inner farm mineral nutrient flows of P, K and magnesium (Mg) among the farmland sub-compartments arable land and permanent grassland via the dairy stable were analysed. The objectives of the current study were (1) to quantify the inner farm nutrient flows among different farmland sub-compartments, and (2) to assess the effect of purchased biomass on inner farm nutrient cycles. Results indicated that the ratio of the nutrients N, P and K in the stable inputs (feed, bedding) greatly differed depending on the kind of biomass introduced into the stable (roughage in comparison to concentrates or straw for bedding), i.e. via grassland biomass much more K (7.9 kg) per kg P were introduced than with feeds harvested on arable land like silage maize (4.9 kg K per kg P), concentrates like cereals (1.3–1.6 kg K per kg P) or grain pulses like peas (2.4 kg K per kg P). The different inputs are mixed in the manures leading to intermediate concentration in the stable manures, with the consequence that nutrient composition of the manures does not match the composition of the single stable inputs. Therefore, balances of nutrient flows in such mixed systems indicate a relative transfer of K from grassland to arable land via the stable manure (approximately 10–30% of the manure derived from grassland K, depending among others on the amounts of straw high in K needed for animal bedding), if P was used as reference nutrient for stable manure allocation to permanent grassland and arable land. Yields of non-legumes in arable cropping in organic farming systems is very often limited by nitrogen (N) supply, whereas it is well known that manure additions are rather ineffective on permanent grassland high in legumes. The higher N demand of arable crops as well as P and K offtakes from arable land via sold animal and plant products give some scope for a preferable use of stable manures for manuring arable land to replace mineral nutrient outputs and to improve the soil N and the soil humus status, increasing the demand for supplement of mineral nutrients on the permanent grassland area to avoid long-term impoverishment of soil fertility. 相似文献
10.
黄淮海平原南部不同种植体系周年气候资源分配与利用特征研究 总被引：3，自引：0，他引：3
ZHOU Bao-Yuan GE Jun-Zhu HOU Hai-Peng SUN Xue-Fang DING Zai-Song LI Cong-Feng MA Wei ZHAO Ming 《作物学报》2020,46(6):937-949
探明不同种植体系周年产量、气候资源分配及其利用效率特征,建立周年气候资源优化配置的定量指标,为进一步提升黄淮海区域周年产量潜力和资源利用效率提供理论依据。本研究利用2011—2015年河南新乡定位试验数据,定量分析了冬小麦–夏玉米、冬小麦–夏大豆、双季玉米和一季春玉米4个种植体系产量、生物量、干物质产能、光温资源分配及其利用效率。结果表明,冬小麦–夏玉米和双季玉米体系4年产量、生物量和干物质产能差异均不显著,但显著高于冬小麦–夏大豆和一季春玉米体系,平均增幅分别为45.4%～61.5%、37.3%～71.3%和35.7%～70.7%;双季玉米和一季春玉米体系周年辐射生产效率、籽粒及总生物量光能利用效率均显著高于冬小麦–夏玉米和冬小麦–夏大豆体系,其中周年辐射生产效率平均增幅为11.8%～66.7%,籽粒及总生物量光能利用效率分别提高0.13～0.42和0.18～0.69百分点。进一步分析周年气候资源分配特征,冬小麦–夏玉米体系两季积温分配率分别为45.6%和54.4%,积温比值为0.8,双季玉米两季积温分配率为51.4%和48.6%,积温比值为1.1。综合分析产量和资源利用效率,冬小麦–夏玉米和双季玉米种植体系可作为黄淮海区种植模式优化布局和农业生产可持续发展的重要支撑,而明确主要种植体系积温分配率和积温比值等定量指标可为进一步优化周年气候资源配置,挖掘黄淮海两熟区周年产量潜力和资源利用效率提供重要参考。 相似文献
11.
作为有机农业的重要组成部分,小麦有机生产对于改善农业生态环境、增加优质农产品供给和促进农业增效、农民增收具有重要意义。以湖北省南漳县小麦有机生产为例,总结了发展小麦有机生产在改善农业生态环境、标准生产过程和提高种植效益方面取得的主要成效;分析了适度规模经营、中长期规划和集成绿色综合防控技术等措施缓解小麦有机生产中存在的监管难、周年生产衔接难和病虫草害防控难等问题的进展;提出了通过积极拓宽销售渠道、加快新品种新技术转化以及与养殖业的合理布局和深度融合等建议,以助力小麦有机产品认证基地创建。因地制宜地利用有机农业理论和技术改造常规农业,可更广泛地促进我国小麦产业健康持续发展。 相似文献
12.
马铃薯种植中超量和长期施用化肥已造成产量、品质和耐贮性下降,为了充分利用农牧交错区产生的有机肥,提高马铃薯产量、品质和耐贮性,实现马铃薯产业可持续发展,研究了化肥减量施用和增施有机肥对马铃薯产量、品质和耐贮性的影响。结果表明,化肥减量施用和增施有机肥提高了马铃薯品质和耐贮性。处理2（50%常规施肥量+4 m3有机肥）的产量、蛋白质、淀粉、干物质、可溶性糖和VC含量最高,较对照（CK）分别提高了1.67%、15.66%、13.58%、11.63%、31.91%和21.17%,贮藏期软腐病、干腐病、环腐病和晚疫病发病率较低,较对照（CK）分别降低了44.72%、45.61%、50.14%和39.39%。建议在农牧交错区采用处理2来提高马铃薯产量、品质和耐贮性,降低化肥用量和施肥成本。 相似文献
13.
不同水肥调控对冬小麦群体动态及产量的影响 总被引：1，自引：1，他引：0
为探索渭北旱塬冬小麦高产高效栽培措施,通过大田试验研究渭北旱塬干旱气候条件下优化水氮管理、有机无机肥结合和秸秆覆盖对冬小麦群体数量与产量的影响。结果表明,各处理冬小麦群体数量从出苗期不断增加,到返青期达最大后开始下降。返青期以前,各处理群体数量没有显著差异,且以返青期漫灌的农户传统耕作处理最高;返青期后经拔节期追氮补灌,小麦群体数量和干物质量出现显著性差异,最终以增加秸秆覆盖和有机肥的优化水氮处理OM3最高。从经济效益上看,小麦籽粒产量和利润以有效穗数最多的OM3处理最高,分别为4500 kg/hm2和4534元/hm2,产量较传统耕作方式和对照分别提高了33.4%、127.8%,利润分别提高了22.7%、322.2%。因此,在渭北旱塬有限灌溉条件下,优化水氮管理不仅节约大量水资源,而且显著提高了小麦产量和农民的收益,具有很大的推广潜力。 相似文献
14.
为筛选稻虾共作模式下优质高产且多抗的水稻品种,提高稻、虾综合效益,以11个优良食味粳稻品种为试验对象,研究不同品种在稻虾共作模式下物质生产及产量形成特性。结果表明,稻虾共作模式下,不同品种干物质积累均符合Logistic曲线。干物质快增期在拔节后10d至抽穗后10d,最大增长速率和干物质积累量最多时期出现在拔节至齐穗期之间,泗稻301、南粳5718和南粳9108干物质平均增速较高,干物质积累多。泗稻301、南粳9108和南粳5718后期茎叶物质转运量较多,丰粳1606、金香玉1号和南粳9108茎鞘物质转运率和贡献率较高,武香粳5245、宁香粳11和泗稻301叶片物质转运率和贡献率较高。干物质生产主要与产量和千粒重有显著线性正相关关系,结实率主要受后期干物质转运影响。稻虾共作模式下可以选用生长势强、干物质积累快且多、穗大粒多、产量高的泗稻301和南粳5718。 相似文献
15.
Productivity of organic and conventional arable cropping systems in long-term experiments in Denmark
A field experiment comparing different arable crop rotations was conducted in Denmark during 1997–2008 on three sites varying in climatic conditions and soil types, i.e. coarse sand (Jyndevand), loamy sand (Foulum), and sandy loam (Flakkebjerg). The crop rotations followed organic farm management, and from 2005 also conventional management was included for comparison. Three experimental factors were included in the experiment in a factorial design: 1) crop rotation (organic crop rotations varying in use of whole-year green manure (O1 and O2 with a whole-year green manure, and O4 without), and a conventional system without green manure (C4)), 2) catch crop (with and without), and 3) manure (with and without). The experiment consisted of three consecutive cycles using four-course rotations with all crops present every year, i.e. 1997–2000 (1st cycle), 2001–2004 (2nd cycle), and 2005–2008 (3rd cycle). In the 3rd cycle at all locations C4 was compared with two organic rotations, i.e. O2 and O4. The O2 rotation in the third cycle included spring barley, grass-clover, potato, and winter wheat, whereas C4 and O4 included spring barley, faba bean, potato, and winter wheat. For the O2 rotation with green manure there was a tendency for increased DM yield over time at all sites, whereas little response was seen in N yield. In the O4 rotation DM and N yields tended to increase at Foulum over time, but there was little change at Flakkebjerg. The DM yield gap between organic and conventional systems in the 3rd cycle varied between sites with 34–66% at Jyndevad, 21–44% at Foulum, and 32–52% at Flakkebjerg. The inclusion of grass-clover resulted in lower cumulated yield over the rotation than the treatment without grass-clover. The use of manure reduced the DM yield gap between conventional and organic systems on an average by 15 and 21%-points in systems with and without grass-clover, respectively, and the use of catch crops reduced the yield gap by 3 and 5%-points in the respective systems. Across all crops the agronomic efficiency of N in manure (yield benefit for each kg of mineral N applied) was greater in O4 compared with O2 for all crops. 相似文献
16.
Because of the complexity of farming systems, the combined effects of farm management practices on nitrogen availability, nitrogen uptake by the crop and crop performance are not well understood. To evaluate the effects of the temporal and spatial variability of management practices, we used data from seventeen farms and projections to latent structures analysis (PLS) to examine the contribution of 11 farm characteristics and 18 field management practices on barley performance during the period 2009–2012. Farm types were mixed (crop-livestock) and arable and were categorized as old organic, young organic or conventional farms. The barley performance indicators included nitrogen concentrations in biomass (in grain and whole biomass) and dry matter at two growing stages. Fourteen out of 29 farm characteristics and field management practices analysed best explained the variation of the barley performance indicators, at the level of 56%, while model cross-validation revealed a goodness of prediction of 31%. Greater crop diversification on farm, e.g., a high proportion of rotational leys and pasture, which was mostly observed among old organic farms, positively affected grain nitrogen concentration. The highest average grain nitrogen concentration was found in old organic farms (2.3% vs. 1.7 and 1.4% for conventional and young organic farms, respectively). The total nitrogen translocated in grain was highest among conventional farms (80 kg ha−1 vs. 33 and 39 kg ha−1 for young and old organic farms, respectively). The use of mineral fertilizers and pesticides increased biomass leading to significant differences in average grain yield which became more than double for conventional farms (477 ± 24 g m−2) compared to organic farms (223 ± 37 and 196 ± 32 g m−2 for young and old organic farms, respectively). In addition to the importance of weed control, management of crop residues and the organic fertilizer application methods in the current and three previous years, were identified as important factors affecting the barley performance indicators that need closer investigation. With the PLS approach, we were able to highlight the management practices most relevant to barley performance in different farm types. The use of mineral fertilizers and pesticides on conventional farms was related to high cereal crop biomass. Organic management practices in old organic farms increased barley N concentration but there is a need for improved management practices to increase biomass production and grain yield. Weed control, inclusion of more leys in rotation and organic fertilizer application techniques are some of the examples of management practices to be improved for higher N concentrations and biomass yields on organic farms. 相似文献
17.
Integrated no-till crop and livestock production systems may help rejuvenate degraded pastures, increase land use efficiency (LUE), and increase enterprise revenue. Our objectives were to evaluate: (1) planting date effects on seed yield and nutrient concentration of an early-maturing, no-till system (NTS) soybean (Glycine max) when intercropped with palisade grass (Brachiaria brizantha); (2) dry matter production and protein concentration of the grass pasture after soybean harvest; and (3) overall revenue and LUE for the intercrop system. Experiments were performed during two growing seasons in Botucatu, Brazil using a randomized complete block experimental design. When palisade grass and soybean were sown simultaneously, soybean yield averaged 3.28 Mg ha−1. Similar seed yields were observed when palisade grass was planted either 30 d after soybean emergence (DAE) (3.29 Mg ha−1) or at the soybean reproductive stage R6 (full seed) (3.50 Mg ha−1). Monocrop soybean yield averaged 3.50 Mg ha−1. First cut dry matter forage production was greater when palisade grass was sown at the same time as soybean or 30 DAE of soybean. This indicates that interseeding palisade grass with soybean does not significantly affect soybean nutrition or yield. Intercropping did increase LUE and resulted in 1.6 times more revenue than soybean alone. However, sowing palisade grass at the soybean reproductive stage R6 (full seed) significantly reduced the forage yield compared to early planting. 相似文献
18.
While intercropping annual non nitrogen-fixing crops with deciduous hardwood species is now well documented, there is a need to investigate if nitrogen-fixing intercrops may succeed in agroforestry systems. Intercropping with trees usually leads to a decline in crop yield, and could in addition possibly reduce the biological N fixation (BNF) over time due to the competition for resources. In a Mediterranean experimental site, 17 year-old hybrid walnut trees (Juglans nigra x Juglans regia L.) planted in East-West oriented lines were intercropped with alfalfa (Medicago sativa L.) to assess the impact of competition for light and water on alfalfa yield and BNF. Alfalfa yield and shoot δ15N values (a proxy for the proportion of N derived from the air, %Ndfa) were measured during one year at different distances from the tree row in two directions (north and south). Alfalfa yield was reduced close to the tree row (−28% and −22% on the northern and southern sides respectively), but less than the reduction of irradiation (−59% and −33% respectively). Shading improved by 35% the apparent light use efficiency (LUE: aboveground biomass produced per unit of global radiation) of alfalfa, indicating that alfalfa was shade tolerant at this Mediterranean site. Alfalfa shoot δ15N values were lower close to the tree rows than at mid inter-row: BNF was stimulated close to the trees. Compensative and facilitative mechanisms between trees and alfalfa plants led to a rise in LUE and%Ndfa in shaded areas. These results contradict the frequent assumption that N fixation is reduced in the shade of trees. Appropriate tree canopy management may help maintain light competition between trees and alfalfa to a level that still enhance complementary, which would further improve the sustainability of the use of alfalfa as an intercrop in Mediterranean regions. 相似文献
19.
稻鸭共作农作系统的生态效应与技术模式 总被引：4，自引：3，他引：4
稻鸭共作生态技术是将雏鸭全天候放入稻田,利用鸭子不间断的活动来刺激水稻生长、促进物质循环和改善稻田环境,构建了种养结合、节本增效、物质循环的优质安全农产品生产的农作模式,笔者综述了稻鸭共作技术对水稻的物质积累、壮秆效应、根系活力、病虫草害控制及生物多样性、土壤理化性质、稻田甲烷排放及控氮截流的影响,阐述了近年来稻鸭共作生态农业实施中投放绿萍、一稻两鸭、零日龄放鸭、沼稻鸭循环及防虫网全程覆盖等成功实践的种养模式,指出了稻鸭共作生态农业发展中亟待解决的问题,为稻鸭共作农作系统的技术理论和实践发展提供借鉴。 相似文献
20.
《European Journal of Agronomy》2007,26(2):130-143
As with conventional farming, the improvement of organic farming systems requires agronomic planning tools to enhance economic performance. Crop rotation planning plays a crucial role in organic arable farming systems due to the renunciation of mineral nitrogen fertilisers and pesticides. Our objective was to develop a tool for generating and evaluating site-specific and agronomically sustainable crop rotations for organic farming systems in central Europe. The resulting static rule-based model, called ROTOR, consists of two basic steps: (A) A set of annual crop production activities (CPAs) is assembled semi-automatically from single site and crop-specific field operations using a relational data base. The database includes all relevant crops recorded separately with inputs and outputs, machinery and timing. Starting from stubble tillage and ending with the last harvest measure, the CPAs describe the current best cropping practices. Different CPAs are included for each crop according to (i) the type of crop preceding and (ii) the field operations following: whether ploughing or non-inverting tillage, undersowing crops, using catch crops, manuring, straw harvesting, or mechanical weed control. The former allows for the modelling of all possible positions of a crop within a crop rotation and the consequential effects of preceding crops. The CPAs are evaluated using rule-based assessment modules for yield, economic performance, N balance, nitrate leaching, and weed infestation risks. These modules have been developed using data from field experiments, farm trials and surveys, expert knowledge and a soil–crop simulation model. (B) Within the crop generation module, all possible sequences of CPAs are linked to 3–8-year preliminary crop rotations. Agronomically sustainable crop rotations are selected according to exclusion criteria (i.e., thresholds for N balance, weed infestation risks, phytosanitary and chronological restrictions) and ranked, e.g. by economic performance. The model was tested by comparing (i) estimated with observed yields and (ii) generated with existing rotations. These comparisons, based on data obtained from two farm surveys from North Eastern Germany, indicate the validity and usability of the model approach. ROTOR was found to support the complex crop rotation planning in organic farming systems requiring rotations with overlapping undersown main and cover crops. ROTOR is able to reduce the risk of planning failures by offering a quantitative method of optimisation of weed and site-specific N management. 相似文献