Management of Soil Micronutrient Deficiencies in the Rice-Wheat Cropping System

Summary

Within the last three decades, the rice-wheat cropping system has triggered, and with time, aggravated soil micronutrient deficiencies in the Indo-Gangetic Plains (IGP). This has largely been due to the shift from an earlier rice and wheat monoculture with low yielding, long duration indigenous varieties, to an intensive rice-wheat rotation cropping system with short duration modern high yielding varieties on the same piece of land. The problems related to micronutrient deficiency in the IGP are more due to the size of its available pools in the soil rather than its total contents and are greatly influenced by crop management, or rather its mismanagement. Deficiency of zinc is widespread in the IGP, but with the extensive use of zinc sulfate, zinc deficiency has reduced in some areas of the region. Meanwhile, the deficiency of Fe, Mn and B has increased in the IGP. Deficiency of Cu and Mo is location specific and can limit rice and wheat yields. The adoption and spread of the rice-wheat system in permeable coarse textured soils, particularly in the western IGP, not only caused iron deficiency in rice but also resulted in the emergence of manganese deficiency in wheat. In highly calcareous and acidic soils, boron is the next limiting micronutrient in crop production after zinc. Bumper rice and wheat harvests in the past decade, the declining use of organic manures in the region and except for the widespread use of zinc sulfate, a general lack of awareness amongst farmers on micronutrient deficiency problems has contributed to micronutrients limiting rice and wheat yields in the IGP. Approaches to alleviating micronutrient deficiencies include matching the crop removals of the micronutrients with its replenishments through their respective external carriers, supplementation through organic sources and mobilization/utilization through cultivation of micronutrient efficient crop cultivars. Identification of efficient micronutrient carriers and finding the optimum rate, mode and time of its application is important in ameliorating the micronutrient deficiencies. This article reviews the extent of micronutrient deficiency and discusses various management options available to reduce micronutrient deficiency induced crop yield reduction for rice and wheat in the Indo-Gangetic Plains.     

Comparison of Different Methods of Rice Establishment and Nitrogen Management Strategies for Lowland Rice

Abstract

Shortage of labor and water are forcing farmers to explore the alternatives of transplanting. A field experiment was conducted at the experimental farm of International Rice Research Institute (IRRI), Philippines during the 2003 wet season and the 2004 dry season to (1) evaluate the effects of different crop-establishment methods and N management on yield and yield parameters of rice; (2) determine N-use efficiency and water-use efficiency under different methods of rice establishment; and (3) analyze the economics of different crop-establishment methods. Crop-establishment method did not influence grain yield during the wet or dry seasons, indicating the potential of the three variants of direct seeding as alternative methods of establishing lowland rice. Direct-seeded rice had shorter crop duration, required less water and therefore had higher water-use efficiency than the transplanting method. Crop establishment did not influence the various indices of nitrogen-utilization efficiency except partial factor productivity of N (PFPN) during the wet season. During the dry season, dry-seeded rice had the lowest recovery efficiency. In contrast, agronomic-use efficiency and recovery efficiency were significantly higher in the SPAD-based (soil plant analyses development) N management strategy during the dry season. PFPN was significantly higher in the SPAD-based N management strategy during the wet and dry seasons. The interaction effect of crop establishment and N management indicated that for smaller N input and higher efficiency of N usage, N requirement for direct-seeded rice should be based on SPAD N technique. The cost-and-return analysis showed that benefit-cost ratio was consistently higher in dry seeding rice than transplanted rice using a SPAD-based N management.     

Shifts in Cropping System and Its Effect on Human Nutrition: Case Study from India

SUMMARY

More than twenty cropping systems are practiced in India. Rice-wheat and rice-rice are the major cropping systems practiced in an estimated 120 districts and 50 districts of the country, respectively. The rice-wheat cropping system (RWCS) of the Indo-Gangetic Plains (IGP) region of South Asia (Bangladesh, India, Nepal, and Pakistan) is the creation of the agricultural green revolution. Higher production of rice and wheat was necessary to meet the calorie needs of an increasing population in this region; as a result, the percent of malnutrition amongst children and adults decreased during the green revolution era. However, in recent years, there has been a reduction in both the rate of malnutrition decline and of the partial and total factor productivity of the RWCS in India. One of the many reasons for the decreased rate of malnutrition decline is micronutrient deficiency. Malnutrition amongst children and adults is a silent emergency in South Asia, including India. This review compares the food consumption habits, nutritional status, and cropping system practiced for different states of India to provide reasons for shifting the rice-wheat cropping system through crop diversification. Diversification of the RWCS will increase the supply of legumes and vegetables, help to diversify the diets consumed, and increase micronutrient intake. This approach is important for a largely vegetarian population of India, and is therefore, considered to be one of several important Food Systems strategy to address the silent emergency of malnutrition in the region.     

南方红壤区稻 稻连作体系下氮肥减施模式研究

 进行了连续3年6季的定位试验,比较了不施氮（N0）、常规施氮（NNL）2个对照处理与6个氮肥减施处理对双季稻产量及其构成因素、经济效益、土壤肥力水平的影响。结果表明,在低于传统施氮量20%的条件下, 30%常规氮肥用量 + 50%厩肥有机氮肥用量（30F + 50M）、30%常规氮肥用量 + 50%缓释氮肥用量（30F+ 50S）产量与NNL持平,比80%传统氮肥用量（80F）分别增产4.7％和5.2％;其余减施氮肥处理与80F产量基本持平。产量构成因子在不同施氮处理之间有明显差异,其中有效穗数、每穗粒数与产量正相关,结实率与产量负相关。经过3年6季水稻种植,土壤肥力除有效钾外,处理30F + 50M有机质、全氮、碱解氮、有效磷含量和pH值分别比NNL处理提高了21.3％、7.0％、34.7％、4.9％、41％。其中,有机质、有效磷含量、pH值均显著高于80F处理。其余各减施氮肥处理与80F相比无显著差异。因此,在南方双季稻连作区,在减少施氮20％的条件下,30F + 50M、30F+ 50S是值得推荐的施肥措施。     

Application of Micronutrients in Rice-Wheat Cropping System of South Asia

Rice-wheat cropping system(RWCS) is one of the most important cropping systems in South Asia. However, sustainability of this system is under threat owing to several factors, of which deficiency of micronutrients particularly zinc(Zn), boron(B) and manganese(Mn) is one of the major problems. Continuous rotation of rice and wheat, imbalanced fertilizer use and little/no use of micronutrient-enriched fertilizers induce deficiencies of Zn, B and Mn in the RWCS of South Asia. Here we review that(i) imbalanced fertilizer use and organic matter depletion deteriorate soil structure resulting in low efficiency of applied macro-and micro-nutrients in RWCS.(ii) The micronutrients(Zn, B and Mn) are essentially involved in metabolism of rice and wheat plants, including chlorophyll synthesis, photosynthesis, enzyme activation and membrane integrity.(iii) Availability and uptake of Zn, B and Mn from rhizosphere depend on the physico-chemical soil properties(which differ under aerobic and anaerobic conditions) including soil p H, soil organic matter, soil moisture and interaction of these micronutrients with other nutrients.(iv) Plant ability to uptake and utilize the nutrients is affected by several plant factors such as root architecture, root hairs, transport kinetics parameter and root exudates.(v) Crop management and application of these microelements can help correct the micronutrients deficiency and enhance their grain concentration.     

Improving Rice-Based Cropping Pattern Through Soil Moisture and Integrated Nutrient Management in Mid-Tropical Plain Zone of Tripura,India

An experiment was conducted in three fallow paddy fields situated on the mid-tropical plain zone of a northeastern Indian state(Tripura) to provide rice fallow management options using leftover soil moisture and nutrients. The three experimental fields were managed by growing rice under the system of rice intensification as the rainy season crop and then groundnut, lentil, rapeseed and potato as the post-rainy season crops. Fertilization under the integrated nutrient management system and lifesaving irrigation at critical stages of each post-rainy season crop were provided. Results showed that the field water use efficiency values were 5.93, 2.39, 2.37 and 59.76 kg/(hm2·mm) and that the yield of these crops increased by approximately 20%, 34%, 40% and 20% after applying two lifesaving irrigations in groundnut, lentil, rapeseed and potato, respectively. Therefore, fallow paddy field can provide possible profitable crops during the post-rainy season by utilizing the residual moisture and minimum supplemental irrigation under improved nutrient management practices.     

冬作物秸秆还田对双季稻产量和土壤肥力的影响

为探讨冬作物秸秆还田对双季稻产量和土壤肥力的影响,以冬闲—双季稻为对照,设计了油菜—双季稻、紫云英—双季稻、黑麦草—双季稻、马铃薯—双季稻4种复种模式,进行对比试验。试验结果显示:与冬闲相比,油菜、紫云英、黑麦草和马铃薯秸秆还田提高了水稻有效穗数和穗粒数,水稻平均产量增加,增幅分别为4. 44%、6. 50%、4. 76%、6. 69%;油菜、紫云英、黑麦草和马铃薯秸秆还田后土壤平均pH值比冬闲分别下降0. 07、0. 11、0. 25、0. 08个单位,平均有效磷含量分别下降25. 0%、17. 6%、22. 5%、28. 6%,降幅明显;土壤碱解氮含量增幅大小顺序为紫云英还田处理>油菜秸秆还田处理>黑麦草秸秆还田处理,增幅分别为4. 41%、1. 39%、1. 36%;有机质含量增幅大小顺序为油菜秸秆还田处理>马铃薯秸秆还田处理,增幅分别为3. 0%、1. 2%;速效钾含量增加的只有黑麦草秸秆还田处理,增幅为7. 4%。表明紫云英—双季稻和油菜—双季稻是较好的复种模式。     

Trends of climatic potential and on-farm yields of rice and wheat in the Indo-Gangetic Plains

Rice and wheat are the two most important cereals in the Indo-Gangetic Plains (IGP) and are responsible for the food security of the region. To understand the productivity trends in the transects of the IGP: (1) the climatic potential yields of rice and wheat were simulated using a crop simulation modeling approach and (2) the long-term trends of potential and on-farm yields were compared. The potential yields of rice and wheat in the IGP ranged from 7.7 to 10.7 and 5.2 to 7.9 Mg ha⁻¹, respectively. The upper transects of the IGP are more productive and yield decreases by 27% for rice and by 32% for wheat from transect 2 to transect 5. The rate of change in the potential yield trend of rice from 1985 to 2000 ranged from −0.12 to 0.05 Mg ha⁻¹ per year. Negative yield trends were observed at six of the nine sites, four of which were statistically significant (P<0.05). The decrease in radiation and increase in minimum temperature were the reasons for the yield decline. The potential yield trend of wheat, however, appeared to be stable. On-farm yields of rice also showed a negative trend but for wheat the trend was mostly positive. The adverse changes in the weather parameters and declining trends of potential and on-farm yields of rice should be taken as an indication of a future problem. Regular on-farm monitoring of crops and climatic factors is urgently needed for predicting problems and allowing measures to be taken to improve productivity.     

集约化种植砖红壤养分变化分析

调查分析位于广东省湛江农垦属下华海公司、南华农场、红星农场、丰收公司、广前公司、五一农场、湖光农场和友好农场等8个单位1 918个土样的养分状况,与第二次土壤普查比较,对比集约化种植后砖红壤肥力变化。结果发现：pH呈下降趋势,即有土壤酸化特征;土壤有机质含量总体呈现较高水平,但也呈现下降趋势;土壤全氮总体仍处于中等偏上水平;土壤有效磷含量明显提高,总体处于良好水平;土壤速效钾含量有很大程度增加,但仍处于中等水平。     

Enhancing Productivity of Rice-Wheat System Through Integrated Crop Management in the Eastern-Gangetic Plains of South Asia

Abstract

Rice (Oryza sariva)-wheat (Triticum aestivum) rotation is the major production system in the Indo-Gangetic plains of South Asia and mid hills and is important for the food security of the region. The productivity and profitability of the rice-wheat system are very low mainly because of inappropriate nutrient input and poor crop management practices. Field experiments were conducted in 21 farmers' fields in Bara and Parsa districts in the Eastern-Gangetic plains of Nepal from May 1999 to April 2002 to evaluate site-specific nutrient management (SSNM) and integrated crop management (ICM) for improving rice-wheat productivity and profitability. Soil nutrient-supplying capacity (based on omission plot method) varied largely among farmers' fields. Rice soil had a higher N, P, and K-supplying capacity (35–76, 8–17, and 63–98 kg ha¹, compared with wheat (16–41, 6–12, and 20–104 kg ha¹, respectively). Both SSNM and ICM strategies significantly improved the grain yields of rice and wheat. Overall yield increment by ICM over farmers' practice (FP) reached up to 2.3 Mg ha¹ (66%) in rice and 2.3 Mg ha¹ (87%) in wheat, suggesting that there is a large potential for increasing rice and wheat yields in Nepal. Yield gap 1 (maximum attainable yieldaverage yield in ICM) was 1.3 to 1.4 Mg ha¹ for rice and 0.3 to 1.0 Mg ha¹ for wheat. While yield gap 2 (maximum attainable yieldaverage yield in FP) ranged from 2.8 to 3.5 Mg ha-1 for rice and 2.3 to 2.8 Mg ha-1 for wheat. Rice N-use efficiencies increased up to 50% and 70% with SSNM and ICM, respectively, over FP. In wheat, N-use efficiency increased up to 46% by ICM over SSNM. The net profit gained by applying ICM over FP was higher in wheat (US$ 217) than in rice (US$ 73). The findings suggest the urgent need to develop an effective program for wider dissemination of ICM technology in the Eastern-Gangetic plains.     

Effect of Indigenous Nitrogen Supply of Soil on the Grain Yield and Fertilizer-N Use Efficiency in Rice

The effects of application of N fertilizer on wheat on the grain yield and N use efficiency （FNUE） of rice in the wheat-rice rotation system, as well as on the soil fertility were studies. N-fertilizer application on wheat significantly increased total N, arnrnoniurn-N and nitrate-N contents in paddy field, resulting in high indigenous N supply of soil （INS）. Compared with low INS, the effect of N rate on the grain yield of rice was reduced significantly, and FNUE was decreased under high INS. These results indicated that high INS was one of the main reasons for the low FNUE in rice.     

有机无机复混肥在热带地区双季稻上化肥减施的应用效果

以热带地区典型酸性水稻土为载体,通过设置不施肥处理(CK)、常规化肥(T)、有机无机复混肥(OF)、有机无机复混肥减施10％(10％OF)和有机无机复混肥减施20％(20％OF)等不同试验处理,研究化肥、有机无机复混肥和减量施用对海南省双季稻的产量、养分积累和肥料利用率的影响,评估有机无机复混肥及其减量施用对热带地区土...     

油稻稻秸秆还田下氮肥运筹对双季稻产量及氮素吸收利用的影响

为明确油稻稻三熟制秸秆还田条件下双季水稻适宜的氮肥运筹方式,2018年在长江中游三熟制区(江西进贤)开展5个处理(秸秆不还田+氮肥3次施用、秸秆还田+氮肥3次施用、秸秆不还田+氮肥2次施用、秸秆还田+氮肥2次施用、秸秆还田+高量氮肥3次施用)的田间试验,探究该模式下氮肥运筹对双季稻产量与氮素吸收利用的影响。结果表明,在油稻稻三熟制下,秸秆还田和氮肥运筹对水稻产量的影响在早稻季和晚稻季均存在显著的互作效应,而水稻基肥中增施20%氮肥对产量的影响不明显,氮肥2次施用(后氮前移)即可实现水稻高产和稳产。秸秆还田并配合氮肥2次施用(后氮前移)可以满足水稻生育期氮素需求,从而保证水稻正常生长,氮素吸收量能够达到甚至优于3次施氮处理水平,并明显提高氮肥利用率,增加氮肥用量则不利于氮肥偏生产力的提高。     

稻茬小麦高产稳产、节本增效栽培模式研究

为探索适宜的稻茬小麦栽培模式,基于本课题组近13年的田间试验数据,分析了播期、基本苗和肥料运筹对稻茬小麦产量及经济效益的影响,进而构建不同高产栽培模式,并比较其高产、稳产、节本增效的能力。结果表明,适播(10月29日~(-1)1月4日)条件下稻茬小麦产量、净效益和产投比均显著高于早播(10月17日~(-1)0月26日)和晚播(11月6日~(-1)1月20日),增幅分别为12%~13%、24%~27%和22%~27%,但不同播期之间的投入差异不显著。在适播条件下基本苗和施氮量、晚播条件下基本苗与产量和净收益均呈抛物线关系。适播基本苗210×10~4~240×10~4株·hm-2和施氮量180~225kg·hm~(-2)、晚播基本苗240×10~4~270×10~4株·hm-2和施氮量240~270kg·hm~(-2)构建的高产模式下产量分别达8.21和7.46t·hm-2,这两种模式均具有高经济效益和低投入特点,在不同年度、地点和品种下稳产性好。     

宁夏引黄灌区麦稻水旱轮作二熟制双免耕的土壤培肥效应

为评价麦稻水旱轮作二熟制双免耕的土壤培肥作用,采用常规测定法、比重计法、Biology-ECO法分别对参试的土壤养分、质地、微生物功能多样性等进行检测.结果表明,与传统耕作相比,连续4年冬小麦水稻全免耕轮作后,0～40 cm土壤有机质、全氮、全磷、速效氮、速效磷含量分别增加11,9％、17.1％、9.2％、26.5％、19.1％,全钾、速效钾含量分别减少0.9％、10.2％,0～20 cm土层的土壤粘粒、砂粒比例明显增加,粉粒比例明显减少.免耕冬小麦成熟期的土壤微生物功能多样性代谢活性显著高于传统耕作.0～20和20～40 cm土壤层次内反映微生物功能多样性的4种指数(Shannon-Wiener指数、Pielou均匀度指数、丰富度和Simpson优势度指数)在冬小麦整个生长季节中的变化趋于一致,即在分蘖期和拔节期传统耕作高于连续4年免耕处理,在灌浆期和成熟期连续4年免耕处理高于传统耕作处理.连续4年免耕0～40 cm土壤肥力明显优于连续3年双免耕的肥力.免耕对提高土壤肥力,尤其是对促进冬小麦中、后期生长有利.     

Use and Management of Poor Quality Waters for the Rice-Wheat Based Production System

Summary

India's major improvements in food production have been made possible via a shift towards rice-wheat systems as a consequence of enhanced utilization of ground waters. Rice-wheat rotation covering 10.5 million ha contribute about 75 percent of total food production. But it is being observed now that yield increases in rice and wheat has slowed down and there is rather a decline in factor productivity. One of the major reasons for this decline is indiscriminate use of alkali waters constituting about 25-42 percent of ground waters surveyed especially in the northwestern states of the Indo-Gangetic Plains (IGP). Because of high water requirements of the system, sodication rates of soil being irrigated and their steady state pH and sodicity values are much more (about 1.8 times) than that of the low water requiring rotations like millet/maize-wheat. So there has been a dilemma on whether or not rice-wheat system should be advocated with alkali irrigation waters. Consistent research efforts have lead to the guidelines for irrigation with such waters with respect to their amendment needs (gypsum requirements, frequency and mode of application), conjunctive use with canal waters and use of organic materials and chemical fertilizers, etc. These results do show that subject to the following of specific soil-water-crop management systems, it is possible to control the build up of sodicity in soils and sustain crop yields. Options available in terms of management practices and some of the researchable issue are discussed in this paper.     

减量施氮对甘蔗//大豆间作系统产量稳定性的影响

在广州华南农业大学试验中心,通过10 a（2009—2018年）的田间定位试验,对比研究了2种施氮水平[减量施氮300 kg/hm²（N₁）、常规施氮525 kg/hm²（N₂）]和4种种植模式[甘蔗单作（MS）、甘蔗//大豆1∶1间作（SB₁）、甘蔗//大豆1∶2间作（SB₂）、大豆单作（MB）]的甘蔗、大豆和系统总产量的动态变化,以及对甘蔗品质和土壤肥力的影响,采用Wi²（Wricke’s ecovalence）、变异系数（CV）和可持续指数（SYI）评价了产量的时间稳定性,旨在为华南蔗区农业绿色发展的可持续生产模式提供理论依据。结果表明：（1）各处理的甘蔗、大豆以及系统总产量呈现明显的年际变化。年份和种植模式对甘蔗和大豆产量有极显著影响,系统总产量受种植年份的极显著影响。施氮量对甘蔗、大豆和系统总产量均无显著影响。（2）不同间作模式的土地当量比（LER）均大于1,间作稳定且显著地提高了土地利用率。（3）不同处理甘蔗产量的Wi²和CV差异不显著,减量施氮单作甘蔗的SYI值显著高于常规施氮,表明减量施氮单作甘蔗的产量稳定性显著高于常规施氮处理。单作大豆产量的Wi²显著高于间作,说明单作大豆产量稳定性显著低于间作。不同处理的系统总产量Wi²值差异不显著,说明甘蔗//大豆间作和施氮量不影响系统总产量的稳定性。（4）种植年限的增加对甘蔗蔗糖分和纤维分、蔗汁糖锤度、蔗汁旋光度和蔗糖分无显著影响,同一年份不同种植模式和施氮量处理的甘蔗品质差异不显著。（5）与2010年相比,2018年底,除大豆单作模式外,其他处理的土壤pH、有机质、全氮含量显著下降,但所有处理的土壤全磷、有效磷和速效钾没有显著差异。甘蔗连作和连续施用化肥,导致土壤有机质逐步下降、pH降低。减量施氮甘蔗//大豆间作模式能够保持系统生产力和地力的稳定性,但需施用有机肥和推广蔗叶还田技术来培肥蔗田地力。     

不同肥料对华南双季稻产量及氮肥利用效率的影响

肥料种类和施肥方式会影响水稻产量和养分吸收利用效率。本文研究了等氮条件下不同肥料对华南双季稻产量及其构成因子、物质转运和氮肥利用效率的影响。结果表明,与施控释肥(N、P、K含量分别为25%、6%和19%)处理相比,施传统复合肥(N、P、K含量均为15%)和快美复混肥(N、P、K含量分别为24%、7%和19%)的处理,水稻抽穗期叶片SPAD值显著增加,穗部干物质累积量、穗部干物质累积速率和库容量分别增加2.7%~17.1%、1.6%~17.1%和5.4%~11.0%;水稻总吸氮量、氮肥利用率、氮肥农学利用效率、氮肥偏生产力分别增加9.4%~38.2%、26.6%~102.4%、19.3%~76.7%和4.5%~15.1%。在本试验条件下,快美复混肥是提高华南双季稻产量、氮肥利用效率的优势肥源。     

有机无机肥配施对冬水田水稻产量和耕层土壤性质的影响

在农业生产要求全面减施化肥农药的大背景下,综合评价四川冬水稻田区有机无机配施对水稻产量和土壤肥力的效应具有一定意义。本试验在冬水稻田区,比较了在等氮量替代条件下,无N(CK)、单施化肥N、P、K(T1)、30%有机肥N+70%化肥N(T2)、50%有机肥N+50%化肥N(T3)、100%有机肥N(T4)等处理的水稻产量、氮肥利用和土壤肥力变化情况。结果表明,有机无机肥配施处理的水稻产量较CK增加17.29%~31.43%,T2处理最高,且明显提高了氮肥利用率、氮肥农学效率和氮肥偏生产力;有机无机肥配施具有提升土壤有机质、培肥地力的作用。可见,冬水稻田区适宜的有机肥替代方案为30%有机N+70%化肥N,既可稳定水稻产量、降低成本,又可提高氮素利用率和降低对农田环境的不良影响。     

"莲味宝"有机无机复合肥对玉米增产效果研究

采用两年定位试验,研究"莲味宝"有机无机复合肥对玉米增产效果及土壤理化性状的影响。结果表明:施"莲味宝"有机无机复合肥1 050 kg/hm2玉米籽粒产量最高,为7 570.5kg/hm2,比对照增产46.4%,施用有机无机复合肥比施等氮量尿素玉米增产4.7%,行粒数增加1.8粒,单株鲜、干重分别增加0.5 kg和0.002 kg,土壤有机质、全氮、有效磷、速效钾分别增加0.488%、0.0097%、4.1 mg/kg、1.3 mg/kg。