Sequestering soil carbon in the low input farming systems of the semi-arid tropics – does litter quality matter?

Maintaining soil organic matter (SOM) in low input smallholder rice cropping systems worldwide is of paramount importance to maintaining livelihoods and food security. A long term rainfed lowland rice experiment tested the hypothesis that applying small (1.5 t/ha dry matter) annual additions of slowly decomposable plant materials which were grown offsite and applied prior to land preparation, could result in increased soil organic carbon, crop yield and improve the recovery of nutrients compared with plant materials of higher quality or straw retention alone. Annual leaf litter applications over 9 seasons resulted in significant increases in SOC of 39% (from 3.5 to 4.9 mg/g) in the leaf litter treatments compared to only 13 % in the noleaf litter control. In terms of rice grain production and nutrient use efficiency, leaf litter quality was an important driver. Apparent nutrient recovery of nitrogen and sulfur reflected the decomposition rate of the added residues. Sustainable farming systems will require that crop yields are stable through the maintenance of soil fertility and the balanced use of nutrients in the system. The results of this study are therefore highly significant and provide evidence that low rate, long term residue management can have profound effects

Management of chemical and organic fertilizer applications for decreasing the risk in rice production

Twenty one experiments were conducted during 2004-2008 at two locations in Ubon Ratchathani (Ban Donchi and Ban Khem) and two locations in Surin (Ban Nonkan and Surin Rice Research Center) to compare effects of chemical and organic fertilizer in single and combine applications. Each location had randomized complete block design with three replications of 10 treatments ( 3-4-4,6-4-4 kg of N-P2O5-K2O/rai, 1,000 kg/rai of 4 organic fertilizers which were rice straw compost (RSC1000), farmyard manure (FYM1000), green manure (GM1000), rice husk (RH1000), 500 kg/rai of each kind of organic fertilizer applied with N at the rate of 3 kg/rai: RSC500+3N, FYM500+3N, GM500+3N, RH500+3N). KDML105 rice variety was transplanted with 20*20 cm spacing (except 25*25 cm at SRNRRC). Rice grain yield obtained with 3-4-4 and 6-4-4 kg of N-P2O5-K2O/rai were not different from 1,000 kg/rai of RSC, GM and RH, correspond to rice yield of 379, 394,393, 390, 370 kg/rai respectively. Only the FYM1000 gave grain yield of 427 kg/rai higher than those of single application treatments. The greatest fertilizer response was FYM500+3N and GM500+3N which gave 431 and 422 kg/rai respectively. Although soil chemical properties were not improved by the application of chemical and organic fertilizer with an average over 4 locations of 5.0 soil pH, 0.6 percent organic mater, 5.1 mg/kg soil available P and 10 mg/kg soil exchangeable K. However, application of chemical with organic fertilizer especially FYM and GM was necessary in unfertile sandy soil.Summaries (En, Th)1 ill., 5 tablesผลการทดลองพบว่าการใส่ปุ๋ยเคมี อัตรา 3-4-4 และ 6-4-4 กก. ของ N-P2O5-K2O /ไร่ และใส่ปุ๋ยหมักฟางข้าว ปุ๋ยพืชสด และแกลบ อัตรา 1,000 กิโลกรัมต่อไร่ ให้ผลผลิตโดยเฉลี่ยไม่แตกต่างกัน โดยได้ผลผลิตเฉลี่ยตามลำดับดังนี้ 379 394 393 390 และ 370 กิโลกรัมต่อไร่ แต่การใส่ปุ๋ยคอก อัตรา 1,000 กิโลกรัมต่อไร่ ที่ให้ผลผลิต 427 กิโลกรัมต่อไร่ สูงกว่า กรรมวิธีที่กล่าวมาข้างต้น การใส่ปุ๋ยคอกและปุ๋ยพืชสดอัตรา 500 กิโลกรัมต่อไร่ ร่วมกับปุ๋ยไนโตรเจน 3 กิโลกรัมต่อไร่ ได้ผลผลิตข้าวเฉลี่ยจากทุกแห่ง 431 และ 422 กิโลกรัมต่อไร่ ตามลำดับ แม้ว่าผลวิเคราะห์คุณสมบัติของดินหลังการทดลองทุกปีพบว่าคุณสมบัติต่างๆ ยังไม่เปลี่ยนแปลง ค่าเฉลี่ยของจากทุกกรรมวิธีและทุกแห่งที่ทำการทดลองดังนี้ pH มีค่าเฉลี่ยเท่ากับ 5.0 อินทรียวัตถุ 0.6 เปอร์เซ็นต์ ฟอสฟอรัสที่เป็นประโยชน์ได้ 5.1 มิลลิกรัม/ดิน 1 กก. และโพแทสเซียม 10 มิลลิกรัม/ดิน 1 กก. อย่างไรก็ดี การใส่ปุ๋ยทั้งปุ๋ยเคมีและปุ๋ยอินทรีย์ มีความจำเป็นในการผลิตข้าวในดินนาที่ไม่อุดมสมบูรณ์ โดยเฉพาะใส่ปุ๋ยคอกหรือปุ๋ยพืชสดอัตรา 500 กิโลกรัมต่อไร่ร่วมกับปุ๋ยไนโตรเจน อัตรา 3 กิโลกรัมต่อไร

Evaluation of nitrogen balance in a direct-seeded-rice field experiment using Hydrus-1D

Nitrogen (N) pollution is a global environmental problem that has greatly increased the risks of both the eutrophication of surface waters and contamination of ground waters. The majority of N pollution mainly comes from agricultural fields, in particular during rice growing seasons. In recent years, a gradual shift from the transplanting rice cultivation method to the direct seeding method has occurred, which results in different water and N losses from paddy fields and leads to distinct impacts on water environments. The N transport and transformations in an experimental direct-seeded-rice (DSR) field in the Taihu Lake Basin of east China were observed during two consecutive seasons, and simulated using Hydrus-1D model. The observed crop N uptake, ammonia volatilization (AV), N concentrations in soil, and N leaching were used to calibrate and validate the model parameters. The two most important inputs of N, i.e., fertilization and mineralization, were considered in the simulations with 220 and 145.5kgha-1 in 2008 and 220 and 147.8kgha-1 in 2009, respectively. Ammonia volatilization and nitrate denitrification were the two dominant pathways of N loss, accounting for about 16.0% and 38.8% of the total N input (TNI), respectively. Both nitrification and denitrification processes mainly occurred in the root zone. N leaching at 60 and 120cm depths accounted for about 6.8% and 2.7% of TNI, respectively. The crop N uptake was 32.1% and 30.8% of TNI during the 2008 and 2009 seasons, respectively, and ammonium was the predominant form (74% of the total N uptake on average). Simulated N concentrations and fluxes in soil matched well with the corresponding observed data. Hydrus-1D could simulate the N transport and transformations in the DSR field, and could thus be a good tool for designing optimal fertilizer management practices in the future

Study on the Behavioral Change, Prevention and Control of Complications in Diabetic Patients in Ongkharak District, Nakhon Nayok, Thailand: Application of Motivational Theory to Disease Prevention

Adaptive Behavior Change Prevention Program for Diabetes Mellitus by Applying Prevention Motivation Theory with Teaching and Public Health Counseling. Amphoe Ongkharak Nakhon Nayok This research was a quasi-experimental research. The experimental group consisted of 34 people aged 35 years and older who were diabetic. Before-After one group design was used to collect data. The data were analyzed by frequency, percentage, mean and standard deviation. Paired Samples t-test and Pearson Product Moment Correlation Coefficient. The results of the study revealed that the experimental group had demographic characteristics. The demographic characteristics of the experimental group were mostly 70.6 percent women aged 50 years and over. 85.3 major occupations were farmers, 44.1 percent had diabetes. Most of the patients had hypertension (44.1%), diabetic eye disease (20.6%), and comparison of mean scores in the experimental group before and after the experiment. Statistics at 0.05. When analyzing the relationship between the variables studied and their practice in preventing complications from lung disease. It found no relationship. The results of this study conclude that the behavioral modification program for preventing complications from diabetes by applying preventive motivation theory to health counseling techniques. Can change the behavior of diabetes prevention complications

Growth of rice cultivars by direct seeding and transplanting under upland and lowland conditions

Rainfed rice crops are grown under both upland and lowland conditions. While upland crops are almost always direct seeded, both transplanting and direct seeding are commonly practiced for lowland crops in Asia. Direct seeding may be by broadcasting or dibbling. The effects of these various rice cultural practices on shoot and root growth and grain yield were examined using four contrasting cultivars in each of three years at Surin, Northeast Thailand. Under upland conditions, no yield was obtained under severe drought in two of the three years and yield was less than half that under lowland conditions in the third year. Lowland crops did not suffer water stress. Under lowland conditions, direct-seeded crops yielded more than transplanted crops in one year, slightly less in another when establishment was a problem in direct seeding, and similar between the two methods in the other. Direct seeding, particularly broadcasting, produced more total dry matter than transplanting. Root dry-matter growth was small after panicle initiation under all conditions, and was greater in direct seeding than transplanting in lowland conditions. Root growth occurred mostly in the top 10 or 15 cm soil layer in both upland and lowland crops. Root mass below 30 cm depth exceeded 10% of the total root mass at maturity in only one crop in which seeds were dibbled under upland conditions. Cultivar differences in root growth were generally small among all experiments. One notable exception was high tool mass near the soil surface for IR20, a cultivar suitable for irrigated conditions, when transplanted under lowland conditions. Although shoot growth was also similar among cultivars, there were often significant cultivar differences in grain yield. The highest yield was produced by IR57514-PMI-5- B-1-2, a semi dwarf cultivar that produced a large number of panicles in most experiments

Internal efficiency, nutrient uptake, and the relation to field water resources in rainfed lowland rice of northeast Thailand

Rice-based (Oryza sativa L.) rainfed lowlands are the major cropping system in northeast Thailand. Average yields are low, which is generally explained by frequent drought events, low soil fertility, and poor fertilizer response. However, neither the relative importance of these factors nor their interaction is well understood. Therefore, we analyzed an existing database on fertilizer trials conducted between 1995 and 1997 at eight different sites in northeast Thailand with the objective to determine indigenous nutrient supplies, internal efficiencies, and recovery efficiencies of applied nutrients in rainfed lowland rice. Of particular interest was the effect of variety type (traditional) and water supply on these components. Comparison of N, P, and K concentrations in grain and straw (average N-P-K grain concentration of 11.0-2.7-3.4 g kg ; average N-P-K straw concentration of 5.2-0.9-16.4 g kg ) in the traditional-type varieties used at all trial sites with literature values showed no differences for these parameters between traditional and modern-type varieties or between irrigated and rainfed environments. In contrast, internal efficiencies of N, P, and K (average IEN: 46 kg grain per kg N uptake; IEP: 218 kg grain per kg P uptake; IEK: 25 kg grain per kg K uptake) were much lower than reported for irrigated systems, and the difference was greatest for K, which is mainly accumulated in the straw. Indigenous nutrient supply (average INS: 38 kg ha; IPS: 10 kg ha; IKS: 89 kg ha) and recovery efficiency (average REN: 0.28 kg kg ; REP: 0.13 kg kg; REK: 0.49 kg kg) were low but comparable to the lower values reported from irrigated systems. Average seasonal field water resources seemed to reduce the indigenous nutrient supply but had no or little effect on internal efficiency and recovery efficiency. We concluded that the main reason for the low system productivity without and with fertilizer in northeast Thailand is the dominant use of traditional-type varieties with low harvest indices, which was the dominant cause for the observed low internal nutrient efficiency. Therefore, intensification of rainfed systems through substantially increased nutrient inputs can be recommended only where varieties with an average harvest index of close to 0.4 or higher are available

Growth and grain yield of contrasting rice cultivars grown under different conditions of water availability

Rice crops are susceptible to drought, which causes large yield losses in many Asian countries. The development of drought-resistant cultivars may be assisted if mechanisms of drought resistance are known. This work was carried out to elucidate how some rice cultivars achieve higher yield than others under water-limiting conditions. A total of 11 experiments were conducted in northeast Thailand, and four contrasting cultivars were compared in each experiment for phenological development, dry matter growth, leaf death, grain yield and yield components. High-yielding cultivars were generally short statured and had high harvest index, and they tended to perform better than others in all conditions of water availability. When drought developed during late growth stages, early flowering to escape water stress was an important character. During late drought some cultivars were able to retain green leaves longer than others and increased dry matter when others stopped growing. It is thus concluded that cultivars suitable for rainfed conditions are those with high yield potential resulting from high harvest index under favourable growing conditions, appropriate flowering time to escape severe water stress that commonly develops after the end of the rainy season, and an ability to maintain growth during drought so that yield determining processes can be completed with minimum disturbance

Nutrient requirements in rainfed lowland rice

In rainfed lowland rice, nutrient status of soils is often poor, and response to applied nutrients is often unreliable. This paper seeks an improved understanding of these patterns of nutrient response, then considers likely approaches for increasing and stabilising yields of rainfed lowland rice in south and southeast Asia. At each of 78 locations across India, Bangladesh, Thailand, Indonesia and the Philippines during 1995-1997, three replicates of each of six treatments were established: (no fertiliser control (NIL), farmyard manure (FYM), phosphorus and potassium only (PK), application of nitrogen as well as P and K (NPK), a controlled-release formulation of N together with P and K (CR-NPK), and an all-nutrient dressing (ALL)). Combined analysis of variance and cluster analysis were used to examine the patterns of nutrient response. Yields obtained without applied fertiliser were not closely related to soil test values. The greatest nutrient response was to nitrogen, with NPK increasing yields from 2.25 to 4.00 t/ha on average. The effect of adding micronutrients was small, and PK was of little benefit unless N was added. But the magnitude of the N response varied substantially with water regime. We conclude that substantial yield gains are possible in rainfed systems with application of appropriate nutrients, especially if used in conjunction with cultivars suitably adapted to the target environments. (C) 1999 Elsevier Science B.V. All rights reserved

Factors affecting rice yield and fertilizer response in rainfed lowlands of northeast Thailand

Rice-based (Oryza sativa L.) rainfed lowlands are the major cropping system in northeast Thailand. Earlier research on nutrient management of rainfed lowland rice produced conflicting results with respect to inherent soil fertility, fertilizer response, and the importance of organic fertilizers. most probably because of highly variable soil quality and water resources. The objectives of this paper were to advance the understanding of soil fertility and fertilizer response in northeast Thailand and thereby provide a basic framework for improved nutrient management of rainfed lowland rice. For this purpose, we analyzed an existing database on fertilizer trials conducted between 1995 and 1997 at eight different sites in northeast Thailand, which were previously described by Wade et al. [Wade, L.J., Amarante, S.T., Olea, A., Hampichitvitaya. D., Naklang, K., Wihardjaka, A., Sengar, S.S., Mazid, M.A., Singh, G., McLaren, C.G., 1999a. Nutrient requirements in rainfed lowland rice. Field Crops Res., 64, 91-107]. Average annual rainfall across sites and seasons was 1300 rum, but half of all rainfed trials (12 of 23) experienced substantial water stress during the growing season. Average grain yield in N-omission plots was low (1.6 t ha(-1)), even when compared with that of rainfed lowlands in neighboring Lao PDR. Nitrogen was clearly the most limiting element, whereas PK treatments increased yields significantly in only 6 out of 78 observations. Average agronomic efficiency of applied N was good ( 16 kg grain kg 1 N). but highly variable among sites. Two groups of soils (i.e., sites) were separated because of their distinct differences in reaction to inorganic and organic fertilizer. Better nutrient availability improved crop performance at all field water stress levels occurring at the trial sites. However, yield reductions caused by water stress seemed to interact with the level of nutrient supply, that is, absolute yield differences between different fertilizer treatments decreased with increasing water stress. We concluded that efficient fertilizer use in rainfed rice of northeast Thailand can be achieved, but that existing uniform recommendations do not provide farmers with much useful advice. Therefore, we proposed a set of basic guidelines for improved nutrient management, which, after further efforts of all stakeholders involved, could contribute to increased system productivity. (c) 2006 Elsevier B.V. All rights reserved