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CONSERVATION AGRICULTURE IN UZBEKISTAN - STATUS AND PERSPECTIVES.
Azizbek Nurbekov,
Food and Agriculture Organization of the United Nations and Tashkent State Agrarian University
Abstract. This article presents the current status and perspectives of Conservation Agriculture (CA) in Uzbekistan. The on-going widespread degradation of soil resources represents a critical threat to agricultural production in Uzbekistan. Research findings show that the application of CA systems increased wheat and mungbeanyields by 10% in the country, while increasing their water use efficiency by 30% and improves soil structure, increases organic matter and overall soil fertility.
Key words: Conservation agriculture, crop residue, crop rotation, no-till, ground cover.
Annotatsiya. Ushbu maqola O'zbekistonda qishloq xo'jaligida tuproqni himoya qiluvchi va resurs tejovchi texnologiyalarni joriy etishning hozirgi holati va istiqbollari to'g'risidagi tahlillari bayon etgan. Tuproq resurslarining keng miqyosda tanazzulga uchrashi O'zbekistonda qishloq xojaligi ishlab chiqarish uchun jiddiy xavf tug'dirmoqda. Tadqiqot natijalari shuni ko'rsatadiki, tuproqni homoya qiluvchi va resurs tejovchi texnologiyalar tizimlarini qo llash mamlakatda bug'doy va mosh hosildorligini 10% ga oshirgan, shu bilan birga suvdan foydalanish samaradorligini 30% ga oshgan va tuproq tuzilishini yaxshilangan, tuproqdagi gumus/chirindi miqdori hamda tuproq unumdorligi oshgan.
Аннотация. В данной статье представлены текущее состояние и перспективы почвозащитного ресурсосберегающего земледелия (ПРЗ) в Узбекистане. Продолжающаяся повсеместная деградация почвенных ресурсов представляет серьезную угрозу для сельскохозяйственного производства в Узбекистане. Результаты исследований показывают, что применение систем ПРЗ увеличило урожайность пшеницы и маша на 10% в стране, при этом повысив эффективность использования воды на 30% и улучшив структуру почвы, повысив органические вещества и общее плодородие почвы.
1. Introduction
Agriculture plays a strategic role in the economy in Uzbekistan. In 2016, agriculture accounted for 17% of gross domestic product, 15% of export revenues, and over one-third of employment (World Bank, 2018). Yet, there is considerable potential for improving the productivity of agriculture to meet the national food demands, and to generate rural employment and incomes. Crop production in Uzbekistan is significantly on irrigated and only to some extent on rainfed agriculture. Wheat and cotton are the most important agricultural crops in the irrigated areas. Cotton and wheat are grown either continuously or in crop rotation, consecutively. FAO defines Conservation Agriculture (CA) as an approach to managing agro-ecosystems for improved and sustained productivity, increased profits and food security while preserving and enhancing the resource base and the environment. CA is a sustainable agricultural production system that includes a set of agronomic practices adapted to the demands of the crop and the local conditions of each region, whose techniques of cultivation
and soil management protect it from erosion and degradation, improve its quality and biodiversity, contribute to the preservation of natural resources such as water and air, without impairing the production levels of the farms. Conversely, CA spearheads an alternative agro-ecological paradigm that is making an increasing contribution to sustainable production intensification in many regions of the world.
2. Principles of Conservation Agriculture
The principles of Conservation Agriculture (Figure 1), and its practical application, are as follows:
• No-till or minimal soil disturbance
This principle means in the practice sowing without removing the soil, i.e. no-tillage. At least 30% of the soil must be covered after sowing to effectively protect it against erosion. However, it is recommendable to leave more than 60% of the soil covered to have almost complete control over this soil degradation process.
• Crop residue retention or permanent crop residue
Maintaining groundcovers throughout the
year. In other words, it means to keep the more stubble the better in arable crops, and to grow cover crops, or preserve groundcovers between rows of trees in woody crops. In this way, soil organic matter and water infiltration into the soil are increasing, some weeds are inhibited, and water evaporation from the soil is reduced.
• Crop rotation or crop diversification.
In this way, pests and diseases are better controlled by breaking cycles that are maintained in monocultures, in addition to including crops that can improve the natural fertility of the soil and biodiversity.
Crop residue retention J ф
No-till
Figure 1. Principles of Conservation Agriculture.
According to Nurbekov (2008), the main crop grown in Uzbekistan is cotton, followed by wheat, barley, rice, maize, potato, vegetables, and fruits. However, cotton and winter wheat occupies 80% of the total irrigated area. The most representative agronomic practice of CA in annual crops is no-tillage, which can be implemented in many crops, i.e. cotton, winter and spring cereals (including maize, wheat and barley), legumes in a rotation with cereals and oleaginous crops, among others. The most representative agronomic practice in permanent crops such as vine, pear, apple, olive, citrus and almond trees, among others. Since the main technical basis of Conservation Agriculture is the maintenance of soil covers, which reduces soil erosion and feeds it from organic matter it is necessary to discard techniques that are based on the soil tillage to prepare the seedbed. It is therefore very important to assess which field practices meet these requirements and, therefore, can be identified as CA. This is particularly relevant at times when
we have to respond to global challenges such as climate change, the fight against desertification and soil degradation, and the preservation and improvement of water and biodiversity. The combination of the three pillars of CA can provide ecosystem with services needed to improve the current situation.
According to studies (Márquez-García et al., 2013; Ordóñez-Fernández et al., 2007) the threshold of 30% of residues necessary to protect the soil matches with the one established by Conservation Technology Information Center (CTIC, 2018).
Wheat and maize are major crops in no-tillage in the world. They can be easily integrated in a proper crop rotation in conservation agriculture. In maize, the general care to be taken into account are essentially the same as in conventional sowing. The temperature in the soil is lower than in tilled soils, due to the soil cover, which is why fast start varieties should be chosen. The increase in the soil molture in no-tillage management is due to the residues left on the ground, which provide pr otectkn against moisture loss. This is considered essential in Uzbekistan, where evapotranspiration beiomes critical for cultivation.
Figure 2. Figure shows how under soil cover there is less salts on top of the soil due to less evaporation. Conservation Agriculture results in less salt transport in the soil profile.
In some regions of Uzbekistan, i.e. the Republic of Karakalpakstan, salinity is a problem for agricultural land. As water quality is acceptable (less than 2 dS/m), in order to minimise salinity problems a valid strategy considered is to leach salts through the irrigation schemes and to reduce capillarity to avoid salt movement in the soil profile.
Flooding is the common irrigation system. This method has an advantage, which is salt leaching, but also a drawback: if over irrigated,
this method raises water table (and salts). A more efficient irrigation system, such as sprinkler, could be an option to keep water table down in the soil profile.
Conservation Agriculture has already demonstrated evidences in the field that due to a less evaporation the salts remain in deeper soil layers (Figure 2). However, to achieve the objective of less salt movement in the soil profile, the soil cover should be more than 60%, but to avoid evaporation from the soil (which would imply salt ascension) the optimum would be to cover 100% of the soil surface with crop residues.
3. Status of Conservation Agriculture in Uzbekistan
For spreading Conservation Agriculture in the country, it would be needed to adapt the system to the major crops in the country. Some of the crops are easier to be adapted than others, however experiences in the world show strategies that can be applied in Uzbekistan. As an example, a potato crop is presented in Figure 3. Usually, potatoes are difficult to grow under CA, due to the need of soil removal at harvest. In the figure, a potato farm is managed in CA in Vietnam. No soil disturbance is performed, as potatoes are grown over the soil surface, covered by a thick layer of residues.
In Conservation Agriculture, all the crops of the rotation, may be fine grains, coarse, perennial pastures or annual forage resources, should be under no-tillage. Therefore, it is necessary, to adopt a productive strategy, respecting the basic premises
of the sy stem. Ea>h farmer must consider a rotation consid'^ng the productive characteristics of their reg;on, such as water regime, frost-free period, temperatures, soil water accumulation capacity, texture, among others. Design and implementation of crop rotations according to the various oL'ectives: food and fodder production (grain, leaf, stalks); residue production; pest and weed control; nutrient uptake and biological subsurface mixing / cultivation, etc. It is recommended to use of appropriate / improved seeds for high yields as well as high residue production of above-ground and below-ground parts, given the soil and climate conditions.
Wheat allows to intensify the rotation, also generating an abundant coverage and slow decomposition, legumes improve soil natural fertility and, some ofthem, do not leavea high amount of residues that would difficult seeder performance. Good results with mung beans have been reported under irrigated wheat-cotton rotation (Nurbekov et al, 2016). Maize provides with abundant residues, whereas cotton is well known among Uzbek farmers. After a correct implementation in the field, the crop management should not considerable differ from the conventional, but for the avoidance of tillage.
In Uzbekistan, CA has been already addressed and several good quality publications are available on its deliverables (Nurbekov et al, 2008, 2012a, 2012b, 2013, 2016). The characteristics of locally adapted CA production systems together with
the rational and responsible use of external inputs will optimize crop yields, farm income, competitiveness and biodiversity, and minimize some negative ecological impacts associated with intensive farming. Nurbekov (2018) reports that winter wheat and mungbean grain yield was significantly higher under no-till method compared to conventional. The same (2018) reports where grain yield of mungbean among conventional and minimum till did not significantly differ while mungbean yield within no-till treatment was higher up to 30%. Several authors studied water use efficiency under CA practices and found that no-till has the advantages to reduce irrigation rate and at same time to improve soil structure and crop productivity (Nurbekov 2018; Ibragimov et al.,
2011; Tischbein et al., 2012).
Over the last 20 years, Uzbekistan has been researching ways of introducing grain crops into existing crop rotation mainly with cotton and alfalfa. Earlier only irrigated cotton or rainfed winter wheat was grown. However, now with well-proven research findings, timely planting of winter wheat in standing cotton has shown promising results. As a result, annual area under planting of winter wheat into standing cotton reached 720,000 ha (Figure 3). It should be mention here that in 2015, no-till practice was introduced on an area of 30 thousand ha (Figure 3) while in 2020 the area under no-till practices was increased up to 130 thousand hectare.
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These advantages of greater soil health and productive capacity and lower cost of production leads to higher crop yields and factor productivities. Also, lower costs of production with CA leads to greater profit margins and competitiveness. To the mechanised farmers in Uzbekistan, CA offers reduced fuel use, lower capital outlay on machinery and decreased maintenance costs. Overall, CA has a much lower carbon foot print than tillage agriculture, and greenhouse gas (GHG) emissions of
CO2, CH4 and NO2 are all reduced with CA (Kassam, 2009).
An adequate management of the vegetal covers is fundamental to optimize the consumption of water and to maintain the potential productivity of the tree crop, especially in dry climates like Uzbekistan, in which the annual regimen of precipitations is low and markedly seasonal. Therefore, the most important factors to be taken into account in the management of the cover will
be determined by the balance of water in the soil: firstly, the method of mowing to be used; and secondly, the moment of mowing of the cover, in order to reduce to the maximum consumption of water at the moments of maximum need for the crop, as well as to avoid competition for nutrients. It is therefore necessary to control the growth of the groundcover in order to avoid the above mentioned negative effects. Ground cover or planting field crops as intercropping between the trees is not new approach in Tajikistan (Nurbekov et al., 2019) including Uzbekistan as this practice is widely used in the irrigated conditions of the country. Many farmers grow different fruit trees in their farm and do grow alfalfa, wheat, barley and legume crops in the alleyways between widely spaced rows of the fruit trees. Considering this, we added permanent fruit tree orchards and plantation of grapevines with vegetative cover as CA (Figure 3). Total area of permanent fruit tree orchards and plantation of grapevines with vegetative cover is about 390 thousand hectares, making the total area of CA practices in Uzbekistan equal 520 thousand ha.
There are still considerable potential productivity gains that are attainable in diverse regions and in certain production sectors through structural and operational improvements. However, the major contribution to enhancing farm incomes and competitiveness in the future must be attained through: (i) a reduction of production factor inputs and costs, i.e., an improved efficiency of the resources used, and (ii) an improvement of the quality of the resource base that can maintain or improve farm output and also harness a range of ecosystem services needed by the society. Both outcomes are achievable concomitantly only through farming practices based on an alternate paradigm that enhances soil quality and its productive capacity, while maintaining or improving yield levels at reduced input levels. Any farming approach capable of satisfying all these conditions can only do so if it is based on the principles and practices of CA.
In arable farming systems costs for soil tillage both in terms of machinery (purchase, depreciation, maintenance) and fuel consumption can make up a considerable part of the variable production costs. CA systems, instead, rely on crop establishment without soil tillage, using appropriate no-till seeding equipment for the placement of seeds into undisturbed soil. Depending on farm type and size, labour may also represent a restrictive factor when
it comes to cost efficient management or when a farmer could spend his time with other activities instead of driving a tractor tilling his fields.
4. Conclusions
The adoption of CA principles in Uzbekistan adapted to local production systems for the growth of annual and perennial crops, pastures and forages, together with good quality seeds and optimally integrated nutrient, water and pest management would deliver the following benefits:
• Providing similar or even higher yields through improvements in soil structure, organic matter and overall soil fertility.
• Maintaining less favoured rural areas under production through adoption of economically and environmentally viable production methods.
• Mitigating CO2 emissions through reduced fuel consumption and sequestration of atmospheric carbon into so;l organic matter, and reducing N2O and CH4 em'ss'ons through reduced use of mineral nitrogen and improved soil drainage.
• >owerivg production costs through reduced inputs or ener gy, labour, machinery, fertilizers, water and pesticides, thus raising related productivity and eff^eney.
• Reducing runoff and erosion through better soil aggregate stability and improved water infiltration and protective cover of the soil by crops and/or crop residues.
• Diminishing off-site damage of infrastructures and pollution of water bodies through less runoff with a much reduced sediment load.
• Maintaining in-field and off-site biodiversity through the absence of destructive soil disturbance, protective soil shelter and less off-site transport of contaminants.
• Maintaining the diversity of rural landscape through enhanced crop and species diversity and cover crops.
The achievement of those benefits is considered of high value and would support the implementation of national policies supportive to Conservation Agriculture. The potential contribution of Conservation Agriculture to the commitments of Uzbekistan in international agreements, such as the Paris Agreement on Climate Change, could serve as a catalyser for implementing actions that would result in the transformation of Uzbek agriculture towards CA.
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